Department of Publish Health and Environment REGULATION #93 - COLORADO'S SECTION 303(D) LIST OF IMPAIRED WATERS AND MONITORING AND EVALUATION LIST 5 CCR 1002-93 [Editor’s Notes follow the text of the rules at the end of this CCR Document.]

93.1 Authority

These regulations are promulgated pursuant to section 25-8-101 et seq C.R.S. as amended, and in particular, 25-8-202 (1) (a), (b), (i), (2) and (6); 25-8-203 and 25-8-204.

93.2 Purpose

This regulation establishes Colorado’s Lists of Impaired Waters. These waters include Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (“TMDLs”), Impaired Water Bodies with Approved TMDLs and 4b Plans, and Colorado’s Monitoring and Evaluation List.

(1) The list of Water-Quality-Limited Segments Requiring TMDLs fulfills requirements of section 303(d) of the federal Clean Water Act which requires that states submit to the U.S. Environmental Protection Agency a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards. These segments are identified in Section 93.3 with an entry of “5. – 303(d) list” in the Category/List column.

(2) Colorado’s Monitoring and Evaluation List (M&E List) identifies water bodies where there is reason to suspect water quality problems, but there is also uncertainty regarding one or more factors, such as the representative nature of the data. This M&E List is a state-only document that is not subject to EPA approval. These segments are identified in Section 93.3 with an entry of “3b. – M&E list” in the Category/List column.

(3) Waterbodies where at least one classified use is not being supported, but a TMDL is not needed because either a TMDL or a 4b plan (i.e., other pollution control requirements) has already been developed, are identified in Section 93.3 with an entry of “4a. - TMDL” or “4b. - 4b plan” in the Category/List column.

93.3 Waterbodies that are Impaired or Identified for Monitoring and Evaluation

Only those segments where a Clean Water Section 303(d) Impairment has been determined require TMDLs. For these segments, TMDLs are only required for those parameters that are identified as impairments.

The table below includes several key data elements that warrant description. They are: Waterbody ID and Listed Portion/Assessment Unit ID (AUID), Affected Use, Category/List, and Priority.

• Waterbody ID and Listed Portion/Assessment Unit ID (AUID): For each impairment listed in the table, both a Waterbody ID (WBID) and an Assessment Unit ID (AUID) description are provided. The WBID ID describes the entire segment and is derived from basin regulations 32-38. The AUID, which includes an underscore and letter, describes the spatial extent of the impairment listings within the waterbody ID. The AUID is referred to as the “Listed Portion.” In situations when the listed portion description matches the segment description, the entire segment is listed. • Affected Use: The Affected Use refers to a designated use that is applied to the water body segment.

• Category/List: These categories describe waterbody attainment status. These entries are aligned with Environmental Protection Agency reporting categories.

1. 1a. - Attaining Meets designated uses 1b. - Attaining with Meets designated uses and a TMDL exists TMDL 3b. - M&E list Insufficient data to make a determination 4a. - TMDL Impaired with an approved TMDL 4b. - 4b Plan Impaired with an approved 4b plan 4c. - 4c Impaired due to pollution 5. - 303(d) list Impaired without a TMDL completed • Priority: This is the Total Maximum Daily Load development priority. Priority options within Regulation #93 include:
   1. H= High Priority o M= Medium Priority o L= Low Priority o

93.3 Waterbodies that are Impaired or Identified for Monitoring and Evaluation

COARFO01a 1a. Mainstem of Fountain Creek, including all tributaries and wetlands, from the source to a point immediately above the confluence with Monument Creek, except for specific listings in segment 1b. Listed portion: COARFO01a_C Mainstem of Fountain Creek from source to a point immediately upstream of the confluence with Camp Creek.

1. Water Supply Use Uranium (Total) 3b. - M&E List N/A Water Supply Use Lead (Total) 5.- 303(d) List H Recreational Use E.coli 5.- 303(d) List H Water Supply Use Arsenic (Total) 5.- 303(d) List L Listed portion: COARFO01a_D Mainstem of Fountain Creek from a point immediately upstream of the confluence with Camp Creek to the confluence with Monument Creek.

   Water Supply Use Uranium (Total) 3b. - M&E List N/A Water Supply Use Lead (Total) 5.- 303(d) List H Recreational Use E.coli 5.- 303(d) List H Water Supply Use Arsenic (Total) 5.- 303(d) List L Water Supply Use Manganese (Dissolved) 5.- 303(d) List L COARFO01b 1b. Severy Creek, including all tributaries and wetlands, from the source to a point just upstream of where US Forest Service Road 330 crosses the stream.

Listed portion: COARFO01b_A Severy Creek and all tributaries from the source to a point just upstream of where US Forest Service Road 330 crosses the stream.

1. Aquatic Life Use Zinc (Dissolved) 5.- 303(d) List H COARFO02a 2a. Mainstem of Fountain Creek from a point immediately above the confluence with Monument Creek to a point immediately above the State Highway 47 Bridge.

Listed portion: COARFO02a_B Mainstem of Fountain Creek from a point immediately above the confluence with Monument Creek to a point immediately above the confluence with Sand Creek. Aquatic Life Use Cyanide (Total) 3b. - M&E List N/A Aquatic Life Use Temperature 5.- 303(d) List M Water Supply Use Lead (Total) 5.- 303(d) List H Recreational Use E.coli 5.- 303(d) List H Listed portion: COARFO02a_C Mainstem of Fountain Creek from a point immediately below the confluence with Sand Creek to a point immediately above the conflunce with Young Hollow. Water Supply Use Lead (Total) 3b. - M&E List N/A Aquatic Life Use Temperature 5.- 303(d) List M Recreational Use E.coli 5.- 303(d) List H Listed portion: COARFO02a_D Mainstem of Fountain Creek from a point immediately below the confluence with Young Hollow to a point immediately above the State Highway 47 Bridge. Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Lead (Total) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Temperature 5.- 303(d) List M Recreational Use E.coli 5.- 303(d) List H COARFO02b 2b. Mainstem of Fountain Creek from a point immediately above the State Highway 47 Bridge to the confluence with the Arkansas River.

Listed portion: COARFO02b_A Mainstem of Fountain Creek from a point immediately above the State Highway 47 Bridge to the confluence with the Arkansas River.

1. Recreational Use E.coli 5.- 303(d) List H Water Supply Use Iron (Dissolved) 5.- 303(d) List L Aquatic Life Use Temperature 5.- 303(d) List M Water Supply Use Chromium VI (Total) 5.- 303(d) List H COARFO03a 3a. All tributaries to Fountain Creek which are within the boundaries of National Forest or Air Force Academy lands, including all wetlands, from a point immediately above the confluence with Monument Creek to the confluence with the Arkansas River, except for the mainstem of Monument Creek in the Air Force Academy lands and specific listings in segment 3b. Cheyenne Creek, including tributaries and wetlands from the source to the confluence with Fountain Creek. Bear Creek below Gold Camp Road to the confluence with Fountain Creek. Little Fountain Creek from the source to Highway 115. Rock Creek from the source to Highway 115. North Monument Creek from the source to the confluence with Monument Creek. Beaver Creek from the source to the confluence with Monument Creek.

Listed portion: COARFO03a_B West Monument Creek and tributaries. Aquatic Life Use Macroinvertebrates (Provisional) 5.- 303(d) List H Listed portion: COARFO03a_C Tributaries and wetlands to Cheyenne Creek not within National Forest boundaries. Bear Creek below Gold Camp Road to the confluence with Fountain Creek. Rock Creek from the National Forest boundary to Highway 115. North Monument and Beaver creeks from the source to the confluence with Monument Creek.

1. Recreational Use E.coli 5.- 303(d) List H Listed portion: COARFO03a_E Cheyenne Creek from the confluence with North and South Cheyenne Creeks to its confluence with Fountain Creek.

   Aquatic Life Use Macroinvertebrates 5.- 303(d) List H Aquatic Life Use Copper (Dissolved) 5.- 303(d) List H COARFO04a 4a. Mainstems of Jackson Creek, Monument Branch, Elkhorn Springs, Pine Creek, South Pine Creek, South Rockrimmon Creek, Templeton Gap North, Templeton Gap Floodway, Douglas Creek and South Douglas Creek, from the sources to confluences with Monument Creek, including all tributaries and wetlands, which are not within the boundaries of the National Forest or Air Force Academy lands. Listed portion: COARFO04a_A Mainstem of Jackson Creek, Monument Branch, Elkhorn Springs, Pine Creek, South Pine Creek, South Rockrimmon Creek, Templeton Gap North, Templeton Gap Floodway, Douglas Creek, and South Douglas Creek, from the sources to the confluences with Monument Creek, including all tributaries and wetlands, which are not within the boundaries of the National Forest Academy lands.

   Aquatic Life Use Iron (Total) 3b. - M&E List N/A Recreational Use E.coli 5.- 303(d) List H COARFO04b 4b. All tributaries to Monument Creek from the sources to the confluences with Monument Creek which are not within the boundaries of National Forest or Air Force Academy lands, including all wetlands, from a point immediately below the confluence with North Monument Creek to the confluence with Fountain Creek, except for specific listings in segments 3a, 4a and 4c. This includes Dirty Woman Creek, Smith Creek, Black Squirrel Creek, Cottonwood Creek, Dry Creek and an unnamed tributary with the confluence at Monument Creek located near (38.948613, -104.829623).

Listed portion: COARFO04b_A All tributaries to Monument Creek from the sources to the confluences with Monument Creek which are not within the boundaries of National Forest or Air Force Academy lands, including all wetlands, from a point immediately below the confluence with North Monument Creek to the confluence with Fountain Creek, except for specific listings in segments 3a, 4a, and 4c. This includes Dirty Woman Creek, Smith Creek, Black Squirrel Creek, Cottonwood Creek, Dry Creek, and an unnamed tributary with the confluence at Monument Creek located near (38.948613, -104.829623).

1. Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Recreational Use E.coli 5.- 303(d) List H COARFO04c 4c. Mainstems of Kettle Creek, North Rockrimmon Creek and Mesa Creek, including tributaries and wetlands, from the sources to confluences with Monument Creek.

Listed portion: COARFO04c_A Mainstems of Kettle Creek, North Rockrimmon Creek and Mesa Creek, including all tributaries and wetlands, from the sources to the confluences with Monument Creek. Recreational Use E.coli 5.- 303(d) List H COARFO04d 4d. All tributaries to Fountain Creek from South Academy Blvd (CO83) to below the unnamed tributary immediately south of Old Pueblo Road (38.585843, -104.669591), including all wetlands, except for Little Fountain Creek and its tributaries and wetlands, and specific listings in segments 3a, 5a and 5b. All tributaries to Fountain Creek from a point immediately above University Blvd (CO47) (38.312846, -104.590524), to the confluence with the Arkansas River.

Listed portion: COARFO04d_A All tributaries with confluences with Fountain Creek from South Academy Blvd (CO83) including the unnamed tributary immediately south of Old Pueblo Road (38.585843, -104.669591), including tributaries and wetlands, except for Little Fountain Creek and its tributaries and wetlands, and specific listings in segments 3a, 5a, and 5b. All tributaries with confluences with Fountain Creek from a point immediately above University Blvd

1. (CO47) (38.312846, -104.590524) to the confluence with the Arkansas River. Recreational Use E.coli 5.- 303(d) List H COARFO04e 4e. All tributaries to Fountain Creek, including all wetlands, from a point immediately below the confluence with Monument Creek to University Blvd (CO47) near Pueblo except for specific listings in 3a, 4d, 5a and 5b. Listed portion: COARFO04e_B Sand Creek (near Wigwam), including all tributaries and wetlands. Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Recreational Use E.coli 5.- 303(d) List H Listed portion: COARFO04e_C Sand Creek (near Colorado Springs), including all tributaries and wetlands. Water Supply Use Sulfate 3b. - M&E List N/A Water Supply Use Uranium (Total) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List H Aquatic Life Use Macroinvertebrates 5.- 303(d) List M Listed portion: COARFO04e_E Little Fountain Creek, including all tributaries and wetlands, from immediately below Deadman Canyon to the confluence with Fountain Creek.

   Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List M Recreational Use E.coli 5.- 303(d) List H Listed portion: COARFO04e_F Spring Creek from its source to the confluence with Fountain Creek. Recreational Use E.coli 5.- 303(d) List H Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List M Water Supply Use Sulfate 5.- 303(d) List L Listed portion: COARFO04e_G All tributaries to Fountain Creek, including tributaries and wetlands, from a point immediately below the confluence with Monument Creek to University Blvd (CO47) except for Little Fountain Creek, Sand Creek(s) (near Wigwam and Colorado Springs), Spring Creek, and specific listings in segments 3a, 4d, 5a and 5b.

   Recreational Use E.coli 5.- 303(d) List H COARFO05a 5a. Jimmy Camp Creek, including all tributaries and wetlands, from the source to Old Pueblo Road (38.673200, -104.696739). Williams Creek, including all tributaries and wetlands, from the source to the confluence with Fountain Creek.

Listed portion: COARFO05a_A Jimmy Camp Creek, including all tributaries and wetlands from the source to the irrigation diversion east of Old Pueblo Road (38.694, -104.683). Williams Creek, including all tributaries and wetlands, from the source to the confluence with Fountain Creek Recreational Use E. coli 5. - 303(d) List H Listed portion: COARFO05a_B Jimmy Camp Creek, including all tributaries and wetlands from the irrigation diversion east of Old Pueblo Road (38.694, -104.683) to Old Pueblo Road (38.6732, -104.696739). Aquatic Life Use Iron (Total) 3b. - M&E List N/A COARFO05b 5b. Jimmy Camp Creek from Old Pueblo Road (38.673200, -104.696739) to the confluence with Fountain Creek, including the marshland located on the 60-acre parcel at 13030 Old Pueblo Road. Unnamed tributary from the boundary of Fort Carson (38.694465, -104.738735) to the confluence with Fountain Creek. Listed portion: COARFO05b_A Jimmy Camp Creek from Old Pueblo Road (38.6732, -104.696739) to the confluence with Fountain Creek, including the marshland located on the 60-acre parcel at 13030 Old Pueblo Road. Unnamed tributary from the boundary of Fort Carson (38.694465, -104.738735). Aquatic Life Use Iron (Total) 3b. - M&E List N/A COARFO06 6. Mainstem of Monument Creek, from the boundary of National Forest lands to the confluence with Fountain Creek.

Listed portion: COARFO06_B Mainstem of Monument Creek, from the boundary of National Forest lands to the confluence with Jackson Creek.

1. Aquatic Life Use Macroinvertebrates 5. - 303(d) List M Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Recreational Use E. coli (May-October) 5. - 303(d) List H Aquatic Life Use Temperature 5. - 303(d) List M Listed portion: COARFO06_C Mainstem of Monument Creek, from the confluence with Jackson Creek to the confluence with Fountain Creek.

   Aquatic Life Use Cyanide (Total) 3b. - M&E List N/A Recreational Use E. coli 5. - 303(d) List H Aquatic Life Use Macroinvertebrates 5. - 303(d) List M Aquatic Life Use Temperature 5. - 303(d) List M Water Supply Use Lead (Total) 5. - 303(d) List H COARFO07b 7b. Prospect Lake, Quail Lake, and Monument Lake. Listed portion: COARFO07b_B Prospect Lake.

   Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Ammonia 3b. - M&E List N/A Aquatic Life Use Arsenic (Total) 3b. - M&E List N/A COARLA01a 1a. Mainstem of the Arkansas River from a point immediately above the confluence with Fountain Creek to immediately above the Colorado Canal headgate near Avondale. Listed portion: COARLA01a_A Mainstem of the Arkansas River from a point immediately above the confluence with Fountain Creek to immediately above the Colorado Canal headgate near Avondale. Recreational Use E.coli 5.- 303(d) List H Water Supply Use Manganese (Dissolved) 5.- 303(d) List L Water Supply Use Iron (Dissolved) 5.- 303(d) List L COARLA01b 1b. Mainstem of the Arkansas River from the Colorado Canal headgate to the inlet to John Martin Reservoir. Listed portion: COARLA01b_A Mainstem of the Arkansas River from the Colorado Canal headgate to the inlet to John Martin Reservoir.

   Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List L Water Supply Use Arsenic (Total) 5.- 303(d) List L Aquatic Life Use Temperature 5.- 303(d) List H Water Supply Use Chromium VI (Total) 5.- 303(d) List H COARLA01c 1c. Mainstem of the Arkansas River from the outlet of John Martin Reservoir to the Colorado/Kansas border. Listed portion: COARLA01c_A Mainstem of the Arkansas River from the outlet of John Martin Reservoir to the Colorado/Kansas border.

   Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List H Water Supply Use Arsenic (Total) 5.- 303(d) List L Water Supply Use Manganese (Dissolved) 5.- 303(d) List L Water Supply Use Uranium (Total) 5.- 303(d) List H COARLA02a 2a. All tributaries to the Arkansas River, including wetlands, from the Colorado Canal headgate to the Colorado/Kansas border except for specific listings in segments 2b, 2c, 2d, 3a, through 9b, and Middle Arkansas Basin listings.

Listed portion: COARLA02a_C Crooked Arroyo Water Supply Use Uranium (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5.- 303(d) List H Water Supply Use Sulfate 5.- 303(d) List H Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List M Listed portion: COARLA02a_D All tributaries of excluding the mainstems of Little Horse Creek, Breckenridge Creek, or Horse Creek.

1. Water Supply Use Uranium (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5.- 303(d) List H Water Supply Use Sulfate 5.- 303(d) List H Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List M Listed portion: COARLA02a_E All tributaries of Adobe Creek, from their source to its confluence to Adobe Creek Water Supply Use Uranium (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5.- 303(d) List H Water Supply Use Sulfate 5.- 303(d) List H Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List M Listed portion: COARLA02a_F All tributaries of Chicosa Creek, from its source to its confluence to Chicosa Creek Water Supply Use Uranium (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5.- 303(d) List H Water Supply Use Sulfate 5.- 303(d) List H Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List M Listed portion: COARLA02a_G Tributaries to Mustang Creek Water Supply Use Uranium (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5.- 303(d) List H Water Supply Use Sulfate 5.- 303(d) List H Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List M Listed portion: COARLA02a_H All tributaries of Timpas Creek, from its source to its confluence to Timpas Creek Water Supply Use Uranium (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5.- 303(d) List H Water Supply Use Sulfate 5.- 303(d) List H Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List M Listed portion: COARLA02a_I All tributaries to the Arkansas River, including wetlands, except for specific listings in segments 2a, 2b, 2c, 2d, 3a through 9b, and Middle Arkansas Basin listings Water Supply Use Uranium (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5.- 303(d) List H Water Supply Use Sulfate 5.- 303(d) List H Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List M COARLA03a 3a. Mainstem of the Apishapa River, including all tributaries and wetlands, from the source to I-25, except for specific listings in Middle Arkansas segment 1 and Lower Arkansas segments 3b and 3c. Listed portion: COARLA03a_A Mainstem of the Apishapa River, including all tributaries and wetlands, from the source to I-25, except for specific listings in Middle Arkansas segment 1 and Lower Arkansas segments 3b and 3c.

   Recreational Use E.coli 3b. - M&E List N/A Aquatic Life Use Temperature 5.- 303(d) List H COARLA04a 4a. Mainstem of the Apishapa River from I-25 to the confluence with the Arkansas River. Mainstem of Timpas Creek from the source to the Arkansas River.

Listed portion: COARLA04a_A Mainstem of Timpas Creek from the source to the Arkansas River. Water Supply Use Uranium (Total) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List L Aquatic Life Use Iron (Total) 5.- 303(d) List H Water Supply Use Arsenic (Total) 5.- 303(d) List H Listed portion: COARLA04a_B Mainstem of the Apishapa River from I-25 to the confluence with the Arkansas River. Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List L Water Supply Use Sulfate 5.- 303(d) List L Aquatic Life Use Iron (Total) 5.- 303(d) List H Water Supply Use Arsenic (Total) 5.- 303(d) List L Agricultural Use Selenium (Total) 5.- 303(d) List M COARLA05a 5a. Mainstem of the North Fork of the Purgatoire River, including all tributaries and wetlands, from the source to a point immediately below the confluence with Guajatoyah Creek. Mainstem of the Middle Fork of the Purgatoire River, including all tributaries and wetlands, from the source to the Bar Ni Ranch Road at Stonewall

1. Gap. Mainstem of the South Fork of the Purgatoire River, including all tributaries and wetlands, from the source to Tercio.

Listed portion: COARLA05a_A Mainstem of the North Fork of the Purgatoire River, including all tributaries and wetlands, from the source to a point immediately below the confluence with Guajatoyah Creek; mainstem of the Middle Fork of the Purgatoire River, including all tributaries and wetlands, from the source to the Bar Ni Ranch Road at Stonewall Gap; Mainstem of the South Fork of the Purgatoire River, including all tributaries and wetlands, from the source to Tercio. Aquatic Life Use Copper (Dissolved) 5.- 303(d) List H COARLA05b 5b. Mainstem of the North Fork of the Purgatoire River, including all tributaries and wetlands, from a point immediately below the confluence with Guajatoyah Creek to the confluence with the Purgatoire River. Mainstem of the Middle Fork of the Purgatoire River from the Bar Ni Ranch Road at Stonewall Gap to the confluence with the North Fork of the Purgatoire River. Mainstem of the South Fork of the Purgatoire River from Tercio to the confluence with the Purgatoire River. Mainstem of the Purgatoire River to Trinidad Lake. Mainstem of Long Canyon Creek from the source to Trinidad Reservoir. Listed portion: COARLA05b_A NF of the Purgatoire River, including all tributaries and wetlands, from Guajatoyah Ck to Purgatoire River. Middle Fork of the Purgatoire River from the Bar Ni Ranch Road at Stonewall Gap to NF of the Purgatoire River. SF of the Purgatoire River from Tercio to the confluence with the Purgatoire River. Mainstem of the Purgatoire River to Trinidad Lake. Mainstem of Long Canyon Creek from the source to Trinidad Reservoir. Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COARLA05b_B Long Canyon Creek from source to Trinidad Reservoir. Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COARLA06a 6a. All tributaries to the Purgatoire River, including all wetlands, from the source to I-25, except for specific listings in segments 4b, 5a, 5b, 5c and 6b.

Listed portion: COARLA06a_C Sarcillo Canyon and tributaries. Aquatic Life Use Temperature 3b. - M&E List N/A Listed portion: COARLA06a_D Reilly Canyon and tributaries. Aquatic Life Use Temperature 3b. - M&E List N/A Listed portion: COARLA06a_F Bingham Canyon Aquatic Life Use Macroinvertebrates 3b. - M&E List N/A COARLA07 7. Mainstem of the Purgatoire River from Interstate 25 to the confluence with the Arkansas River. Listed portion: COARLA07_A Mainstem of the Purgatoire River from Interstate 25 to the confluence with the Arkansas River.

1. Aquatic Life Use Sediment 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COARLA09a 9a. Mainstems of Adobe, Buffalo, Cheyenne, Clay, Gageby, Horse, Two Butte, Wildhorse and Wolf Creeks from their sources to their confluences with the Arkansas River. Mainstems of Chacuacho Creek, San Francisco Creek, Trinchera Creek and Van Bremer Arroyo from their sources to their confluences with the Purgatoire River. Mainstem of Willow Creek from Highway 287 to the confluence with the Arkansas River. Mainstem of Big Sandy Creek from the source to the El Paso/Elbert county line. Mainstem of South Rush Creek from the source to the confluence with Rush Creek. Mainstem of Middle Rush Creek from the source to the confluence with North Rush Creek. North Rush Creek from the source to the confluence with South Rush Creek. Mainstem of Rush Creek to the Lincoln County Line. Mainstem of Antelope Creek from the source to the confluence with Rush Creek.The West May Valley drain from the Fort Lyon Canal to the confluence with the Arkansas River. Listed portion: COARLA09a_B Mainstem of Horse Creek.

   Water Supply Use Sulfate 3b. - M&E List N/A Water Supply Use Uranium (Total) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List L Water Supply Use Arsenic (Total) 5.- 303(d) List H Aquatic Life Use Iron (Total) 5.- 303(d) List H Water Supply Use Manganese (Dissolved) 5.- 303(d) List L Listed portion: COARLA09a_C Mainstem of Adobe Creek.

   Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Recreational Use E.coli 5.- 303(d) List H Listed portion: COARLA09a_E Wiley Drainage Ditch.

   Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List L Water Supply Use Arsenic (Total) 5.- 303(d) List H Water Supply Use Manganese (Dissolved) 5.- 303(d) List L Water Supply Use Uranium (Total) 5.- 303(d) List H Aquatic Life Use Iron (Total) 5.- 303(d) List H Agricultural Use Selenium (Total) 5.- 303(d) List L Listed portion: COARLA09a_F Wild Horse Creek.

   Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List L Water Supply Use Arsenic (Total) 5.- 303(d) List H Water Supply Use Uranium (Total) 5.- 303(d) List H Aquatic Life Use Iron (Total) 5.- 303(d) List H Listed portion: COARLA09a_G Gageby Creek Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List L Water Supply Use Arsenic (Total) 5.- 303(d) List H Water Supply Use Manganese (Dissolved) 5.- 303(d) List L Water Supply Use Uranium (Total) 5.- 303(d) List H COARLA09b 9b. Mainstem of Apache Creek from the source to the confluence with North Rush Creek. Mainstem of Breckenridge Creek from the source to the confluence with Horse Creek. Mainstem of Little Horse Creek from the source to the confluence with Horse Creek. Mainstem of Bob Creek from the source to Meredith Reservoir. Mainstem of Big Sandy Creek within Prowers County. Mainstem of Rule Creek from the Bent/Las Animas county line to John Martin Reservoir. Mainstem of Muddy Creek from the south boundary of the Setchfield State Wildlife Area to the confluence with Rule Creek. Mainstem of Caddoa Creek from CC Road to the confluence with the Arkansas River. Mainstem of Cat Creek from the source to the confluence with Clay Creek. Mainstem of Mustang Creek from the source to the confluence with Apishapa River. Mainstem of Chicosa Creek from the source to the Arkansas River. Mainstem of Smith Canyon from the Otero/Las Animas county line to the confluence with the Purgatoire River. Mainstem of Mud Creek from V Road to the confluence with the Arkansas River. Mainstems of Frijole Creek and Luning Arroyo from their sources to their confluences with the Purgatoire River. Mainstem of Blackwell Arroyo from its source to the confluence with Luning Arroyo. Mainstem of San Isidro Creek from the source to the confluence with San Francisco Creek. Listed portion: COARLA09b_B Big Sandy Creek within Prowers County. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Temperature 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List L Aquatic Life Use Iron (Total) 5.- 303(d) List M Water Supply Use Arsenic (Total) 5.- 303(d) List L Water Supply Use Iron (Dissolved) 5.- 303(d) List L Water Supply Use Uranium (Total) 5.- 303(d) List H Listed portion: COARLA09b_C Mainstems of Breckenridge Creek and Little Horse Creek from their sources to the confluence with Horse Creek.

   Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Uranium (Total) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List L Aquatic Life Use Iron (Total) 5.- 303(d) List M Listed portion: COARLA09b_D Mainstem of Chicosa Creek from the source to the Arkansas River. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Uranium (Total) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5.- 303(d) List L Aquatic Life Use Iron (Total) 5.- 303(d) List M Listed portion: COARLA09b_E Mainstem of Mustang Creek from the source to the confluence with Apishapa River. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Uranium (Total) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List M Listed portion: COARLA09b_F Mainstem (MS) of Apache Ck. MS of Bob Ck. MS of Rule Ck from Bent/Las Animas County line. MS of Muddy Ck from south boundary of Setchfield SWA. MS of Caddoa Ck from CC Rd. MS of Cat Ck. MS of Smith Canyon from Otero/Las Animas county line to the confl. with Purgatoire R. MS of Mud Ck from V Rd to the confl. with the Arkansas R. MS of Frijole Ck and Luning Arroyo from sources to confl. with Purgatoire R. MS of Blackwell Arroyo from source to the confl. with Luning Arroyo. MS of San Isidro Ck from source to the confl. with San Francisco Ck.

   Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Uranium (Total) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List M COARLA10 10. Two Buttes Reservoir, Two Buttes Pond, Lake Hasty, Holbrook Reservoir, Burchfield Lake, Nee-Skah (Queens) Reservoir, Adobe Creek Reservoir, Neeso Pah Reservoir, Nee Noshe Reservoir; Nee Gronda Reservoir. Listed portion: COARLA10_B Adobe Creek Reservoir.

   Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COARLA10_C Nee Gronda Reservoir.

   Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L COARLA11 11. John Martin Reservoir.

Listed portion: COARLA11_A John Martin Reservoir.

1. Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List H COARLA12 12. Lake Henry, Lake Meredith.

Listed portion: COARLA12_A Lake Meredith.

1. Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L Listed portion: COARLA12_B Lake Henry.

   Aquatic Life Use Iron (Total) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L COARLA15 15. All lakes and reservoirs tributary to the mainstem of the North Fork of the Purgatoire River from the source to a point immediately below the confluence with Guajatoyah Creek. All lakes and reservoirs tributary to the Middle Fork of the Purgatoire River from the source to the USGS gage at Stonewall. Mainstem of the South Fork of the Purgatoire River, from the source to Tercio. Monument Lake, North Lake, Trinidad Lake, Long Canyon Reservoir and Lake Dorothey.

Listed portion: COARLA15_B Trinidad Reservoir.

1. Aquatic Life Use Dissolved Oxygen (Temperature) 5. - 303(d) List H Aquatic Life Use Fish (Mercury) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H COARMA02 2. Mainstem of the Arkansas River from the outlet of Pueblo Reservoir to a point immediately above the confluence with Wildhorse/Dry Creek Arroyo.

Listed portion: COARMA02_A Mainstem of the Arkansas River from Blue Ribbon Creek to a point immediately above the confluence with Wildhorse/Dry Creek Arroyo.

1. Aquatic Life Use Temperature 5. - 303(d) List H Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H Listed portion: COARMA02_B Mainstem of the Arkansas River from Pueblo Reservoir to Blue Ribbon Creek. Aquatic Life Use Temperature 5. - 303(d) List H Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H COARMA03 3. Mainstem of the Arkansas River from a point immediately above the confluence with Wildhorse/Dry Creek Arroyo to a point immediately above the confluence with Fountain Creek. Listed portion: COARMA03_A Mainstem of the Arkansas River from a point immediately above the confluence with Wildhorse/Dry Creek Arroyo to a point immediately above the confluence with Fountain Creek.

   Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Recreational Use E. coli 5. - 303(d) List H Water Supply Use Sulfate 5. - 303(d) List L COARMA04a 4a. Mainstem of Wildhorse Creek from the source to the confluence with the Arkansas River. Listed portion: COARMA04a_A Mainstem of Wildhorse Creek from the source to the confluence with the Arkansas River. Recreational Use E. coli 4a. - TMDL N/A COARMA04b 4b. Mainstem of Rock Creek, Salt Creek and Peck Creek from their sources to the confluence with the Arkansas River.

Listed portion: COARMA04b_B Mainstem of Salt Creek Aquatic Life Use Macroinvertebrates 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H COARMA04c 4c. Mainstem of Chico Creek, including all tributaries and wetlands, from the source to the confluence with the Arkansas River, except for specific listings in segment 4f. Listed portion: COARMA04c_A Mainstem of Chico Creek, including all tributaries and wetlands, from the source to the confluence with the Arkansas River, except for specific listings in segment 4f. Aquatic Life Use Ammonia 5. - 303(d) List H COARMA04g 4g. Mainstem of Pesthouse Gulch, from the source to the confluence with Wildhorse Creek. Listed portion: COARMA04g_A Mainstem of Pesthouse Gulch, from the source to the confluence with Wildhorse Creek. Recreational Use E. coli 3b. - M&E List N/A COARMA06b 6b. Mainstem of the Saint Charles River from the confluence with Edson Arroyo to the confluence with the Arkansas River.

Listed portion: COARMA06b_A Mainstem of the Saint Charles River from the confluence with Edson Arroyo to the confluence with the Arkansas River.

1. Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Chromium VI (Total) 5. - 303(d) List H COARMA07b 7b. Mainstem of Greenhorn Creek, including all tributaries and wetlands, from the San Isabel National Forest boundary to a point immediately below the Greenhorn Highline (Hayden Supply Ditch) diversion dam. Mainstem of Graneros Creek below the San Isabel National Forest boundary. Muddy Creek, including all tributaries and wetlands, from the San Isabel National Forest boundary to 232/Bondurant Road. Listed portion: COARMA07b_A Mainstem of Greenhorn Creek, including all tributaries and wetlands, from the San Isabel National Forest boundary to a point immediately below the Greenhorn Highline (Hayden Supply Ditch) diversion dam. Mainstem of Graneros Creek below the San Isabel National Forest boundary. Muddy Creek, including all tributaries and wetlands, from the San Isabel National Forest boundary to 232/Bondurant Road.

   Water Supply Use Arsenic (Total) 5. - 303(d) List H COARMA09 9. Mainstem of Greenhorn Creek, from a point immediately below the Greenhorn Highline (Hayden Supply Ditch) diversion dam, to the confluence with the Saint Charles River. Listed portion: COARMA09_A Mainstem of Greenhorn Creek, from a point immediately below the Greenhorn Highline (Hayden Supply Ditch) diversion dam, to the confluence with the Saint Charles River. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M COARMA10 10. Mainstem of Sixmile Creek from the source to the confluence with the Arkansas River. Listed portion: COARMA10_A Mainstem of Sixmile Creek from the source to the confluence with the Arkansas River. Aquatic Life Use Iron (Total) 5. - 303(d) List L Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L COARMA11b 11b. Mainstem of the Huerfano River, including all tributaries and wetlands, from 570 Road near Malachite to Highway 69 at Badito, except for the specific listings in segment 1, 11a and 17. Listed portion: COARMA11b_A Mainstem of the Huerfano River, including all tributaries and wetlands, from 570 Road near Malachite to Highway 69 at Badito, except for the specific listings in segment 1, 11a and 17. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COARMA12 12. Mainstem of Huerfano River from Highway 69 at Badito to the confluence with the Arkansas River. Listed portion: COARMA12_A Mainstem of Huerfano River from Highway 69 at Badito to the confluence with the Arkansas River.

   Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L Water Supply Use Chromium VI (Total) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COARMA13a 13a. All tributaries, including wetlands, to the Cucharas River within the San Isabel National Forest boundaries, except for the specific listings in segment 1. Mainstem of the Cucharas River, from the source to a point immediately above the confluence with Middle Creek, except for the specific listings in segment 1. Wahatoya Creek, including all tributaries and wetlands, from the source to the confluence with the Cucharas River, except for the specific listings in segment 1. All tributaries to Middle Creek, including wetlands, from the source to a point immediately below the confluence of North and South Middle Creeks. Listed portion: COARMA13a_B Wahatoya Creek within the national forest boundary. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COARMA13a_D Wahatoya Creek, including all tributaries and wetlands, from the national forest boundary to the confluence with the Cucharas River.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A COARMA13c 13c. All tributaries and wetlands to the Cucharas and Huerfano Rivers not on Forest Service lands, except for waterbodies in segments 13a and 13b.

Listed portion: COARMA13c_A All tributaries and wetlands to the Cucharas and Huerfano Rivers not on forest service lands, except for specific listings in 13a and 13b.

1. Water Supply Use Manganese (Dissolved) 5. - 303(d) List H Water Supply Use Sulfate 5. - 303(d) List H COARMA14 14. Mainstem of the Cucharas River from the point of diversion for the Walsenburg public water supply to the outlet of Cucharas Reservoir.

Listed portion: COARMA14_A Mainstem of the Cucharas River from the point of diversion for the Walsenburg public water supply to the outlet of Cucharas Reservoir.

1. Aquatic Life Use Iron (Total) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H COARMA18a 18a. Mainstem of Boggs Creek from the source to Pueblo Reservoir. Listed portion: COARMA18a_A Mainstem of Boggs Creek from the source to Pueblo Reservoir. Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Water Supply Use Uranium (Total) 4a. - TMDL N/A Agricultural Use Selenium (Total) 4a. - TMDL N/A Water Supply Use Sulfate 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COARMA20 20. Pueblo Reservoir.

Listed portion: COARMA20_A Pueblo Reservoir.

1. Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H COARMA26 26. Horseshoe Lake, Martin Lake (Ohem Lake) and Walsenburg Lower Town Lake. Listed portion: COARMA26_B Horseshoe Lake (Lake Meriam). Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Fish (Mercury) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COARMA26_C Martin Lake (Ohem Lake)

   Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Temperature 5. - 303(d) List L COARUA01a 1a. All streams and wetlands within Mount Massive and Collegiate Peaks Wilderness areas. Listed portion: COARUA01a_B (McNasser Gulch, South Fork of Lake Creek, and Sayres Gulch) within Mount Massive and Collegiate Peaks Wilderness areas.

   Aquatic Life Use Aluminum (Total) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 4a. - TMDL N/A Listed portion: COARUA01a_C (Graham Gulch, Mountain Boy Gulch, and North Fork of Lake Creek) within Mount Massive and Collegiate Peaks Wilderness areas.

   Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A COARUA01b 1b. Mainstem of the East Fork Arkansas River from its source to a point immediately above the confluence with Birdseye Gulch.

Listed portion: COARUA01b_A Mainstem of the East Fork of the Arkansas River from its source to a point immediately above the confluence with Birdseye Gulch.

1. Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A COARUA02a 2a. Mainstem of the East Fork Arkansas River and the Arkansas River from a point immediately above the confluence with Birdseye Gulch to a point immediately above the confluence with California Gulch. Listed portion: COARUA02a_A Mainstem of the East Fork of the Arkansas River and the Arkansas River from a point immediately above the confluence with Birdseye Gulch to a point immediately above the confluence with the California Gulch.

   Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H COARUA02b 2b. Mainstem of the Arkansas River from a point immediately above California Gulch to a point immediately above the confluence with Lake Fork.

Listed portion: COARUA02b_A Mainstem of the Arkansas River from a point immediately above California Gulch to a point immediately above the confluence with Lake Fork.

1. Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A COARUA02c 2c. Mainstem of the Arkansas River from a point immediately above the confluence with the Lake Fork to a point immediately above the confluence with Lake Creek. Listed portion: COARUA02c_A Mainstem of the Arkansas River from a point immediately above the confluence with Lake Fork to a point immediately above the confluence with Lake Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List H COARUA04a 4a. Mainstem of the Arkansas River from the Chaffee/Fremont County Line to a point immediately above Highway 115 bridge (38.390243, -105.068648), due east of Florence. Listed portion: COARUA04a_B Mainstem of the Arkansas River from the Chaffee/ Fremont County Line to Texas Creek. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Listed portion: COARUA04a_C Mainstem of the Arkansas River from Texas Creek to a point immediately above Hwy 115 bridge, (38.390243, -105.068648) due east of Florence.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Temperature 5. - 303(d) List H COARUA04b 4b. Mainstem of the Arkansas River from a point immediately above Highway 115 bridge (38.390243, -105.068648), due east of Florence, to the inlet of Pueblo Reservoir. Listed portion: COARUA04b_A Mainstem of the Arkansas River from a point immediately above Highway 115 bridge, (38.390243, -105.068648) due east of Florence, to the inlet of Pueblo Reservoir. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A COARUA05a 5a. All tributaries to the Arkansas River, including wetlands, from the source to immediately below the confluence with Browns Creek, except for specific listings in segments 5b through 12b. Listed portion: COARUA05a_A All tributaries to the Arkansas River, including wetlands, from the source to immediately below the confluence with Brown’s Creek, except for the Lake Fork below Sugarloaf Dam, Colorado Gulch and its tributaries, Halfmoon Creek, and specific listings in segments 5b through 12b.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COARUA05a_C Colorado Gulch and its tributaries Aquatic Life Use Silver (Dissolved) 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Water Supply Use Iron (Dissolved) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Cadmium (Total) 5. - 303(d) List H Aquatic Life Use pH 5. - 303(d) List H Listed portion: COARUA05a_D Halfmoon Creek Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COARUA05a_E Lake Fork below Sugarloaf Dam to County Road 5. Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Listed portion: COARUA05a_F Lake Fork from County Road 5 to the confluence of the Arkansas River. Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H COARUA05b 5b. Mainstem of Trout Creek from its source to Trout Creek Reservoir, including all tributaries and wetlands. Listed portion: COARUA05b_A Mainstem of Trout Creek from its source to Trout Creek Reservoir, including all tributaries and wetlands.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L COARUA07 7. Mainstem of Evans Gulch from the source to the confluence with the Arkansas River. Listed portion: COARUA07_A Mainstem of Evans Gulch from the source to the confluence with the Arkansas River. Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H COARUA08b 8b. Mainstem of Iowa Gulch from a point immediately below the historic upper ASARCO water supply intake at 39.224327, -106.223432 to a point immediately below the headgate of the Paddock #1 Ditch (Iowa Ditch) at 39.215532, -106.286037.

Listed portion: COARUA08b_A Mainstem of Iowa Gulch from a point immediately below the ASARCO water supply intake to a point immediately below the headgate of the Paddock #1 Ditch (Iowa Ditch). Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A COARUA10 10. Mainstem of Lake Creek, including all tributaries and wetlands, from the source to the confluence with the Arkansas River, except for the specific listing in segment 11. Listed portion: COARUA10_A Mainstem of Lake Creek, including all tributaries and wetlands, from the source to the confluence with the Arkansas River, except for the specific listing in segment 11. Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H Aquatic Life Use pH 5. - 303(d) List H COARUA11 11. Mainstem of South Fork of Lake Creek, including all tributaries and wetlands, from the source to the confluence with Lake Creek.

Listed portion: COARUA11_A Mainstem of South Fork of Lake Creek, including all tributaries and wetlands, from the source to the confluence with Lake Creek.

1. Aquatic Life Use Aluminum (Total) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A COARUA12a 12a. Mainstem of Chalk Creek from the source to the confluence with the Arkansas River. Listed portion: COARUA12a_A Mainstem of Chalk Creek from the source to the confluence with the Arkansas River. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H COARUA14c 14c. Mainstems of North and South Hardscrabble Creeks, including all tributaries and wetlands, from their sources to their confluences.

Listed portion: COARUA14c_B North Hardscrabble Creek and tributaries, from the source to the confluence. Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List H COARUA14f 14f. Turkey Creek including all tributaries and wetlands from its source to immediately below the confluence with Little Turkey Creek at 38.594727, -104.851458.

Listed portion: COARUA14f_B Turkey Creek above the unnamed tributary that drains Mount Pittsburg (38.615, -104.903) Aquatic Life Use Total Phosphorus 3b. - M&E List N/A COARUA15a 15a. Mainstem of Badger Creek from the source to the confluence with the Arkansas River, including all tributaries and wetlands. Mainstem of Texas Creek from the Forest Service boundary to the confluence with the Arkansas River, including all tributaries and wetlands which are not on Forest Service land. Listed portion: COARUA15a_A Mainstem of Badger from the source to the confluence with the Arkansas, including all tributaries ans wetlands, Mainstem of Texas Creek from the forest service boundry to the confluence with the Arkansas River, including all tributaries and wetlands which are not on the forest service land.

1. Aquatic Life Use Macroinvertebrates 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List H COARUA15b 15b. Mainstem of Grape Creek, including all tributaries and wetlands, from the source to the outlet of De Weese Reservoir, except for specific listings in segment 25. Mainstems of Hayden, Hamilton, Stout, and Big Cottonwood Creeks, including all tributaries and wetlands, from their sources to their confluences with the Arkansas River. Tributaries and wetlands to Texas Creek which are on Forest Service Land. Mainstem of Newlin Creek from the National Forest boundary to County Road 92 (38.300765, -105.140927). Listed portion: COARUA15b_A Mainstem of Grape Creek, including all tributaries and wetlands, from the source to Antelope Creek, except for specific listings in segment 25. Mainstems of Hayden, Hamilton, Stout, and Big Cottonwood Creeks, including all tributaries and wetlands, from their sources to their confluences with the Arkansas River. Tributaries and wetlands to Texas Creek which are on Forest Service Land. Mainstem of Newlin Creek from the National Forest boundary to County Road 92 (38.300765, -105.140927).

   Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COARUA15b_B Grape Creek and its tributaries from Antelope Creek to Deweese Reservoir Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H COARUA20b 20b. Mainstem of Fourmile Creek, including all tributaries and wetlands, from the confluence with Long Gulch to the confluence with the Arkansas River.

Listed portion: COARUA20b_A Mainstem of Fourmile Creek, including all tributaries and wetlands, from the confluence with Long Gulch to the confluence with the Arkansas River. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H COARUA21a 21a. Mainstem of Cripple Creek from the source to a point 1.5 miles upstream of the confluence with Fourmile Creek.

Listed portion: COARUA21a_B Mainstem of Cripple Creek from Squaw Creek to a point 1.5 miles upstream of the confluence with Fourmile Creek.

1. Aquatic Life Use Macroinvertebrates 3b. - M&E List N/A COARUA30 30. Turquoise Reservoir, Clear Creek Reservoir, Twin Lakes and Mt. Elbert Forebay. Listed portion: COARUA30_B Twin Lake West.

   Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H COARUA35 35. DeWeese Reservoir.

Listed portion: COARUA35_A DeWeese Reservoir.

1. Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Total Phosphorus 5. - 303(d) List H COARUA38 38. All lakes and reservoirs tributary to the mainstem of East and West Beaver Creeks from the source to the confluence with Beaver Creek. This segment includes Skagway and Bison Reservoirs. Listed portion: COARUA38_B Skagway Reservoir.

   Aquatic Life Use Mercury (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List H COARUA40 40. Brush Hollow Reservoir.

Listed portion: COARUA40_A Brush Hollow Reservoir.

1. Aquatic Life Use Fish (Mercury) 5. - 303(d) List H COARUA41 41. Teller Reservoir.

Listed portion: COARUA41_A Teller Reservoir.

1. Aquatic Life Use Fish (Mercury) 3b. - M&E List N/A COGULD02 2. Mainstem of the Dolores River from the Highway 141 road crossing near Slick Rock to the Colorado/Utah border.

Listed portion: COGULD02_B Mainstem of Dolores River from Big Gypsum Creek to East Paradox Creek. Aquatic Life Use Temperature (Provisional) 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List H Listed portion: COGULD02_C Mainstem of Dolores River from East Paradox Creek to the San Miguel River. Water Supply Use Chloride 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List H Aquatic Life Use Temperature (Provisional) 5. - 303(d) List H Listed portion: COGULD02_D Mainstem of the Dolores River Above Big Gypsum Creek. Aquatic Life Use Iron (Total) 5. - 303(d) List H COGULD03a 3a. All tributaries to the Dolores River, including all wetlands, from the bridge at Bradfield Ranch (Forest Route 505, near Montezuma/Dolores County Line) to the Colorado/Utah border, except for specific listings in Segments 3b, 3c, 4, 5, and 6.

Listed portion: COGULD03a_B Disappointment Creek.

1. Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Nitrate 3b. - M&E List N/A COGULD04 4. Mainstem of West Paradox Creek from the Manti-La Sal National Forest boundary to the confluence with the Dolores River. Mainstem of Blue Creek, including all tributaries and wetlands, from the Uncompahgre National Forest boundary to the confluence with the Dolores River. Listed portion: COGULD04_B Mainstem of West Paradox Creek. Recreational Use E. coli 3b. - M&E List N/A COGULD05 5. Mainstem of West Creek from the source to the confluence with the Dolores River. Roc Creek including all tributaries and wetlands from the Manti-La Sal National Forest boundary to the confluence with the Dolores River. La Sal Creek, including all tributaries and wetlands, from the Utah/Colorado border to the confluence with the Dolores River. Mesa Creek, including all tributaries and wetlands, from the Uncompahgre National Forest boundary to the confluence with the Dolores River. Listed portion: COGULD05_B Rock Creek and its tributaries. Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List H Listed portion: COGULD05_D Mesa Creek and tributaries.

   Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGULD05_E Mainstem of West Creek from the source to the confluence with the Dolores River. Water Supply Use Arsenic (Total) 5. - 303(d) List L COGULG01 1. Mainstem of the Gunnison River from the outlet of Crystal Reservoir to Highway 65 (38.772574, -108.002634).

Listed portion: COGULG01_C Mainstem of the Gunnison River from North Fork to Highway 65. Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A COGULG02 2. Mainstem of the Gunnison River from Highway 65 (38.772574, -108.002634) to the confluence with the Colorado River.

Listed portion: COGULG02_A Mainstem of the Gunnison River from a point immediately above the confluence with the Uncompahgre River to the confluence with the Colorado River. Aquatic Life Use Sediment 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Recreational Use E. coli 5. - 303(d) List H Water Supply Use Sulfate 5. - 303(d) List L Listed portion: COGULG02_B Mainstem of the Gunnison River from Highway 65 to a point immediately above the confluence with the Uncompahgre River.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COGULG04a 4a. All tributaries to the Gunnison River, including all wetlands which are not within national forest boundaries, from the outlet of Crystal Reservoir to the confluence with the Colorado River, except for specific listings in the North Fork of the Gunnison River sub-basin, the Uncompahgre River sub-basin, and in Segments 3a, 3b, 4b, 4c, 5a, 5b, 5c, 6a, 6b, 6c, 7, 8a, 8b, 10 and 12. Listed portion: COGULG04a_D Whitewater Creek from below Brandon Ditch to confluence with Gunnison River. Water Supply Use Selenium (Total) 4a. - TMDL N/A Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Agricultural Use Selenium (Total) 4a. - TMDL N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Sulfate 5. - 303(d) List L Listed portion: COGULG04a_E Wells Gulch.

   Aquatic Life Use pH 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Selenium (Total) 4a. - TMDL N/A Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Agricultural Use Selenium (Total) 4a. - TMDL N/A Listed portion: COGULG04a_K All tributaries to the Gunnison River, including all wetlands, which are not within national forest boundaries and to which a TMDL does apply, from the outlet of Crystal Reservoir to the confluence with the Colorado River, except for Cummings Gulch, Whitewater Creek below Brandon Ditch, Wells Gulch, Peach Valley Creek, and specific listings in the North Fork of the Gunnison River sub-basin, the Uncompahgre River sub-basin, and Segments 3, 4b, 4c, 5a, 5b, 6a, 6b, 6c, 7, 8a, 8b, 10 and 12.

   Aquatic Life Use Iron (Total) 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Water Supply Use Selenium (Total) 4a. - TMDL N/A Agricultural Use Selenium (Total) 4a. - TMDL N/A Listed portion: COGULG04a_L Cummings Gulch, Peach Valley Creek, and Sunflower Drain including its tributaries and wetlands.

   Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Water Supply Use Selenium (Total) 4a. - TMDL N/A Agricultural Use Selenium (Total) 4a. - TMDL N/A Aquatic Life Use Total Phosphorus 5. - 303(d) List M Water Supply Use Nitrate 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List M COGULG04b 4b. All tributaries and wetlands to Reeder, Hollenbeck, and Juniata Reservoirs, and the mainstem of Kannah Creek below the point of diversion for public water supply (38.961321, -108.229830). Listed portion: COGULG04b_B Mainstem of Kannah Creek below point of diversion for public water system (38.961321, -108.229830).

   Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Selenium (Total) 4a. - TMDL N/A Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Listed portion: COGULG04b_C All tributaries and wetlands to Reeder, Hollenbeck and Juniata Reservoirs, excluding Kannah Creek.

   Aquatic Life Use Iron (Total) 3b. - M&E List N/A COGULG04c 4c. Mainstem of Red Rock Creek from the boundary of Black Canyon of the Gunnison National Park to the confluence of the Gunnison River.

Listed portion: COGULG04c_A Mainstem of Red Rock Creek from the boundary of Black Canyon of the Gunnison National Park to the confluence of the Gunnison River.

1. Water Supply Use Selenium (Total) 4a. - TMDL N/A Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Recreational Use E. coli 5. - 303(d) List H COGULG05a 5a. Mainstem of North Fork Escalante Creek from the national forest boundary to the confluence with Escalante Creek.

Listed portion: COGULG05a_A Mainstem of North Fork Escalante Creek from the national forest boundary to the confluence with Escalante Creek.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COGULG06a 6a. Mainstem of Escalante Creek from the national forest boundary to the Delta/Montrose County line (38.668215, -108.328144); mainstem of Little Dominguez from the national forest boundary to Big Dominguez Creek; mainstem of Big Dominguez from the national forest boundary to the Gunnison River. Listed portion: COGULG06a_A Mainstem of Escalante Creek from the national forest boundary to the Delta County Line; mainstem of Little Dominguez from the national forest boundary to Big Dominguez Creek; mainstem of Big Dominguez from the national forest boundary to the Gunnison River. Recreational Use E. coli 3b. - M&E List N/A COGULG06c 6c. Mainstem of Escalante Creek from the Delta/Montrose County line (38.668215, -108.328144) to the Gunnison River.

Listed portion: COGULG06c_A Mainstem of Escalante Creek from the Delta County line to the Gunnison River. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H COGULG07a 7a. Mainstem of Ward Creek, from the national forest boundary to the confluence with Dirty George Creek. Listed portion: COGULG07a_A Mainstem of Ward Creek, from the national forest boundary to the confluence with Dirty George Creek.

1. Aquatic Life Use Iron (Total) 3b. - M&E List N/A COGULG07b 7b. Mainstem of Surface Creek from the point of diversion of water supply (38.965216, -107.876031) to the confluence with Tongue Creek; mainstem of Tongue Creek from its inception at the confluence of Ward Creek and Dirty George Creek to the confluence with the Gunnison River; mainstem of Youngs Creek from the national forest boundary to the confluence with Kiser Creek; mainstem of Kiser Creek from the national forest boundary to the confluence with Ward Creek.

Listed portion: COGULG07b_A Youngs Creek from the USFS boundary to Kiser Creek; Kiser Creek from the USFS boundary to the confluence with Ward Creek.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COGULG07b_C Mainstem of Tongue Creek from its inception at the confluence of Ward Creek and Dirty George Creek to the confluence with the Gunnison River. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List H Listed portion: COGULG07b_D Mainstem of Surface Creek from the point of diversion of water supply to the confluence with Tongue Creek.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L COGULG09 9. Fruitgrowers Reservoir.

Listed portion: COGULG09_A Fruitgrowers Reservoir.

1. Aquatic Life Use Dissolved Oxygen 4a. - TMDL N/A COGULG11b 11b. All tributaries to the Smith Fork, including all wetlands, which are within the West Elk Wilderness Area. Listed portion: COGULG11b_B Lunch Creek.

   Aquatic Life Use Sediment 3b. - M&E List N/A COGULG12 12. All tributaries to the Smith Fork, including all wetlands, which are not within national forest boundaries, except for the specific listing in Segment 11a.

Listed portion: COGULG12_B Muddy Creek.

1. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List M Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COGULG15 15. Island Lake, Eggleston Lake, and Trickle Park Reservoir (aka Park Reservoir). Listed portion: COGULG15_B Eggleston Lake.

   Aquatic Life Use pH 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List H COGULG16 16. All lakes and reservoirs that are tributary to the Gunnison River, from the outlet of Crystal Reservoir to the confluence with the Colorado River, and not within national forest boundaries, excluding the listings in the North Fork of the Gunnison sub-basin, the Uncompahgre River sub-basin, and Segments 9, 13, and 19. This segment includes Poison Springs Reservoir, Dry Fork Reservoir, Delta Reservoir, Winkler Reservoir, Desert Reservoir, Alkali Reservoir, Cheney Reservoir, Juniata Reservoir, Hallenbeck Reservoir, Reeder Reservoir, Enochs Lake, Gobbo Reservoir, Schrader Reservoir, and King Reservoir. Listed portion: COGULG16_B Jatz Bottomlands.

   Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Listed portion: COGULG16_C Maggio Ponds.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COGULG16_D Peters Ponds 1, 2, 3, and 4. Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A COGUNF02 2. Mainstem of North Fork of the Gunnison River from its inception at the confluence of Muddy Creek and Anthracite Creek to the Black Bridge (41.75 Drive) above Paonia. Listed portion: COGUNF02_A Mainstem of North Fork of the Gunnison River from its inception at the confluence of Muddy Creek and Anthracite Creek to the Black Bridge (41.75 Drive) above Paonia. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COGUNF03 3. Mainstem of North Fork of the Gunnison River from the Black Bridge (41.75 Drive) above Paonia to the confluence with the Gunnison River.

Listed portion: COGUNF03_B Mainstem of North Fork of the Gunnison River from the Black Bridge (41.75 Drive) above Paonia to the confluence with the unnamed tributary east of Lazear Colorado. Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COGUNF03_C Mainstem of North Fork of the Gunnison River from the unnamed tributary east of Lazear Colorado to the confluence with the Gunnison River.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List H COGUNF04a 4a. All tributaries and wetlands to Muddy Creek within national forest boundaries. Anthracite Creek, including all tributaries and wetlands, from the source to the confluence with Muddy Creek. All tributaries and wetlands to the North Fork of the Gunnison from its inception at the confluence of Muddy Creek and Anthracite Creek to the confluence with the Gunnison River within national forest boundaries. This segment excludes the listings in Segments 1 and 4c.

Listed portion: COGUNF04a_B Ruby Anthracite Creek and its tributaries in the National forest except for the tributaries to Lake Irwin.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COGUNF04a_C Anthracite Creek and its tributaries and all tributaries to the North Fork of the Gunnison within the national forest boundaries. Except for specific listings in Segments 1 and 4c. Aquatic Life Use Temperature 3b. - M&E List N/A COGUNF04b 4b. Muddy Creek, including all tributaries and wetlands, from the national forest boundary to the confluence with Anthracite Creek, except for the specific listings in Segment 1. Listed portion: COGUNF04b_B East Muddy Creek from Forest Boundary to Confluence with Muddy Creek. Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUNF04b_D Mainstem of Muddy Creek to Paonia Reservoir. Recreational Use E. coli (May-October) 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUNF04b_E Mainstem of Muddy Creek from Paonia Reservoir to Anthracite Creek. Water Supply Use Lead (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Temperature 3b. - M&E List N/A Recreational Use E. coli (May-October) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COGUNF04c 4c. All tributaries and wetlands to Lake Irwin from their sources to the inlet of Lake Irwin. Listed portion: COGUNF04c_B All tributaries and wetlands to Lake Irwin. Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Aquatic Life Use Silver (Dissolved) 5. - 303(d) List H Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H COGUNF05a 5a. Mainstems of Hubbard Creek, Terror Creek, and Minnesota Creek, from the national forest boundary to their confluences with the North Fork of the Gunnison River; mainstem of Jay Creek from its source to its confluence with the North Fork of the Gunnison River.

Listed portion: COGUNF05a_C Mainstem of Jay Creek.

1. Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A COGUNF05b 5b. Mainstem of Roatcap Creek, including all tributaries and wetlands, from the source to the confluence with the North Fork of the Gunnison. Leroux Creek from the national forest boundary to its confluence with the North Fork of the Gunnison River.

Listed portion: COGUNF05b_B Mainstem of Leroux Creek from the forest to the confluence with North Fork of the Gunnison River.

1. Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A COGUNF06a 6a. All tributaries, including wetlands, to the North Fork of the Gunnison River from its inception at the confluence of Muddy Creek and Anthracite Creek to the confluence with the Gunnison River, and not within national forest boundaries, except for the specific listings in Segments 5a, 5b, 6b, and 6c. Listed portion: COGUNF06a_B Unnamed tributary to North Fork Gunnison River near Hotchkiss. Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Listed portion: COGUNF06a_C Coal Gulch, Hawksnest Creek, and Gribble Gulch. Aquatic Life Use Iron (Total) 3b. - M&E List N/A COGUNF06b 6b. Mainstem of Bear Creek and Stevens Gulch, including all tributaries and wetlands. All tributaries and wetlands to the North Fork of the Gunnison River that are north of the North Fork of the Gunnison River, from a point immediately above the confluence with Roatcap Creek to the confluence with the Gunnison River, and are not within national forest boundaries. All tributaries and wetlands to the North Fork of the Gunnison River that are south of the North Fork of the Gunnison River, from a point immediately above the confluence with Minnesota Creek to the confluence with the Gunnison River, and are not within national forest boundaries. This segment excludes the listings in Segments 5a and 5b. Listed portion: COGUNF06b_B Cottonwood Creek.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Total) 5. - 303(d) List M Water Supply Use Sulfate 5. - 303(d) List L Listed portion: COGUNF06b_C Alum Gulch.

   Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List M Water Supply Use Sulfate 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Listed portion: COGUNF06b_D Big Gulch.

   Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Listed portion: COGUNF06b_E Short Draw.

   Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Listed portion: COGUNF06b_F Bell Creek and its tributaries. Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Listed portion: COGUNF06b_G Mainstems, tributaries, and wetlands of Bear, Reynolds, Bell, McDonald, Cow, Denver, German and Miller Creeks; and Love, Stevens, Big and Stingley Gulches that are not within national forest boundaries, from the source to the North Fork of the Gunnison River, excluding the specific listings in Segments 5a and 5b.

   Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M COGUSM02 2. All tributaries and wetlands to the San Miguel River from its source to a point immediately below the confluence of Leopard Creek, except for listings in Segments 1, 6a, 6b, 7a, 7b, and 8. Listed portion: COGUSM02_B Bear Creek.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COGUSM02_C Cornet Creek.

   Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUSM02_D Howard Fork above Swamp Canyon. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H Aquatic Life Use pH 5. - 303(d) List H Listed portion: COGUSM02_E Muddy Creek and its tributaries. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COGUSM02_F All tributaries, including all wetlands, to the San Miguel River, from the source to Leopard Creek, excluding Bear Creek, Cornet Creek, Muddy Creek and Howard Fork above Swamp Canyon.

   Water Supply Use Sulfate 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L COGUSM03a 3a. Mainstem of the San Miguel River from its inception at the confluence of Bridal Veil and Ingram Creeks to a point immediately above the confluence of Marshall Creek. Listed portion: COGUSM03a_A Mainstem of the San Miguel River from its inception at the confluence of Bridal Veil and Ingram Creeks to a point immediately above the confluence of Marshall Creek. Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A COGUSM03b 3b. Mainstem of the San Miguel River from a point immediately above the confluence of Marshall Creek to a point immediately above the confluence of the South Fork San Miguel River. Listed portion: COGUSM03b_A Mainstem of the San Miguel River from a point immediately above the confluence of Marshall Creek to a point immediately above the confluence of the South Fork San Miguel River.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Temperature 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Sediment 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A COGUSM04a 4a. Mainstem of the San Miguel River from a point immediately above the confluence of the South Fork of the San Miguel River to a point immediately below the CC ditch. Listed portion: COGUSM04a_A Mainstem of the San Miguel River from Leopard Creek to below the CC ditch. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUSM04a_B Mainstem of the San Miguel River from South Fork San Miguel to confluence with Leopard Creek.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A COGUSM06a 6a. Mainstem of Ingram Creek, including all tributaries and wetlands, from the source to the confluence with the San Miguel River.

Listed portion: COGUSM06a_A Mainstem of Ingram Creek including, all tributaries and wetlands, from the source to the confluence with the San Miguel River.

1. Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M Aquatic Life Use Manganese (Dissolved) 5. - 303(d) List M COGUSM06b 6b. Mainstem of Marshall Creek, including all tributaries and wetlands, from the source to the confluence with the San Miguel River.

Listed portion: COGUSM06b_A Mainstem of Marshall Creek, including all tributaries and wetlands, from the source to the confluence with the San Miguel River.

1. Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Lead (Dissolved) 5. - 303(d) List M Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M COGUSM07a 7a. Mainstem of Howard Fork, including all tributaries and wetlands, from a point immediately below the confluence of Swamp Gulch to the confluence with the South Fork of the San Miguel River, except for listings in Segment 7b.

Listed portion: COGUSM07a_A Mainstem of the Howard Fork, all tributaries and wetlands, from the Swamp Gulch to the South Fork of the San Miguel River, excluding the Chapman Creek, Iron Bog Creek, and Waterfall Creek.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H Listed portion: COGUSM07a_B Chapman Creek and its tributaries. Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H Listed portion: COGUSM07a_C Iron Bog Creek and its tributaries. Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Aquatic Life Use pH 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List H Water Supply Use Iron (Dissolved) 5. - 303(d) List L Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Macroinvertebrates 5. - 303(d) List H COGUSM07b 7b. Mainstem of Waterfall Creek, including all tributaries and wetlands, from the source to the confluence with Howard Fork.

Listed portion: COGUSM07b_A Mainstem of Waterfall Creek, including all tributaries and wetlands, from the source to the confluence with Howard Fork.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H COGUSM08 8. Mainstem of the South Fork of the San Miguel River from its inception at the confluence of the Howard and Lake Forks to its confluence with the San Miguel River. Listed portion: COGUSM08_A Mainstem of the South Fork of the San Miguel River from its inception at the confluence of the Howard and Lake Forks to its confluence with the San Miguel River. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H COGUSM10b 10b. Mainstem of Naturita Creek from the point it exits the Uncompahgre National Forest at the most downstream boundary to the confluence with the San Miguel River. Listed portion: COGUSM10b_B Mainstem of Naturita Creek from the national forest to the confluence with the San Miguel River.

   Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A COGUSM12a 12a. All tributaries and wetlands to Naturita Creek. All tributaries and wetlands to the San Miguel River from a point immediately below the confluence with Leopard Creek to a point immediately above Horsefly Creek. This segment excludes the listings in Segments 9a, 11a, 11b, 12b, and 12c. Listed portion: COGUSM12a_D Specie Creek and its tributaries. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUSM12a_E McKenzie Creek.

   Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L COGUSM12b 12b. All tributaries and wetlands to the San Miguel River from a point immediately above Horsefly Creek to the confluence with the Dolores River, excluding the listings in Segments 9a, 9b, 10a, 10b, 10c, 11a, 12a, 12c, and 12d. Maverick Draw, including all tributaries and wetlands, from its source to the confluence with Naturita Creek.

Listed portion: COGUSM12b_D Mainstem of Maverick Draw.

1. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Listed portion: COGUSM12b_F Coal Canyon and its tributaries, except for the North and South tributaries in Second Park. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M Aquatic Life Use Iron (Total) 5. - 303(d) List M Listed portion: COGUSM12b_G Tuttle Draw and its tributaries. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List M Listed portion: COGUSM12b_H Dry Creek and its tributaries. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COGUSM12b_I Second Park Tributary South. Aquatic Life Use Iron (Total) 5. - 303(d) List M COGUSM12c 12c. Mainstem of Calamity Draw from Lincoln Street in Nucla (38.264075, -108.555087) to the confluence with the San Miguel River.

Listed portion: COGUSM12c_A Calamity Draw below Lincoln Street. Aquatic Life Use Iron (Total) 3b. - M&E List N/A COGUSM14 14. All lakes and reservoirs tributary to the San Miguel River from its source to a point immediately below the confluence of Leopard Creek, except for the specific listings in Segments 13, 15, 16, 17 and 20. This segment includes Lake Hope, Cushman Lake, Alta Lakes, Blue Lake, Mud Lake, and Woods Lake. Listed portion: COGUSM14_B Applebaugh Pond.

1. Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Aquatic Life Use Temperature 3b. - M&E List N/A COGUSM20 20. Trout Lake, Gurley Reservoir, Cone Reservoir, and Miramonte Reservoir. Listed portion: COGUSM20_B Miramonte Reservoir.

   Aquatic Life Use Dissolved Oxygen (Temperature) 5. - 303(d) List H COGUUG01 1. All tributaries and wetlands to the Gunnison River within the La Garita, Powderhorn, West Elk, Collegiate Peaks, Maroon Bells, Raggeds, Fossil Ridge, or Uncompahgre Wilderness Areas. Listed portion: COGUUG01_B Stewart Creek.

   Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUUG01_D All tributaries and wetlands to the Gunnison River within the La Garita, Powderhorn, West Elk, Collegiate Peaks, Maroon Bells, Raggeds, Fossil Ridge, or Uncompahgre Wilderness Areas, excluding Stewart Creek.

   Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H COGUUG02 2. All tributaries and wetlands from Beaver Creek to Meyers Gulch, from the West Elk Wilderness boundary to their confluences with Blue Mesa Reservoir, Morrow Point Reservoir, or the Gunnison River, excluding Steuben Creek and Willow Creek and their tributaries.

Listed portion: COGUUG02_D Red Creek and East Elk Creek and their tributaries. Aquatic Life Use Total Phosphorus 3b. - M&E List N/A COGUUG04 4. Mainstem of the Taylor River, including all tributaries and wetlands, from a point immediately below the confluence with Illinois Creek to the confluence with the Gunnison River, except for listings in Segment 1. Listed portion: COGUUG04_D Mainstem of Taylor River, from Illinois Creek to the confluence with the Gunnison River. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COGUUG05a 5a. Mainstem of the East River, including all tributaries and wetlands, from its source to a point immediately above the confluence with the Slate River, except for specific listings in Segment 1. Listed portion: COGUUG05a_A Mainstem of the East River, including all tributaries and wetlands, from its sources to a point immediately above the confluence with the Slate River, except for specific listings in Segments 1.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COGUUG06c 6c. Cement Creek, including all tributaries and wetlands, from a point immediately above the confluence with Horse Basin Creek to the confluence with the East River. Listed portion: COGUUG06c_A Cement Creek, including all tributaries and wetlands, from a point immediately above the confluence with Horse Basin Creek to the confluence with the East River. Water Supply Use Arsenic (Total) 5. - 303(d) List H COGUUG07 7. Mainstem of the Slate River from its source to a point immediately above the confluence with Coal Creek. Listed portion: COGUUG07_A Mainstem of the Slate River from its source to Oh-Be-Joyful Creek. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUUG07_B Mainstem of the Slate River from Oh-Be-Joyful Creek to a point immediately above the confluence with Coal Creek.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H COGUUG08 8. Mainstem of the Slate River from a point immediately above the confluence with Coal Creek to the confluence with the East River.

Listed portion: COGUUG08_A Mainstem of the Slate River from a point immediately above the confluence with Coal Creek to the confluence with the East River.

1. Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H COGUUG09 9. All tributaries and wetlands to the Slate River except for specific listings in Segments 1, 10a, 10b, 11, 12 and 13.

Listed portion: COGUUG09_B Mainstem of Coal Creek from source to Elk Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COGUUG09_C Mainstem of Washington Gulch. Aquatic Life Use Temperature 3b. - M&E List N/A Recreational Use E. coli 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUUG09_E All tributaries and wetlands to the Slate River, excluding Coal Creek (above Elk Creek) and Washington Gulch.

1. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COGUUG09_G Drainage from natural iron fen (38.863897, -107.041530) tributary to Coal Creek. Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L Water Supply Use Cadmium (Total) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COGUUG10a 10a. Mainstem of Oh-Be-Joyful Creek from the boundary of the Raggeds Wilderness Area to the confluence with the Slate River.

Listed portion: COGUUG10a_A Mainstem of Oh-Be-Joyful Creek from the boundary of the Raggeds Wilderness Area to the confluence with the Slate River.

1. Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Aquatic Life Use Macroinvertebrates 5. - 303(d) List H COGUUG10b 10b. Mainstem of Redwell Creek, including all tributaries and wetlands, from the source to the confluence with Oh-Be-Joyful Creek.

Listed portion: COGUUG10b_B Mainstem of Redwell Creek, Including all tributaries and wetlands, from the source to the confluence with Oh-Be Joyful Creek.

1. Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Silver (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Macroinvertebrates 5. - 303(d) List H COGUUG11 11. Mainstem of Coal Creek from a point immediately above the confluence with Elk Creek to a point immediately above the Keystone Mine discharge (38.867117, -107.023627). Elk Creek and its tributaries and wetlands from its source to its confluence with Coal Creek. Listed portion: COGUUG11_B Elk Creek and its tributaries. Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUUG11_D Mainstem of Coal Creek from a point immediately above the confluence with Elk Creek to a point immediately above the Keystone discharge (38.867117, -107.023627) . Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COGUUG12 12. Mainstem of Coal Creek, including all tributaries and wetlands, from a point immediately above the Keystone Mine discharge (38.867117, -107.023627) to the confluence with the Slate River, with the exception of Wildcat Creek.

Listed portion: COGUUG12_C Mainstem of Coal Creek, from a point immediately below the Keystone discharge (38.867117, -107.023627) to the confluence with the Slate River. Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COGUUG12_D Unnamed tributary draining Red Lady Basin to Coal Creek. Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H COGUUG15a 15a. All tributaries and wetlands to the Gunnison River from its inception at the confluence of the East and Taylor Rivers to the County Road 32 road crossing near the inlet of Blue Mesa Reservoir except for the specific listings in Segments 1, 15b, 16a, 16b, 17 through 24, and 26. Listed portion: COGUUG15a_A All tributaries and wetlands to the Gunnison River from the confluence of the East and Taylor Rivers to the inlet of Blue Mesa Reservoir, excluding South Beaver Creek. Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Listed portion: COGUUG15a_B Mainstem of South Beaver Creek from Saguache/Gunnison County Line to the confluence with the Gunnison River.

1. Aquatic Life Use Temperature 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COGUUG16a 16a. Mainstem of Ohio Creek, including all tributaries and wetlands, from the source to a point immediately below 7 Road, except for listings in Segment 1.

Listed portion: COGUUG16a_E Ohio Creek including its tributaries and wetlands, below Baldwin. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COGUUG16a_F Ohio Creek including its tributaries and wetlands, above Baldwin. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H COGUUG16b 16b. Mainstem of Ohio Creek from a point immediately below 7 Road to the confluence with the Gunnison River.

Listed portion: COGUUG16b_A Mainstem of Ohio Creek from a point immediately below 7 Road to the confluence with the Gunnison River.

1. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A COGUUG17a 17a. West Antelope Creek, including all tributaries and wetlands, from the source to the confluence with Antelope Creek.

Listed portion: COGUUG17a_A West Antelope Creek, including all tributaries and wetlands, from the source to the confluence with Antelope Creek.

1. Recreational Use E. coli 3b. - M&E List N/A COGUUG17b 17b. Mainstem of Antelope Creek, including all tributaries and wetlands, from the source to the confluence with the Gunnison River, excluding the listings in Segment 17a. Listed portion: COGUUG17b_A Mainstem of Antelope Creek, including all tributaries and wetlands, from the source to the confluence with the Gunnison River, excluding the listings in Segment 17a. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A COGUUG18a 18a. Mainstem of Tomichi Creek and its wetlands from the source to the confluence with Porphyry Creek. Listed portion: COGUUG18a_A Mainstem of Tomichi Creek and its wetlands from the source to the confluence with Porphyry Creek.

   Aquatic Life Use Macroinvertebrates 3b. - M&E List N/A COGUUG18b 18b. Mainstem of Tomichi Creek and its wetlands from the confluence with Porphyry Creek to the confluence with the Gunnison River.

Listed portion: COGUUG18b_A Mainstem of Tomichi Creek and its wetlands from the confluence with Porphyry Creek to the confluence with the Gunnison River.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Aquatic Life Use Temperature 5. - 303(d) List H COGUUG19 19. All tributaries to Tomichi Creek, including wetlands, which are within the boundaries of the Gunnison National Forest, except for specific listings in Segments 20 through 24. Mainstems of Barret, Razor, and Quartz Creeks from their sources to their confluences with Tomichi Creek. Hot Springs Creek from its source to the inlet of Hot Springs Reservoir.

Listed portion: COGUUG19_B Mainstem of Razor Creek from source to confluence with Tomichi Creek. Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COGUUG21 21. Mainstem of Marshall Creek, including all tributaries and wetlands, from the source to the confluence with Tomichi Creek, except for listings in Segment 20.

Listed portion: COGUUG21_A Mainstem of Marshall Creek, including all tributaries and wetlands, from the source to the confluence with Tomichi Creek, except for specific listings in Segment 20. Water Supply Use Uranium (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H COGUUG23 23. Mainstem of Cochetopa Creek, including all tributaries and wetlands, from the source to a point immediately below the confluence with West Pass Creek with the exception of Segment 1. Listed portion: COGUUG23_A All tributaries and wetlands to mainstem Cochetopa Creek, from the sources to a point immediately below the confluence with West Pass Creek, excluding mainstem Cochetopa Creek.

1. Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUUG23_B Mainstem of Cochetopa Creek from Nutras Creek to West Pass Creek. Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H COGUUG24 24. Mainstem of Cochetopa Creek from a point immediately below the confluence with West Pass Creek to the confluence with Tomichi Creek.

Listed portion: COGUUG24_A Mainstem of Cochetopa Creek from West Pass Creek to Forest Road 3076/Co. Rd 43. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUUG24_B Mainstem of Cochetopa Creek, from Forest Road 3076/Co. Rd 43 to the confluence with Tomichi Creek.

1. Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List H COGUUG25 25. The segments of the Gunnison River which interconnect Blue Mesa Reservoir, Morrow Point Reservoir, and Crystal Reservoir.

Listed portion: COGUUG25_A The segments of the Gunnison River which interconnect Blue Mesa Reservoir, Morrow Point Reservoir, and Crystal Reservoir.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List H COGUUG26 26. All tributaries, including wetlands, which are tributary to the Gunnison River from County Road 32 to the inlet of Blue Mesa Reservoir, Blue Mesa Reservoir, Morrow Point Reservoir, Crystal Reservoir, or the segments of the Gunnison River that interconnect those reservoirs, except for specific listings in Segments 1, 2, 29a, 29b, 30, 31, and 32.

Listed portion: COGUUG26_B Blue Creek and its tributaries. Aquatic Life Use Temperature 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUUG26_C Mainstem of Crystal Creek from source to confluence with the Gunnison River. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Listed portion: COGUUG26_D Willow Creek terminating at Blue Mesa Reservoir near (38.43676, -107.288995) and its tributaries.

1. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUUG26_E All tributaries, including wetlands which are tributary to the Gunnison River from County Road 32 to the inlet of Blue Mesa Reservoir, Blue Mesa Reservoir, Morrow Point Reservoir, Crystal Reservoir or the segments of the Gunnison River that interconnect those reservoirs, except for (specific listings in Segments 1, 2, 29a, 29b, 30, 31, and 32) and the portions of Blue, Willow and Crystal Creeks.

   Recreational Use E. coli 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List H COGUUG29a 29a. Mainstem of the Lake Fork of the Gunnison including all tributaries and wetlands, from the source to a point immediately above the confluence with Eaton Creek. Cebolla Creek, including all tributaries and wetlands, from the source to the Hinsdale/Gunnison County line. Powderhorn Creek, including all tributaries and wetlands, from the source to the confluence with Cebolla Creek. This segment excludes the specific listings in Segments 1, 29b, 30, 31, and 32.

Listed portion: COGUUG29a_B Deadman Creek/Gulch and its tributaries. Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List H Aquatic Life Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use pH 5. - 303(d) List H Water Supply Use Iron (Dissolved) 5. - 303(d) List L Listed portion: COGUUG29a_C Lake Fork of the Gunnison River between Cooper and Silver Creek. Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Listed portion: COGUUG29a_D Lake Fork of the Gunnison above Cooper Creek. Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Listed portion: COGUUG29a_I Lake Fork of the Gunnison between Silver Creek and Cottonwood Creek. Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A COGUUG29b 29b. Mainstem of the Lake Fork of the Gunnison, including all tributaries and wetlands, from a point immediately above the confluence with Eaton Creek, to Blue Mesa Reservoir. Cebolla Creek, including all tributaries and wetlands, from the Hinsdale/Gunnison County line, to Blue Mesa Reservoir, excluding the listings in Segment 29a.

Listed portion: COGUUG29b_C Mainstem of the Lake Fork of the Gunnison, including all tributaries and wetlands, from a point immediately above the confluence with Eaton Creek, to Blue Mesa Reservoir. Cebolla Creek, including all tributaries and wetlands, from the Hinsdale/Gunnison County line, to Blue Mesa Reservoir, excluding the listings in Segment 29a and Powderhorn Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List H COGUUG30 30. Mainstem of Henson Creek, including all tributaries and wetlands, from the source to the confluence with the Lake Fork of the Gunnison, except for the specific listings in Segments 31 and 32. Listed portion: COGUUG30_B Mainstem of Henson Creek from the source to the confluence with the Lake Fork of the Gunnison.

1. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COGUUG30_C All tributaries and wetlands of Henson Creek, from the source to the confluence with the Lake Fork of the Gunnison, except for the specific listing in Segments 31 and 32. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COGUUG31 31. Mainstem of Palmetto Gulch Creek, including all tributaries and wetlands. Listed portion: COGUUG31_B Mainstem of Palmetto Gulch Creek including all tributaries and wetlands. Aquatic Life Use Silver (Dissolved) 3b. - M&E List N/A Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M Aquatic Life Use Iron (Total) 5. - 303(d) List M Aquatic Life Use Manganese (Dissolved) 5. - 303(d) List L COGUUG32 32. North Fork of Henson Creek including all tributaries and wetlands, from its source to the confluence with Henson Creek, except for specific listings in Segment 1. Listed portion: COGUUG32_A North Fork of Henson Creek including all tributaries and wetlands, from its source to the confluence with Henson Creek, except for specific listings in Segment 1. Water Supply Use Arsenic (Total) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COGUUN02 2. Mainstem of the Uncompahgre River from the source (Poughkeepsie Gulch) to a point immediately above the confluence with Red Mountain Creek.

Listed portion: COGUUN02_B Mainstem of the Uncompahgre River from the source (Poughkeepsie Gulch) to a point immediately above the confluence with Silver Creek.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Water Supply Use Cadmium (Total) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use pH 5. - 303(d) List H Listed portion: COGUUN02_C Mainstem of the Uncompahgre River from a point immediately above the confluence with Silver Creek to a point immediately above the confluence with Red Mountain Creek. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 5. - 303(d) List H COGUUN03a 3a. Mainstem of the Uncompahgre River from a point immediately above the confluence with Red Mountain Creek to a point immediately above the confluence with Cascade Creek. Listed portion: COGUUN03a_A Mainstem of the Uncompahgre River from a point immediately above the confluence with Red Mountain Creek to a point immediately above the confluence with Cascade Creek. Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Agricultural Use Copper (Total) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use pH 5. - 303(d) List H COGUUN03b 3b. Mainstem of the Uncompahgre River from a point immediately above the confluence with Cascade Creek to a point immediately above the confluence with Dexter Creek. Listed portion: COGUUN03b_A Mainstem of the Uncompahgre River from a point immediately above the confluence with Cascade Creek to a point immediately above the confluence with Dexter Creek. Aquatic Life Use Iron (Total) 4a. - TMDL N/A Aquatic Life Use pH 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COGUUN03d 3d. Mainstem of the Uncompahgre River from a point immediately below the confluence with Dallas Creek to the inlet of Ridgway Reservoir.

Listed portion: COGUUN03d_A Mainstem of the Uncompahgre River from a point immediately below the confluence with Dallas Creek to the inlet of Ridgway Reservoir.

1. Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Total) 4a. - TMDL N/A COGUUN04a 4a. Mainstem of the Uncompahgre River from the Highway 90 bridge at Montrose to Gunnison Road. Listed portion: COGUUN04a_B Mainstem of the Uncompahgre River from Cedar Creek to Gunnison Road. Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Sediment 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List H Listed portion: COGUUN04a_C Mainstem of the Uncompahgre River from the Highway 90 bridge at Montrose to Cedar Creek.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Sediment 3b. - M&E List N/A COGUUN04b 4b. Mainstem of the Uncompahgre River from Gunnison Road to the upstream boundary of Confluence Park. Listed portion: COGUUN04b_A Mainstem of the Uncompahgre River from Gunnison Road to the upstream boundary of Confluence Park.

   Aquatic Life Use Sediment 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COGUUN04c 4c. Mainstem of the Uncompahgre River from the upstream boundary of Confluence Park to the confluence with the Gunnison River.

Listed portion: COGUUN04c_A Mainstem of the Uncompahgre River from the upstream boundary of Confluence Park to the confluence with the Gunnison River.

1. Aquatic Life Use Sediment 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A COGUUN05 5. All tributaries to the Uncompahgre River, including all wetlands, from the source to a point immediately below the confluence with Dexter Creek, except for specific listings in Segments 1, 6a, 6b, and 7 through 9. Listed portion: COGUUN05_B Commodore Gulch and its tributaries. Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List M Listed portion: COGUUN05_C Governor Basin.

   Water Supply Use Lead (Total) 5. - 303(d) List L Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List M Water Supply Use Manganese (Dissolved) 5. - 303(d) List M Aquatic Life Use Lead (Dissolved) 5. - 303(d) List M Listed portion: COGUUN05_D Silver Creek.

   Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Listed portion: COGUUN05_E Sneffels Creek below Governor Basin. Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List M Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M Water Supply Use Manganese (Dissolved) 5. - 303(d) List M Aquatic Life Use Macroinvertebrates 5. - 303(d) List M Aquatic Life Use Lead (Dissolved) 5. - 303(d) List M Listed portion: COGUUN05_G Alaska Basin.

   Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use pH 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List M Listed portion: COGUUN05_H Miner's Creek.

   Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A COGUUN06a 6a. Mainstem of Red Mountain Creek from the source to immediately above the confluence with the East Fork of Red Mountain Creek.

Listed portion: COGUUN06a_A Mainstem of Red Mountain Creek from the source to immediately above the confluence with the East Fork of Red Mountain Creek.

1. Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Silver (Dissolved) 5. - 303(d) List M Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M COGUUN07 7. Mainstem of Gray Copper Gulch from the source to the confluence with Red Mountain Creek. Listed portion: COGUUN07_A Mainstem of Gray Copper Gulch from the source to the confluence with Red Mountain Creek. Aquatic Life Use pH 5. - 303(d) List M Aquatic Life Use Lead (Dissolved) 5. - 303(d) List M Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List M Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M COGUUN08 8. Mainstem of Mineral Creek from the source to the confluence with the Uncompahgre River. Listed portion: COGUUN08_A Mainstem of Mineral Creek from the source to the confluence with the Uncompahgre River. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List M Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M COGUUN09 9. Mainstem of Imogene Creek from its source to its confluence with Sneffels Creek. Mainstem of Sneffels Creek, including all tributaries and wetlands, from a point 1.5 miles above its confluence with Imogene Creek at 37.974979, -107.753960 (WGS84) to its confluence with Imogene Creek. Mainstem of Canyon Creek from its inception at the confluence of Imogene Creek and Sneffels Creek to the confluence with the Uncompahgre River.

Listed portion: COGUUN09_B Mainstem and all tributaries of Sneffels Creek from a point 1.5 miles above its confluence with Imogene Creek at 37.974979, -107.753960 (WGS84) to its confluence with Imogene Creek.

1. Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H Listed portion: COGUUN09_C Mainstem of Canyon Creek from its inception at the confluence of Imogene Creek and Sneffels Creek to the confluence with the Uncompahgre River. Aquatic Life Use pH 3b. - M&E List N/A Listed portion: COGUUN09_D Mainstem of Imogene Creek from its source to its confluence with Sneffels Creek. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List M COGUUN10a 10a. All tributaries to the Uncompahgre River, including all wetlands, from a point immediately below the confluence with Dexter Creek to the South Canal near Uncompahgre, except for specific listings in Segments 1, 10b, and 11.

Listed portion: COGUUN10a_B Alkali Creek and all tributaries. Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COGUUN10a_C Mainstem of Cow Creek from the confluence of Nate Creek to the Uncompahgre River. Water Supply Use Arsenic (Total) 5. - 303(d) List H COGUUN11 11. Mainstem of Coal Creek from the source to the Park Ditch. Mainstem of Dallas Creek from the source of the East and West Forks to the confluence with the Uncompahgre River. Mainstem of Cow Creek from the Uncompahgre Wilderness Area boundary to a point immediately below the confluence with Nate Creek. All tributaries and wetlands to Cow Creek from the Uncompahgre Wilderness Area boundary to the confluence with the Uncompahgre River. Mainstems of Billy Creek, Onion Creek and Beaton Creek from the source to the confluence with the Uncompahgre River. Mainstem of Beaver Creek from the source to the confluence with the East Fork of Dallas Creek. Mainstem of Pleasant Valley Creek from the source to the confluence with Dallas Creek.

Listed portion: COGUUN11_C Deer Creek from source to Cow Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUUN11_G Mainstem of Dallas Creek.

1. Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUUN11_H Mainstem of Billy Creek.

   Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUUN11_I Mainstems of Coal, Pleasant Valley, and Beaton Creeks. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUUN11_J Onion Creek and its tributaries. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COGUUN11_K Mainstem of Cow Creek from the wilderness to the confluence with Nate Creek and all tributaries and wetlands of Cow Creek.

   Water Supply Use Arsenic (Total) 5. - 303(d) List H COGUUN12 12. All tributaries to the Uncompahgre River, including all wetlands, from the South Canal near Uncompahgre to the confluence with the Gunnison River, except for specific listings in Segments 13, 14, 15a and 15b. Listed portion: COGUUN12_C Mainstem of Dry Creek from Coal bank Canyon Creek to Uncompahgre River. Aquatic Life Use Total Phosphorus 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List H Listed portion: COGUUN12_D Loutzenhizer Arroyo and its tributaries. Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Agricultural Use Selenium (Total) 5. - 303(d) List M Aquatic Life Use Total Phosphorus 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List H Listed portion: COGUUN12_E All tributaries to the Uncompahgre River, including all wetlands, from the South Canal near Uncompahgre to the confluence with the Gunnison River, except for specific listings in Segments (13, 14, 15a and 15b), Loutzenhizer Arroyo, Dry Creek, Cedar Creek, and Dry Cedar Creek.

   Agricultural Use Selenium (Dissolved) 4a. - TMDL N/A Listed portion: COGUUN12_G Montrose Arroyo from headwaters to confluence with Cedar Creek. Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Agricultural Use Selenium (Total) 5. - 303(d) List M Listed portion: COGUUN12_H Cedar Creek and Dry Cedar Creek with their tributaries, except Montrose Arroyo. Aquatic Life Use Total Phosphorus 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A COGUUN15b 15b. Mainstem of Dry Creek from the confluence of the East and West Forks to immediately above the confluence with Coalbank Canyon Creek.

Listed portion: COGUUN15b_A Mainstem of Dry Creek from the confluence of the East and West Forks to immediately above the confluence with Coalbank Canyon Creek.

1. Aquatic Life Use Sediment 3b. - M&E List N/A COGUUN19 19. Ridgway Reservoir.

Listed portion: COGUUN19_A Ridgway Reservoir.

1. Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A COGUUN20 20. Sweitzer Lake (a.k.a. Garnet Mesa Reservoir). Listed portion: COGUUN20_A Sweitzer Lake (a.k.a. Garnet Mesa Reservoir). Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H COLCLC01 1. Mainstem of the Colorado River from the confluence with the Roaring Fork River to immediately below the confluence with Rifle Creek.

Listed portion: COLCLC01_A Colorado River from Paradise Creek to below the confluence with Rifle Creek. Aquatic Life Use Sediment 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COLCLC01_B Colorado River from Roaring Fork to Paradise Creek. Aquatic Life Use Sediment 3b. - M&E List N/A Water Supply Use Chloride 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCLC02a 2a. Mainstem of the Colorado River from immediately below the confluence with Rifle Creek to immediately above the confluence of Rapid Creek.

Listed portion: COLCLC02a_A Mainstem of the Colorado River from immediately below the confluence with Rifle Creek to immediately above the confluence of Rapid Creek.

1. Aquatic Life Use Sediment 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCLC02b 2b. Mainstem of the Colorado River from a point immediately above the confluence with Rapid Creek to immediately above the confluence of the Gunnison River. Listed portion: COLCLC02b_A Mainstem of the Colorado River from Rapid Creek to Gunnison River except for the Humphrey Backwater area.

   Aquatic Life Use Sediment 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Listed portion: COLCLC02b_B Humphrey Backwater area.

   Aquatic Life Use Sediment 3b. - M&E List N/A Aquatic Life Use Nitrite 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Sulfate 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H COLCLC03 3. Mainstem of the Colorado River from immediately above the confluence of the Gunnison River to the Colorado-Utah state line.

Listed portion: COLCLC03_C Mainstem of the Colorado River from above Reed Wash to the Colorado-Utah state line. Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List H COLCLC04a 4a. All tributaries, including wetlands, to the Colorado River from the confluence with the Roaring Fork River to below the confluence with Parachute Creek except for listings in Segments 4b, 4c, 4d, 4e, 5, 6, 7a, 7b, 8, 9a, 9c, 10, 11a ? c.

Listed portion: COLCLC04a_A Tributaries to Colorado River, Roaring Fork to Parachute Creek, except for Mamm Creek and Alkali Creek.

1. Aquatic Life Use Total Phosphorus 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M Listed portion: COLCLC04a_B Mamm Creek and its East, Middle, and West Mamm Creek tributaries from the sources to the confluence with the Colorado River.

   Aquatic Life Use Total Phosphorus 3b. - M&E List N/A Agricultural Use Selenium (Total) 3b. - M&E List N/A Water Supply Use Sulfate 5. - 303(d) List L Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M Aquatic Life Use Macroinvertebrates 5. - 303(d) List M Listed portion: COLCLC04a_C Alkali Creek.

   Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Total Phosphorus 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M Listed portion: COLCLC04a_D South Canyon Creek sections above hot springs. Aquatic Life Use Total Phosphorus 3b. - M&E List N/A Water Supply Use Sulfate 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List H Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M COLCLC04b 4b. South Canyon Hot Springs (39.552964, -107.414232). Listed portion: COLCLC04b_A South Canyon Hot Springs. (39.552964, -107.414232). Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A COLCLC04c 4c. The mainstem of South Canyon Creek from the South Canyon Hot Springs to the confluence with the Colorado River.

Listed portion: COLCLC04c_A South Canyon Creek from South Canyon Hot Springs to Colorado River. Recreational Use E. coli (May-October) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCLC04e 4e. Mainstem of Dry Creek, including all tributaries and wetlands, from the source to immediately above the Last Chance Ditch (39.526106, -107.745212).

Listed portion: COLCLC04e_B Mainstem of Dry Creek, including all tributaries and wetlands, from the source to immediately above the Last Chance Ditch (39.526106, -107.745212). Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A COLCLC07a 7a. Mainstem of Mitchell, Canyon, Elk, Garfield, Beaver, and Cache Creeks, including all tributaries and wetlands, from the boundary of the White River National Forest to their confluences with the Colorado River. Listed portion: COLCLC07a_B Mainstem of Mitchell, Canyon, Beaver, and Cache Creeks, including all tributaries and wetlands, from the boundary of the White River National Forest to their confluences with the Colorado River.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COLCLC07a_C Garfield Creek and its tributaries from the headwaters to the confluence with the Colorado River.

   Aquatic Life Use Iron (Total) 3b. - M&E List L Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Listed portion: COLCLC07a_D Elk Creek and its tributaries from the White River National Forest boundary to the confluence with the Colorado River.

   Water Supply Use Cadmium (Total) 5. - 303(d) List L COLCLC07b 7b. Mainstem of Divide Creek, including all tributaries and wetlands, from the boundary of the White River National Forest to the confluence with the Colorado River. Listed portion: COLCLC07b_A Mainstem of Divide Creek, including all tributaries and wetlands, from the boundary of the White River National Forest to the confluence with the Colorado River. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A COLCLC10 10. West Rifle Creek, including all tributaries and wetlands, from the source to Rifle Gap Reservoir. East Rifle Creek, including all tributaries and wetlands, from the White River National Forest boundary to Rifle Gap Reservoir. Rifle Creek, including all tributaries and wetlands, from Rifle Gap Reservoir to the confluence with the Colorado River.

Listed portion: COLCLC10_A East Rifle Creek from the White River NF boundary to Rifle Gap Reservoir. Rifle Creek from Rifle Gap Reservoir to the Colorado River.

1. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H Listed portion: COLCLC10_B West Rifle Creek and tributaries. Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCLC11c 11c. Mainstem of Parachute Creek from the confluence of the West and East Forks to the confluence with the Colorado River. All tributaries and wetlands to Parachute Creek on the west side of Parachute Creek from the confluence of the East and West Forks to the confluence with the Colorado River. Listed portion: COLCLC11c_B Mainstem of Parachute Creek from the confluence of the West and East Forks to the confluence with the Colorado River. All tributaries and wetlands to Parachute Creek on the west side of Parachute Creek from the confluence of the East and West Forks to the confluence with the Colorado River.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Cadmium (Total) 5. - 303(d) List H COLCLC13a 13a. All tributaries to the Colorado River including wetlands, from a point immediately below the confluence of Roan Creek to the Colorado/Utah border, except for listings in Segments 13b through 19. Listed portion: COLCLC13a_A All tributaries to the Colorado River, including wetlands,from a point immediately below the confluence of Roan Creek to the Colorado/Utah border, except for listings in Segments 13b through 19.

   Aquatic Life Use Nitrite 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List M Listed portion: COLCLC13a_B Sulphur Gulch and tributaries. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A COLCLC13b 13b. All tributaries to the Colorado River, including wetlands, from the Government Highline Canal Diversion to a point immediately below Salt Creek, and downgradient from the Government Highline Canal, the Orchard Mesa Canal No. 2, Orchard Mesa Drain, Stub Ditch and the northeast Colorado National Monument boundary. Listed portion: COLCLC13b_B Salt Creek and tributaries below lake and reservoir, including Mack Wash. Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Total) 4a. - TMDL N/A Aquatic Life Use Sediment 5. - 303(d) List L Listed portion: COLCLC13b_C Adobe Creek, Leach Creek and tributaries below canal. Recreational Use E. coli 4a. - TMDL N/A Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Total) 4a. - TMDL N/A Listed portion: COLCLC13b_D Indian Wash.

   Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Total) 4a. - TMDL N/A Listed portion: COLCLC13b_E Unnamed tributary to the Colorado River from its source to its confluence with the Colorado River near 39.081, -108.592.

   Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M Aquatic Life Use Iron (Total) 5. - 303(d) List M Listed portion: COLCLC13b_F All tributaries to the Colorado River from Government Highline Canal Diversion to below Salt Creek, and downgradient from Government Highline Canal, Orchard Mesa Canal No. 2, Orchard Mesa Drain, Stub Ditch and northeast Colorado National Monument boundary, except Salt, Adobe, Leach Creeks, Indian Wash, Unnamed Tributary and Mack Wash. Aquatic Life Use Nitrite 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Total) 4a. - TMDL N/A COLCLC14b 14b. Clear Creek, including all tributaries and wetlands, from a point immediately below the confluence with Tom Creek to the confluence with Roan Creek. Roan Creek, including all tributaries and wetlands, from a point immediately above the confluence with Clear Creek to a point immediately below the confluence with Kimball Creek.

Listed portion: COLCLC14b_A Clear Creek, including all tributaries and wetlands, from a point immediately below the confluence with Tom Creek to the confluence with Roan Creek. Roan Creek, including all tributaries and wetlands, from a point immediately above the confluence with Clear Creek to a point immediately below the confluence with Kimball Creek Aquatic Life Use Iron (Total) 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A COLCLC14c 14c. Mainstem of Roan Creek, including all tributaries and wetlands, from a point immediately below the confluence with Kimball Creek to the confluence with the Colorado River. Listed portion: COLCLC14c_B North, South and mainstem of Dry Fork including tributaries. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L Listed portion: COLCLC14c_C Roan Creek and tributaries including Conn Cr, Logan Wash, Bloat Gulch and Gibler Gulch. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List H COLCLC15a 15a. Mainstem of Plateau Creek from its source to the inlet of Vega Reservoir. All tributaries and wetlands to Plateau Creek from its source to a point immediately above the confluence with Buzzard Creek. Kimball Creek, Grove Creek, Big Creek, Cottonwood Creek, Bull Creek, Spring Creek, Coon Creek, and Mesa Creek, including all tributaries and wetlands, from their sources to their confluences with Plateau Creek. The mainstem of Buzzard Creek, including all tributaries and wetlands, within the Grand Mesa National Forest. Listed portion: COLCLC15a_A Mainstem of Plateau Creek from its source to the inlet of Vega Reservoir. All tributaries and wetlands to Plateau Creek from its source to a point immediately above the confluence with Buzzard Creek. Kimball Creek, Grove Creek, Big Creek, Cottonwood Creek, Bull Creek, Spring Creek, Coon Creek, and Mesa Creek, including all wetlands and tributaries, from their sources to their confluences with Plateau Creek. The mainstem of Buzzard Creek, including all tributaries and wetlands, within the Grand Mesa National Forest. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCLC15c 15c. Mainstem of Plateau Creek from the outlet of Vega Reservoir to a point immediately below the confluence with Buzzard Creek.

Listed portion: COLCLC15c_A Mainstem of Plateau Creek from the outlet of Vega Reservoir to a point immediately below the confluence with Buzzard Creek.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCLC15d 15d. Mainstem of Buzzard Creek from the Grand Mesa National Forest boundary to its confluence with Plateau Creek.

Listed portion: COLCLC15d_A Mainstem of Buzzard Creek from the Grand Mesa National Forest boundary to its confluence with Plateau Creek.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCLC16 16. Plateau Creek including all tributaries and wetlands, from a point immediately below the confluence with Buzzard Creek, to the confluence with the Colorado River, excluding listings in segments 5, 15a and 21. Listed portion: COLCLC16_A Plateau Creek including all tributaries and wetlands, from a point immediately below the confluence with Buzzard Creek, to the confluence with the Colorado River, excluding specific listings in segment 5, 15a, and 21.

   Aquatic Life Use Iron (Total) 3b. - M&E List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCLC17a 17a. Rapid Creek, including all tributaries and wetlands, from its source to below the confluence with Cottonwood Creek (39.130512, -108.301028), including Kruzen Springs. Listed portion: COLCLC17a_A Rapid Creek, including all tributaries and wetlands, from its source to below the confluence with Cottonwood Creek (39.130512, -108.301028) including Kruzen Springs. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCLC19 19. All lakes and reservoirs tributary to the Colorado River from a point immediately below the confluence of the Colorado River and Parachute Creek to the Colorado-Utah border, except for listings in segments 9b, 13c, 20, and 21. This segment includes Highline Reservoir.

Listed portion: COLCLC19_E West Lake in James M. Robb Colorado River State Park. Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H COLCLC20 20. Rifle Gap Reservoir, Harvey Gap Reservoir, and Vega Reservoir. Listed portion: COLCLC20_B Rifle Gap Reservoir.

1. Aquatic Life Use Fish (Mercury) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COLCLC20_C Harvey Gap Reservoir.

   Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COLCLC20_D Vega Reservoir.

   Water Supply Use Arsenic (Total) 5. - 303(d) List H COLCLY02 2. Mainstem of the Yampa River from a point immediately below the confluence with Elkhead Creek to the confluence with the Green River.

Listed portion: COLCLY02_C Mainstem of the Yampa River from a point immediately below the confluence with Little Snake River to the confluence with the Green River.

1. Aquatic Life Use Temperature 5. - 303(d) List H COLCLY03c 3c. Mainstem of Milk Creek, including all tributaries and wetlands, from Thornburgh (County Rd 15) to the confluence with the Yampa River, except for listings in Segment 3b and 3e. Listed portion: COLCLY03c_B Wilson Creek and tributaries. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List L Water Supply Use Sulfate 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COLCLY03c_C Stinking Gulch and tributaries. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Sulfate 5. - 303(d) List L COLCLY03e 3e. Mainstem of Good Spring Creek, including all tributaries and wetlands, above Wilson Reservoir. Listed portion: COLCLY03e_B Mainstem of Good Spring Creek, including all tributaries and wetlands, above Wilson Reservoir.

   Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List M COLCLY03i 3i. Lower Johnson Gulch from the confluence with Pyeatt Gulch at CO 107 to the confluence with the Yampa River.

Listed portion: COLCLY03i_A Lower Johnson Gulch from the confluence with Pyeatt Gulch at CO 107 to the confluence with the Yampa River.

1. Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A COLCLY05 5. Mainstem of Fortification Creek from the confluence of the North Fork and South Fork to the confluence with the Yampa River.

Listed portion: COLCLY05_A Mainstem of Fortification Creek from the confluence of the North Fork and South Fork to the confluence with the Yampa River.

1. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H COLCLY06 6. All tributaries to Fortification Creek, including all wetlands, from the confluence of the North and South Forks to the confluence with the Yampa River, except for listings in Segments 4 and 7. Listed portion: COLCLY06_A All tributaries to Fortification Creek, including all wetlands, from the confluence of the North and South Forks to the confluence with the Yampa River, except for listings in Segments 4 and 7.

   Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A COLCLY12a 12a. Mainstem of the South Fork of the Williams Fork River and Beaver Creek, including all tributaries and wetlands, from the boundary of Routt National Forest to their mouths. Milk Creek, including all tributaries and wetlands, from the source to a point just below the confluence with Clear Creek. Morapos Creek, including all tributaries and wetlands, from the source to the confluence with the Williams Fork River. Listed portion: COLCLY12a_B Mainstem of the South Fork of the Williams Fork River and Beaver Creek, including all tributaries and wetlands, from the boundary of Routt National Forest to their mouths. Milk Creek, including all tributaries and wetlands, from the source to a point just below the confluence with Clear Creek.

   Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H Listed portion: COLCLY12a_C Morapos Creek, including all wetlands and tributaries, from the source to the confluence with the Williams Fork River.

   Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H COLCLY16 16. Mainstem of the Little Snake River from a point immediately above the confluence with Powder Wash to the confluence with the Yampa River.

Listed portion: COLCLY16_A Mainstem of the Little Snake River from a point immediately above the confluence with Powder Wash to the confluence with the Yampa River.

1. Aquatic Life Use Sediment 3b. - M&E List N/A COLCLY22c 22c. Mainstem of Vermillion Creek from HWY 318 to the confluence with the Green River. Listed portion: COLCLY22c_A Mainstem of Vermillion Creek from HWY 318 to the confluence with the Green River. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A COLCWH03 3. Mainstem of the North Fork of the White River and mainstem of the White River from the Flat Tops Wilderness Area boundary to a point immediately above the confluence with Miller Creek. Listed portion: COLCWH03_A Mainstem of the North Fork of the White River and mainstem of the White River from the Flat Tops Wilderness Area boundary to a point immediately above the confluence with Miller Creek.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A COLCWH04a 4a. All tributaries to the North Fork White River, including all wetlands, from the Flat Tops Wilderness Area boundary to the confluence with the South Fork White River, except for listings in Segment 1 and 4b. Listed portion: COLCWH04a_A All tributaries to the North Fork White River, including all wetlands, from the Flat Tops Wilderness Area boundary to the confluence with the South Fork White River except for listings in Segment 1 and 4b.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCWH04b 4b. Lost Creek, including tributaries and wetlands, from the source to the confluence with the North Fork White River. Snell Creek, including all tributaries and wetlands, from the source to the confluence with the North Fork White River.

Listed portion: COLCWH04b_B Lost Creek, including tributaries and wetlands, from the source to the confluence with the North Fork White River. Snell Creek, including all wetlands and tributaries, from the source to the confluence with the North Fork White River.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COLCWH07 7. Mainstem of the White River from a point immediately above the confluence with Miller Creek to a point immediately above the confluence with Piceance Creek.

Listed portion: COLCWH07_B White River below Meeker to the confluence with Piceance Creek. Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCWH09b 9b. All tributaries to the White River, including wetlands, from a point immediately above the confluence with Flag Creek, to a point immediately above the confluence with Piceance Creek, which are not within the boundary of National Forest lands, except for listings in segments 9c and 9d. Listed portion: COLCWH09b_A Tributaries to the White River from above the confluence with Flag Creek, to above the confluence with Piceance Creek, which are not within the boundary of National Forest lands, except for listings in segment 9c and 9d.

1. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A COLCWH09d 9d. Sulphur Creek, including all tributaries and wetlands, from the source to the confluence with the White River. Flag Creek, including all tributaries and wetlands, from a point just below the confluence with the East Fork of Flag Creek to the confluence with the White River. Listed portion: COLCWH09d_A Sulphur Creek, including all tributaries and wetlands, from the source to the confluence with the White River. Flag Creek, including all tributaries and wetlands, from a point just below the confluence with the East Fork of Flag Creek to the confluence with the White River.

   Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L COLCWH11 11. Rio Blanco Lake and Taylor Draw Reservoir (a.k.a. Kenney Reservoir). Listed portion: COLCWH11_A Taylor Draw Reservoir (a.k.a. Kenney Reservoir). Aquatic Life Use Fish (Mercury) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COLCWH11_B Rio Blanco Lake.

   Aquatic Life Use pH 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H COLCWH12 12. Mainstem of the White River from a point immediately above the confluence with Piceance Creek to a point immediately above the confluence with Douglas Creek. Listed portion: COLCWH12_A Mainstem of the White River from a point immediately above the confluence with Piceance Creek to a point immediately above the confluence with Douglas Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCWH13b 13b. Mainstem of Yellow Creek including all wetlands from the source to immediately below the confluence with Barcus Creek. All tributaries to Yellow Creek from the source to the White River, including wetlands. Listed portion: COLCWH13b_A Yellow Creek from source to below the confluence with Barcus Creek. Tributaries to Yellow Creek from the source to the White River, except for Corral Gulch and tributaries, Stake Springs Draw and tributaries above Stake Springs and Duck Creek and tributaries. Aquatic Life Use Sediment 5. - 303(d) List M Aquatic Life Use Macroinvertebrates 5. - 303(d) List M Listed portion: COLCWH13b_B Corral Gulch and tributaries. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Sediment 5. - 303(d) List M Listed portion: COLCWH13b_C Stake Springs Draw and tributaries above Stake Springs. Water Supply Use Sulfate 3b. - M&E List N/A Aquatic Life Use Sediment 5. - 303(d) List M Listed portion: COLCWH13b_D Duck Creek and tributaries. Aquatic Life Use Macroinvertebrates 3b. - M&E List N/A Aquatic Life Use Sediment 5. - 303(d) List M COLCWH13c 13c. Mainstem of Yellow Creek, including all wetlands from immediately below the confluence with Barcus Creek to the confluence with the White River.

Listed portion: COLCWH13c_A Yellow Creek from immediately below the confluence with Barcus Creek to the confluence with Greasewood Creek.

1. Aquatic Life Use Macroinvertebrates 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List L Listed portion: COLCWH13c_B Yellow Creek below Greasewood Creek to the confluence with the White River. Aquatic Life Use Macroinvertebrates 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List M COLCWH14a 14a. Mainstem of Piceance Creek from the source to a point just below the confluence with Hunter Creek. Listed portion: COLCWH14a_A Piceance Creek from the source to below confluence with Willow Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COLCWH14a_B Piceance Creek from Willow Creek to Hunter Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List H COLCWH15 15. Mainstem of Piceance Creek from a point just below the confluence with Ryan Gulch to the confluence with the White River. The Dry Fork of Piceance Creek, including all tributaries and wetlands, from a point just below the confluence with Little Reigan Gulch to the confluence with Piceance Creek, except for listings in Segment 18.

Listed portion: COLCWH15_B Mainstem of Piceance Creek.

1. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Listed portion: COLCWH15_C Piceance Creek from 3 miles above the confluence with White River, to the confluence with White River.

   Aquatic Life Use Macroinvertebrates 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List M COLCWH16b 16b. All tributaries to Piceance Creek, including all wetlands, from a point immediately below the confluence with Dry Thirteenmile Creek to the confluence with the White River, except for listings in Segments 15, 17, 18a, 18b, 19 and 20.

Listed portion: COLCWH16b_B Ryan Gulch and tributaries. Recreational Use E. coli 3b. - M&E List N/A COLCWH20 20. Mainstem of Black Sulphur Creek, including all tributaries and wetlands, from the source to the confluence with Piceance Creek, except for the listing in Segment 19. Listed portion: COLCWH20_B Mainstem of Black Sulphur Creek from source to Piceance Creek. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COLCWH20_C All Tributaries of Black Sulphur Creek from source to Piceance Creek, except for the listing in Segment 19.

1. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCWH21 21. Mainstem of the White River from a point immediately above the confluence with Douglas Creek to the Colorado/Utah border.

Listed portion: COLCWH21_A Mainstem of the White River from a point immediately above the confluence with Douglas Creek to the Colorado/Utah border.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L COLCWH22 22. All tributaries to the White River, including all wetlands, from a point immediately above the confluence with Douglas Creek to the Colorado/Utah border, except for specific listings in Segment 23. Listed portion: COLCWH22_B West Evacuation Wash with tributaries and Douglas Creek. Aquatic Life Use Sediment 5. - 303(d) List L COLCWH23 23. Mainstems of East Douglas Creek and West Douglas Creek, including all tributaries and wetlands, from their sources to their confluence.

Listed portion: COLCWH23_A West Douglas Creek from its source to confluence. Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COLCWH23_B East Douglas creek from the point below Tommy's Draw a point above its confluence with Douglas Creek.

1. Aquatic Life Use Temperature 5. - 303(d) List H Aquatic Life Use Sediment 5. - 303(d) List H Listed portion: COLCWH23_C Mainstem of East Douglas Creek and tributaries from the source to a point below Tommy's Draw.

   Aquatic Life Use Temperature 5. - 303(d) List H COLCWH24 24. All lakes and reservoirs tributary to the White River, which are within the boundaries of the Flat Tops Wilderness Area, including Trappers Lake.

Listed portion: COLCWH24_C Ned Wilson Lake.

1. Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H COLCWH25 25. Lake Avery (a.k.a Big Beaver Reservoir).

Listed portion: COLCWH25_A Lake Avery (a.k.a Big Beaver Reservoir). Water Supply Use Arsenic (Total) 5. - 303(d) List H CORGAL02 2. Mainstem of the Alamosa River, including all tributaries and wetlands, from the source to immediately above the confluence with Alum Creek, except for specific listings in segments 1, 4a, and 4b. Tributaries to the Alamosa River, including wetlands, from a point immediately below the confluence of Bitter Creek to the inlet of Terrace Reservoir, except for waterbodies in segments 4a, 5, 6, and 7. Listed portion: CORGAL02_B Mainstem of the Alamosa River. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: CORGAL02_C All tributaries and wetlands of the Alamosa River, from the source to immediately above the confluence with Alum Creek, except for tributaries to lower Iron Creek and specific listings in segments 1, 4a, and 4b.

1. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: CORGAL02_D Tributaries to the Alamosa River from a point immediately below the confluence of Bitter Creek to the inlet of Terrace Reservoir, except for specific listings in segments 4a, 5, 6, and 7.

   Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use pH 5. - 303(d) List H CORGAL03a 3a. Mainstem of the Alamosa River from immediately above the confluence with Alum Creek to immediately above the confluence of Wightman Fork.

Listed portion: CORGAL03a_A Mainstem of the Alamosa River from immediately above the confluence with Alum Creek to immediately above the confluence of Wightman Fork.

1. Aquatic Life Use Aluminum (Total) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M CORGAL03b 3b. Mainstem of the Alamosa River from immediately above the confluence with Wightman Fork to immediately above the confluence with Fern Creek.

Listed portion: CORGAL03b_A Mainstem of the Alamosa River from immediately above the confluence with Jasper Creek to immediately above the confluence with Fern Creek.

1. Aquatic Life Use Aluminum (Total) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 4a. - TMDL N/A Listed portion: CORGAL03b_B Mainstem of the Alamosa River from immediately above the confluence with the Wightman Fork to Jasper Creek.

   Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Aluminum (Total) 4a. - TMDL N/A Aquatic Life Use pH 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A CORGAL03c 3c. Mainstem of the Alamosa River from immediately above the confluence with Fern Creek to immediately below the confluence with Ranger Creek.

Listed portion: CORGAL03c_A Mainstem of the Alamosa River from immediately above the confluence with Fern Creek to immediately below the confluence with Ranger Creek.

1. Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Aluminum (Total) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 4a. - TMDL N/A CORGAL03d 3d. Mainstem of the Alamosa River from immediately below the confluence with Ranger Creek to the inlet of Terrace Reservoir.

Listed portion: CORGAL03d_A Mainstem of the Alamosa River from immediately below the confluence with Ranger Creek to the inlet of Terrace Reservoir.

1. Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 4a. - TMDL N/A Aquatic Life Use Aluminum (Total) 5. - 303(d) List H CORGAL05 5. Mainstem of Wightman Fork, including all tributaries and wetlands, from the source to the west line of S30, T37N, R4E (37.43127, -106.60325).

Listed portion: CORGAL05_A Mainstem of Wightman Fork from the source to the west line of S30, T37N, R4E, including all tributaries and wetlands.

1. Aquatic Life Use pH 4a. - TMDL N/A CORGAL07 7. Jasper Creek, including all tributaries and wetlands, from the source to the confluence with the Alamosa River.

Listed portion: CORGAL07_A Jasper Creek, including all tributaries and wetlands, from the source to the confluence with the Alamosa River.

1. Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Nickel (Total) 3b. - M&E List N/A CORGAL08 8. Terrace Reservoir.

Listed portion: CORGAL08_A Terrace Reservoir.

1. Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Total) 4a. - TMDL N/A CORGAL09 9. Mainstem of the Alamosa River from the outlet of Terrace Reservoir to Hwy 15 (Gunbarrel Road). Listed portion: CORGAL09_A Mainstem of Alamosa River from the outlet of Terrace Reservoir to Hwy 15 (Gunbarrel Road). Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A CORGAL10 10. Mainstem of the Alamosa River from Hwy 15 (Gunbarrel Road) to its point of final diversion (37.398484, -105.838986).

Listed portion: CORGAL10_A Mainstem of the Alamosa River from Hwy 15 (Gunbarrel Road) to its point of final diversion. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List M CORGAL11b 11b. Mainstem of La Jara Creek from the outlet of La Jara Reservoir to a point immediately above the confluence with Hot Creek. All tributaries and wetlands to La Jara Creek from a point immediately below the confluence with Jarosa Creek to a point immediately above the confluence with Hot Creek. Listed portion: CORGAL11b_A Mainstem of La Jara Creek from the outlet of La Jara Reservoir to a point immediately above the confluence with Hot Creek. All tributaries, including wetlands, to La Jara Creek from a point immediately below the confluence with Jarosa Creek to a point immediately above the confluence with Hot Creek.

1. Aquatic Life Use Temperature 5. - 303(d) List H CORGAL12 12. Mainstem of La Jara Creek from immediately above the confluence with Hot Creek to the confluence with the Rio Grande.

Listed portion: CORGAL12_A Mainstem of La Jara Creek from immediately above the confluence with Hot Creek to the confluence with the Rio Grande.

1. Aquatic Life Use Iron (Total) 3b. - M&E List N/A CORGAL13 13. Mainstem of Hot Creek from the source to the confluence with La Jara Creek. Listed portion: CORGAL13_A Mainstem of Hot Creek from the source to the confluence with La Jara Creek. Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List H CORGAL14a 14a. Mainstem of the Conejos River, including all tributaries and wetlands, from the source to immediately below the confluence with Elk Creek, excluding the specific listings in segment 1. Listed portion: CORGAL14a_B La Manga Creek and its tributaries. Water Supply Use Arsenic (Total) 5. - 303(d) List H CORGAL25 25. All lakes and reservoirs tributary to La Jara Creek from the source to a point immediately above the confluence with Hot Creek.

Listed portion: CORGAL25_B La Jara Reservoir.

1. Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H CORGAL30 30. Platoro Reservoir.

Listed portion: CORGAL30_A Platoro Reservoir.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A CORGCB02a 2a. Mainstem of La Garita Creek, including all tributaries and wetlands, from the source to a point immediately below the confluence with Geronimo Creek. The North, Middle, and South Forks of Carnero Creek, including all tributaries and wetlands, from their sources to their confluences at the inception of the mainstem of Carnero Creek.

Listed portion: CORGCB02a_B North Fork of Carnero Creek, including all tributaries and wetlands. Aquatic Life Use Total Phosphorus 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: CORGCB02a_C South Fork of Carnero Creek, including all tributaries and wetlands. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H CORGCB02b 2b. Mainstem of La Garita Creek, including all tributaries and wetlands, from a point immediately below the confluence with Geronimo Creek to 38 Road. All tributaries, including wetlands, to the mainstem of Carnero Creek from its inception at the confluence of the North, Middle, and South Forks to 42 Road, excluding the waterbodies in Segment 2a.

Listed portion: CORGCB02b_B Mainstem of La Garita Creek, including all tributaries and wetlands, from a point immediately below the confluence with Geronimo Creek to 38 Road. Aquatic Life Use Iron (Total) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H CORGCB02c 2c. Mainstem of Carnero Creek from its inception at the confluence of the North, Middle, and South Forks to 42 Road.

Listed portion: CORGCB02c_A Mainstem of Carnero Creek from its inception at the confluence of the North, Middle, and South Forks to 42 Road.

1. Aquatic Life Use Total Phosphorus 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H CORGCB03 3. All tributaries to the Closed Basin excluding the listings in segments 1, 2a, 2b, 2c, and 4 through 13. Listed portion: CORGCB03_B Cottonwood Creek, including all tributaries and wetlands. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Listed portion: CORGCB03_C Major Creek, including all tributaries and wetlands. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Listed portion: CORGCB03_D Willow Creek, including all tributaries and wetlands. Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H CORGCB04 4. Mainstem of San Luis Creek, including all tributaries and wetlands, from the source to a point immediately below the confluence with Piney Creek, excluding the specific listings in segments 8, 9a, and 9b. Garner Creek, including all tributaries and wetlands, from the Rio Grande Forest Boundary to the mouth. Listed portion: CORGCB04_A Mainstem of San Luis Creek, including all tributaries and wetlands, from the source to a point immediately below the confluence with Piney Creek, excluding the specific listings in segments 8, 9a and 9b. Garner Creek, including all tributaries and wetlands, from the Rio Grande Forest Boundary to the mouth.

   Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L CORGCB05 5. Mainstem of San Luis Creek from a point immediately below the confluence with Piney Creek to the inlet to San Luis Lake.

Listed portion: CORGCB05_A Mainstem of San Luis Creek from a point immediately below the confluence with Piney Creek to the inlet to San Luis Lake.

1. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A CORGCB09a 9a. Mainstem of Kerber Creek, including all tributaries and wetlands, from a point immediately above the Cocomongo Mill site to immediately above the confluence of Brewery Creek, excluding the specific listings in segment 8.

Listed portion: CORGCB09a_A Mainstem, tributaries and wetlands of Kerber Creek, including all tributaries and wetlands,from the source to immediately above the confluence of Brewery Creek, except for Squirrel Creek and excluding the specific listings in segment 8. Water Supply Use Silver (Total) 4a. - TMDL N/A Water Supply Use Cadmium (Total) 4a. - TMDL N/A Water Supply Use Lead (Total) 4a. - TMDL N/A Water Supply Use pH 4a. - TMDL N/A Listed portion: CORGCB09a_B Squirrel Creek from a point immediately below the confluence with Bear Creek to the confluence with Kerber Creek.

1. Water Supply Use Silver (Total) 4a. - TMDL N/A Water Supply Use Lead (Total) 4a. - TMDL N/A Water Supply Use Cadmium (Total) 4a. - TMDL N/A Water Supply Use pH 4a. - TMDL N/A CORGCB09b 9b. Mainstem of Kerber Creek from a point immediately above the confluence with Brewery Creek to the confluence with San Luis Creek.

Listed portion: CORGCB09b_A Mainstem of Kerber Creek from a point immediately above the confluence with Brewery Creek to the confluence with U S Gulch.

1. Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: CORGCB09b_B Mainstem of Kerber Creek from a point immediately above the confluence with U S Gulch to the confluence with San Luis Creek.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L CORGCB10 10. Mainstem of Sand Creek, including all tributaries and wetlands, from the source to the mouth. Mainstem of Medano Creek, including all tributaries and wetlands, from the source to the mouth. Listed portion: CORGCB10_B Mainstem of Sand Creek, including all tributaries and wetlands, from the source to the mouth.

   Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 3b. - M&E List N/A CORGCB12a 12a. Mainstem of Saguache Creek, including all tributaries and wetlands, from the boundary of the La Garita Wilderness Area to a point just below the confluence with Ford Creek, excluding the specific listings in segments 1 and 12b.

Listed portion: CORGCB12a_B East Pass Creek, including all tributaries and wetlands. Aquatic Life Use Sediment 5. - 303(d) List H Listed portion: CORGCB12a_C Ford Creek, including all tributaries and wetlands. Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Listed portion: CORGCB12a_F Mainstem of Saguache Creek from the boundary of the La Garita Wilderness Area to a point just below the confluence with Ford Creek, excluding the specific listings in segment 12b. Aquatic Life Use Temperature 3b. - M&E List N/A Aquatic Life Use Total Phosphorus 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List L CORGCB12b 12b. Mainstem of Saguache Creek from a point just below the confluence of Fourmile Creek to a point just below the confluence with Ford Creek.

Listed portion: CORGCB12b_B Mainstem of Saguache Creek from a point just below the confluence of Fourmile Creek to a point just below the confluence with Ford Creek.

1. Aquatic Life Use Total Phosphorus 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List L CORGCB12c 12c. Mainstem of Saguache Creek, including all tributaries and wetlands, from a point just below the confluence with Ford Creek to Hwy 285.

Listed portion: CORGCB12c_A Mainstem of Saguache Creek, including all tributaries and wetlands, from a point just below the confluence with Ford Creek to Hwy 285.

1. Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A CORGCB13 13. Mainstem of Saguache Creek from Hwy 285 to the confluence with San Luis Creek. Mainstem of Russell Creek from its source at Russell Springs to the confluence with La Garita Creek. Mainstem of Cottonwood Creek downstream of the Rio Grande National Forest Boundary. Listed portion: CORGCB13_A Mainstem of Saguache Creek from Hwy 285 to the confluence with San Luis Creek. Mainstem of Russel Creek. Mainstem of Cottonwood Creek downstream of the Rio Grande National Forest Boundary.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A CORGCB19 19. San Luis Lake.

Listed portion: CORGCB19_A San Luis Lake.

1. Aquatic Life Use Iron (Total) 5. - 303(d) List H Aquatic Life Use Ammonia 5. - 303(d) List H CORGRG02 2. Mainstem of the Rio Grande, including all tributaries and wetlands, from the source to a point immediately above the confluence with Willow Creek, excluding the listings in segments 1 and 3. Listed portion: CORGRG02_B South Clear Creek and its tributaries. Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List H Water Supply Use Iron (Dissolved) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: CORGRG02_D Mainstem of Seepage Creek from the outlet of Santa Maria Reservoir to a point one mile below the outlet of Santa Maria Reservoir.

   Aquatic Life Use Iron (Total) 3b. - M&E List N/A Listed portion: CORGRG02_E Mainstem and tributaries of the Rio Grande from the source to Rio Grande Reservoir. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: CORGRG02_F Mainstem of the Rio Grande from the outlet of Rio Grande Reservoir to the confluence of Squaw Creek.

   Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Listed portion: CORGRG02_G Mainstem and Tributaries of the Rio Grand from Squaw Creek to Willow Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List H CORGRG03 3. Mainstem of North Clear Creek from the outlet of Continental Reservoir to a point immediately above the confluence with Rito Hondo Creek.

Listed portion: CORGRG03_B Mainstem of North Clear Creek from the outlet of Continental Reservoir to a point immediately above the confluence with Rito Hondo Creek. Aquatic Life Use Iron (Total) 3b. - M&E List N/A CORGRG04a 4a. Mainstem of the Rio Grande from a point immediately above the confluence with Willow Creek to a point immediately above the confluence with the South Fork Rio Grande. Listed portion: CORGRG04a_B Mainstem of the Rio Grande from a point immediately above the confluence with Willow Creek to Blue Creek at Wagon Wheel Gap.

1. Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: CORGRG04a_C Mainstem of the Rio Grande from a point immediately below the confluence with Blue Creek at Wagon Wheel Gap to a point immediately above the confluence with the South Fork Rio Grande.

   Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H CORGRG04b 4b. Mainstem of the Rio Grande from a point immediately above the confluence with South Fork Rio Grande to the Hwy 285 crossing.

Listed portion: CORGRG04b_B Mainstem of the Rio Grande from Del Norte to the Hwy 285 crossing. Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: CORGRG04b_C Mainstem of the Rio Grande from a point immediately above the confluence with Pinos Creek to Del Norte.

1. Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: CORGRG04b_D Mainstem of the Rio Grande from the confluence of South Fork to a point immediately above the confluence with Pinos Creek.

   Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Macroinvertebrates 5. - 303(d) List H CORGRG04c 4c. Mainstem of the Rio Grande from the Hwy 285 crossing to the Rio Grande/Alamosa County line. Listed portion: CORGRG04c_A Mainstem of the Rio Grande from the Hwy 285 crossing to the Rio Grande/Alamosa County line.

   Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H CORGRG05a 5a. All tributaries to the Rio Grande, including all wetlands, from immediately above the confluence with Willow Creek to the Hwy 112 bridge near Del Norte, excluding the listings in segments 5b through 10. Listed portion: CORGRG05a_A Nelson Creek.

   Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: CORGRG05a_B Embargo Creek, including all tributaries and wetlands, from the source to immediately above the confluence with Dyers Creek. West Alder Creek, including all tributaries and wetlands.

   Water Supply Use Arsenic (Total) 5. - 303(d) List H CORGRG05b 5b. Mainstem of Alder Creek. Mainstem of East Alder Creek, including all tributaries and wetlands, from the source to the confluence with Alder Creek. Mainstem of Agua Ramon Creek, including all tributaries and wetlands, from the source to the confluence with the Rio Grande. Mainstem of Embargo Creek, including all tributaries and wetlands, from immediately above the confluence with Dyers Creek to the confluence with the Rio Grande.

Listed portion: CORGRG05b_B Mainstem of Embargo Creek, including all tributaries and wetlands, from immediately above the confluence with Dyers Creek to the confluence with the Rio Grande. Water Supply Use Arsenic (Total) 5. - 303(d) List H CORGRG06 6. Mainstem of West Willow Creek from immediately above Deerhorn Creek to the Park Regent Mine dump (37.890445, -106.936868). East Willow Creek from the confluence with Whited Creek to the confluence with West Willow Creek.

Listed portion: CORGRG06_B East Willow Creek from the confluence with Whited Creek to the confluence with West Willow Creek.

1. Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A CORGRG07 7. Mainstem of West Willow Creek from the Park Regent Mine dump (37.890445, -106.936868) to the confluence with East Willow Creek. Mainstem of Willow Creek, including all tributaries and wetlands, from the confluence of East and West Willow Creeks to the confluence with the Rio Grande. Listed portion: CORGRG07_A Mainstem of West Willow Creek from the Park Regent Mine dump to the confluence with Nelson Creek. Mainstem of Willow Creek, including all tributaries from the confluence of East and West Willow Creeks, to the confluence with the Rio Grande. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Listed portion: CORGRG07_B West Willow Creek below Nelson Creek to East Willow Creek. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A CORGRG09a 9a. Mainstem of the South Fork Rio Grande, including all tributaries and wetlands, from the source to a point just below the confluence with Decker Creek, excluding the specific listings in segment 1. Mainstem of Beaver Creek, including all tributaries and wetlands, from the source to the inlet of Beaver Creek Reservoir. Listed portion: CORGRG09a_A North Branch of Pass Creek. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L CORGRG10 10. Mainstem of Pinos Creek, including all tributaries and wetlands, from the source to the confluence with the Rio Grande.

Listed portion: CORGRG10_A Mainstem of Pinos Creek, including all tributaries and wetlands, from the source to the confluence with the Rio Grande.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A CORGRG11 11. Mainstem of San Francisco Creek (Rio Grande County), including all tributaries and wetlands, from the source to the confluence with the Rio Grande.

Listed portion: CORGRG11_C Mainstem of San Francisco Creek (Rio Grande County), including all tributaries and wetlands, from the source to a point immediately below the confluence with Spring Branch. Water Supply Use Arsenic (Total) 5. - 303(d) List L CORGRG12 12. Mainstem of the Rio Grande from the Rio Grande/Alamosa County line to Conejos County Road G (37.07831, -105.75665).

Listed portion: CORGRG12_A Mainstem of the Rio Grande from the Rio Grande/Alamosa County line to the Old State Bridge east of Lobatos (Conejos County Road G).

1. Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L CORGRG13 13. Mainstem of the Rio Grande from Conejos County Road G (37.07831, -105.75665) to the Colorado/New Mexico border.

Listed portion: CORGRG13_A Mainstem of the Rio Grande from Old State Bridge east of Lobatos (Conejos County Road G) to the Colorado/New Mexico border.

1. Aquatic Life Use Sediment 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A CORGRG19 19. Mainstem of Rock Creek, including all tributaries and wetlands, from the source to the Monte Vista Canal (37.52773, -106.16826).

Listed portion: CORGRG19_A Mainstem of Rock Creek, including all tributaries and wetlands, from the source to the Monte Vista Canal.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L CORGRG20a 20a. Mainstem of Cat Creek, including all tributaries and wetlands, from the source to the Rio Grande National Forest boundary.

Listed portion: CORGRG20a_B Deer Creek and its tributaries. Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List H CORGRG23a 23a. Mainstem of Sangre de Cristo Creek, including all tributaries and wetlands, from the source to Hwy 159, excluding the specific listings in segment 23b.

Listed portion: CORGRG23a_C Placer Creek and its Tributaries. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Listed portion: CORGRG23a_E Blind Canyon, Black Canyon, Malo Vega Creek, Gomer Gulch, Sawmill Gulch, West Indian Creek, and their tributaries.

1. Aquatic Life Use Iron (Total) 3b. - M&E List N/A CORGRG23b 23b. Mainstem of Sangre de Cristo Creek from a point immediately below the confluence with Placer Creek to Hwy 159.

Listed portion: CORGRG23b_A Mainstem of Sangre de Cristo Creek from a point immediately below the confluence with Placer Creek to Hwy 159.

1. Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List H CORGRG25 25. Mainstem of Trinchera Creek, including all tributaries and wetlands, from the source to the inlet of Mountain Home Reservoir.

Listed portion: CORGRG25_A Mainstem of Trinchera Creek including all tributaries and wetlands, from the source to the inlet of Mountain Home Reservoir.

1. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A CORGRG26 26. Mainstem of Trinchera Creek from the outlet of Mountain Home Reservoir to the Rio Grande. Listed portion: CORGRG26_A Mainstem of Trinchera Creek from the outlet of Mountain Home Reservoir to the Rio Grande. Aquatic Life Use Iron (Total) 3b. - M&E List N/A CORGRG28 28. Mainstem of Rito Seco, including all tributaries and wetlands, from the source to the road crossing at 37.218809, -105.411762.

Listed portion: CORGRG28_B Mainstem of Rito Seco, including all tributaries and wetlands, from the Battle Mountain Gold Mine to Salazar Reservoir.

1. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Recreational Use E. coli 5. - 303(d) List H CORGRG33 33. All lakes and reservoirs tributary to the Rio Grande from the source to the Hwy 112 bridge near Del Norte, excluding the specific listings in segments 32 and 38. All lakes and reservoirs tributary to San Francisco Creek from the source to a point immediately below the confluence with Spring Branch. Listed portion: CORGRG33_B Alberta Park Reservoir.

   Aquatic Life Use Silver (Dissolved) 3b. - M&E List N/A CORGRG37 37. Sanchez Reservoir.

Listed portion: CORGRG37_A Sanchez Reservoir.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Fish (Mercury) 4a. - TMDL N/A CORGRG38 38. Continental Reservoir, Upper Brown Lake, Santa Maria Reservoir, Road Canyon Reservoir, Rio Grande Reservoir, Big Meadows Reservoir, Beaver Creek Reservoir, Smith Reservoir, Mountain Home Reservoir. Listed portion: CORGRG38_B Smith Reservoir.

   Aquatic Life Use pH 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Temperature 3b. - M&E List N/A Listed portion: CORGRG38_C Big Meadows Reservoir.

   Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: CORGRG38_D Road Canyon Reservoir.

   Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: CORGRG38_E Mountain Home Reservoir.

   Aquatic Life Use Dissolved Oxygen (Temperature) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: CORGRG38_G Continental Reservoir.

   Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H COSJAF02 2. Mainstem of the Animas River, including all tributaries and wetlands, from the outlet of Denver Lake to a point immediately above the confluence with Minnie Gulch, except for specific listings in Segment 6. Listed portion: COSJAF02_B Mainstem of the Animas River, including all tributaries and wetlands, from the outlet of Denver Lake to a point immediately above the confluence with Minnie Gulch, except for specific listings in Segment 6.

   Aquatic Life Use Aluminum (Total) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Dissolved) 4a. - TMDL N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A COSJAF03a 3a. Mainstem of the Animas River, including wetlands, from a point immediately below the confluence with Minnie Gulch to immediately above the confluence with Cement Creek. Listed portion: COSJAF03a_A Mainstem of the Animas River, including wetlands, from a point immediately below the confluence with Minnie Gulch to immediately above the confluence with Cement Creek. Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Listed portion: COSJAF03a_B Mainstem of the Animas River, including wetlands, From Minnie Gulch to Maggie Gulch. Aquatic Life Use Silver (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A COSJAF03b 3b. Mainstem of the Animas River, including wetlands, from a point immediately above the confluence with Cement Creek to a point immediately above the confluence with Mineral Creek. Listed portion: COSJAF03b_A Mainstem of the Animas River, including wetlands, from a point immediately above the confluence with Cement Creek to a point immediately above the confluence with Mineral Creek.

   Aquatic Life Use Aluminum (Total) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Dissolved) 4a. - TMDL N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A COSJAF03c 3c. Arrastra Gulch including all tributaries and wetlands from the source to the confluence with the Animas River.

Listed portion: COSJAF03c_A Arrastra Gulch including all tributaries and wetlands from the source to the confluence with the Animas River.

1. Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List M COSJAF04a 4a. Mainstem of the Animas River, including wetlands, from a point immediately above the confluence with Mineral Creek to a point immediately above the confluence with Deer Park Creek. Listed portion: COSJAF04a_A Mainstem of the Animas River, including wetlands, from a point immediately above the confluence with Mineral Creek to a point immediately above the confluence with Deer Park Creek.

   Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M Aquatic Life Use Aluminum (Total) 5. - 303(d) List M Aquatic Life Use Manganese (Dissolved) 5. - 303(d) List M COSJAF04b 4b. Mainstem of the Animas River, including wetlands, from a point immediately above the confluence with Deer Park Creek to Bakers Bridge (37.458620, -107.799194). Listed portion: COSJAF04b_A Mainstem of the Animas River, including wetlands, from a point immediately above the confluence with Deer Park Creek to Bakers Bridge.

   Aquatic Life Use Aluminum (Total) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COSJAF05a 5a. Mainstem of the Animas River, including wetlands, from Bakers Bridge (37.458620, -107.799194) to the Southern Ute Indian Reservation boundary.

Listed portion: COSJAF05a_B Mainstem of the Animas River, including wetlands, from Bakers Bridge to Junction Creek. Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Listed portion: COSJAF05a_C Mainstem of the Animas River, including wetlands, from Junction Creek to the Southern Ute Indian Reservation boundary.

1. Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COSJAF06 6. All tributaries and wetlands to the Animas River from the source to the outlet of Denver Lake. Mainstem, including all tributaries and wetlands of Cinnamon Creek, Grouse Gulch, Picayne Gulch, and Minnie Gulch. All tributaries and wetlands to the Animas River from immediately above Maggie Gulch to a point immediately above Elk Creek, except for those listed under segments 3c, 7, 8a, 8b, 9, and 12c. South Mineral Creek and all other tributaries and wetlands to Mineral Creek, except for those specifically listed in segments 8a, 9, and 12c.

Listed portion: COSJAF06_D Mill Creek, Porphyry Gulch, and Big Horn Gulch. Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Aluminum (Total) 4a. - TMDL N/A COSJAF07 7. Mainstem of Cement Creek, including all tributaries, and wetlands, from the source to the confluence with the Animas River.

Listed portion: COSJAF07_A Mainstem of Cement Creek, including all tributaries, and wetlands, from the source to the confluence with the Animas River.

1. Aquatic Life Use Aluminum (Total) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Dissolved) 4a. - TMDL N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A COSJAF08a 8a. Mainstem of Mineral Creek, including all wetlands and tributaries on the east side (except for Big Horn Creek), from the source to a point immediately above the confluence with South Mineral Creek, except for the listing in segment 8b. Mainstem of the Middle Fork of Mineral Creek, including all tributaries and wetlands, from the source to the confluence with Mineral Creek, except for the unnamed tributary exiting Crystal Lake, from the outlet of Crystal Lake to the confluence with the Middle Fork of Mineral Creek. Listed portion: COSJAF08a_A Mainstem of Mineral Creek, including all wetlands, and tributaries on the east side (except for Big Horn Creek), from the source to a point immediately above the confluence with South Mineral Creek except for the listing in segment 8b. Aquatic Life Use Aluminum (Total) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Dissolved) 4a. - TMDL N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A Listed portion: COSJAF08a_B Mainstem of the Middle Fork of Mineral Creek, including all tributaries and wetlands, from the source to the confluence with Mineral Creek, except for the unnamed tributary exiting Crystal Lake, from the outlet of Crystal Lake to the confluence with the Middle Fork of Mineral Creek.

   Aquatic Life Use Aluminum (Total) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Dissolved) 4a. - TMDL N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A COSJAF08b 8b. Mainstem of Mineral Creek from a point immediately below the confluence with Mill Creek to a point immediately above the confluence with the Middle Fork of Mineral Creek. Listed portion: COSJAF08b_A Mainstem of Mineral Creek from a point immediately below the confluence with Mill Creek to a point immediately above the confluence with the Middle Fork of Mineral Creek. Aquatic Life Use Aluminum (Total) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Dissolved) 4a. - TMDL N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A COSJAF09 9. Mainstem of Mineral Creek, including wetlands, from immediately above the confluence with South Mineral Creek to the confluence with the Animas River.

Listed portion: COSJAF09_A Mainstem of Mineral Creek, including wetlands, from immediately above the confluence with South Mineral Creek to the confluence with the Animas River. Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Total) 4a. - TMDL N/A Water Supply Use Iron (Dissolved) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Aluminum (Total) 5. - 303(d) List M COSJAF10a 10a. Mainstem of the Florida River from the boundary of the Weminuche Wilderness Area to the inlet of Lemon Reservoir.

Listed portion: COSJAF10a_A Mainstem of the Florida River from the boundary of the Weminuche Wilderness Area to the inlet of Lemon Reservoir.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COSJAF13a 13a. Mainstem of Junction Creek, including tributaries and wetlands, from the U.S. Forest Boundary to the confluence with Animas River.

Listed portion: COSJAF13a_B Junction Creek from US Forest Boundary to confluence with the Animas River. Aquatic Life Use Silver (Dissolved) 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A COSJAF14b 14b. Mainstem of Lightner Creek, including wetlands, from below the confluence with Deep Creek to the confluence with the Animas River.

Listed portion: COSJAF14b_B Mainstem of Lightner Creek, including wetlands, from below the confluence with Deep Creek to the confluence with the Animas River.

1. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H COSJAF22 22. Electra Lake. Lake Nighthorse.

Listed portion: COSJAF22_A Lake Nighthorse.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSJAF22_B Electra Lake.

   Aquatic Life Use Silver (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L COSJDO03 3. Mainstem of the Dolores River from a point immediately above the confluence with Horse Creek to a point immediately above the confluence with Bear Creek.

Listed portion: COSJDO03_A Mainstem of the Dolores River from a point immediately above the confluence with Horse Creek to a point immediately above the confluence with Bear Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List L COSJDO04a 4a. Mainstem of the Dolores River from a point immediately above the confluence with Bear Creek to the bridge at Bradfield Ranch (Forest Route 505, near Montezuma/Dolores County Line). Listed portion: COSJDO04a_B Mainstem of the Dolores River from a point immediately above the confluence with Bear Creek to McPhee Reservior.

1. Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H COSJDO04b 4b. McPhee Reservoir and Summit Reservoir.

Listed portion: COSJDO04b_A Summit Reservoir.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Iron (Dissolved) 5. - 303(d) List L Listed portion: COSJDO04b_B McPhee Reservoir Aquatic Life Use Fish (Mercury) 4a. - TMDL N/A COSJDO05a 5a. All tributaries to the Dolores River and West Dolores River, including all wetlands, from the source to a point immediately below the confluence with the West Dolores River except for specific listings in Segments 1 and 5b through 10.

Listed portion: COSJDO05a_B Fish Creek and its tributaries. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COSJDO05a_C Roaring Forks Creek and its tributaries. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A COSJDO09 9. Mainstem of Silver Creek, including wetlands, from a point immediately below the Town of Rico's water supply diversion to the confluence with the Dolores River. Listed portion: COSJDO09_B Mainstem of Silver Creek, including wetlands, from a point immediately below the Town of Rico's water supply diversion to the confluence with the Dolores River. Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A COSJDO10b 10b. Mainstem of the West Dolores River, including wetlands, from above the confluence with Fish Creek to the confluence with the Dolores River.

Listed portion: COSJDO10b_B Mainstem of the West Dolores River, including wetlands, from above the confluence with Fish Creek to the confluence with the Dolores River.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COSJDO11b 11b. All tributaries to the Dolores River, including all wetlands, from a point immediately below the confluence of the West Dolores River to the inlet of McPhee Reservoir, except for the specific listing in Segments 4a and 11a.

Listed portion: COSJDO11b_A All tributaries to the Dolores River, including all wetlands, from below West Dolores River to the inlet of McPhee Reservoir, except for 4a, 11a.

1. Recreational Use E. coli 3b. - M&E List N/A COSJLP01 1. Mainstem of the La Plata River, including all wetlands and tributaries from the source to the Hay Gulch diversion south of Hesperus.

Listed portion: COSJLP01_A Mainstem of the La Plata River, including all wetlands and tributaries from the source to the Hay Gulch diversion south of Hesperus.

1. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Silver (Dissolved) 5. - 303(d) List H COSJLP02a 2a. Mainstem of the La Plata River from the Hay Gulch diversion south of Hesperus to the boundary of Southern Ute Indian Reservation.

Listed portion: COSJLP02a_A Mainstem of the La Plata River from the Hay Gulch diversion south of Hesperus to the boundary of Southern Ute Indian Reservation.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COSJLP04a 4a. Mainstem of the Mancos River, including all wetlands and tributaries, from the source of the East, West and Middle Forks to the San Juan National Forest Boundary. Listed portion: COSJLP04a_A All Tributaries and wetlands to the mainstem of the Mancos River, from the source of West and Middle Forks to the San Juan, except for the East Mancos River and Box Canyon Creek. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COSJLP04a_D Box Canyon Creek.

   Aquatic Life Use Sediment 4a. - TMDL N/A Listed portion: COSJLP04a_E Mainstem of E. Mancos River. Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Water Supply Use Manganese (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Sulfate 5. - 303(d) List L Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H Aquatic Life Use Nickel (Dissolved) 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List H Water Supply Use Iron (Dissolved) 5. - 303(d) List L Agricultural Use Copper (Total) 5. - 303(d) List M Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSJLP04a_F Tributaries of E. Mancos River. Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Mercury (Total) 3b. - M&E List N/A Agricultural Use Copper (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Silver (Dissolved) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Water Supply Use Manganese (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H COSJLP04c 4c. Mainstem of the Mancos River, including tributaries and wetlands, from below the San Juan National Forest Boundary to Hwy 160. Chicken Creek, including tributaries and wetlands, from its source to the confluence with the Mancos River.

Listed portion: COSJLP04c_C Mainstem of the Mancos River the confluence of the East and West Forks to Hwy 160. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H Listed portion: COSJLP04c_D East Mancos River from the National Forest boundary to the confluence with Middle Mancos River.

1. Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COSJLP04c_H Chicken Creek, including all tributaries and wetlands, from its source to the confluence with the Mancos River.

   Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COSJLP05 5. Mainstem of the Mancos River from Hwy 160 to the boundary of the Ute Mountain Indian Reservation and mainstem of Weber Canyon, including wetlands, from source to boundary of the Ute Mountain Ute Indian Reservation.

Listed portion: COSJLP05_B Mainstem of the Mancos River from Hwy 160 to the boundary of the Ute Mountain Indian Reservation.

1. Water Supply Use Sulfate 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L COSJLP06a 6a. All tributaries to the Mancos River, including wetlands, from Hwy 160 to the boundary of the Ute Mountain Indian Reservation, except for specific listings in segment 4c, 5, 6b and 6c. Navajo Wash, including tributaries and wetlands, from the source to the Ute Mountain Indian Reservation Boundary. Listed portion: COSJLP06a_D All tributaries to the Mancos River, including all wetlands, from Hwy 160 to the boundary of the Ute Mountain Indian Reservation, except for portion 6a_C (Navajo Wash) and specific listings in segment 4c, 5a, 6b and 6c.

   Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Listed portion: COSJLP06a_E Navajo Wash, including tributaries and wetlands, from the source to the Ute Mountain Indian Reservation Boundary.

   Aquatic Life Use Iron (Total) 3b. - M&E List N/A Agricultural Use Selenium (Total) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L COSJLP07a 7a. Mainstem of McElmo Creek from the source to the confluence with Alkali Canyon. Mainstem of Yellow Jacket Creek, including tributaries and wetlands, from the source to the confluence with McElmo Creek. Listed portion: COSJLP07a_C Mainstem of McElmo Creek, from the source to Alkali Canyon. Aquatic Life Use Iron (Total) 5. - 303(d) List H Recreational Use E. coli 5. - 303(d) List H Aquatic Life Use Macroinvertebrates 5. - 303(d) List H COSJLP07b 7b. Mainstem of McElmo Creek from the confluence with Alkali Canyon to the Colorado/Utah border, except portion within the Ute Mountain Indian Reservation.

Listed portion: COSJLP07b_B Mainstem of McElmo Creek from Alkali Canyon to the Utah border except for portions within the Ute Mountain Ute boundry.

1. Aquatic Life Use Iron (Total) 5. - 303(d) List H COSJLP08 8. All tributaries to McElmo Creek, including wetlands, from the source to the Colorado/Utah border, except for the portions within the Ute Mountain Indian Reservation and except for specific listings in Segments 7a and 9.

Listed portion: COSJLP08_A All tributaries and wetlands to McElmo Creek, except Mud Creek, Hartman Draw, and Ritter Draw.

1. Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Sulfate 5. - 303(d) List L Listed portion: COSJLP08_B Mud Creek and all tributaries. Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Sulfate 5. - 303(d) List L Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M Listed portion: COSJLP08_C Hartman Draw and all tributaries. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Sulfate 5. - 303(d) List L Listed portion: COSJLP08_D Trail Canyon and its tributaries. Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List M Listed portion: COSJLP08_E Ritter Draw and its tributaries. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Sulfate 5. - 303(d) List L COSJLP09 9. Unnamed tributary to Ritter Draw (confluence at 37.4059, -108.5325), including wetlands. Listed portion: COSJLP09_C Unnamed tributary to Ritter Draw (confluence at 37.4059,-108.5325), and wetlands. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H COSJLP11 11. Narraguinnep, Puett and Totten Reservoirs. Listed portion: COSJLP11_A Puett Reservoir.

   Aquatic Life Use Fish (Mercury) 5. - 303(d) List H Listed portion: COSJLP11_B Narraguinnep Reservoir.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Fish (Mercury) 4a. - TMDL N/A Listed portion: COSJLP11_C Totten Reservoir.

   Aquatic Life Use Fish (Mercury) 5. - 303(d) List H COSJPI05a 5a. All tributaries to the Piedra River, including all wetlands, from the boundary of the Weminuche Wilderness Area to a point immediately below the confluence with the First Fork of the Piedra River. Devil Creek, including all tributaries and wetlands, from the source to a point below the confluence with Dunagan Canyon. Listed portion: COSJPI05a_B Williams Creek and its tributaries. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COSJPI05a_C All tributaries to the Piedra River, including all wetlands, from the boundary of the Weminuche Wilderness Area to the confluence with First Fork, Devil Creek including its tributaries and wetlands to Dunagan Creek, except for segments 2a, 3 and Williams Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List H COSJPI06a 6a. All tributaries to the Piedra River, including all wetlands, from a point immediately below the confluence with Devil Creek to Southern Ute Indian Reservation boundary, except the specific listing in Segment 6d. Listed portion: COSJPI06a_E Mainstem of Stollsteimer Creek from Martinez Creek to the confluence with Hall Canyon. Aquatic Life Use Sediment 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List M Listed portion: COSJPI06a_F Tributaries to Stollsteimer Creek to the confluence with Hall Canyon not on the the Southern Ute Reservation.

   Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L COSJPI08 8. Williams Creek Reservoir.

Listed portion: COSJPI08_A Williams Creek Reservoir.

1. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use pH 5. - 303(d) List H COSJPN02a 2a. Mainstem of the Los Pinos River from the boundary of the Weminuche Wilderness Area to the boundary of the Southern Ute Indian Reservation except for the specific listing in Segment 3. Listed portion: COSJPN02a_A Mainstem of the Los Pinos River from the boundary of the Weminuche Wilderness Area to the boundary of the Southern Ute Indian Reservation except for the specific listing in Segment 3.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A COSJPN03 3. Vallecito Reservoir.

Listed portion: COSJPN03_A Vallecito Reservoir.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Fish (Mercury) 5. - 303(d) List H Aquatic Life Use Dissolved Oxygen (Temperature) 5. - 303(d) List H COSJPN04 4. All tributaries to the Los Pinos River and Vallecito Reservoir, including all wetlands, from the boundary of the Weminuche Wilderness Area to a point immediately below the confluence with Bear Creek, except for the specific listing in Segment 5; mainstems of Beaver Creek, Ute Creek, and Spring Creek, including wetlands, from their sources to the boundary of the Southern Ute Indian Reservation. Listed portion: COSJPN04_B All tributaries to the Los Pinos River and Vallecito Reservoir, including all wetlands, from the boundary of the Weminuche Wilderness Area to a point immediately below the confluence with Bear Creek (T35N, R7W), except for the specific listing in Segment 5; mainstems of Beaver Creek, Ute Creek, and Spring Creek, including wetlands, from their sources to the boundary of the Southern Ute Indian Reservation.

   Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A COSJPN05 5. Mainstem of Vallecito Creek, including wetlands, from the boundary of the Weminuche Wilderness Area to Vallecito Reservoir.

Listed portion: COSJPN05_B Mainstem of Vallecito Creek, including wetlands, from the boundary of the Weminuche Wilderness Area to Vallecito Reservoir.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COSJSJ01b 1b. Mainstem of the Navajo River, including all wetlands and tributaries from below the confluence with Sheep Creek to the Colorado/New Mexico border, except for specific listings in Segment 3. Listed portion: COSJSJ01b_B Mainstem of the Navajo River. Recreational Use E. coli 3b. - M&E List N/A COSJSJ03 3. Mainstem of the Little Navajo River from the San Juan-Chama diversion to the confluence with the Navajo River; all tributaries to the Navajo River and the Little Navajo River, including all wetlands, from the San Juan-Chama diversions to the confluence with the San Juan River. Listed portion: COSJSJ03_A Mainstem of the Little Navajo River from the San Juan-Chama diversion to the confluence with the Navajo River; all tributaries to the Navajo River and the Little Navajo River, including all wetlands, from the San Juan-Chama diversions to the confluence with the San Juan River.

   Recreational Use E. coli 3b. - M&E List N/A COSJSJ06b 6b. Mainstem of the San Juan River from Highway 160 in Pagosa Springs to the Southern Ute Indian Reservation Northern boundary. Mainstem of Mill Creek, including wetlands, from the source to the confluence with the San Juan River.

Listed portion: COSJSJ06b_C Mainstem of the San Juan River from Hwy 160 to the Southern Ute Reservation Boundary. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COSJSJ06b_D Mainstem of Mill Creek, including wetlands, from the source to confluence with the San Juan River.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List H COSJSJ08 8. Navajo Reservoir. Echo Canyon Reservoir.

Listed portion: COSJSJ08_B Echo Canyon Reservoir.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Fish (Mercury) 5. - 303(d) List H Listed portion: COSJSJ08_C Navajo Reservoir.

   Aquatic Life Use Fish (Mercury) 5. - 303(d) List H COSJSJ09a 9a. Mainstem of the Rio Blanco, including all tributaries and wetlands, from a point immediately below the confluence with Leche Creek to the Southern Ute Indian Reservation boundary, except for specific listings in Segment 10.

Listed portion: COSJSJ09a_A Mainstem of the Rio Blanco, including all tributaries and wetlands, from a point immediately below the confluence with Leche Creek to the Southern Ute Indian Reservation boundary, except for specific listings in Segment 10.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List H COSJSJ10 10. Mainstem of the Rito Blanco River, including wetlands, from Echo Ditch to the confluence with the Rio Blanco River.

Listed portion: COSJSJ10_B Mainstem of the Rito Blanco River, including wetlands, from Echo Ditch to the confluence with the Rio Blanco River.

1. Aquatic Life Use Temperature 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A COSPBD01 1. Mainstem of Big Dry Creek, including all tributaries and wetlands, from the outlet of Standley Lake to the confluence with the South Platte River. Walnut Creek, including tributaries and wetlands, from the outlet of Great Western Reservoir to the confluence with Big Dry Creek. Listed portion: COSPBD01_A Mainstem of Big Dry Creek, including all tributaries and wetlands, from the oulet of Standley Lake to Weld County road 8. Walnut Creek, including tributaries and wetlands, from the outlet of Great Western Reservoir to the confluence with Big Dry Creek. Recreational Use E. coli 4a. - TMDL N/A Listed portion: COSPBD01_B Mainstem of Big Dry Creek from Weld County Road 8 to the confluence with the South Platte River.

   Recreational Use E. coli 4a. - TMDL N/A Aquatic Life Use Iron (Total) 5. - 303(d) List M COSPBD04a 4a. Mainstem and all tributaries to Woman and Walnut Creeks from sources to Standley Lake and Great Western Reservoir, respectively, except for listings in Segments 4b and 5a. Listed portion: COSPBD04a_A Mainstem and all tributaries to Woman and Walnut Creeks from sources to Standley Lake and Great Western Reservoir, respectively, except for specific listings in Segments 4b and 5. Aquatic Life Use Iron (Total) 5. - 303(d) List M COSPBD05a 5a. North Walnut Creek from the western edge of the Central Operable Unit and South Walnut Creek from its source, including all tributaries and wetlands, to the eastern boundary of the Central Operable Unit. Listed portion: COSPBD05a_A North Walnut Creek from the western edge of the Central Operable Unit and South Walnut Creek from its source, including all tributaries, and wetlands, to the eastern boundary of the Central Operable Unit.

   Water Supply Use NO2+NO3 5. - 303(d) List L COSPBE01a 1a. Mainstem of Bear Creek from the boundary of the Mt. Evans Wilderness area to the inlet of Evergreen Lake.

Listed portion: COSPBE01a_A Mainstem of Bear Creek from the boundary of the Mt. Evans Wilderness area to Yankee Creek.

1. Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COSPBE01a_B Bear Creek below Yankee Creek to the inlet of Evergreen Lake. Aquatic Life Use Temperature 5. - 303(d) List H COSPBE01b 1b. Mainstem of Bear Creek from Harriman Ditch to the inlet of Bear Creek Reservoir. Listed portion: COSPBE01b_A Mainstem of Bear Creek from Harriman Ditch to the inlet of Bear Creek Reservoir. Aquatic Life Use Temperature 5. - 303(d) List M COSPBE01c 1c. Bear Creek Reservoir.

Listed portion: COSPBE01c_A Bear Creek Reservoir.

1. Aquatic Life Use Chlorophyll-A 5. - 303(d) List H Aquatic Life Use Total Phosphorus 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H COSPBE01d 1d. Evergreen Lake.

Listed portion: COSPBE01d_A Evergreen Lake.

1. Water Supply Use Chlorophyll-A 5. - 303(d) List H Aquatic Life Use Temperature 5. - 303(d) List H COSPBE01e 1e. Mainstem of Bear Creek from the outlet of Evergreen Lake to the Harriman Ditch. Listed portion: COSPBE01e_A Mainstem of Bear Creek from Kerr/Swede Gulch to Mount Vernon Creek. Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COSPBE01e_B Bear creek from Mount Vernon Creek to the Harriman Ditch. Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COSPBE01e_C Bear Creek From the outlet of Evergreen Lake to Kerr/Swede Gulch. Aquatic Life Use Temperature 5. - 303(d) List H COSPBE02 2. Mainstem of Bear Creek from the outlet of Bear Creek Reservoir to the confluence with the South Platte River.

Listed portion: COSPBE02_B Bear Creek from Kipling Parkway to Wadsworth Boulevard. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPBE02_C Bear Creek from Wadsworth Boulevard to South Platte River. Recreational Use E. coli (May-October) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPBE02_D Bear Creek from the outlet of Bear Creek Reservior to Kipling Parkway. Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPBE03 3. All tributaries to Bear Creek, including all wetlands, from the source to the outlet of Evergreen Lake, except for listings in Segment 7.

Listed portion: COSPBE03_B Vance Creek and tributaries. Aquatic Life Use Temperature 5. - 303(d) List H COSPBE04 4. All tributaries to Bear Creek, including all wetlands, from the outlet of Evergreen Lake to the confluence with the South Platte River, except for specific listings in Segments 5, 6a, and 6b. Listed portion: COSPBE04_B Mt. Vernon Creek and all of its tributaries. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List M COSPBE06a 6a. Turkey Creek system, including all tributaries and wetlands, from the source to the inlet of Bear Creek Reservoir, except for listings in Segment 6b.

Listed portion: COSPBE06a_A Turkey Creek system, including all tributaries and wetlands, from Parmalee Gulch to the inlet of Bear Creek Reservoir, except for listings in Segment 6b. Aquatic Life Use Temperature 5. - 303(d) List M Listed portion: COSPBE06a_B Turkey Creek system, including all tributaries and wetlands, from the source to Parmalee Gulch, except for listings in Segment 6b.

1. Aquatic Life Use Temperature 5. - 303(d) List M COSPBE06b 6b. Mainstem of North Turkey Creek, from the source to the confluence with Turkey Creek. Listed portion: COSPBE06b_A Mainstem of North Turkey Creek, from the source to the confluence with Turkey Creek. Aquatic Life Use Temperature 5. - 303(d) List H COSPBE11 11. Lakes and reservoirs in the Bear Creek system from the outlet of Evergreen Lake to the confluence with the South Platte River, except for lakes and reservoirs in Segments 1c, 10, and 12; includes Soda Lakes. Listed portion: COSPBE11_B Harriman Reservoir.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COSPBE11_D Big Soda Lake Water Supply Use Arsenic (Total) 3b. - M&E List N/A COSPBO02a 2a. Mainstem of Boulder Creek, including all tributaries and wetlands, from the boundary of the Indian Peaks Wilderness Area to a point immediately below the confluence with North Boulder Creek, except for the specific listings in Segment 3.

Listed portion: COSPBO02a_A Mainstem of Middle Boulder Creek below 39.971 -105.4755, including all tributaries and wetlands, from the boundary of the Indian Peaks Wilderness Area to a point immediately below the confluence with North Boulder Creek, except for the specific listings in Segment 3.

1. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPBO02a_B North Boulder Creek from Caribou Creek to the confluence with Como Creek. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPBO02a_C North Boulder Creek to the confluence with Caribou Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H Listed portion: COSPBO02a_D Middle Boulder Creek from the outlet at Baker Reservoir to Longitude:-105.475577° Latitude: 39.971275°.

   Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPBO02a_E Mainstem of North Boulder Creek from Como Creek to the confluence of Middle Boulder Creek.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPBO02a_F Como Creek and its tributaries from source to North Boulder Creek. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L COSPBO02b 2b. Mainstem of Boulder Creek, including all tributaries and wetlands, from a point immediately below the confluence with North Boulder Creek to a point immediately above the confluence with South Boulder Creek. Listed portion: COSPBO02b_B Mainstem of Boulder Creek from 13th St. to immediately above the confluence with South Boulder Creek.

   Recreational Use E. coli 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Silver (Dissolved) 5. - 303(d) List H Listed portion: COSPBO02b_D Mainstem of Boulder Creek, including all tributaries and wetlands, from the City of Boulder boundary (40.013181, -105.301472) to a point immediately above 13th St (40.0143, -105.2779), except for Bear 0Canyon and Gregory Creeks. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Silver (Dissolved) 5. - 303(d) List H Listed portion: COSPBO02b_E Mainstem of Fourmile Creek, including all tributaries and wetlands, from the source to the confluence of Boulder Creek, except Gold Run Creek.

   Water Supply Use Sulfate 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPBO02b_F Gold Run Creek and its tributaries. Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Listed portion: COSPBO02b_G Mainstem of Boulder Creek, including all tributaries and wetlands, from a point immediately below the confluence with North Boulder Creek to a point immediately above the City of Boulder boundary (40.013181, -105.301472), including the entirety of Bear Canyon and Gregory creeks, and except for specific listings in Four Mile and Gold Run Creeks. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Silver (Dissolved) 5. - 303(d) List H COSPBO03 3. Mainstem of Middle Boulder Creek, including all tributaries and wetlands, from the source to the outlet of Barker Reservoir, except for specific listings in Segment 1. Listed portion: COSPBO03_A Tributaries and wetlands to Middle Boulder Creek, from the source to the outlet of Barker Reservoir, except for specific listings in Segment 1.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L Recreational Use E. coli 5. - 303(d) List H Listed portion: COSPBO03_B Mainstem of the Middle Boulder Creek, from the source to the outlet of Barker Reservoir, except for specific listings in Segment 1.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPBO04a 4a. Mainstem of South Boulder Creek, including all tributaries and wetlands, from the source to the outlet of Gross Reservoir except for specific listings in Segment 1. Listed portion: COSPBO04a_A Mainstem of South Boulder Creek, including all tributaries and wetlands, from the source to the outlet of Gross Reservoir except for specific listings in Segment 1 and Gamble Gulch. Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COSPBO04a_B Gamble Gulch.

   Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List H COSPBO04b 4b. Mainstem of South Boulder Creek, including all tributaries and wetlands, from the outlet of Gross Reservoir to South Boulder Road, except for specific listings in Segments 4c and 4d. Listed portion: COSPBO04b_C Mainstem of South Boulder Creek, including all tributaries and wetlands, from the outlet of Gross Reservoir to the mouth of Eldorado Canyon above the Community Ditch diversion structure (39°55'56.82"N, 105°16'50.56"W), except for specific listings in Segments 4c and 4d.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COSPBO04b_D Mainstem of South Boulder Creek, including all tributaries and wetlands, from below the Community Ditch diversion structure (39°55'56.82"N, 105°16'50.56"W), to South Boulder Road, except for specific listings in Segments 4c and 4d. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Silver (Dissolved) 5. - 303(d) List H COSPBO07b 7b. Mainstem of Coal Creek from Highway 36 to the confluence with Boulder Creek. Listed portion: COSPBO07b_A Mainstem of Coal Creek from Highway 36 to the confluence with Rock Creek. Aquatic Life Use Macroinvertebrates (Provisional) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Chloride 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Recreational Use E. coli 5. - 303(d) List H Listed portion: COSPBO07b_B Mainstem of Coal Creek from Rock Creek to Boulder Creek. Aquatic Life Use Macroinvertebrates (Provisional) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Recreational Use E. coli 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Nitrate 5. - 303(d) List H COSPBO08 8. All tributaries to South Boulder Creek, including all wetlands from South Boulder Road to the confluence with Boulder Creek and all tributaries to Coal Creek, including all wetlands from Highway 93 to the confluence with Boulder Creek.

Listed portion: COSPBO08_B Rock Creek.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Chloride 3b. - M&E List N/A Recreational Use E. coli 5. - 303(d) List M Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COSPBO09 9. Mainstem of Boulder Creek from a point immediately above the confluence with South Boulder Creek to the confluence with Coal Creek.

Listed portion: COSPBO09_A Mainstem of Boulder Creek from a point immediately above the confluence with South Boulder Creek to 107th Street.

1. Recreational Use E. Coli (July - October) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPBO09_B Mainstem of Boulder Creek from 107th Street to Coal Creek. Recreational Use E. Coli (July - October) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPBO10 10. Mainstem of Boulder Creek from the confluence with Coal Creek to the confluence with St. Vrain Creek. Listed portion: COSPBO10_A Mainstem of Boulder Creek from the confluence with Coal Creek to the confluence with St. Vrain Creek.

   Recreational Use E. coli 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPBO14 14. All lakes and reservoirs tributary to Boulder Creek from the source to a point immediately above the South Boulder Creek confluence, except as specified in Segment 13. This segment includes Barker and Lakewood Reservoir.

Listed portion: COSPBO14_B Barker Reservoir.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use pH 5. - 303(d) List H Listed portion: COSPBO14_D Silver Lake.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Silver (Dissolved) 3b. - M&E List N/A Aquatic Life Use pH 5. - 303(d) List H COSPBO18 18. Gross Reservior.

Listed portion: COSPBO18_A Gross Reservoir.

1. Aquatic Life Use Fish (Mercury) 3b. - M&E List N/A COSPBT01 1. Mainstem of the Big Thompson River, including all tributaries and wetlands, within Rocky Mountain National Park.

Listed portion: COSPBT01_B Mainstem of the Big Thompson River, including all tributaries and wetlands, within Rocky Mountain National Park.

1. Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Temperature 5. - 303(d) List H COSPBT02 2. Mainstem of the Big Thompson River from the boundary of Rocky Mountain National Park to the Greeley-Loveland Canal Diversion (40.397884, -105.106482). All tributaries to the Big Thompson River, including all wetlands, from the boundary of Rocky Mountain National Park to the Home Supply Canal diversion (40.424430, -105.210449).

Listed portion: COSPBT02_A Mainstem of the Big Thompson River, including all tributaries and wetlands, from the Upper Thompson Sanitaton District discharge to a point immediately below Cedar Creek, except for the North Fork Big Thompson River and Fish Creek.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPBT02_B Fish Creek below Mary's Lake. Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use pH 5. - 303(d) List H Water Supply Use Nitrate 5. - 303(d) List H Listed portion: COSPBT02_C Mainstem of the Big Thompson River, including all tributaries and wetlands, from the boundary of Rocky Mountain National Park to the Upper Thompson Sanitation District discharge.

   Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M Listed portion: COSPBT02_D Mainstem of the Big Thompson River, including all tributaries and wetlands, from immediately below Cedar Creek to the Home Supply Canal diversion (40.424430, -105.210449).

   Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COSPBT02_E Mainstem of the North Fork Big Thompson River from the boundary of Rocky Mountain National Park to the confluence with the Big Thompson River. Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPBT02_F Mainstem of the Big Thompson River from the Home Supply Canal diversion (40.424430, -105.210449) to the Big Barnes Ditch (40.406, -105.143). Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M Listed portion: COSPBT02_G Mainstem of the Big Thompson River from the Big Barnes Ditch (40.406, -105.143) to the Greeley-Loveland Canal Diversion (40.397884, -105.106482). Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H COSPBT03 3. Mainstem of the Big Thompson River from the Greeley-Loveland Canal diversion (40.397884, -105.106482) to County Road 11H.

Listed portion: COSPBT03_B Mainstem of the Big Thompson from the Greeley-Loveland Canal diversion (40.397884, -105.106482) to County Road 11H.

1. Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPBT05 5. Mainstem of The Big Thompson River from I-25 to the confluence with the South Platte River. Listed portion: COSPBT05_A Mainstem of The Big Thompson River from I-25 to the confluence with the South Platte River.

   Recreational Use E. coli 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPBT06 6. All tributaries to the Big Thompson River, including all wetlands, from the Home Supply Canal diversion (40.424430, -105.210449) to the confluence with the South Platte River, except for listings in segments 7, 8, 9, and 10.

Listed portion: COSPBT06_A All tributaries to the Big Thompson River, including all wetlands, from the Home Supply Canal diversion (40.24430, -105.210449) to the confluence with the South Platte River, except for Dry Creek and listings in Segments 7, 8, 9, and 10. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Sulfate 5. - 303(d) List L COSPBT07 7. Buckhorn Creek from the source to the confluence with the Big Thompson River. Listed portion: COSPBT07_A Buckhorn Creek from the source to the confluence with the Big Thompson River. Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COSPBT08 8. Mainstem of the Little Thompson River, including all tributaries and wetlands, from the source to the Culver Ditch diversion (40.259242, -105.200029).

Listed portion: COSPBT08_A Mainstem of the Little Thompson River, including all tributaries and wetlands, from the the

1. St. Vrain Supply Canal to the Culver Ditch diversion (40.253242, -105.200029). Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPBT08_B Mainstem of the Little Thompson River, including all tributaries and wetlands, from the source to the St. Vrain Supply Canal.

   Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPBT09 9. Mainstem of the Little Thompson River from the Culver Ditch diversion (40.259242, -105.200029) to the confluence with the Big Thompson River.

Listed portion: COSPBT09_A Mainstem of the Little Thompson River from the Culver Ditch diversion (40.259242, -105.200029) to the confluence with the Big Thompson River. Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L Recreational Use E. coli (May-October) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPBT10 10. All tributaries to the Little Thompson River, including all wetlands, from the Culver Ditch diversion (40.259242, -105.200029) to the confluence with the Big Thompson River. Listed portion: COSPBT10_A All tributaries to the Little Thompson River, including all wetlands, from the Culver Ditch diversion (40.259242, -105.200029) to the confluence with the Big Thompson River, except Big Hollow Creek.

1. Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A COSPBT11 11. Carter Lake.

Listed portion: COSPBT11_A Carter Lake.

1. Aquatic Life Use Fish (Mercury) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H COSPBT12 12. Lake Loveland, Horseshoe Lake, Boyd Lake.

Listed portion: COSPBT12_B Boyd Lake.

1. Aquatic Life Use pH 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPBT14 14. Welch Reservoir, Lonetree Reservoir, Boedecker Lake, Lon Hagler Reservoir. Listed portion: COSPBT14_D Lon Hagler Reservoir.

   Aquatic Life Use pH 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPBT16 16. All lakes and reservoirs tributary to the Big Thompson River from the boundary of Rocky Mountain National Park to the Home Supply Canal diversion (40.424430, -105.210449). This segment includes Lake Estes and St Mary?s Lake.

Listed portion: COSPBT16_B Lake Estes.

1. Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H COSPCH01 1. Mainstem of Cherry Creek from the source of East and West Cherry Creek to the inlet of Cherry Creek Reservoir.

Listed portion: COSPCH01_A Mainstem of Cherry Creek from the source of East and West Cherry Creek to the inlet of Cherry Creek Reservoir.

1. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPCH02 2. Cherry Creek Reservoir.

Listed portion: COSPCH02_A Cherry Creek Reservoir.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Mercury (Total) 3b. - M&E List N/A Aquatic Life Use Chlorophyll-A 5. - 303(d) List H Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H COSPCH03 3. Mainstem of Cherry Creek from the outlet of Cherry Creek Reservoir to the confluence with the South Platte River.

Listed portion: COSPCH03_A Mainstem of Cherry Creek from the outlet of Cherry Creek Reservoir to Holly Street. Recreational Use E. coli 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPCH03_B Mainstem of Cherry Creek from Holly street to the confluence with the South Platte River. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Recreational Use E. coli 5. - 303(d) List H Water Supply Use Chloride 5. - 303(d) List L COSPCH04a 4a. All tributaries to Cherry Creek, including all wetlands, from the source of East and West Cherry Creeks to the confluence with the South Platte River except for listings in Segment 4b. Listed portion: COSPCH04a_B Goldsmith Gulch.

1. Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M Recreational Use E. coli 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Sulfate 5. - 303(d) List L Water Supply Use Chloride 5. - 303(d) List L Listed portion: COSPCH04a_C McMurdo Gulch.

   Aquatic Life Use Total Phosphorus 5. - 303(d) List M Listed portion: COSPCH04a_D West Cherry Creek and its tributaries from the source to a point just above the confluence with Antelope Creek.

   Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Iron (Dissolved) 5. - 303(d) List L COSPCH04b 4b. Cottonwood Creek, including all tributaries and wetlands, from the source to Cherry Creek Reservoir. Listed portion: COSPCH04b_B Upper Windmill Creek.

   Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L COSPCL02a 2a. Mainstem of Clear Creek, including all tributaries and wetlands, from the I-70 bridge above Silver Plume to a point just above the confluence with West Fork Clear Creek, except for listings in Segments 3a and 3b. Listed portion: COSPCL02a_B Mainstem of Clear Creek, including all tributaries and wetlands, from the I-70 bridge above Silver Plume to the inlet of Georgetown Lake, except for listings in Segments 3a and 3b. Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Listed portion: COSPCL02a_C Mainstem of Clear Creek, including all tributaries and wetlands, from the outlet of Georgetown Lake to a point just above the confluence with West Fork Clear Creek, except for listings in Segments 3a and 3b.

   Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Macroinvertebrates 5. - 303(d) List H COSPCL02b 2b. Mainstem of Clear Creek, including all tributaries and wetlands, from the confluence with West Fork Clear Creek to a point just below the confluence with Mill Creek, except for listings in Segments 4 through 8. Listed portion: COSPCL02b_B Mainstem of Clear Creek from the confluence with West Fork Clear Creek to a point just below the confluence with Mill Creek, except for listings in Segments 4 through 8. Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Listed portion: COSPCL02b_C All tributaries and wetlands to Clear Creek, from the confluence with West Fork Clear Creek to a point just below the confluence with Mill Creek, except for listings in Segments 4 through 8.

   Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H COSPCL02c 2c. Mainstem of Clear Creek, including all tributaries and wetlands, from a point just below the confluence with Mill Creek to a point just above the Argo Tunnel discharge, except for listings in Segments 9a, 9b, and 10. Listed portion: COSPCL02c_B Turkey Gulch below Rockford Tunnel. Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Chromium VI (Total) 3b. - M&E List N/A Water Supply Use Lead (Total) 3b. - M&E List N/A Water Supply Use Nickel (Total) 3b. - M&E List L Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Nickel (Dissolved) 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Iron (Dissolved) 5. - 303(d) List L Water Supply Use Uranium (Total) 5. - 303(d) List L Water Supply Use Sulfate 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L Agricultural Use Copper (Total) 5. - 303(d) List L Aquatic Life Use Lead (Dissolved) 5. - 303(d) List L Water Supply Use Cadmium (Total) 5. - 303(d) List L Listed portion: COSPCL02c_E Virginia Canyon from its source to its confluence with Clear Creek. Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use pH 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Cadmium (Total) 5. - 303(d) List L Water Supply Use Nickel (Total) 5. - 303(d) List L Water Supply Use Sulfate 5. - 303(d) List L Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Manganese (Dissolved) 5. - 303(d) List H Aquatic Life Use Nickel (Dissolved) 5. - 303(d) List H Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H COSPCL03a 3a. Mainstem of South Clear Creek, including all tributaries and wetlands, from the source to the confluence with Clear Creek, except for the listings in Segments 3b and 19. Listed portion: COSPCL03a_A Mainstem of South Clear Creek, including all tributaries and wetlands, from the source to Lower Cabin Creek Reservoir, except for the listings in Segments 3b and 19. Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Listed portion: COSPCL03a_B Mainstem of South Clear Creek, including all tributaries and wetlands, from a point just above Clear Lake to the confluence with Clear Creek.

   Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Listed portion: COSPCL03a_C Mainstem of South Clear Creek from Lower Cabin Creek Reservoir to Clear Lake. Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Aquatic Life Use Temperature 5. - 303(d) List H COSPCL03b 3b. Mainstem of Leavenworth Creek from source to confluence with South Clear Creek. Listed portion: COSPCL03b_A Mainstem of Leavenworth Creek from source to confluence with South Clear Creek. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M COSPCL05 5. Mainstem of West Fork Clear Creek from the confluence with Woods Creek to the confluence with Clear Creek.

Listed portion: COSPCL05_B West Fork of Clear Creek from Hoop Creek to the confluence with Clear Creek. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A COSPCL06 6. All tributaries to West Fork Clear Creek, including all wetlands, from the source to the confluence with Clear Creek, except for listings in Segments 7a and 8.

Listed portion: COSPCL06_C North Empire Creek.

1. Water Supply Use pH 3b. - M&E List N/A Water Supply Use Nickel (Total) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Sulfate 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Manganese (Dissolved) 5. - 303(d) List H Aquatic Life Use Nickel (Dissolved) 5. - 303(d) List H Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H COSPCL09a 9a. Mainstem of Fall River, including all tributaries and wetlands, from the source to the confluence with Clear Creek.

Listed portion: COSPCL09a_B Silver Creek.

1. Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Lead (Dissolved) 5. - 303(d) List H Listed portion: COSPCL09a_C Mainstem of Fall River from the source to the confluence with Clear Creek. Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H COSPCL09b 9b. Mainstem of Trail Creek, including all tributaries and wetlands from the source to the confluence with Clear Creek.

Listed portion: COSPCL09b_A Mainstem of Trail Creek, including all tributaries and wetlands from the source to the confluence with Clear Creek.

1. Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Water Supply Use Cadmium (Total) 5. - 303(d) List L COSPCL10 10. Mainstem of Chicago Creek, including all tributaries and wetlands, from the source to the confluence with Clear Creek, except for listings in Segment 19.

Listed portion: COSPCL10_A Mainstem of Chicago Creek, including all tributaries and wetlands, from the source to the confluence with Clear Creek, except for listings in Segment 19. Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H COSPCL11 11. Mainstem of Clear Creek from a point just above the Argo Tunnel discharge to the Farmers Highline Canal diversion in Golden, Colorado.

Listed portion: COSPCL11_A Mainstem of Clear Creek from a point just above the Argo Tunnel discharge to the Farmers Highline Canal diversion in Golden, Colorado.

1. Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPCL12a 12a. All tributaries to Clear Creek, including all wetlands, from the Argo Tunnel discharge to the Farmers Highline Canal diversion in Golden, Colorado, except for listings in Segments 12b, 13a and 13b. Listed portion: COSPCL12a_A All tributaries to Clear Creek, including all wetlands, from the Argo Tunnel discharge to the Farmers Highline Canal diversion in Golden, Colorado, except for Gilson Gulch and listings in Segments 12b, 13a, and 13b.

   Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Listed portion: COSPCL12a_B Gilson Gulch and its tributaries. Aquatic Life Use pH 3b. - M&E List N/A Agricultural Use Copper (Total) 3b. - M&E List N/A Water Supply Use Zinc (Total) 3b. - M&E List N/A Water Supply Use Sulfate 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M Aquatic Life Use Nickel (Dissolved) 5. - 303(d) List M Aquatic Life Use Lead (Dissolved) 5. - 303(d) List M Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Cadmium (Total) 5. - 303(d) List L Water Supply Use Lead (Total) 5. - 303(d) List L Water Supply Use Nickel (Total) 5. - 303(d) List L Aquatic Life Use Chromium VI (Dissolved) 5. - 303(d) List L COSPCL12b 12b. Beaver Brook, from the source to the confluence with Soda Creek, and Soda Creek, from the source to the confluence with Clear Creek.

Listed portion: COSPCL12b_A Beaver Brook, from the source to the confluence with Soda Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COSPCL13a 13a. Mainstem of North Clear Creek, including all tributaries and wetlands, from its source to its confluence with Chase Gulch, and Four Mile Gulch, including all tributaries and wetlands, from their sources to their confluence with North Clear Creek and Eureka Gulch, including all tributaries and wetlands, from its source to its confluence with Gregory Gulch.

Listed portion: COSPCL13a_C Chase Gulch, including all tributaries and wetlands, from its source to its confluence with North Clear Creek.

1. Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H COSPCL13b 13b. Mainstem of North Clear Creek including all tributaries and wetlands from a point just below the confluence with Chase Gulch to the confluence with Clear Creek, except for the listings in Segment 13a. Listed portion: COSPCL13b_B Mainstem of North Clear Creek from a point just below the confluence with Chase Gulch to the confluence with Clear Creek, except for the listings in Segment 13a. Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M Aquatic Life Use Temperature 5. - 303(d) List M Aquatic Life Use Macroinvertebrates 5. - 303(d) List M Listed portion: COSPCL13b_D All tributaries and wetlands to North Clear Creek from a point just below the confluence with Chase Gulch to the confluence with Clear Creek, except for Gregory Gulch, Russell Guclh, Silver Gulch, and the listings in Segment 13a.

   Aquatic Life Use Iron (Total) 4a. - TMDL N/A Aquatic Life Use Manganese (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M Listed portion: COSPCL13b_E Russell Gulch, and Silver Gulch, including all tributaries and wetlands, from their sources to their confluences with North Clear Creek.

   Water Supply Use Arsenic (Total) 5. - 303(d) List M Listed portion: COSPCL13b_F Gregory Gulch Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Lead (Dissolved) 3b. - M&E List N/A Water Supply Use Chloride 3b. - M&E List N/A Aquatic Life Use Iron (Total) 4a. - TMDL N/A Aquatic Life Use Manganese (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Cadmium (Total) 5. - 303(d) List L Water Supply Use Sulfate 5. - 303(d) List L COSPCL14a 14a. Mainstem of Clear Creek from the Farmers Highline Canal diversion in Golden, Colorado to the Denver Water conduit #16 crossing.

Listed portion: COSPCL14a_A Mainstem of Clear Creek from the Farmers Highline Canal diversion in Golden, Colorado to Croke Canal Diversion, and from McIntyre St. to the Denver Water conduit #16 crossing. Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Aquatic Life Use Ammonia 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List M Aquatic Life Use Macroinvertebrates 5. - 303(d) List L Listed portion: COSPCL14a_B Mainstem of Clear Creek from Croke Canal Diversion to McIntyre Street. Aquatic Life Use Macroinvertebrates 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List M COSPCL14b 14b. Mainstem of Clear Creek from the Denver Water conduit #16 crossing to a point just below Youngfield Street in Wheat Ridge, Colorado.

Listed portion: COSPCL14b_A Mainstem of Clear Creek from the Denver Water conduit #16 crossing to a point just below Youngfield Street in Wheat Ridge, Colorado.

1. Aquatic Life Use Ammonia 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Organic Sediment 5. - 303(d) List L COSPCL15 15. Mainstem of Clear Creek from Youngfield Street in Wheat Ridge, Colorado, to the confluence with the South Platte River.

Listed portion: COSPCL15_B Mainstem of Clear Creek from Youngfield Street in Wheat Ridge, Colorado, to Wadsworth Blvd (39.7845, -105.0814).

1. Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Aquatic Life Use Ammonia 5. - 303(d) List L Recreational Use E. coli (May-October) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Organic Sediment 5. - 303(d) List L Aquatic Life Use Macroinvertebrates 5. - 303(d) List L Listed portion: COSPCL15_C Mainstem of Clear Creek from Wadsworth Blvd (39.2492, -105.6608) to the confluence with the South Platte River.

   Recreational Use E. coli (May-October) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Organic Sediment 5. - 303(d) List L Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Water Supply Use Chloride 5. - 303(d) List L COSPCL16a 16a. Mainstem of Lena Gulch including all tributaries and wetlands from its source to the inlet of Maple Grove Reservoir.

Listed portion: COSPCL16a_A Mainstem of Lena Gulch including all tributaries and wetlands from its source to the inlet of Maple Grove Reservoir.

1. Water Supply Use Chloride 5. - 303(d) List L COSPCL17a 17a. Arvada Reservoir.

Listed portion: COSPCL17a_A Arvada Reservoir.

1. Aquatic Life Use Dissolved Oxygen (Temperature) 5. - 303(d) List H COSPCL17b 17b. Mainstem of Ralston Creek, including all tributaries and wetlands, from the source to the inlet of Arvada Reservoir.

Listed portion: COSPCL17b_A Mainstem of Ralston Creek, including all tributaries and wetlands, from the source to the inlet of Arvada Reservoir.

1. Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M COSPCL18a 18a. Mainstem of Ralston Creek, including all tributaries and wetlands, from the outlet of Arvada Reservoir to the confluence with Clear Creek.

Listed portion: COSPCL18a_A Mainstem of Ralston Creek, including all tributaries and wetlands, from the outlet of Arvada Reservoir to the confluence with Clear Creek.

1. Recreational Use E. coli 5. - 303(d) List H COSPCP02a 2a. Mainstem of the Cache La Poudre River, including all tributaries and wetlands, from the boundaries of Rocky Mountain National Park and the Rawah, Neota, Comanche Peak, and Cache La Poudre Wilderness Areas to a point immediately below the confluence with the South Fork Cache La Poudre River. Listed portion: COSPCP02a_B Mainstem of the Cache La Poudre River from the boundaries of Rocky Mountain National Park, and the Rawah, Neota, Comanche Peak, and Cache La Poudre Wilderness Areas to a point immediately below the confluence with the South Fork Cache La Poudre River. Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COSPCP02a_C All tributaries and wetlands of the Cache la Poudre River from the boundaries of Rocky Mountain National Park, and the Rawah, Neota, Comanche Peak, and Cache La Poudre Wilderness Areas to a point immediately below the confluence with the South Fork Cache La Poudre River.

   Water Supply Use Arsenic (Total) 5. - 303(d) List H COSPCP02b 2b. Mainstem of the Cache La Poudre River, including all tributaries and wetlands, from a point immediately below the confluence with the South Fork Cache La Poudre River to the Munroe Gravity Canal Headgate (also known as the North Poudre Supply Canal diversion; 40.691700, -105.255292), except for listings in segments 1 and 3.

Listed portion: COSPCP02b_D Mainstem of the Cache La Poudre River, including all tributaries and wetlands, from Gordon Creek to the Munroe Gravity Canal Headgate (also known as the North Poudre Supply Canal diversion; 40.691700, -105.255292).

1. Aquatic Life Use Temperature 5. - 303(d) List H COSPCP03 3. Elkhorn Creek, including all tributaries and wetlands, from the source to a point immediately above the confluence with Manhattan Creek.

Listed portion: COSPCP03_B Elkhorn Creek, including all tributaries and wetlands, from the source to a point immediately above the confluence with Manhattan Creek.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPCP06 6. North Fork of the Cache La Poudre River, including all tributaries and wetlands, from the source to the inlet of Halligan Reservoir.

Listed portion: COSPCP06_A North Fork of the Cache La Poudre River, including all tributaries and wetlands, from the source to the inlet of Halligan Reservoir.

1. Aquatic Life Use Silver (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPCP07 7. North Fork of the Cache La Poudre River, including all tributaries and wetlands, from the inlet of Halligan Reservoir to the confluence with the Cache La Poudre River, except for listings in segments 8 and 20. Listed portion: COSPCP07_C Mainstem of the North Fork of the Cache la Poudre River, including wetlands, from immediately below the outlet of Halligan Reservoir to a point five miles downstream. Aquatic Life Use Sediment 4a. - TMDL N/A Aquatic Life Use Silver (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Listed portion: COSPCP07_D Tributaries to the North Fork of the Cache La Poudre River, including wetlands, from the inlet of Halligan Reservoir to the confluence with the Cache La Poudre River, except Lone Pine Creek, Rabbit Creek, and listings in segments 8 and 20. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPCP07_E Mainstem of the North Fork of the Cache la Poudre River from a point five miles downstream of Halligan Reservoir to Seaman Reservoir.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPCP07_F Mainstem of the North Fork of the Cache la Poudre River from below Seaman Reservoir to the confluence with the Cache La Poudre River.

   Aquatic Life Use Temperature 5. - 303(d) List M Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Listed portion: COSPCP07_G Mainstem of Lone Pine Creek, including wetlands, from the confluence of North Fork Lone Pine Creek and South Fork Lone Pine Creek to the confluence with the North Fork of the Cache La Poudre River.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L Listed portion: COSPCP07_H Mainstem of Rabbit Creek, including wetlands, from the source to the confluence with the North Fork of the Cache La Poudre River.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPCP08 8. Middle Fork Rabbit Creek, including all tributaries and wetlands, from the source to the confluence with Rabbit Creek. Stonewall Creek, including all tributaries and wetlands, from the source to the confluence with the North Fork of the Cache La Poudre River. North Fork Lone Pine Creek and South Fork Lone Pine Creek, including all tributaries and wetlands, from the source to the confluence with Lone Pine Creek. Listed portion: COSPCP08_B Middle Fork of Rabbit Creek, including all tributaries and wetlands, from the source to the confluence with Rabbit Creek. Stonewall Creek, including all tributaries and wetlands, from the source to the confluence with the North Fork of the Cache La Poudre River. North Fork Lone Pine Creek and South Fork Lone Pine Creek, including all tributaries and wetlands, from the source to the confluence with Lone Pine Creek. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPCP10a 10a. Mainstem of the Cache La Poudre River from the Munroe Gravity Canal Headgate (also known as the North Poudre Supply Canal diversion; 40.691700, -105.255292) to a point immediately above the Larimer County Ditch diversion (40.656612, -105.185244).

Listed portion: COSPCP10a_A Mainstem of the Cache La Poudre River from the Munroe Gravity Canal Headgate (also known as the North Poudre Supply Canal diversion; 40.691700, -105.255292) to a point immediately above the Larimer County Ditch diversion (40.656612, -105.185244). Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List H COSPCP10b 10b. Mainstem of the Cache La Poudre River from a point immediately above the Larimer County Ditch diversion (40.656612, -105.185244) to Shields Street in Ft. Collins, Colorado. Listed portion: COSPCP10b_A Mainstem of the Cache La Poudre River from a point immediately above the Larimer County Ditch diversion (40.656612, -105.185244) to Shields Street in Ft. Collins, Colorado. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Nitrite 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List L COSPCP11 11. Mainstem of the Cache La Poudre River from Shields Street in Ft. Collins to Prospect Road. Listed portion: COSPCP11_B Mainstem of the Cache La Poudre River from Shields Street in Ft. Collins to Prospect Road. Recreational Use E. coli 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List L COSPCP12a 12a. Mainstem of the Cache La Poudre River from Prospect Road to U.S. Hwy 85 in Greeley. Listed portion: COSPCP12a_A Mainstem of the Cache La Poudre River from Boxelder Creek to US Hwy 85 in Greeley. Recreational Use E. coli (May-October) 5. - 303(d) List H Listed portion: COSPCP12a_B Mainstem of the Cache La Poudre River from Prospect Road to Boxelder Creek. Recreational Use E. coli 5. - 303(d) List L Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List L COSPCP12b 12b. Mainstem of the Cache La Poudre River from U.S. Hwy 85 in Greeley to the confluence with the South Platte River.

Listed portion: COSPCP12b_A Mainstem of the Cache La Poudre River from U.S. Hwy 85 in Greeley to the confluence with the South Platte River.

1. Recreational Use E. coli (May-October) 5. - 303(d) List H COSPCP13a 13a. All tributaries to the Cache La Poudre River, including all wetlands, from the Munroe Gravity Canal Headgate (also known as the North Poudre Supply Canal diversion; 40.691700, -105.255292) to the confluence with the South Platte River, except for listings in segments 6, 7, 8, 13b, and 13c. Listed portion: COSPCP13a_B Dry Creek and all tributaries. Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M Listed portion: COSPCP13a_D Spring Creek and its tributaries. Recreational Use E. coli (May-October) 5. - 303(d) List H Listed portion: COSPCP13a_E Fossil Creek and its tributaries. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Recreational Use E. coli (May-October) 5. - 303(d) List H COSPCP13b 13b. Mainstem of Boxelder Creek from its source to a point immediately above Slab Canyon Wash. Mainstems of South Branch of Boxelder Creek, North Branch of Boxelder Creek, and Sand Creek from their sources to their confluences with the mainstem of Boxelder Creek.

Listed portion: COSPCP13b_C Mainstem of Boxelder Creek from its source to a point immediately above Slab Canyon Wash.

1. Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L Recreational Use E. coli 5. - 303(d) List L Aquatic Life Use Macroinvertebrates 5. - 303(d) List H COSPCP13c 13c. Mainstem of Boxelder Creek from a point immediately above Slab Canyon Wash to the confluence with the Cache La Poudre River.

Listed portion: COSPCP13c_B Mainstem of Boxelder Creek from a point immediately above Slab Canyon Wash to the confluence with the Cache La Poudre River.

1. Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L Recreational Use E. coli 5. - 303(d) List L Aquatic Life Use Macroinvertebrates 5. - 303(d) List H COSPCP14 14. Horsetooth Reservoir.

Listed portion: COSPCP14_A Horsetooth Reservoir.

1. Aquatic Life Use Fish (Mercury) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List H COSPCP18 18. All lakes and reservoirs tributary to the Cache La Poudre River from the boundaries of Rocky Mountain National Park and the Rawah, Neota, Comanche Peak, and Cache La Poudre Wilderness Areas to the Munroe Gravity Canal Headgate (also known as the North Poudre Supply Canal diversion; 40.691700, -105.255292). Listed portion: COSPCP18_C Chambers Lake.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Mercury (Total) 3b. - M&E List N/A COSPCP19 19. All lakes and reservoirs tributary to the North Fork of the Cache La Poudre River from the source to the inlet of Halligan Reservoir.

Listed portion: COSPCP19_C Dowdy Lake.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Dissolved Oxygen (Temperature) 3b. - M&E List N/A COSPCP20 20. All lakes and reservoirs tributary to the North Fork of the Cache La Poudre River from the inlet of Halligan Reservoir to the confluence with the Cache La Poudre River. This segment includes Halligan Reservoir and Seaman Reservoir.

Listed portion: COSPCP20_B Seaman Reservoir.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Dissolved Oxygen 5. - 303(d) List M COSPCP21 21. All lakes and reservoirs tributary to the Cache La Poudre River from the Munroe Gravity Canal Headgate (also known as the North Poudre Supply Canal diversion; 40.691700, -105.255292) to the confluence with the South Platte River, except for listings in segments 14, 15, 16, 19, 20, and 22. Listed portion: COSPCP21_C Douglas Reservoir.

   Aquatic Life Use pH 3b. - M&E List N/A Listed portion: COSPCP21_D Windsor Lake at intersection of CO 392 and CO 257. Aquatic Life Use Mercury (Total) 3b. - M&E List N/A Aquatic Life Use Chlorophyll-A 3b. - M&E List N/A COSPLA02a 2a. Mainstem of the Laramie River from the source to the National Forest boundary, and all tributaries and wetlands from the source to the Colorado/Wyoming border, except for listings in Segment 1. Listed portion: COSPLA02a_A Mainstem of the Laramie River from the source to the National Forest boundary, and all tributaries and wetlands from the source to the Colorado/Wyoming border, except for listings in Segment 1.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A COSPLA02b 2b. Mainstem of the Laramie River from the National Forest boundary to the Colorado/Wyoming border. Listed portion: COSPLA02b_A Mainstem of the Laramie River from the National Forest boundary to the Colorado/Wyoming border.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H COSPLS01a 1a. Mainstem of the South Platte River from the Weld/Morgan County line to the Morgan/Washington County line.

Listed portion: COSPLS01a_A Mainstem of the South Platte River from the Weld/Morgan County line to the Morgan/Washington County line.

1. Water Supply Use Uranium (Total) 5. - 303(d) List H Water Supply Use Sulfate 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPLS01b 1b. Mainstem of the South Platte River from the Morgan/Washington County line to the Colorado/Nebraska border.

Listed portion: COSPLS01b_A Mainstem of the South Platte River from the Morgan/Washington County line to the Colorado/Nebraska border.

1. Water Supply Use Uranium (Total) 5. - 303(d) List H Water Supply Use Sulfate 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPLS02 2. All tributaries to the South Platte River, including all wetlands, from the Weld/Morgan County line to the Colorado/Nebraska border.

Listed portion: COSPLS02_B Beaver Creek from the source to South Platte River, except for the portion of Beaver Creek from its source to the Fort Morgan Canal.

1. Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H Recreational Use E. coli 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPLS02_C Kiowa Creek and its tributaries from the source to the confluence with the South Platte River.

   Aquatic Life Use Macroinvertebrates 5. - 303(d) List L Aquatic Life Use Dissolved Oxygen 5. - 303(d) List M COSPLS03 3. Jackson Reservoir, Prewitt Reservoir, North Sterling Reservoir, Jumbo (Julesburg), Empire Reservoir, Vancil Reservoir.

Listed portion: COSPLS03_B North Sterling Reservoir.

1. Water Supply Use Uranium (Total) 3b. - M&E List N/A Aquatic Life Use Mercury (Total) 3b. - M&E List N/A Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COSPLS03_C Jumbo Reservoir (Julesburg Reservoir). Aquatic Life Use Ammonia 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Water Supply Use Uranium (Total) 5. - 303(d) List L Listed portion: COSPLS03_D Jackson Reservoir.

   Aquatic Life Use pH 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H COSPMS01a 1a. Mainstem of the South Platte River from a point immediately below the confluence with Big Dry Creek to the confluence with St. Vrain Creek.

Listed portion: COSPMS01a_B Mainstem of the South Platte River from a point immediately below the confluence with Big Dry Creek to a point immediately below the Platteville Ditch diversion (40.094236, -104.819022).

1. Recreational Use E. coli 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPMS01a_C Mainstem of the South Platte River from a point immediately below the Platteville Ditch diversion (40.094236, -104.819022) to the confluence with St. Vrain Creek. Recreational Use E. coli 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List L COSPMS01b 1b. Mainstem of the South Platte River from a point immediately below the confluence with St. Vrain Creek to the Weld/Morgan County Line.

Listed portion: COSPMS01b_A Mainstem of the South Platte River from a point immediately below the confluence with St. Vrain Creek to the Weld/Morgan County Line.

1. Recreational Use E. coli 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPMS04 4. Barr Lake and Milton Reservoir.

Listed portion: COSPMS04_A Barr Lake.

1. Aquatic Life Use Dissolved Oxygen 4a. - TMDL N/A Aquatic Life Use pH 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Chlorophyll-A 5. - 303(d) List M Listed portion: COSPMS04_B Milton Reservoir.

   Aquatic Life Use Dissolved Oxygen 4a. - TMDL N/A Aquatic Life Use pH 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Chlorophyll-A 5. - 303(d) List L COSPMS05a 5a. Mainstem of Lone Tree Creek from the source to the confluence with the South Platte River. Listed portion: COSPMS05a_A Mainstem of Lone Tree Creek from the source to the confluence with the South Platte River. Water Supply Use Nitrate 5. - 303(d) List H COSPMS05c 5c. Mainstems of Crow Creek and Box Elder Creek from their sources to their confluences with the South Platte River, except for listings in Segment 5b.

Listed portion: COSPMS05c_B Mainstem of Crow Creek from its source to the confluence with the South Platte River. Aquatic Life Use Total Phosphorus 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPMS05c_C Mainstem of Box Elder Creek from its source to its confluence with the South Platte River, except for listings in Segment 5b.

1. Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List M COSPMS07 7. All lakes and reservoirs tributary to the South Platte River from a point immediately below the confluence with Big Dry Creek to the Weld/Morgan County line, except for listings in the subbasins of the South Platte River, and in segments 4 and 8.

Listed portion: COSPMS07_B Prospect Lake.

1. Aquatic Life Use Chlorophyll-A 3b. - M&E List N/A Aquatic Life Use pH 5. - 303(d) List L Listed portion: COSPMS07_C Horse Creek Reservoir.

   Aquatic Life Use Chlorophyll-A 3b. - M&E List N/A COSPRE01 1. Mainstem of the South Fork of the Republican River from a point 23 miles above the Colorado/Kansas border (39.582154, -102.350838) to the Colorado/Kansas border. Listed portion: COSPRE01_A Mainstem of the South Fork of the Republican River from a point 23 miles above the Colorado/Kansas border (39.582154, -102.350838) to the Colorado/Kansas border. Water Supply Use Arsenic (Total) 5. - 303(d) List H Water Supply Use Lead (Dissolved) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List H COSPRE03 3. Mainstem of the North Fork of the Republican River from the source to the Colorado/Nebraska border. Mainstem of Chief Creek from the source to the confluence with the North Fork of the Republican River. Listed portion: COSPRE03_A Mainstem of the North Fork of the Republican River from the source to the Colorado/Nebraska border. Mainstem of Chief Creek from the source to the confluence with the North Fork of the Republican River.

   Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPRE05 5. Mainstem of Black Wolf Creek from the source to the confluence with the Arikaree River. Listed portion: COSPRE05_A Mainstem of the Black Wolf Creek from the source to the confluence with the Arikaree River. Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A COSPSV01 1. All tributaries to St. Vrain Creek, including all wetlands, which are within the Indian Peaks Wilderness Area and Rocky Mountain National Park.

Listed portion: COSPSV01_B Mainstem of South St. Vrain Creek, including all wetlands, which are within the Indian Peaks Wilderness Area and Rocky Mountain National Park.

1. Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H Listed portion: COSPSV01_C All tributaries to St. Vrain Creek, including all wetlands, which are within the Indian Peaks Wilderness Area and Rocky Mountain National Park, except for the maintsem of South St. Vrain.

   Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Aquatic Life Use pH 5. - 303(d) List H COSPSV02a 2a. Mainstem of St. Vrain Creek, including all tributaries and wetlands, from the boundary of the Indian Peaks Wilderness Area and Rocky Mountain National Park to the eastern boundary of Roosevelt National Forest. Listed portion: COSPSV02a_A Mainstem of St. Vrain Creek, including all tributaries and wetlands, from the boundary of the Indian Peaks Wilderness Area and Rocky Mountain National Park to the eastern boundary of Roosevelt National Forest.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A COSPSV02b 2b. Mainstem of St. Vrain Creek, including all tributaries and wetlands, from the eastern boundary of Roosevelt National Forest to Hygiene Road.

Listed portion: COSPSV02b_A Mainstem of St. Vrain Creek, including all tributaries and wetlands, from the eastern boundary of Roosevelt National Forest to Hygiene Road. Except part of South Saint Vrain Creek.

1. Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPSV02b_B South Saint Vrain Creek from just below its confluence with Red Hill Gulch to its confluence with North Saint Vrain Creek.

   Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPSV03 3. Mainstem of St. Vrain Creek from Hygiene Road to the confluence with the South Platte River. Listed portion: COSPSV03_B Mainstem of St. Vrain Creek from the confluence with Left Hand Creek to the confluence with Boulder Creek.

   Aquatic Life Use Ammonia 4a. - TMDL N/A Recreational Use E. coli 5. - 303(d) List H Listed portion: COSPSV03_C Mainstem of St. Vrain Creek from Hover Road to Left Hand Creek. Recreational Use E. coli 5. - 303(d) List H Listed portion: COSPSV03_D Mainstem of St. Vrain Creek from Hygiene Road to Hover Road and St. Vrain Creek from I-25 to the confluence with the South Platte River.

   Recreational Use E. coli 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPSV03_E Mainstem of St. Vrain Creek from Boulder Creek to I-25. Aquatic Life Use Ammonia 4a. - TMDL N/A Recreational Use E. coli 5. - 303(d) List H COSPSV04a 4a. Mainstem of Left Hand Creek, including all tributaries and wetlands, from the source to a point immediately below the confluence with James Creek, except for specific listings in Segment 4b. Listed portion: COSPSV04a_B Mainstem of Left Hand Creek, including all tributaries and wetlands from Hwy 72 to James Creek.

   Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Water Supply Use Cadmium (Total) 5. - 303(d) List L COSPSV04b 4b. Mainstem of James Creek, including all tributaries and wetlands, from the source to the confluence with Left Hand Creek.

Listed portion: COSPSV04b_A Mainstem of James Creek, including all tributaries and wetlands, from the source to the confluence with Left Hand Creek, excluding Little James Creek. Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use pH 5. - 303(d) List H Listed portion: COSPSV04b_B Little James Creek.

1. Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Manganese (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A Water Supply Use Sulfate 5. - 303(d) List L Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H COSPSV04c 4c. Mainstem of Left Hand Creek, including all tributaries and wetlands, from a point immediately below the confluence with James Creek to Highway 36.

Listed portion: COSPSV04c_A Mainstem of Left Hand Creek, including all tributaries and wetlands, from a point immediately below the confluence with James Creek to Highway 36. Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A COSPSV05 5. Mainstem of Left Hand Creek, including all tributaries and wetlands from Highway 36 to the confluence with St. Vrain Creek.

Listed portion: COSPSV05_A Mainstem of Left Hand Creek, including all tributaries and wetlands from a point above the Boulder Feeder Canal to the confluence with St. Vrain Creek. Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List M Listed portion: COSPSV05_B Mainstem of Left Hand Creek, including all tributaries and wetlands from Highway 36 to a point above the Boulder Feeder Canal.

1. Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPSV06a 6a. All tributaries to Dry Creek, including wetlands, from the source to the inlet of Boulder Reservoir. Listed portion: COSPSV06a_A All tributaries to Dry Creek, including wetlands, from the source to the inlet of Boulder Reservior, except Little Dry Creek.

   Recreational Use E. coli 5. - 303(d) List H Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M Listed portion: COSPSV06a_B Little Dry Creek.

   Recreational Use E. coli 5. - 303(d) List H COSPSV06b 6b. All tributaries to St. Vrain Creek, including wetlands from Hygiene Road to the confluence with the South Platte River, except for specific listings in the Boulder Creek subbasin and in Segments 4a, 4b, 4c and 5 and 6a.

Listed portion: COSPSV06b_A All tributaries to St. Vrain Creek, including wetlands from Hygiene Road to the confluence with the South Plate River, except for Dry Creek and specific listings in the Boulder Creek subbasin and in Segments 4a, 4b, 4c and 5 and 6a.

1. Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Water Supply Use Sulfate 3b. - M&E List N/A Listed portion: COSPSV06b_B Dry Creek.

   Recreational Use E. coli 5. - 303(d) List H Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M COSPSV07 7. Boulder Reservoir, Coot Lake, Left Hand Valley Reservoir and Spurgeon Reservoir. Listed portion: COSPSV07_B Boulder Reservoir.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Chlorophyll-A 5. - 303(d) List L COSPSV13 13. All lakes and reservoirs tributary to St. Vrain Creek from Hygiene Road to the confluence with the South Platte River, except as specified in Segments 7, 10, 11 and 12. Listed portion: COSPSV13_D Union Reservoir.

   Aquatic Life Use pH 3b. - M&E List N/A COSPUS01a 1a. Mainstem of the South Platte River from the source of the South and Middle Forks to the inlet of Cheesman Reservoir.

Listed portion: COSPUS01a_A Mainstem of the South Platte River from the source of the South and Middle Forks to the Elevenmile Reservoir, except for the Middle Fork South Platte River. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPUS01a_B Middle Fork South Platte River. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COSPUS01a_C South Platte River from the outlet of Elevenmile Reservoir to the Idlewilde picnic area. Aquatic Life Use Sediment 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPUS01a_D South Fork of the South Platte from Antero Reservoir to the confluence with the Middle Fork of the South Platte. Was Listed incorrectly in Reg. 93 as COSPUS02a. Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPUS01a_E South Platte River from Idlewilde picnic area to Cheesman Reservoir. Aquatic Life Use Sediment 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPUS01b 1b. All tributaries to the South Platte River, including wetlands within the Lost Creek and Mt. Evans Wilderness Areas.

Listed portion: COSPUS01b_C Hankins Gulch.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COSPUS02a 2a. All tributaries to the South Platte River system, including all wetlands from the headwaters of the South and Middle Forks to a point immediately below the confluence with Tarryall Creek except for listings in Segment 1b, 2b and 2c.

Listed portion: COSPUS02a_B Twin Creek, on USFS Land.

1. Aquatic Life Use Temperature 3b. - M&E List N/A Listed portion: COSPUS02a_E All tributaries to the South Platte River system, including all wetlands from the headwaters of the South and Middle Forks to a point immediately below the confluence with Tarryall Creek except for Snyder Creek and for specific listings in Segment 1b, 2b and 2c. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COSPUS02a_F Snyder Creek and its tributaries. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H COSPUS02b 2b. Mainstem of Mosquito Creek from Road #698 (39.270971, -106.098846) to its confluence with the Middle Fork of the South Platte River.

Listed portion: COSPUS02b_B Mainstem of Mosquito Creek from Road #698 (39.270971, -106.098846) to its confluence with the Middle Fork of the South Platte River.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COSPUS02c 2c. South Mosquito Creek from the source to confluence with Mosquito Creek, Mosquito Creek from the confluence with South Mosquito Creek to Road #698 (39.270971, -106.098846), and No Name Creek from the source to the confluence with South Mosquito Creek.

Listed portion: COSPUS02c_A No Name Creek from the source to the confluence with South Mosquito Creek. Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Listed portion: COSPUS02c_D South Mosquito Creek from the source to the London Mine. Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Listed portion: COSPUS02c_E Mosquito Creek from the confluence with South Mosquito Creek to Road #698 (39.27901, -106.098846).

1. Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H COSPUS03 3. All tributaries to the South Platte River, including all wetlands from a point immediately below the confluence with Tarryall Creek to a point immediately above the confluence with the North Fork of the South Platte River, except for listings in Segment 1b.

Listed portion: COSPUS03_B Trout Creek and tributaries on USFS property. Aquatic Life Use Temperature 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List L Listed portion: COSPUS03_C Pine Creek.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPUS03_D Fourmile Creek.

   Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List H Aquatic Life Use Mercury (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPUS03_E Horse Creek and its tributaries. Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPUS03_F West Creek.

   Aquatic Life Use Mercury (Dissolved) 3b. - M&E List N/A Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COSPUS03_G Wigwam Creek.

   Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COSPUS03_H Goose Creek.

   Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H COSPUS04 4. Mainstem of the North Fork of the South Platte River, including all tributaries and wetlands from the source to the confluence with the South Platte River, except for listings in Segments 1b, 5a, 5b, and 5c. Listed portion: COSPUS04_C Mainstem of the North Fork of the South Platte River, including all tributaries and wetlands from the source to the confluence with Sawmill Gulch.

   Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 5. - 303(d) List H Aquatic Life Use Sediment 5. - 303(d) List H Listed portion: COSPUS04_E Mainstem of North Fork of the South Platte River, including all tributaries and wetlands from Sawmill Gulch to Geneva Creek.

   Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 5. - 303(d) List H Aquatic Life Use Sediment 5. - 303(d) List H Aquatic Life Use Iron (Total) 5. - 303(d) List H Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Listed portion: COSPUS04_F Mainstem of the North Fork of the South Platte River, including all tributaries and wetlands from Geneva Creek to the confluence with the South Platte River, except for listings in Segments 1b, 5a, 5b, and 5c.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Recreational Use E. coli 5. - 303(d) List H Aquatic Life Use Temperature 5. - 303(d) List H COSPUS05a 5a. Mainstem of Geneva Creek from the source to the confluence with Scott Gomer Creek. Listed portion: COSPUS05a_A Mainstem of Geneva Creek from the source to the confluence with Scott Gomer Creek. Aquatic Life Use Cadmium (Total) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Manganese (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Iron (Total) 5. - 303(d) List H COSPUS05b 5b. Mainstem of Geneva Creek from the confluence with Scott Gomer Creek to the confluence with the North Fork of the South Platte River; all tributaries of Geneva Creek including wetlands from source to confluence with the North Fork of the South Platte River.

Listed portion: COSPUS05b_A All tributaries of Geneva Creek including wetlands from source to confluence with the North Fork of the South Platte River. Excludes Geneva Creek.

1. Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Listed portion: COSPUS05b_B Mainstem of Geneva Creek from the confluence with Scott Gomer Creek to the confluence with the North Fork of the South Platte River.

   Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COSPUS05c 5c. Mainstem of Gooseberry Gulch and all tributaries from source to Sunset Trail. Listed portion: COSPUS05c_B Unnamed Tributary to Gooseberry Creek. Aquatic Life Use Ammonia 5. - 303(d) List M COSPUS06a 6a. Mainstem of the South Platte River from the outlet of Cheesman Reservoir to the inlet of Chatfield Reservoir.

Listed portion: COSPUS06a_A Mainstem of the South Platte River from the Lazy Gulch to the inlet of Chatfield Reservoir. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COSPUS06a_B South Platte River from outlet of Cheesman Reservoir to Lazy Gulch. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPUS06b 6b. Chatfield Reservoir Listed portion: COSPUS06b_A Chatfield Reservoir.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Manganese (Dissolved) 5. - 303(d) List L COSPUS07 7. All tributaries to the South Platte River, including all wetlands from a point immediately below the confluence with the North Fork of the South Platte River to the outlet of Chatfield Reservoir except for listings in Segments 8, 9, 10, 11, 12, and 13.

Listed portion: COSPUS07_B Willow Creek and its tributaries. Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M Water Supply Use Manganese (Dissolved) 5. - 303(d) List M COSPUS09 9. Mainstem of Bear Creek, including all tributaries and wetlands from the source to the inlet of Perry Park Reservoir, a.k.a. Waucondah Reservoir (Douglas County). Listed portion: COSPUS09_B Mainstem of Bear Creek from the source to the inlet of Perry Park Reservoir (Douglas County).

1. Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H COSPUS10 10. Mainstems of East Plum Creek, West Plum Creek, and Plum Creek from the boundary of National Forest lands to Chatfield Reservoir, mainstems of Stark Creek and Gove Creek from the boundary of National Forest lands to their confluence.

Listed portion: COSPUS10_D Mainstem of Plum Creek from the confluence with East and West Plum Creek to Chatfield Reservoir.

1. Aquatic Life Use Temperature 3b. - M&E List N/A Recreational Use E. coli (May-October) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPUS10_F Mainstem of Stark Creek and West Plum Creek from the boundary of National Forest lands to the confluence with East Plum Creek.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Dissolved Oxygen 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List L Listed portion: COSPUS10_G Mainstem of East Plum Creek from the boundary of National Forest lands to the confluence with West Plum Creek..

   Water Supply Use Arsenic (Total) 5. - 303(d) List L COSPUS11a 11a. All tributaries to the East Plum Creek system, including all wetlands which are not on national forest lands.

Listed portion: COSPUS11a_A All tributaries to the East Plum Creek system, including all wetlands which are not on national forest lands. Excludes Cook Creek.

1. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Aquatic Life Use pH 3b. - M&E List N/A COSPUS12 12. Mainstem of Garber Creek and Jackson Creek from the boundary of National Forest lands to the confluence with West Plum Creek; mainstem of Bear Creek from the outlet of Perry Park Reservoir, a.k.a. Waucondah Reservoir, to the confluence with West Plum Creek. Listed portion: COSPUS12_A Mainstem of Garber Creek from the boundary of National Forest lands to the confluence with West Plum Creek; mainstem of Bear Creek from the outlet of Perry Park Reservoir, a.k.a. Waucondah Reservoir, to the confluence with West Plum Creek. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Mercury (Total) 3b. - M&E List N/A Listed portion: COSPUS12_B Jackson Creek from the boundary of National Forest lands to the confluence with West Plum Creek.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A COSPUS14 14. Mainstem of the South Platte River from the outlet of Chatfield Reservoir to the Burlington Ditch diversion in Denver, Colorado.

Listed portion: COSPUS14_B Mainstem of the South Platte River from Bowles Ave. to the Burlington Ditch diversion in Denver, Colorado.

1. Recreational Use E. coli 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPUS14_C Mainstem of the South Platte River from the outlet of Chatfield Reservoir to Bowles Ave. Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Nitrate 5. - 303(d) List L COSPUS15 15. Mainstem of the South Platte River from the Burlington Ditch diversion in Denver, Colorado, to a point immediately below the confluence with Big Dry Creek.

Listed portion: COSPUS15_B Mainstem of the South Platte River from the Burlington Ditch diversion in Denver, Colorado to Sand Creek.

1. Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Recreational Use E. coli 4a. - TMDL N/A Water Supply Use Cadmium (Total) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPUS15_C Mainstem of the South Platte River from Sand Creek, to 180 meters below 120th Ave. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Recreational Use E. coli 4a. - TMDL N/A Aquatic Life Use Temperature 5. - 303(d) List M Water Supply Use Nitrite 5. - 303(d) List H Listed portion: COSPUS15_D Mainstem of the South Platte River from 180 meters below 120th Ave, to a point immediately below the confluence with Big Dry Creek.

   Recreational Use E. coli 4a. - TMDL N/A Aquatic Life Use Temperature 5. - 303(d) List M Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Nitrite 5. - 303(d) List H COSPUS16a 16a. Mainstem of Sand Creek from the confluence of Murphy and Coal Creek in Arapahoe County to the confluence with the Toll Gate Creek.

Listed portion: COSPUS16a_A Mainstem of Sand Creek from the confluence of Murphy and Coal Creek in Arapahoe County to the confluence with the Toll Gate Creek.

1. Recreational Use E. coli 5. - 303(d) List H Water Supply Use Chloride 5. - 303(d) List L COSPUS16c 16c. All tributaries to the South Platte River, including all wetlands, from the outlet of Chatfield Reservoir, to a point immediately below the confluence with Big Dry Creek, except for listings in the subbasins of the South Platte River, and in Segments 16a, 16d, 16e, 16f, 16g, 16h, 16i, 16j, and 16k. Listed portion: COSPUS16c_B All tributaries to the South Platte River, including all wetlands, from the outlet of Chatfield Reservoir, to a point immediately below the confluence with Big Dry Creek, except for Harvard Gulch and West Harvard Gulch, and listings in the subbasins of the South Platte River and Segments 16a, 16d, 16e, 16f, 16g, 16h, 16i, 16j, and 16k. Recreational Use E. coli (May-October) 5. - 303(d) List H Listed portion: COSPUS16c_C Harvard Gulch and West Harvard Gulch. Recreational Use E. coli (May-October) 5. - 303(d) List H Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L COSPUS16d 16d. Second Creek, including all tributaries, from the source to the O?Brian Canal at 39.898789, 104.817661. Listed portion: COSPUS16d_B Second Creek, including all tributaries, from the source to the O'Brian Canal at 39.898789, -104.817661.

   Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A COSPUS16g 16g. Marcy Gulch, including all wetlands from the source to the confluence with the South Platte. Listed portion: COSPUS16g_A Marcy Gulch, including all wetlands from the source to the confluence with the South Platte.

   Aquatic Life Use Temperature 3b. - M&E List N/A Recreational Use E. coli 5. - 303(d) List H COSPUS16i 16i. Mainstem of Sand Creek from the confluence with Toll Gate Creek to the confluence with the South Platte River.

Listed portion: COSPUS16i_A Mainstem of Sand Creek from the confluence with Toll Gate Creek to the confluence with Westerly Creek.

1. Recreational Use E. coli 5. - 303(d) List H Listed portion: COSPUS16i_B Mainstem Sand Creek from the confluence with Westerly Creek to the confluence with the South Platte River.

   Recreational Use E. coli 5. - 303(d) List H Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M COSPUS16k 16k. Mainstem of Lakewood Gulch from the source to the confluence with the South Platte. Listed portion: COSPUS16k_A Mainstem of Lakewood Gulch from the source to the confluence with the South Platte. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Chloride 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COSPUS17a 17a. Washington Park Lakes, City Park Lakes, Rocky Mountain Lake, Berkely Lake. Listed portion: COSPUS17a_B Duck Lake.

   Aquatic Life Use pH 5. - 303(d) List H Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H Listed portion: COSPUS17a_C Ferril Lake.

   Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H Listed portion: COSPUS17a_D Berkeley Lake.

   Aquatic Life Use Chlorophyll-A 3b. - M&E List N/A Aquatic Life Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H Aquatic Life Use Fish (Mercury) 5. - 303(d) List H Listed portion: COSPUS17a_E Rocky Mountain Lake.

   Aquatic Life Use Fish (Mercury) 5. - 303(d) List H Aquatic Life Use Dissolved Oxygen 5. - 303(d) List L Listed portion: COSPUS17a_G Grasmere Lake.

   Aquatic Life Use Ammonia 5. - 303(d) List L Aquatic Life Use Copper (Dissolved) 5. - 303(d) List L Aquatic Life Use Dissolved Oxygen 5. - 303(d) List L COSPUS17b 17b. Sloan?s Lake.

Listed portion: COSPUS17b_A Sloan’s Lake.

1. Aquatic Life Use Chlorophyll-A 3b. - M&E List N/A Aquatic Life Use pH 5. - 303(d) List H COSPUS19 19. Lakes and reservoirs in the South Platte River system from headwaters to Chatfield Reservoir, except for listings in Segment 18. Includes Antero, Spinney Mountain, Elevenmile, Cheesman, and Strontia Springs. Listed portion: COSPUS19_B Cheesman Reservoir.

   Aquatic Life Use Fish (Mercury) 3b. - M&E List N/A Listed portion: COSPUS19_D Antero Reservoir Aquatic Life Use pH 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COSPUS19_E Eleven Mile Reservoir Aquatic Life Use pH 3b. - M&E List N/A Aquatic Life Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H COSPUS23 23. Lakes and reservoirs in watersheds tributary to the Upper South Platte River and within the City and County of Denver, except for listings in the other subbasins of the South Platte River and in Segments 17a and 17b.

Listed portion: COSPUS23_C Vanderbilt Lake.

1. Aquatic Life Use Dissolved Oxygen 5. - 303(d) List M Listed portion: COSPUS23_E Harvey Lake.

   Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Mercury (Total) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List M Aquatic Life Use Dissolved Oxygen 5. - 303(d) List M Listed portion: COSPUS23_F Aqua Golf.

   Aquatic Life Use Mercury (Total) 3b. - M&E List N/A Aquatic Life Use Ammonia 5. - 303(d) List M Aquatic Life Use pH 5. - 303(d) List M Listed portion: COSPUS23_G Parkfield Lake.

   Aquatic Life Use pH 5. - 303(d) List M Aquatic Life Use Dissolved Oxygen 5. - 303(d) List M Listed portion: COSPUS23_H Overland Pond.

   Aquatic Life Use Dissolved Oxygen 5. - 303(d) List M Aquatic Life Use pH 5. - 303(d) List M Aquatic Life Use Copper (Dissolved) 5. - 303(d) List M Listed portion: COSPUS23_I Huston Lake.

   Aquatic Life Use Mercury (Total) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List M Aquatic Life Use Dissolved Oxygen 5. - 303(d) List M COUCBL01 1. Mainstem of the Blue River from the source to above the confluence with French Gulch. Listed portion: COUCBL01_A Mainstem of the Blue River from the source to above the confluence with French Gulch. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COUCBL02a 2a. Mainstem of the Blue River from above the confluence with French Gulch to a point one half mile below Coyne Valley Road (39.523189, -106.050805).

Listed portion: COUCBL02a_A Blue River from South Barton Gulch to one half mile below Summit County Road 3. Aquatic Life Use Cadmium (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Water Supply Use Cadmium (Total) 5. - 303(d) List L Aquatic Life Use Nitrite 5. - 303(d) List L Aquatic Life Use Macroinvertebrates 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCBL02a_B Blue River from the confluence with French Gulch to South Barton Gulch. Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List L Aquatic Life Use Macroinvertebrates 5. - 303(d) List L COUCBL02b 2b. Mainstem of the Blue River from a point one half mile below Coyne Valley Road (39.523189, -106.050805) to above the confluence with the Swan River.

Listed portion: COUCBL02b_A Mainstem of the Blue River from a point one half mile below Summit County Road 3 to the confluence with the Swan River.

1. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L COUCBL02c 2c. Mainstem of the Blue River from above the confluence with the Swan River to Dillon Reservoir. Listed portion: COUCBL02c_A Mainstem of the Blue River from above the confluence with the Swan River to Dillon Reservoir.

   Aquatic Life Use Macroinvertebrates 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List L COUCBL04a 4a. All direct tributaries, including wetlands, to Dillon Reservoir and all tributaries, including wetlands, to the Blue River above Dillon Reservoir, except for specific listings in Segments 1, 2a, 2b, 2c, 4b, 6a, 10-14 and 16. Listed portion: COUCBL04a_B Gold Run Gulch below Jessie Mine. Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCBL04a_C Meadow Creek and its tributaries not in the wilderness. Aquatic Life Use Silver (Dissolved) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Listed portion: COUCBL04a_D Mainstem of Soda Creek from the source to Dillon Reservoir. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L COUCBL06a 6a. Mainstem of the Snake River, including all tributaries and wetlands, from the source to Dillon Reservoir, except for specific listings in Segments 6b, 7, 8 and 9. Listed portion: COUCBL06a_B Mainstem of the Snake River from the source to Dillon Reservoir, including Saint John Creek. Aquatic Life Use Macroinvertebrates 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Listed portion: COUCBL06a_C All tributaries and wetlands of the Snake River from the source to Dillon Reservoir, except for specific listings in Segments 6b, 7, 8, 9, and Saint John Creek. Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List M COUCBL07 7. Mainstem of Peru Creek, including all tributaries and wetlands, from the source to the confluence with the Snake River, except for specific listings in Segment 8. Listed portion: COUCBL07_A Mainstem of Peru Creek, including all tributaries and wetlands from the source to the confluence with the Snake River, except for specific listings in Segment 8. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Copper (Dissolved) 4a. - TMDL N/A Aquatic Life Use Manganese (Dissolved) 4a. - TMDL N/A Aquatic Life Use Lead (Dissolved) 4a. - TMDL N/A Aquatic Life Use pH 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A COUCBL11 11. Mainstem of French Gulch from a point 1.5 miles below Lincoln (39.484661, -105.995074) to the confluence with the Blue River.

Listed portion: COUCBL11_A Mainstem of French Gulch from a point 1.5 miles below Lincoln (39.484661, -105.995074) to the confluence with the Blue River.

1. Aquatic Life Use Macroinvertebrates 3b. - M&E List N/A COUCBL12 12. Mainstem of Illinois Gulch and Fredonia Gulch from their sources to their confluences with the Blue River. Listed portion: COUCBL12_B Mainstem of Illinois Gulch from its source to the confluence with the Blue River. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Cadmium (Dissolved) 4a. - TMDL N/A Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List M Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Macroinvertebrates 5. - 303(d) List M Listed portion: COUCBL12_C Mainstem of Fredonia Gulch from its source to the confluence with the Blue River. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List M COUCBL17 17. Mainstem of the Blue River from the outlet of Dillon Reservoir to the confluence with the Colorado River. Listed portion: COUCBL17_A Blue River from outlet of Dillon Reservoir to Green Mountain Reservoir. Aquatic Life Use Macroinvertebrates 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COUCBL17_B Blue River from Green Mountain Reservoir to confluence with Colorado River Aquatic Life Use Mercury (Total) 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COUCBL18 18. All tributaries to the Blue River, including all wetlands, from the outlet of Dillon Reservoir to the outlet of Green Mountain Reservoir, except for the specific listings in Segment 16. Listed portion: COUCBL18_B Straight Creek.

   Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H COUCBL20 20. Mainstems of Elliot Creek and Spruce Creek, including all tributaries and wetlands, from their sources to the confluence with the Blue River.

Listed portion: COUCBL20_B Spruce Creek and tributaries. Water Supply Use Arsenic (Total) 5. - 303(d) List H COUCEA02 2. Mainstem of the Eagle River from the source to above the compressor house bridge at Belden (39.526879, -106.394950).

Listed portion: COUCEA02_B Mainstem of the Eagle River from the source to Peterson Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COUCEA02_C Eagle River Below Peterson Creek to compressor house bridge at Belden. Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H COUCEA03 3. All tributaries to the Eagle River, including wetlands, from the source to above the compressor house bridge at Belden (39.526879, -106.394950), except for the specific listings in Segments 1 and 4. Listed portion: COUCEA03_A All tributaries to the Eagle River, including wetlands, from the source to the compressor house bridge at Belden, except for the specific listing in Segment 4 and those waters included in Segment 1.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L COUCEA05a 5a. Mainstem of the Eagle River from above the compressor house bridge at Belden (39.526879, -106.394950) to a point immediately above the Highway 24 Bridge near Tigiwon Road (39.554936, -106.401691). Listed portion: COUCEA05a_B Mainstem of the Eagle River from the compressor house bridge in Belden to a point located 600 ft upstream of Rock Creek.

   Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Listed portion: COUCEA05a_C Mainstem of the Eagle River from a point located 600 ft upstream of Rock Creek to a point immediately above the Highway 24 Bridge near Tigiwon Road. Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Water Supply Use Iron (Dissolved) 5. - 303(d) List L Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H COUCEA05b 5b. Mainstem of the Eagle River from a point immediately above the Highway 24 Bridge near Tigiwon Road (39.554936, -106.401691) to a point immediately above the confluence with Martin Creek. Listed portion: COUCEA05b_A Mainstem of the Eagle River from a point immediately above the Highway 24 Bridge near Tigiwon Road (39.554936, -106.401691) to a point immediately above the confluence with Martin Creek.

   Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H COUCEA05c 5c. Mainstem of the Eagle River from a point immediately above Martin Creek to a point immediately above the confluence with Gore Creek.

Listed portion: COUCEA05c_A Mainstem of the Eagle River from a point immediately above Martin Creek to a point immediately above the confluence with Gore Creek.

1. Aquatic Life Use Zinc (Dissolved) 4a. - TMDL N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H Water Supply Use Iron (Dissolved) 5. - 303(d) List H COUCEA06 6. All tributaries to the Eagle River, including all wetlands, from above the compressor house bridge at Belden (39.526879, -106.394950) to a point immediately below the confluence with Lake Creek, except for the specific listings in Segments 1, 7a, 7b, and 8.

Listed portion: COUCEA06_C Lake Creek from below the confluence with East and West Lake Creek to the mouth. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Listed portion: COUCEA06_D Beaver Creek from confluence with Wayne Creek to Mouth. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Listed portion: COUCEA06_E Red Sandstone Creek from USFS Boundary to north side I-70 Frontage Road. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCEA06_F Red Sandstone Creek from north side I-70 Frontage Road to confluence with Gore Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Listed portion: COUCEA06_H Black Gore Creek adjacent to I-70 above Miller Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List H Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H Listed portion: COUCEA06_I Rock Creek from the source to the confluence with the Eagle River. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Aquatic Life Use Cadmium (Dissolved) 5. - 303(d) List H Listed portion: COUCEA06_J All tributaries to the Eagle River, including all wetlands, from above the compressor house bridge at Belden (39.526879, -106.394950) to a point immediately below the confluence with Lake Creek, except for the specific listings in Segments 1, 7a, 7b, and 8. With other exceptions to Black Gore and Rock Creek.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCEA06_K Black Gore Creek from a point immediately below its confluence with Miller Creek to a point immediately above its confluence with Timber Creek.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Sediment 5. - 303(d) List H Listed portion: COUCEA06_L Black Gore Creek from a point immediately below its confluence with Timber Creek to the confluence with Gore Creek.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L COUCEA07a 7a. Mainstem of Cross Creek from the source to below the Minturn Water Facility (39.565419, -106.417032), except for the specific listings in Segment 1.

Listed portion: COUCEA07a_B Mainstem of Cross Creek from the source to below the Minturn Water Facility (39.565419, -106.417032), except for specific listings in Segment 1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COUCEA08 8. Mainstem of Gore Creek from the confluence with Black Gore Creek to the confluence with the Eagle River. Listed portion: COUCEA08_A Mainstem of Gore Creek from the confluence with Black Gore Creek to the confluence with the Eagle River.

1. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List L COUCEA09a 9a. Mainstem of the Eagle River from above Gore Creek to a point immediately below the confluence with Squaw Creek.

Listed portion: COUCEA09a_A Eagle River from Gore Creek to confluence with Berry Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCEA09a_B Eagle River from confluence with Berry Creek to confluence with Squaw Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List L COUCEA09b 9b. Mainstem of the Eagle River from a point immediately below the confluence with Squaw Creek to a point immediately below the confluence with Rube Creek.

Listed portion: COUCEA09b_B Eagle River from Squaw Creek to Ute Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCEA09b_C Eagle River from Ute Creek to Rube Creek. Water Supply Use Arsenic (Total) 5. - 303(d) List H COUCEA09c 9c. Mainstem of the Eagle River from a point immediately below the confluence with Rube Creek to the confluence with the Colorado River.

Listed portion: COUCEA09c_B Mainstem of the Eagle River from a point immediately below the confluence with Rube Creek to Warren Gulch (39.6785, -106.7645).

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COUCEA09c_C Mainstem of the Eagle River from a point immediately below the confluence with Warren Gulch (39.6785, -106.7645) to the confluence with the Colorado River. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List H COUCEA10a 10a. All tributaries to the Eagle River, including all wetlands, from a point immediately below the confluence with Lake Creek to the confluence with the Colorado River, except for specific listings in Segments 10b, 11 and 12, and those waters included in Segment 1.

Listed portion: COUCEA10a_A All tributaries to the Eagle River, including all wetlands, from a point immediately below the confluence with Lake Creek to the confluence with the Colorado River, except for specific listings in Segments 10b, 11 and 12, and those waters included in Segment 1. Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Aquatic Life Use pH 3b. - M&E List N/A Listed portion: COUCEA10a_B Eby Creek and tributaries.

1. Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Sulfate 5. - 303(d) List L COUCNP01 1. All tributaries to the North Platte and Encampment Rivers, including all wetlands, within the Mount Zirkel, Never Summer, and Platte River Wilderness Areas.

Listed portion: COUCNP01_B South Fork Big Creek and tributaries from source to the wilderness boundary. Water Supply Use Arsenic (Total) 5. - 303(d) List H COUCNP03 3. Mainstem of the North Platte River from the confluence of Grizzly Creek and Little Grizzly Creek to the Colorado/Wyoming border.

Listed portion: COUCNP03_A Mainstem of the North Platte River from the confluence of Grizzly Creek and Little Grizzly Creek to the Colorado/Wyoming border.

1. Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A COUCNP04a 4a. All tributaries to the North Platte River, including all wetlands, from the source to the Colorado/Wyoming border, except for those tributaries included in Segments 1, 4b, 5a, 5b, 6, 7a and 7b. Listed portion: COUCNP04a_A Tributaries to the North Platte River, including all wetlands, from the source to the Colorado/Wyoming border, except for those tributaries in Segments 1, 4b, 5a, 5b, 6, 7a and 7b, and except the Canadian and Illinois rivers and their tributaries as well as Grizzly, Little Grizzly, Lake, South Fork Big, Snyder, and North Sand creeks and their tributaries. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCNP04a_B Canadian River and tributaries. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Listed portion: COUCNP04a_C Grizzly Creek.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COUCNP04a_D Little Grizzly Creek and tributaries. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COUCNP04a_E Lake Creek and tributaries. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H Listed portion: COUCNP04a_F Illinois River and tributaries. Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L Listed portion: COUCNP04a_G South Fork Big Creek and tributaries. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCNP04a_H Snyder Creek and tributaries. Aquatic Life Use Iron (Total) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List H Water Supply Use Iron (Dissolved) 5. - 303(d) List H Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H Listed portion: COUCNP04a_I North Sand Creek and its tributaries. Beneficial Use Sediment 5. - 303(d) List H COUCNP04b 4b. Mainstem of the Illinois River, including all tributaries and wetlands, from a point immediately below the confluence with Indian Creek to the confluence with the Michigan River, except for specific listings in Segments 7a and 7b. Mainstem of the Canadian River from below 12E Road (40.720033, -106.088912) to the confluence with the North Platte River. All tributaries to the Canadian River, including wetlands, which enter the mainstem from the southwest from below 12E Road to the confluence with the North Platte River. Listed portion: COUCNP04b_A Canadian River below 12E Road to confluence w/ North Platte River. Tributaries entering mainstem of Canadian River from SW side of mainstem.

   Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCNP04b_B Mainstem of the Illinois River, including all tributaries and wetlands, from a point immediately below the confluence with Indian Creek to the confluence with the Michigan River, except for specific listings in Segment 7a and 7b. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Dissolved Oxygen 5. - 303(d) List H COUCNP05a 5a. Mainstem of the Michigan River from the source to a point immediately below the confluence with the North Fork Michigan River.

Listed portion: COUCNP05a_A Mainstem of the Michigan River from the source to a point immediately below the confluence with the North Fork Michigan River.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COUCNP05b 5b. Mainstem of the Michigan River from a point immediately below the confluence with the North Fork Michigan River to the confluence with the North Platte River. Listed portion: COUCNP05b_A Mainstem of the Michigan River from a point immediately below the confluence with the North Fork Michigan River to the confluence with the North Platte River. Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Iron (Dissolved) 5. - 303(d) List L COUCNP07b 7b. Mainstem of Spring Creek from the outlet of Spring Creek (Number 31) Reservoir to the confluence with the Illinois River.

Listed portion: COUCNP07b_A Mainstem of Spring Creek from the outlet of Spring Creek (Number 31) Reservoir to the confluence with the Illinois River.

1. Aquatic Life Use Dissolved Oxygen 5. - 303(d) List M Aquatic Life Use pH 5. - 303(d) List M COUCNP09 9. All lakes and reservoirs tributary to the North Platte and Encampment Rivers except for specific listings in Segment 8.

Listed portion: COUCNP09_B Big Creek Reservoir.

1. Aquatic Life Use Fish (Mercury) 5. - 303(d) List H Listed portion: COUCNP09_C North Delaney Lake.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCNP09_D Lake John.

   Aquatic Life Use pH 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List H COUCRF02 2. Mainstem of the Roaring Fork River, including all tributaries and wetlands, from the source to a point immediately below the confluence with Hunter Creek, except for those tributaries included in Segment 1. Listed portion: COUCRF02_A Mainstem of the Roaring Fork River, including all tributaries and wetlands, from the source to a point immediately below the confluence with Hunter Creek, except for those tributaries included in Segment 1.

   Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H COUCRF03a 3a. Mainstem of the Roaring Fork River, from a point immediately below the confluence with Hunter Creek, to a point immediately below the confluence with the Fryingpan River. All tributaries to the Roaring Fork River, including wetlands, from a point immediately below the confluence with Hunter Creek to the confluence with the Colorado River, except for those tributaries included in Segment 1, 3b, 3d, 4-10b. Listed portion: COUCRF03a_B Roaring Fork from confluence with Hunter Creek to the confluence of Trentaz Gulch. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COUCRF03a_C West Sopris Creek and tributaries. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COUCRF03a_D Capitol Creek.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COUCRF03a_E Cattle Creek from Fisher Creek to Mouth. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COUCRF03a_F Mainstem of the Roaring Fork River, from a point immediately below the confluence with Trentaz Gulch, to a point immediately below the confluence with the Fryingpan River. All tributaries to the Roaring Fork River, including wetlands, from a point immediately below the confluence with Hunter Creek to the confluence with the Colorado River, except for those tributaries included in Segment 1, 3b, 3d, 4-10b, West Sopris, Capital, Roaring Fork, Cattle Creek, and Three Mile Creek Portions.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COUCRF03a_G Three Mile Creek, including all tributaries, from the source to the Roaring Fork River. Aquatic Life Use Temperature 3b. - M&E List N/A COUCRF03b 3b. Mainstem of Red Canyon, including all tributaries and wetlands, from the source to the confluence with the Roaring Fork River, except for Landis Creek from the source to the Hopkins Ditch (39.522138, -107.223479).

Listed portion: COUCRF03b_B Landis Creek from the Hopkins Ditch (39.522138, -107.223479) to its confluence with Red Canyon.

1. Aquatic Life Use Iron (Total) 3b. - M&E List N/A COUCRF03c 3c. Mainstem of the Roaring Fork River from a point immediately below the confluence with the Fryingpan River to the confluence with the Colorado River.

Listed portion: COUCRF03c_B Roaring Fork below the confluence with the Crystal River to the mouth. Aquatic Life Use Temperature 5.- 303(d) List H Water Supply Use Arsenic (Total) 5.- 303(d) List L Listed portion: COUCRF03c_C Roaring Fork River from the Fryingpan River to the Crystal River. Aquatic Life Use Temperature 5. - 303(d) List H COUCRF04 4. Mainstem of Brush Creek from the source to the confluence with the Roaring Fork River. Listed portion: COUCRF04_A Mainstem of Brush Creek from the source to the confluence with the Roaring Fork River. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COUCRF07 7. All tributaries to the Fryingpan River, including all wetlands, from the source to the confluence with the Roaring Fork River, except for those tributaries included in Segment 1. Listed portion: COUCRF07_B South Fork Frying Pan River from transbasin diversion to confluence with unnamed tributary (39.251280N, -106.594420W).

1. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H COUCRF12 12. All lakes and reservoirs tributary to the Roaring Fork River, except for the specific listings in Segment 11. Listed portion: COUCRF12_C Ruedi Reservoir.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L COUCUC01 1. Mainstem of the Colorado River, including all tributaries and wetlands, within or flowing into Rocky Mountain National Park.

Listed portion: COUCUC01_A Mainstem of the Colorado River, including all tributaries and wetlands, within or flowing into Rocky Mountain National Park.

1. Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List H COUCUC02 2. Mainstem of the Colorado River, including all tributaries and wetlands, within or flowing into Arapahoe National Recreation Area, except for the specific listing in Segment 5. Listed portion: COUCUC02_C Colorado River from Shadow Mountain Reservoir to Granby Reservoir. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCUC02_D Mainstem of North Inlet from Tonahutu Creek to Grand Lake. Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Aquatic Life Use Silver (Dissolved) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCUC02_E Mainstem of East Inlet.

   Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Aquatic Life Use Silver (Dissolved) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCUC02_F Mainstem of the Colorado River, including all tributaries and wetlands within, or flowing into Arapahoe National Recreation Area. Except for Willow, Stillwater, Arapaho Creeks, East Inlet, North Inlet, Roaring Fork, and the Colorado River from Shadow Mountain Reservior to Granby Reservior.

   Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCUC02_I Arapaho Creek downstream of Monarch Lake. Aquatic Life Use Silver (Dissolved) 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCUC02_K Willow Creek, including all tributaries and wetlands, from the National Forest boundary to a point immediately upstream of Willow Creek Reservoir.

   Aquatic Life Use Temperature 3b. - M&E List N/A Listed portion: COUCUC02_L Stillwater Creek, including its tributaries and wetlands, within or flowing into Arapaho Recreation Area.

   Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COUCUC02_M Roaring Fork Arapaho Creek from Indian Peaks Wilderness to Lake Granby. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List H COUCUC03 3. Mainstem of the Colorado River from the outlet of Lake Granby to below the confluence with the Roaring Fork River.

Listed portion: COUCUC03_A Colorado River from outlet of Lake Granby to Windy Gap Reservoir. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COUCUC03_B Colorado River from Windy Gap Reservoir to 578 Road Bridge. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COUCUC03_C Colorado River from 578 Road Bridge to Gore Canyon. Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COUCUC03_D Colorado River from Gore Canyon to Derby Creek. Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COUCUC03_E Colorado River from Derby Creek to below the confluence with the Roaring Fork River. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List H COUCUC04 4. All tributaries to the Colorado River, including all wetlands, from the outlet of Lake Granby to above the confluence with the Roaring Fork River, which are on National Forest lands, except for the specific listings in Segments 2, 8, 9 and 10a.

Listed portion: COUCUC04_B Red Dirt Creek and its tributaries. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H Listed portion: COUCUC04_C All tributaries to the Colorado River, including all wetlands, from the outlet of Lake Granby to above the confluence with the Roaring Fork River, which are on National Forest lands, except for the specific listings in Segments 2, 8, 9 and 10a and Red Dirt Creek. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Cadmium (Total) 3b. - M&E List N/A COUCUC05 5. Mainstem of Willow Creek from the outlet of Willow Creek Reservoir to the confluence with the Colorado River.

Listed portion: COUCUC05_B Mainstem of Willow Creek from the outlet of Willow Creek Reservoir to the confluence with the Colorado River.

1. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COUCUC06a 6a. All tributaries to the Colorado River, including all wetlands, from the border of Rocky Mountain National Park and Arapahoe National Recreation Area to a point immediately above the confluence with the Blue River and Muddy Creek, which are not on National Forest lands, except for the specific listings in Segments 5, 6b, 8 and 10a-c.

Listed portion: COUCUC06a_B All tributaries to the Colorado River, including all wetlands, from the border of Rocky Mountain National Park and Arapahoe National recreation Area to a point immediately above the confluence with the Blue River and Muddy Creek, which are not on the National Foreste lands, except for the specific listings in Segments 5, 6b and 10a-c. Aquatic Life Use Temperature 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Mercury (Total) 3b. - M&E List N/A COUCUC06b 6b. Mainstem of un-named tributary to Willow Creek from the headwaters to the confluence with Willow Creek (40.131422, -105.920895).

Listed portion: COUCUC06b_A Mainstem of un-named tributary from the headwaters to Willow Creek Reservoir Road. Aquatic Life Use Nitrite 5. - 303(d) List M Listed portion: COUCUC06b_B Mainstem of un-named tributary to Willow Creek from the Willow Creek Reservoir Road to the confluence with Willow Creek (40.131422, -105.920895). Aquatic Life Use Ammonia 4a. - TMDL N/A COUCUC07a 7a. All tributaries to the Colorado River, including all wetlands, from a point immediately above the confluence with the Blue River and Muddy Creek to a point immediately below the confluence with the Roaring Fork River, which are not on National Forest lands, except for waterbodies in Upper Colorado Segments 7b, 7c, 7d, and 7e and waterbodies in the Blue River, Eagle River, and Roaring Fork River basins. Listed portion: COUCUC07a_C Mainstem of Muddy Creek.

1. Recreational Use E. coli 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Iron (Total) 5. - 303(d) List H COUCUC07b 7b. All tributaries to Muddy Creek, including all wetlands, from the inlet of Wolford Mountain Reservoir to the confluence with the Colorado River. Mainstems of Rock Creek, Deep Creek, Sheephorn Creek, Sweetwater Creek, Piney River and Blacktail Creek, including all tributaries and wetlands, from their sources to their confluences with the Colorado River, which are not on National Forest lands. Listed portion: COUCUC07b_A Mainstems of Rock Creek, Deep Creek, Sheephorn Creek, Sweetwater Creek and Piney River, including all tributaries and wetlands, from their sources to their confluences with the Colorado River, which are not on National Forest Lands. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COUCUC07b_D All tributaries to Muddy Creek, including all wetlands, from the inlet of Wolford Mountain Reservoir to the confluence with the Colorado River, except Alkali Slough and its tributaries. Water Supply Use Sulfate 3b. - M&E List N/A Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Listed portion: COUCUC07b_E Alkali Slough and its tributaries. Water Supply Use Manganese (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 5. - 303(d) List L Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L Water Supply Use Sulfate 5. - 303(d) List L COUCUC07c 7c. Mainstem of Muddy Creek from the source to a point immediately below the confluence with Eastern Gulch, except those waters on National Forest lands. All tributaries to Muddy Creek, including all wetlands, from the source to the inlet of Wolford Mountain Reservoir, except those waters on National Forest lands. The mainstems of Derby Creek, Cabin Creek, and Red Dirt Creeks (all tributary to the Colorado River), including all tributaries and wetlands, from their sources to their confluences with the Colorado River, except those waters on National Forest lands.

Listed portion: COUCUC07c_B Diamond Creek and its tributaries. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List H COUCUC07d 7d. Mainstem of Muddy Creek from the outlet of Wolford Mountain Reservoir to above the Highway 40 Bridge in Kremmling (40.060574, -106.398739).

Listed portion: COUCUC07d_A Mainstem of Muddy Creek from the outlet of Wolford Mountain Reservoir to Cow Gulch. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COUCUC07d_B Mainstem of Muddy Creek from Cow Gulch to the Highway 40 Bridge in Kremmling (40.060574, -106.398739).

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Water Supply Use Manganese (Dissolved) 5. - 303(d) List L COUCUC07e 7e. Mainstem of Muddy Creek from above the Highway 40 Bridge in Kremmling (40.060574, -106.398739) to the confluence with the Colorado River.

Listed portion: COUCUC07e_A Mainstem of Muddy Creek from above the Highway 40 Bridge in Kremmling (40.060574, -106.398739) to the confluence with the Colorado River. Aquatic Life Use Temperature 5. - 303(d) List H COUCUC08 8. Mainstem of the Williams Fork River, including all tributaries and wetlands, from the source to the confluence with the Colorado River, except for those tributaries in Segment 9. Listed portion: COUCUC08_B Mainstem of Williams Fork River below Kinney Creek. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List H Listed portion: COUCUC08_C Ute Creek and its tributaries. Water Supply Use Arsenic (Total) 3b. - M&E List N/A COUCUC10a 10a. Mainstem of the Fraser River from the source to a point immediately below the Rendezvous Bridge (39.933728, -105.789785). All tributaries to the Fraser River, including wetlands, from the source to the confluence with the Colorado River, except for those tributaries included in Segments 2 and 9. Listed portion: COUCUC10a_B Ranch Creek and its tributaries. Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Aquatic Life Use Temperature 5. - 303(d) List L Listed portion: COUCUC10a_D Vasquez Creek and its tributaries. Aquatic Life Use Macroinvertebrates (Provisional) 5. - 303(d) List L Listed portion: COUCUC10a_G Saint Louis Creek below King Creek. Aquatic Life Use Temperature 5. - 303(d) List H COUCUC10c 10c. Mainstem of the Fraser River from a point immediately below the Hammond No 1 Ditch (39.952113, -105.814481) to the confluence with the Colorado River. Listed portion: COUCUC10c_A Fraser River from below the Hammond No 1 Ditch in Town of Fraser (39.952113, -105.814481) to Fraser Canyon near Tabernash.

1. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCUC10c_B Fraser River from Fraser Canyon near Tabernash to the Town of Granby. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCUC10c_C From the Town of Granby to confluence with the Colorado River. Recreational Use E. coli 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List L COUCUC12 12. Lakes and reservoirs within Arapahoe National Recreation Area, including Grand Lake, Shadow Mountain Lake and Lake Granby.

Listed portion: COUCUC12_B Shadow Mountain Reservoir.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COUCUC12_C Lake Granby.

   Water Supply Use Arsenic (Total) 5. - 303(d) List L Aquatic Life Use Fish (Mercury) 5. - 303(d) List H Listed portion: COUCUC12_D Willow Creek Reservoir.

   Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COUCUC12_E Grand Lake.

   Aquatic Life Use Fish (Mercury) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5. - 303(d) List H COUCUC13 13. All lakes and reservoirs tributary to the Colorado River from the boundary of Rocky Mountain National Park and Arapahoe National Recreation Area to a point immediately above the confluence with the Roaring Fork River, except for specific listings in Upper Colorado Segments 11 and 12 and the Blue River and Eagle River subbasins.

Listed portion: COUCUC13_C Wolford Mountain Reservoir.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COUCUC13_D Williams Fork Reservoir.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COUCUC13_E Windy Gap Reservior.

   Water Supply Use Arsenic (Total) 5. - 303(d) List H COUCYA02a 2a. Mainstem of the Yampa River from the confluence of the Bear River and Phillips Creek to a point immediately above the confluence with Oak Creek.

Listed portion: COUCYA02a_A Mainstem of the Yampa River from the confluence of the Bear River and Phillips Creek to Stagecoach Reservoir.

1. Water Supply Use Arsenic (Total) 5. - 303(d) List L Listed portion: COUCYA02a_B Mainstem of the Yampa River from Stagecoach Reservoir to above confluence with Oak Creek.

   Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COUCYA02b 2b. Mainstem of the Yampa River from a point immediately above the confluence with Oak Creek to a point immediately below the confluence with Elkhead Creek.

Listed portion: COUCYA02b_A Mainstem of the Yampa River from a point immediately above the confluence with Oak Creek to a point immediately below the confluence with Elkhead Creek. Aquatic Life Use Temperature 5. - 303(d) List H Water Supply Use Arsenic (Total) 5. - 303(d) List L COUCYA03 3. All tributaries to the Yampa River, including all wetlands, from the source to above the confluence with the Elk River, except for specific listings in Segments 1 and 4-7. Mainstem of the Bear River, including all tributaries and wetlands, from the boundary of the Flat Tops Wilderness Area to the confluence with the Yampa River.

Listed portion: COUCYA03_A Tributaries to Yampa River except, except for specific listings in Segments 4-8, 13a-f and 19. Mainstem of the Bear River, including all tributaries and wetlands from the boundary of the Flat Tops Wilderness Area to the confluence with the Yampa River. Also excludes Bushy Creek, Mainstem of Walton Creek, Little Morrison Creek, and Gunn Creek. Water Supply Use Arsenic (Total) 3b. - M&E List N/A Listed portion: COUCYA03_B Bushy Creek.

1. Aquatic Life Use Sediment 5. - 303(d) List L Listed portion: COUCYA03_D Little Morrison Creek.

   Water Supply Use Arsenic (Total) 5. - 303(d) List H Listed portion: COUCYA03_E Gunn Creek.

   Aquatic Life Use Zinc (Dissolved) 5. - 303(d) List L Water Supply Use Arsenic (Total) 5. - 303(d) List H COUCYA04 4. Mainstem of Little White Snake Creek from the source to the confluence with the Yampa River. Listed portion: COUCYA04_A Mainstem of Little White Snake Creek from the source to the confluence with the Yampa River.

   Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 5. - 303(d) List M COUCYA08 8. Mainstem of the Elk River, including all tributaries and wetlands, from the source to the confluence with the Yampa River, except for those tributaries included in Segments 1 and 20a. Mainstem of the West Fork Elk River from the source to the confluence with the Yampa River. Listed portion: COUCYA08_B Mainstem of the Elk River, including all tributaries and wetlands, below Morin Ditch to the confluence with the Yampa River.

   Recreational Use E. coli 5. - 303(d) List H Listed portion: COUCYA08_C Lost Dog Creek and tributaries. Aquatic Life Use Zinc (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 3b. - M&E List N/A COUCYA13b 13b. Mainstem of Foidel Creek, including all tributaries and wetlands, from the source to the confluence with Middle Creek. Mainstem of Fish Creek, including all tributaries and wetlands, from County Road 27 (40.355559, -107.105131) to the confluence with Trout Creek, except for specific listings in Segment 13g. Mainstem of Middle Creek, including all tributaries and wetlands, from County Road 27 (40.339183, -107.025533) to the confluence with Trout Creek.

Listed portion: COUCYA13b_C Foidel Creek and tributaries. Aquatic Life Use Sediment 5. - 303(d) List H Aquatic Life Use Macroinvertebrates 5. - 303(d) List H Listed portion: COUCYA13b_D Middle Creek and tributaries. Aquatic Life Use Sediment 5. - 303(d) List H COUCYA13c 13c. Mainstem of Trout Creek, including all tributaries and wetlands, from the headgate of Spruce Hill Ditch (40.317190, -107.005110) to the confluence with Fish Creek, except for specific listings in Segment 13b. Listed portion: COUCYA13c_B Mainstem of Trout Creek, including all tributaries and wetlands, from the headgate of Spruce Hill Ditch (40.317190, -107.005110) to the confluence with Fish Creek, except for specific listings in Segment 13b.

1. Aquatic Life Use Dissolved Oxygen 3b. - M&E List N/A COUCYA13d 13d. Mainstem of Dry Creek, including all tributaries and wetlands, from the source to above the confluence with Temple Gulch.

Listed portion: COUCYA13d_C Dry Creek from Seneca sample location 5 (WSD5) to above Temple Gulch. Aquatic Life Use Iron (Total) 5. - 303(d) List L Listed portion: COUCYA13d_D Mainstem of Dry Creek, including all tributaries and wetlands, from source to above the confluence with Temple Gulch, except for the mainstem of Dry Creek from Seneca sample location 5 (WSD5) to above Temple Gulch.

1. Aquatic Life Use Iron (Total) 5. - 303(d) List L COUCYA13e 13e. Mainstem of Sage Creek, including all tributaries and wetlands, from the source to the confluence with the Yampa River.

Listed portion: COUCYA13e_A Mainstem of Sage Creek, including all tributaries and wetlands,from the source to above Routt County Road 51D, Grassy Creek and tributaries.

1. Aquatic Life Use Temperature 3b. - M&E List N/A Aquatic Life Use Macroinvertebrates 3b. - M&E List N/A Listed portion: COUCYA13e_B Sage Creek and tributaries below Routt County Road 51D to the confluence with the Yampa River.

   Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List L COUCYA13g 13g. All tributaries to Fish Creek from the confluence with Cow Camp Creek (40.398773, -107.016467) to the confluence with Trout Creek.

Listed portion: COUCYA13g_C Unnamed Tributary (40.419, -107.00) above Fish Creek. Aquatic Life Use Iron (Total) 5. - 303(d) List H COUCYA13h 13h. Mainstem of Dry Creek (near Hayden), including all tributaries and wetlands, from above the confluence with Temple Gulch to the confluence with the Yampa River. Listed portion: COUCYA13h_A Mainstem of Dry Creek, (near Hayden), including all tributaries and wetlands, from Routt County Road 53 to the confluence with the Yampa River.

1. Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M Listed portion: COUCYA13h_B Dry Creek, including Temple Gulch and all tributaries, from the mainstem of Dry Creek just above the confluence with Temple Gulch to Routt County Road 53. Aquatic Life Use Selenium (Dissolved) 5. - 303(d) List M COUCYA13j 13j. Mainstem of Grassy Creek (near Hayden), including all tributaries and wetlands, from above the confluence with Scotchmans Gulch to the confluence with the Yampa River. Listed portion: COUCYA13j_C Scotchmans Gulch and its tributaries above Grassy Creek Aquatic Life Use Selenium (Dissolved) 3b. - M&E List N/A COUCYA15 15. Mainstem of Elkhead Creek, including all tributaries and wetlands, from a point immediately below the confluence with Calf Creek to the confluence with the Yampa River. Dry Fork Elkhead Creek, including all tributaries and wetlands, from a point immediately below 80A Road (40.612676, -107.228533) to the confluence with Elkhead Creek.

Listed portion: COUCYA15_B Mainstem of Elkhead Creek from Calf Creek to Yampa River. Water Supply Use Arsenic (Total) 5. - 303(d) List H COUCYA18 18.South Fork Little Snake River and Middle Fork Little Snake River, including all tributaries and wetlands, from their sources to the confluence with the Little Snake River, which are not on National Forest lands. North Fork Little Snake River, including all tributaries and wetlands, from the Colorado/Wyoming border to the confluence with the Little Snake River.

Listed portion: COUCYA18_A Little Snake River including all tributaries and wetlands from forest boundary to Wyoming border, except for the South Fork of the Little Snake River. Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Listed portion: COUCYA18_B South Fork of Little Snake River and its tributaries. Water Supply Use Iron (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5.- 303(d) List L COUCYA22 22.All lakes and reservoirs tributary to the Yampa River from the source to the confluence with Elkhead Creek, except for those listed in Segment 21. All lakes and reservoirs tributary to Elkhead Creek from the source to the confluence with the Yampa River, except for specific listings in Segment 23. All lakes and reservoirs tributary to the Little Snake River, including those on National Forest lands. Listed portion: COUCYA22_B Catamount Lake.

1. Aquatic Life Use Fish (Mercury) 5.- 303(d) List H Listed portion: COUCYA22_D Pearl Lake.

   Aquatic Life Use Mercury (Total) 3b. - M&E List N/A Aquatic Life Use Copper (Dissolved) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5.- 303(d) List H Listed portion: COUCYA22_E Steamboat Lake.

   Aquatic Life Use Iron (Total) 3b. - M&E List N/A Water Supply Use Arsenic (Total) 5.- 303(d) List H Water Supply Use Iron (Dissolved) 5.- 303(d) List L Listed portion: COUCYA22_F Stagecoach Reservoir.

   Water Supply Use Arsenic (Total) 5.- 303(d) List H Aquatic Life Use Fish (Mercury) 5.- 303(d) List H COUCYA23 23.Elkhead Reservoir Listed portion: COUCYA23_A Elkhead Reservoir.

   Water Supply Use Arsenic (Total) 3b. - M&E List N/A Aquatic Life Use Iron (Total) 3b. - M&E List N/A Aquatic Life Use Fish (Mercury) 5.- 303(d) List H

93.5 - 93.9 Reserved

93.10 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND

PURPOSE; MARCH, 2004 RULEMAKING The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.

BASIS AND PURPOSE (303(d) List)

A. Introduction This regulation establishes Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (“TMDLs”). This list was prepared to fulfill section 303(d) of the federal Clean Water Act (“Act”) which requires that states submit to the U.S. Environmental Protection Agency (“EPA”) a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.

Once listed, the State is required to prioritize these water bodies or segments (rivers, streams, lakes reservoirs) based on the severity of pollution and other factors. It will then determine the causes of the water quality problem and allocate the responsibility for controlling the pollution. This analysis is called the TMDL Process, and results in the determination of: 1) the amount of a specific pollutant that a segment can receive without exceeding a water quality standard (the TMDL), and 2) the apportionment to the different contributing sources of the pollutant loading (the allocation). The TMDL must include a margin of safety, waste load allocation (for point sources) and a load allocation (for non-point sources and natural background). The TMDL must include upstream loads in the assessment and apportionment process.

B. List Development 1. Listing Methodology The “Section 303(d) Listing Methodology - 2004 Listing Cycle” contains a description of the listing process, the criteria for listing, and the criteria for determination of TMDL priority. The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission administrative action hearing on September 9, 2003.

This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2004 Section 303(d) List and the 2004 M&E List. However, this methodology was not adopted by the Commission as a rule. The Commission therefore has the flexibility to take into account other appropriate factors in making site-specific listing decisions.

2. Information Considered The Commission has considered all existing and readily available information in developing the 2004 Section 303(d) List. In determining whether data and information are existing and readily available, it has taken into account such data and information as the Division has utilized in the preparation of those identification processes, calculations and models referenced in 40 CFR §130.7(a)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and submitted in reports provided to the Division as referenced in 40 CFR §130.7(a)(5)(iii). In addition, the Commission accepted credible data and information that was submitted in accordance with the listing process schedule, whether submitted by EPA or any other interested party. The Division also continues to independently collect and analyze new data on a rotating basin basis as part of its triennial review efforts and will utilize such data and information in making future listing determinations. Existing data which was not brought forward through one of the above mechanisms or otherwise presented to the Commission in accordance with the schedule was not treated as “readily available” for purposes of making the 2004 listing decisions. Such information will be considered in the next listing cycle.

C. Prioritization The objective of prioritization is to identify those waterbody segments where the Division and the public should concentrate their resources. Priorities of High, Medium and Low were established according to section IV. of the 2004 Section 303(d) Listing Methodology. Segments/parameters where the Commission determined that an appropriate plan is in place to resolve the uncertainty as specified in section 93.4 have been denoted as “L*”. A Low priority may also be assigned to other segments as per section IV.

D. Discussion of Issues Raised in the Hearing During the course of the hearing, the status of approximately 30 segments was debated. The basis for the Commission’s decisions regarding the major issues for these segments is recorded below.

1. Selenium: Several parties questioned whether selenium, where the source is underlying native shale, should be considered a pollutant. The Commission found that selenium, like many other naturally occurring metals in Colorado is a pollutant and is classified as such on EPA’s list of priority toxic pollutants (62 FR 42160). If the source of impairment is natural, that is grounds for consideration of an ambient quality-based, site-specific standard as described in Regulation No. 31 at 31.7 1(b)(ii). However, the listing decisions must be made based upon a comparison of the current adopted standard and the ambient condition for the segment. Although parties to the rulemaking submitted testimony questioning the decision to list several specific segments for selenium, such as Lower Colorado River segment 3 and Lower Arkansas River segment 1a, the evidence provided was directed largely at questioning the appropriateness of the current selenium standards. The Commission has determined, based on the evidence submitted, that these segments are not in attainment of the current selenium standards.

2. Segments where there is no new data, but following the 2004 Listing Methodology resulted in a different conclusion than in 2002: The following segments had no new data included in the assessments since the 2002 listing cycle. However, clarification and changes in the 2004 Listing Methodology resulted in the segments moving from the Monitoring and Evaluation List to the 303(d) List. The modifications that resulted in the most changes had to do with more clearly specifying that segments with small datasets where the ambient condition exceeds the standard by more than 50 percent should be listed. The following segments were affected:

1. Gunnison River Basin: Lower Gunnison segment 27 Uncompahgre segment 2 Lower Colorado River Basin: White River segment 9b

3. Segments with multiple tributaries: Issues were raised regarding what is the appropriate way to handle segments with multiple tributaries where there is evidence of impairment. The Commission found that since segments are generally treated as having consistent uses and characteristics, their impairment should be handled in a similar fashion. Unless either water quality data or other evidence has been presented that shows that the impairment is not present in the entire segment, the entire segment has been listed as impaired. “Other evidence” may include changes in geology within a segment or the confluence with a stream known to be impaired. Nevertheless, it is anticipated that before any TMDL is developed and implemented in “all tributary” segments, work will be performed to determine the causes and locations of the impairment, such that efforts and controls are not inappropriately directed towards individual tributaries that are not truly of concern, and the Section 303(d) List can be modified accordingly. Where other evidence shows that some portions are in exceedance and other portions are not, only the impaired portion needs to be listed. The following segments were listed based on this rationale: Gunnison River Basin: Lower Gunnison segments 4a and 4b North Fork segments 5 and 6 Lower Colorado River Basin: Lower Colorado segment 4a E. Segment- Specific Issues 1. San Juan Basin, Dolores River below McPhee Reservoir: Despite a recent decline in the fish population in this reach, the Commission found that there was not adequate readily available evidence to conclude that there exists an impairment of the aquatic life use due to other than extraordinary events associated with the long-term drought that has existed in southwest Colorado for several years. In view of evolving operations of McPhee Reservoir and varying (and generally declining) hydrologic conditions, the Commission is not able at this time to identify an “expected condition” upon which to base a decision of impairment. Further, even if an impairment caused by other than the extraordinary events associated with the drought were found to exist, the Commission could not conclude based on this record that the decline was due to a “pollutant” as compared to “pollution.” Nevertheless, the Commission encourages cooperation by all interested parties in the implementation of habitat improvement measures that may serve to enhance the quality of the fishery in the reach. The Commission is prepared to revisit the concept of “expected condition” as it applies to this reach should that be warranted by changes in habitat condition. Certainly the achievement of goals set under the 1996 Operating Agreement for McPhee Reservoir may influence the nature of the expected condition. Finally, any evidence of impairment due to pollutants can be brought forth at the next listing hearing.

2. South Platte Basin, Clear Creek, segments 14b and 15: Available data, with specific reference to biological information on fish species collected over time and visual observations of the physical condition of the stream bed, provide an indication of “use-impairment” for Clear Creek Segments 14b and 15 relative to aquatic life. Though organic sediment appears to be a significant contributor to the impairment, the exact interaction of potentially numerous causative factors need to be further explored. No single source or cause of the impairment has been identified to date. Coors Brewing Company has voluntarily come forward with a study plan for segments 14a, 14b and 15 as part of the “pilot study” approach outlined in the section 309 study report recently submitted to the State Legislature. This pilot study would assist in defining the expected condition for these segments in view of existing hydrological/habitat conditions and in fashioning the best approach to remedying the impairment. Should Coors decide to proceed with the pilot study, the Division will identify segments 14b and 15 as “low priority” and refrain from any further TMDL implementation measures until such time as the study results are known and an appropriate approach to rectifying the identified problems is crafted in cooperation with basin stakeholders.

3. Upper Colorado Basin, Blue River segments 6 and 8 (Camp Cr, Jones Gulch, Keystone Cr, and Mozart Creek): The four identified tributaries in these two segments were proposed by the Division to be listed as impaired relative to measured pH levels. The evidence submitted raised questions regarding the representativeness of the data showing a possible standards exceedance, particularly in the absence of data regarding seasonality of pH levels for multiple years. Therefore, the Commission determined that it is more appropriate to include these specific tributaries on the Monitoring and Evaluation List at this time. Keystone Resorts has stated that it will complete a Use Attainability Analysis for Camp Creek and Jones Gulch, and that it is willing to include Keystone Creek and Mozart Creek in this analysis. The Commission believes that it is appropriate to revisit the attainment status of these segments following completion of the UAA. Depending on the results of this analysis, the adoption of site-specific seasonal pH standards is one option that can be considered. Indeed, the Commission notes that the evidence submitted to it showed that nearby snowmaking actually mitigates pH levels in the snow.

4. Uncompahgre River, segment 6b (Red Mountain Creek): The Commission does not believe that an impairment of the aquatic life use of segment 6b relative to a realistic expected condition for this segment has been shown. The Commission found that the aquatic community in segment 6a is not the appropriate expected condition for this segment. The Commission endorses the Division’s proposal not to list at this time, while moving forward to investigate segment 6b and make a recommendation to the Commission regarding the attainable aquatic life use and appropriate numeric standards in the context of the next basin-wide standards and classification rulemaking proceedings. However, it is uncertain at this time whether any future remediation activities in this area will improve the aquatic life use of this segment. In the absence of documentation that the attainable expected condition for this segment is an aquatic life use that is better than the current condition of this segment, it would be inappropriate to identify this segment as impaired.

5. Bear Creek segment 1a: This segment was proposed by the Division and by Trout Unlimited to be included on the Section 303(d) List. The evidence submitted demonstrated adverse impacts to the aquatic life use in this segment during 2002, and documented that the use had started to recover in 2003, although full recovery had not yet occurred. The evidence also demonstrated that the unusual and extreme drought conditions in 2002 were the determinative cause of the adverse impacts to aquatic life. Although there was evidence submitted indicating that ammonia concentrations or elevated temperatures may have adversely affected the aquatic life, the evidence demonstrated that these potentially harmful conditions would not have been present except for the drought. The Commission has concluded that this segment should be included on the Monitoring and Evaluation List for potential aquatic life, ammonia and temperature impairments, and that its status should be reconsidered in future updates of Regulations No. 93 and No. 94. Any evidence of impairment due to pollutants can be brought forth at the next listing hearing.

6. Lower Colorado segment 13b: This is an “all tributaries” segment that was proposed by the Division to be listed in its entirety for selenium. All of the ambient water quality data available in the record for this hearing was from tributaries on the north side of the Colorado River. In addition, there was testimony regarding significant differences in the geology on the north and south sides of the Colorado River in this area. Therefore, the Commission determined that it is appropriate that only the tributaries on the north side of this segment should be listed as impaired for selenium.

7. West Fork of Clear Creek, segment 5: The Commission found that the acute zinc standard in the West Fork of Clear Creek was exceeded more than once in three years. Because the chronic zinc standard is in attainment, and because Climax presented credible biological evidence that the aquatic life use classification is supported, the Commission determined that listing for acute zinc is not warranted in this instance. This segment is included on the Section 303(d) List as impaired for copper.

8. Middle South Platte segment 1: The Division proposed that the portion of this segment from Big Dry Creek to Highway 60 be included on the Section 303(d) List as impaired for dissolved oxygen during the months of August and September. The evidence submitted offered conflicting interpretations of what the available data for this segment show regarding attainment. Because this segment appears to be in compliance with dissolved oxygen standards based on the established convention of looking at the 15th percentile of the available data for the entire segment, the Commission determined that it is more appropriate at this time to include this segment on the Monitoring and Evaluation List for further assessment of dissolved oxygen conditions. The Commission also believes that future clarification of the appropriate methodology for assessing attainment of dissolved oxygen standards, e.g. within specific months of the year, would be helpful.

F. Plans to Resolve Uncertainty Three parties presented plans to resolve uncertainty for segments that have temporary modifications based on uncertainty [see Regulation No. 31.7(3)(a)(iii)]. These segments will not be subject to the development of a TMDL as long as there is a plan in place that addresses the following:

(1) There is an appropriate plan in place to remove the uncertainty;

(2) The plan includes an implementation schedule that will resolve the uncertainty in a time frame consistent with Colorado’s timeline for the development of TMDLs; and (3) The plan is being implemented in accordance with its terms. The Commission found that the following segments have adequate plans. It is the Commission’s intent to revisit these plans at the next listing cycle to determine if they continue to meet the Commission’s intent.

1. Fountain Creek segment 6 (Monument Creek from the National Forest boundary to Fountain Creek): The selenium water quality standard for Fountain Creek segment 6 has a temporary modification for uncertainty pursuant to section 31.7(3)(a)(iii) of the Basic Standards. The City of Colorado Springs submitted an appropriate plan to remove the uncertainty 2. Lower Arkansas segment 1a (Arkansas River from Fountain Creek to the Colorado Canal): The selenium water quality standard for Lower Arkansas segment 1a has a temporary modification for uncertainty pursuant to section 31.7(3)(a)(iii) of the Basic Standards. The City of Pueblo submitted an appropriate plan to remove the uncertainty 3. Upper Yampa segment 13d (Dry Creek): In the 2003 Upper Colorado River rulemaking hearing, the Commission adopted a temporary modification (based on uncertainty) of 60 ug/L for selenium in Dry Creek. This temporary modification was based on five WQCD samples collected in Dry Creek in 2001 and 2002 near its confluence with the Yampa River. The Commission approved Seneca Coal Company’s plan to monitor Dry Creek with the objective of determining the source or sources of selenium loading, where the loading is isolated in the lower portion of Dry Creek and to determine whether the loading is due to natural or irreversible man-induced sources.

BASIS AND PURPOSE (Monitoring and Evaluation List)

A. Introduction This regulation establishes Colorado’s Monitoring and Evaluation List. This list was prepared as part of the effort to identify water bodies for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards (those impaired waters requiring TMDLs). Regulation No. 93 is the list of impaired waters which require TMDLs. This regulation is the Monitoring and Evaluation List (“M&E List”) that identifies water bodies where there is reason to suspect water quality problems, but there is also uncertainty regarding one or more listing factors, such as the representative nature of the available data. Water bodies that are impaired but it is unclear whether the cause of impairment is attributable to pollutants as opposed to pollution are also included on the M&E List.

B. List Development The statement of basis and purpose for Regulation No. 93 contains a description of how the lists were developed.

C. Prioritization and Scheduling The Division has committed to establishing a plan for monitoring and evaluating these water bodies prior to the list submission date for the subsequent listing cycle. Further, the Commission has committed to determining their appropriate status (as either impaired or fully supporting) within ten years of their placement on the M&E List.

D. Segment-Specific Issues 1. Blue River segment 3: The Commission has included Gold Run Gulch below Jessie Mine (for cadmium and zinc) and the South Branch Swan River below Royal Tiger Mine (for zinc) on the Monitoring and Evaluation List. The Royal Tiger Mine and the Jessie Mine are both part of a CERCLA remediation effort, for which remedial project design is currently out to bid. Therefore, the Commission understands that the conditions in this area affecting water quality will be changing and that it is currently uncertain what uses or water quality can be supported in these waters in the future. The Commission does not intend by including these waters on the Monitoring and Evaluation List to conclude that any actions other than those CERCLA-related activities already underway are necessary or appropriate at this site. The status of those efforts will be reviewed during the next update of this list.

2. Segments proposed for the Section 303(d) List: In several specific instances, the Commission made a determination in this rulemaking hearing that segments proposed by the Division or others for inclusion on the Section 303(d) List should instead be included on the Monitoring and Evaluation List. This applies in particular to Bear Creek segment 1a and Middle South Platte segment 1 in the South Platte Basin and to four named tributaries in Blue River segments 6 and 8 in the Upper Colorado River Basin. In each of these instances, the rationale for the Commission’s decision to included these waters on the Monitoring and Evaluation List is set forth in the Statement of Basis and Purpose adopted for Regulation No. 93 as a result of this rulemaking.

93.11 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND

PURPOSE; FEBRUARY, 2006 RULEMAKING, EFFECTIVE DATE OF APRIL 30, The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.

BASIS AND PURPOSE (303(d) List)

A. Introduction This regulation updates Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (“TMDLs”) to reflect additional water quality information available since the Regulation was promulgated in 2004. This list was prepared to fulfill section 303(d) of the federal Clean Water Act (“Act”) which requires that states submit to the U.S. Environmental Protection Agency (“EPA”) a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.

B. List Development 1. Listing Methodology The “Section 303(d) Listing Methodology - 2006 Listing Cycle” contains a description of the listing process, the criteria for listing, and the criteria for determination of TMDL priority. The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission administrative action hearing on May 9, 2005.

This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2006 Section 303(d) List and the 2006 M&E List. However, this methodology was not adopted by the Commission as a rule. The Commission therefore has the flexibility to take into account other appropriate factors in making site-specific listing decisions.

2. Information Considered The Commission has considered all existing and readily available information in developing the 2006 Section 303(d) List. In determining whether data and information are existing and readily available, it has taken into account such data and information as the Division has utilized in the preparation of those identification processes, calculations and models referenced in 40 CFR §130.7(a)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and submitted in reports provided to the Division as referenced in 40 CFR §130.7(a)(5)(iii). In addition, the Commission accepted credible data and information that was submitted in accordance with the listing process schedule, whether submitted by EPA or any other interested party. The Division also continues to independently collect and analyze new data on a rotating basin basis as part of its triennial review efforts and will utilize such data and information in making future listing determinations. Existing data which was not brought forward through one of the above mechanisms or otherwise presented to the Commission in accordance with the schedule was not treated as “readily available” for purposes of making the 2006 listing decisions. If submitted, such information will be considered in the next listing cycle.

C. Prioritization The objective of prioritization is to identify those waterbody segments where the Division and the public should concentrate their resources. Priorities of High, Medium and Low were established according to section IV. of the 2006 Section 303(d) Listing Methodology.

D. Temporary Modifications and Plans to Eliminate Uncertainty Consistent with the recent changes to the Basic Standards and Methodologies for Surface Water (Regulation No. 31) and the Discharge Permit Regulations (Regulation No. 61), the Commission deleted subsection 93.4 “Plans to Eliminate Uncertainty.” The Statement of Basis for the June 2005 rulemaking hearing for Regulation No. 31 states:

The Commission recognizes that portions of the temporary modification provisions adopted in this rulemaking may be inconsistent with current provisions in Regulation No. 93. The Commission intends that the provisions adopted in this rulemaking will govern until appropriate revisions will be adopted in the Regulation No. 93 in the next rulemaking hearing reviewing that regulation. In 2004, this provision was added to Regulation No. 93 to identify those waterbodies where work independent of the TMDL process was proceeding to identify the appropriate underlying standards. In these cases, TMDLs and permit limits were not to be based on the underlying standards until the uncertainty was resolved. The intent was that dischargers should not be forced to comply with underlying standards where there is ongoing work being done to resolve acknowledged uncertainty regarding the appropriateness of those underlying standards.

Dischargers are now protected from complying with underlying standards before the uncertainty is resolved by recent changes in the Basic Standards and the Permit Regulations. Now, for discharges to waters where a temporary modification has been adopted, a permit may contain compliance schedules that recognize this ongoing work and may extend beyond the end of the permit term. The Commission believes it appropriate for dischargers to focus their available resources on addressing uncertainty with respect to appropriate water quality standards, rather than on complying with standards that may change in a short time.

Consistent with this new approach to temporary modifications, the Commission intends that a more thorough consideration will be given to the causes and sources of non- attainment before temporary modifications are proposed. In cases where the appropriate way to address non-attainment of underlying standards is through the TMDL program, not through adoption of temporary modifications, the Commission may assign a higher TMDL priority to such waters.

E. Segment- Specific Issues Fountain Creek segment 2a: The Division had proposed inclusion of this segment due to non-attainment of the assigned E. coli standard. The Division noted that its proposal erroneously identified the listing as a “low” priority. The Section 303(d) Listing Methodology, 2006 Listing Cycle indicates that TMDLs for waters in non-support of Recreation 1a use classifications be designated as “high” priority. The Commission has therefore adopted a “high” priority designation for this segment. Fountain Creek segment 2b: This segment is the lowermost of three that comprise the mainstem of Fountain Creek. Both of the upper two segments are included on the List of Impaired Waters for E. coli. The Sierra Club had proposed that this lowermost segment should also be listed for E. coli. The Commission has decided that the Division’s analysis of the available data is consistent with the procedures contained in the Section 303(d) Listing Methodology, 2006 Listing Cycle and that the results of that analysis do not support inclusion of this segment on the Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs.

North Fork Gunnison River segment 6: The Division had proposed that this “all tributary” segment be listed in its entirety for non-attainment of the aquatic life use-based chronic selenium standard. The Colorado River Water Conservation District provided evidence that the standard is, in fact, attained at several locations within this segment. It is therefore appropriate that only that portion of the segment for which non-attainment has been documented be included on the list. The Commission has identified the affected portion of the segment as “Cottonwood Creek” and has revised the proposal accordingly.

Uncompahgre River segment 6b (Red Mountain Creek): The Commission had in a February 2004 Rulemaking Hearing determined that there is not adequate data to support a finding of impaired Aquatic Life Use relative to the expected condition. Information offered in the 2006 hearing further reinforces this conclusion by demonstrating that the Commission’s classification assumes an extremely limited aquatic life use in this segment. In a rulemaking hearing scheduled for June 12, 2006, the Commission will consider a proposal to delete the aquatic life use classification for this segment. The Commission has therefore opted not to include Red Mountain Creek on the 2006 Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs. Lower Gunnison segment 2: The Division proposed that this segment be listed for selenium and temperature, with a “high” priority for each. In view of evidence that it may be appropriate to reconsider the cold water aquatic life classification of this segment prior to initiating a TMDL, the Commission chose to change the priority for the temperature listing to “low”.

Lower Colorado River segment 3: The Division had initially proposed listing of this segment for ammonia. During discussions with the City of Grand Junction it was noted that during the course of the Division’s assessment an error had been made relative to the dataset utilized. The Division subsequently modified its proposal to withdraw this segment from its proposal. The Commission has not included the segment on the 2006 Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs. Lower Colorado River segment 13a (Salt Creek): Salt Creek was proposed by the Division to be listed for sediment based upon a study of this and other tributary segments performed in conjunction with the BLM and Chadwick and Associates. Mesa County objected to the inclusion of Salt Creek on the Section 303(d) List of Water- Quality-Limited Segments Requiring TMDLs, arguing that the assessment protocols used were inconsistent with Commission Policy 98-1, the Implementation Guidance for Determining Sediment Deposition Impacts to Aquatic Life in Streams and Rivers. The assessment performed utilized the same approach embodied in the Sediment Guidance with respect to comparison of the affected reach to an expected condition. The validity of this comparative, expected condition analysis is not dependent on this being a high gradient, cobble bottom stream. The Commission has determined that the assessment adequately demonstrated non-attainment of the narrative sediment standard and consequent impairment of Salt Creek.

Bear Creek segment 1a: The Division proposed that this segment be retained on the Monitoring and Evaluation list for non-attainment of the assigned aquatic life use classification and for temperature. The evidence submitted demonstrated adverse impacts to trout populations at two stations (Bear Creek cabins and O’Fallon Park) situated in the upper reach of this segment since 2002 and documented that the use continued to recover well into 2004, although full recovery had not yet occurred. This evidence is consistent with the Commission’s conclusion in 2004 that the demonstrative cause of adverse impacts to aquatic life was the extreme drought in 2002. The 2006 Listing Methodology states that “Data collected during or immediately after temporary events influencing the waterbody that are not representative of normal conditions shall typically be discounted in making the listing decision.” Several parties argued that water quality conditions might have adversely affected the aquatic life. However, there was no evidence submitted demonstrating exceedance of the Mean Average Weekly Temperature criterion during 2004 or 2005, or demonstrating that impairment was otherwise caused by pollutants. The Commission has decided that the Division’s interpretation of the available data is consistent with the procedures contained in the Section 303(d) Listing Methodology, 2006 Listing Cycle and has determined that this segment should be retained on the Monitoring and Evaluation List for aquatic life impairments and temperature, and that its status should be reconsidered in future updates of Regulations No. 93 and No. 94.

The fact that impacts to Bear Creek aquatic life continue to appear to be related to the 2002 extreme drought is an adequate and appropriate basis for including this segment on the Monitoring and Evaluation List, rather than the Section 303(d) List. However, the Commission also notes that, even if continuing impacts did not appear to be tied to the drought, where there is no evidence that a numerical standard has been exceeded, the Commission’s practice has been to place waters on the Monitoring and Evaluation List if there is not evidence that a use impairment has been caused by a pollutant. The 2006 Listing Methodology states “Water bodies that are impaired but it is unclear whether the cause of impairment is attributable to pollutants as opposed to pollution will be placed on the M&E List.” EPA’s guidance for such circumstances differs. EPA’s guidance says that where there is an impairment but there has not been a demonstration that the impact is not caused by a pollutant, the water segment should be included on the Section 303(d) List. Because this provision appears in EPA guidance only, and the Commission is aware of no specific provisions of the Clean Water Act or EPA regulations that would dictate this result, the Commission believes that it has policy discretion to use different approach – i.e., to refrain from listing unless a pollutant has been identified as the cause of the use impairment.

Clear Creek segment 13b (North Fork Clear Creek): The Division had proposed this segment be retained on the Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs for several parameters and for non-attainment of the assigned aquatic life use classification. The Commission has adopted this proposal, but notes that the segment attains the assigned numeric copper standard. The listing therefore does not include copper. Further, the Commission notes that the Division had proposed a “high” priority for completion of TMDLs for this segment, due to the fact that the North Fork of Clear Creek was included on the 1998 List of Impaired Waters and is therefore subject to provisions of the 1999 Settlement Agreement addressing TMDL development by the Division. The Commission has determined that a “medium” priority will be assigned for TMDL development, while recognizing that the Division remains obligated to completion of TMDLs for this segment by June 30, 2008. If the underlying standards are revised in the 2009 South Platte River basin rulemaking, TMDLs and/or Wasteload Allocations based on the superceded standards should be revisited.

Cache la Poudre segment 14 (Horsetooth Reservoir): The Division proposed inclusion of Horsetooth Reservoir on the Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs due to non-attainment of the dissolved oxygen standard. Data for a ten-year period of record was found to be representative of conditions in the Reservoir. The Commission determined that in this instance it is appropriate to consider data for more than the most recent five years, in view of evidence that the most recent five years include a potentially unrepresentative period of reservoir drawdown. While the available data do not include samples spaced throughout a 24-hour period, the data are typical of that usually available for lakes and reservoirs. If diel variation were expected, it is likely that any such data would demonstrate a slight depression of dissolved oxygen concentration in the epilimnion during non-daylight hours. However, the area of non- attainment of dissolved oxygen in Horsetooth Reservoir is in the metalimnion, or middle layer of the reservoir. Testimony from Division staff indicated that it is unlikely that diel variation in dissolved oxygen levels would be expected in the metalimnion, since this deeper layer is unlikely to be affected by photosynthesis that occurs in the epiliminion. The Commission interprets the reference in the Listing Methodology to lake and reservoir samples representative of diel variation to apply only in those factual circumstances (e.g. dissolved oxygen in the epilimnion) where such variation would be expected.

The assessments and recommendations by the Division regarding Horsetooth Reservoir were consistent with the Section 303(d) Listing Methodology, 2006 Listing Cycle. However, the Commission notes that this hearing identified a need to provide further clarifications regarding appropriate procedures for assessing compliance with dissolved oxygen standards, particularly for lakes and reservoirs. The Commission encourages the Division to pursue such clarifications in preparation of the 2008 Listing Methodology, including, e.g., addressing variations in attainment status from year-to- year and further clarification of what constitutes representative data. Evidence regarding the status of aquatic life in Horsetooth Reservoir does not override the fact that the data demonstrate a long term standards exceedance. The Commission’s practice has been to list waterbodies on the Section 303(d) List whenever representative data demonstrate non-attainment of a numerical standard, including dissolved oxygen. For other waters listed for non-attainment of dissolved oxygen, the Commission has not required evidence of the cause of the non-attainment. Although the provisions of the 2006 Listing Methodology arguably contain potentially conflicting language on this point, the Commission’s practice has not been to apply the provision regarding “water bodies that are impaired but it is unclear whether the cause of impairment is attributable to pollutants” to waters with dissolved oxygen impairments. Moreover, although the Commission was willing to consider listing Horsetooth Reservoir on the M&E List if the cause of the dissolved oxygen impairment was recent reservoir draw downs (i.e., reservoir operations), the evidence did not support this conclusion. Middle South Platte River segment 03a (Horse Creek Reservoir): The Division proposed that Horse Creek Reservoir be included on the Section 303(d) List of Water-Quality- Limited Segments Requiring TMDLs due to non-attainment of the assigned pH standard. The recommendation was based upon a representative dataset including four years of water quality monitoring results. The Commission has determined that inclusion of the Reservoir on the Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs for pH is appropriate and consistent with the Section 303(d) Listing Methodology, 2006 Listing Cycle. Dissolved oxygen data for the same four-year period demonstrate attainment of the dissolved oxygen standard. Although EPA questioned the Division’s current practice of averaging dissolved oxygen data within the sampling profile or profiles for a single sampling event, the Commission has determined that this practice is acceptable and appropriate, and consistent with the 2006 Listing Methodology. EPA’s proposal that Horse Creek Reservoir be listed for dissolved oxygen is based upon analytical procedures that are inconsistent with the Division’s current assessment practice. The Commission has determined that the Reservoir is not impaired with respect to the dissolved oxygen standard. Upper Colorado River segment 07b (Muddy Creek): The Division had proposed the listing of Muddy Creek for non-attainment of the assigned temperature standard. The Colorado River Water Conservation District objected to the Division’s proposal and has provided evidence suggesting that the USGS sampling station (data from which formed the basis for the Division’s proposal) is situated such that any temperature data generated is likely not representative. The Commission has therefore included the segment on the 2006 Monitoring and Evaluation List to allow further examination of temperature data from this station.

Upper Yampa River segment 07b: This segment comprises a portion of the Yampa River mainstem. The Division had proposed that this segment be listed for temperature, again based upon USGS monitoring data. The Colorado River Water Conservation District provided evidence concerning the location of the USGS sampling station below the Steamboat Springs hot springs discharge. Again parties have agreed that such data is likely not representative of instream conditions. The Commission has placed the segment on the 2006 Monitoring and Evaluation List.

Upper Yampa River segment 20 (First Creek, Elkhead Creek): These waters are classified for Recreation Use 1a, and are assigned a numeric E coli standard of 126 org./100 mL. Ambient E. coli levels exceed the assigned numeric standard. The U. S. Forest Service has raised concerns regarding the current assigned Recreation Use and the associated numeric standards. The Commission has included the segment on the 2006 Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs based upon the current classification and standards. However, it is the intent of the Commission that these issues be examined in the context of the 2008 Upper Colorado surface water standards rulemaking prior to the initiation of the TMDL development process.

BASIS AND PURPOSE (Monitoring and Evaluation List)

A. Introduction This regulation updates Colorado’s Monitoring and Evaluation List to reflect additional water quality information available since the Regulation was promulgated in 2004.

B. List Development The statement of basis and purpose for Regulation No. 93 contains a description of how the lists were developed.

C. Prioritization and Scheduling The Division remains committed to establishing a plan for monitoring and evaluating these water bodies prior to the list submission date for the subsequent listing cycle. Further, the Commission has committed to determining their appropriate status (as either impaired or fully supporting) within ten years of their placement on the M&E List.

D. Segment-Specific Issues In a number of instances, the Commission chose in this hearing to include on the Monitoring and Evaluation List waters that were initially proposed by the Division, or recommended by other rulemaking participants, for inclusion on the Section 303(d) List, Regulation #93. These waters include Bear Creek segment 1a, Upper Colorado River segment 07b (Muddy Creek), and Upper Yampa River segment 07b. In each instance, the Commission’s rationale for these decisions is set forth in the statement of basis and purpose for Regulation #93.

1. PARTIES TO THE RULEMAKING

1. The City of Grand Junction 2. The Colorado Division of Wildlife 3. Evergreen Trout Unlimited and Colorado Trout Unlimited 4. The City of Colorado Springs 5. The City of Black Hawk 6. The Colorado River Water Conservation District 7. Friends of Bear Creek 8. Big Thompson Watershed Forum 9. The Bear Creek Watershed Association 10. The Northern Colorado Water Conservancy District 11. U.S. Environmental Protection Agency, Region 8 12. Evergreen Metropolitan District and West Jefferson County Metropolitan District 13. USDA Forest Service, Medicine Bow-Routt National Forests 14. Colorado Rock Products Association 15. City and County of Broomfield 16. Climax Molybdenum Company 17. The Metro Wastewater Reclamation District 18. Mount Carbon Metropolitan District

93.12 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND

PURPOSE; FEBRUARY, 2008 RULEMAKING, EFFECTIVE DATE OF APRIL 30, The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.

BASIS AND PURPOSE (303(d) List)

A. Introduction This regulation updates Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (“TMDLs”) to reflect additional water quality information available since the Regulation was promulgated in 2006. This list was prepared to fulfill section 303(d) of the federal Clean Water Act (“Act”) which requires that states submit to the U.S. Environmental Protection Agency (“EPA”) a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.

B. List Development 1. Listing Methodology The “Section 303(d) Listing Methodology - 2008 Listing Cycle” contains a description of the listing process, the criteria for listing, and the criteria for determination of TMDL priority. The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission administrative action hearing on May 15, 2007.

This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2008 Section 303(d) List and the 2008 M&E List. However, this methodology was not adopted by the Commission as a rule. The Commission therefore has the flexibility to take into account other appropriate factors in making site-specific listing decisions.

2. Information Considered The Commission has considered all existing and readily available information in developing the 2008 Section 303(d) List. In determining whether data and information are existing and readily available, it has taken into account such data and information as the Division has utilized in the preparation of those identification processes, calculations and models referenced in 40 CFR §130.7(a)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and submitted in reports provided to the Division as referenced in 40 CFR §130.7(a)(5)(iii). In addition, the Commission accepted credible data and information that was submitted in accordance with the listing process schedule, whether submitted by EPA or any other interested party. The Division also continues to independently collect and analyze new data on a rotating basin basis as part of its triennial review efforts and will utilize such data and information in making future listing determinations. Existing data which was not brought forward through one of the above mechanisms or otherwise presented to the Commission in accordance with the schedule was not treated as “readily available” for purposes of making the 2008 listing decisions. Such information will be considered in the next listing cycle.

C. Prioritization The objective of prioritization is to identify those waterbody segments where the Division and the public should concentrate their resources. Priorities of High, Medium and Low were established according to section IV. of the 2008 Section 303(d) Listing Methodology.

D. Fish Consumption Advisory Listings Consistent with the 2008 Section 303(d) Listing Methodology, the Division proposed to include 12 segments on the 2008 303(d) List for non-attainment of the aquatic life use due to fish consumption advisories for mercury. The 2008 Section 303(d) Listing Methodology, states:

Fish Consumption Advisories are issued by the Colorado Department of Public Health and Environment (“CDPHE”) in instances where analysis of fish tissue samples provides documentation of a public health risk. Issuance of a FCA by CDPHE indicates impairment of an Aquatic Life Use classification for any waters so classified. The 2006 303(d) List included three of these reservoirs for impairment due to mercury: one in the Rio Grande basin: Sanchez Reservoir (Rio Grande, segment 30), and two in the San Juan basin: McPhee Reservoir (Dolores, segment 4) and Narraguinnep Reservoir (La Plata, segment 11). These listing were changed by the Commission to specify that the listing was based on non-attainment of the aquatic life. This is consistent with the 2008 Listing Methodology and avoids confusion that there is non- attainment of the mercury standard in the water column. The Commission has included 12 segments on the 2008 303(d) List for non-attainment of the aquatic life use due to mercury fish consumption advisories for 13 lakes or reservoirs. The Commission also included one listing based on non-attainment of the aquatic life use due to a PCE fish consumption advisory in Willow Springs Ponds, Fountain Creek, segment 7a.

E. Discussion of Issues Raised in the Hearing Dissolved Oxygen Standard in Lakes and Reservoirs: The issue of an appropriate D.O. standard in lakes and reservoirs was raised in this hearing by two parties, Northern and the River District. The River District focused its attention to high elevation lakes and reservoirs while Northern discussed the concept of representative data and assessment methods as outlined in the 2008 Listing Methodology. The Division agreed that work is needed to examine the D.O. standard for lakes and reservoirs and that additional refinement of the Listing Methodology is appropriate including consideration of whether and how refugia should be addressed. This standard is scheduled for review in preparation for the 2010 Basic Standards and Methodology, Regulation No. 31, RMH in June 2010. The Commission directs the Division to work with parties in 2008 and 2009 on any changes that are deemed appropriate for the 2010 Listing Methodology. The Commission made listing decisions based on the available data using the adopted standards and the 2008 Listing Methodology. Site-specific decisions made by the Commission are discussed below.

F. Segment- Specific Issues Fountain Creek segment 6, Monument Creek: Mainstem of Monument Creek from the boundary of National Forest Lands to the confluence with Fountain Creek: The Division had proposed retaining the portion of Monument Creek below Mesa Road on the 2008 303(d) List because selenium concentrations in that portion exceed the water quality standard for Fountain Creek Segment 6. The Commission has determined that it is appropriate at this time to include this portion of Monument Creek on the 2008 303(d) List. However, because there is an appropriate plan in place to address the segment as a whole, the Commission directs the Division and Colorado Springs Utilities to revisit this plan to determine the causes and potential reversal of elevated Se concentrations and the appropriate long-term underlying standard for this section of COARFO06. Lower Colorado segment 2, Colorado River (COLCLC02): Mainstem of the Colorado River from Parachute Creek to the Gunnison River. The Division originally proposed listing this segment based on non-attainment of the selenium standard. The Division based its proposal on data from multiple sampling locations. The River District questioned whether some of the sample locations, including the Humphrey backwater location and others, were in the segment. The Division reviewed the sampling locations and determined that some of the sampling locations used in the original proposal were outside the segment. The segment was reassessed and still showed impairment. The parties disagree whether Humphrey Backwater is located within the segment but agreed that it demonstrated exceedences of the selenium standard. The Commission ultimately decided to list the Humphrey Backwater portion of the Colorado River segment based on those data, rather than listing the entire segment.

White River segment 13b: Shell Frontier Oil and Gas Inc. provided additional analytical results for a number of locations within the Yellow Creek drainage. Re-assessment of several waters which had been proposed for inclusion on the Monitoring and Evaluation List indicated that Corral Creek, Box Elder Gulch, Stake Springs and Duck Creek, are all in attainment of the assigned standard for total recoverable iron. This additional data, however, also demonstrated that the lower portion of Corral Creek and Duck Creek are in non-attainment of the Aquatic Life Use-based chronic selenium standard. The Commission has added these waters to the 303(d) List for selenium. Upper Colorado segment 5, Wolford Mountain Reservoir (COUCUC05): The River District opposed the Division’s proposal to move Wolford Reservoir from the 2006 M&E List to the 2008 303(d) List when no additional data has been collected. In addition, the River District expressed their concerns with the current D.O. standard and Listing Methodology especially as it is applied to high alpine lakes and reservoirs. The Commission moved Wolford Reservoir from the M&E List to the 303(d) List based on the current standards and listing methods. The Commission has encouraged the Division, the River District and other parties to continue to work towards an improved D.O. standard for the 2010 Basic Standards Rulemaking Hearing. The Commission adopted a low priority for this listing, since it is appropriate for the D.O. standard and listing methodology issues to be addressed before substantial resources are expended on development of a TMDL.

Uncompahgre segment 14, Sweitzer Lake (COGUUN14): The Division proposed listing for Sweitzer Lake due to exceedances of the D.O. standard in the mixed layer. The River District pointed out that there was no thermal stratification and adequate refugia present and therefore the segment should not be listed. They also indicated that there is evidence of chemical stratification. The Commission listed Sweitzer Lake, segment COGUUN14, on the 303(d) List due to exceedances in the mixed layer as defined in the Listing Methodology.

Upper Yampa segment 13d, Dry Creek (COUCYA13d): The Division proposed listing the Hubberson Gulch tributary of this segment due to non-attainment of the total recoverable iron standard. Seneca Coal Company (Seneca) provided evidence that the tributary is in attainment of the standard. The Commission did not list the segment for total recoverable iron on the 303(d) List.

Upper Yampa segment 13e, Sage and Grassy Creeks (COUCYA13e): The Division proposed listing this segment due to non-attainment of the total recoverable iron and dissolved selenium standards. Seneca provided evidence that the total recoverable iron standard is attained within the segment. The Commission did not include the segment on the 303(d) List for total recoverable iron. Seneca also provided evidence that the selenium standard is attained in the upper portions of the two creeks in the segment. The Commission did include the lower portion of the creeks (Sage Creek below Routt County Road 51D and Grassy Creek below Routt County Road 27A), on the 303(d) List for dissolved selenium.

BASIS AND PURPOSE (Monitoring and Evaluation List)

A. Introduction This regulation updates Colorado’s Monitoring and Evaluation List to reflect additional water quality information available since the Regulation was promulgated in 2006.

B. List Development The statement of basis and purpose for Regulation No. 93 contains a description of how the lists were developed.

C. Prioritization and Scheduling The Division remains committed to establishing a plan for monitoring and evaluating these water bodies prior to the list submission date for the subsequent listing cycle. Further, the Commission has committed to determining their appropriate status (as either impaired or fully supporting) within ten years of their placement on the M&E List.

D. Segment Specific Issues 1. Lower Dolores segment 3 (COGULD03): The Commission approved resegmentation of Lower Dolores segment 3 at the Regulation 35 Rulemaking Hearing in June 2006. The resegmentation was based on the Division’s investigation identifying Salt Creek draining the Sinbad Valley. The Sinbad Valley is identified by the Colorado Geological Survey as a graben or a collapse feature that formed in response to salt migration and dissolution beneath the area. Based on this information the selenium and zinc standards for the new Salt Creek segment were set at ambient conditions. The Division proposed to delete this from the M&E List based on attainment of the new ambient standards. The Commission removed this segment from the M&E List.

2. Bear Creek segment 1a (COSPBE01a): This segment was removed from the M&E List based on assessment of annual fish surveys, water quality parameters and temperature data. It is noted that Bear Creek has seen significant improvement but still requires continued cooperative efforts by the Division, DOW, the Bear Creek Watershed Authority, Trout Unlimited and others to prevent future impairment or re-listing.

3. Blue River segment 3 (COUCBL03): The Commission has included Gold Run Gulch below Jessie Mine (for cadmium and zinc) and the South Branch Swan River below Royal Tiger Mine (for zinc) on the 2006 Monitoring and Evaluation List. The Royal Tiger Mine and the Jessie Mine are both part of a CERCLA remediation effort completed in 2007. Remediation results with respect to water quality are not yet available. In the past the Commission did not intend by including these waters on the Monitoring and Evaluation List to conclude that any actions other than those completed CERCLA-related activities are necessary or appropriate at this site. The status of those efforts will be reviewed during the next update of this list.

4. White River segment 16 (COLCWH16): The Commission has included Ryan Gulch on the Monitoring and Evaluation List for E. coli. Shell had argued that Ryan Gulch should not be included on the Monitoring and Evaluation List for E. coli due to the lack of more than a single sample and because “the segment does not appear to support classification as recreation class 2.” The Commission notes that placement of the water on the Monitoring and Evaluation List does not indicate a finding that Ryan Gulch is in non-attainment with the assigned Recreational Use, only that more data is needed to accurately assess the attainment status. Further, the Commission would note that alternate Recreation Use designations have more stringent E. coli standards then that assigned with the current Recreation Use designation.

5. Upper Yampa segment 13d, Dry Creek (COUCYA13d): The Division proposed listing this segment due to exceedances of the lead standard. Seneca provided evidence that the lead standard is attained within the upper portion of this segment. The Commission included the lower portions of the segment (below Routt County Road 53 (Sec. 22, T6N, R88W)), on the 2008 M&E List for dissolved lead.

6. Uncompahgre segment 3b, Ridgeway Reservoir (COGUUN03b): Listing methods for temperature in lakes were changed in the Section 303(d) Listing Methodology – 2008 Listing Cycle to reflect changes in the temperature standards in Regulation No. 31. In the Listing Methodology (p. 25) it states: “If the refuge is not adequate because of low dissolved oxygen, the lake or reservoir may be listed as impaired for dissolved oxygen rather than for temperature.” The Division proposed a few segments for the M&E List that are listed for dissolved oxygen due to exceedances of temperature in the epilimnion where there was not adequate refugia in the lower levels of the lake or reservoir. Ridgeway Reservoir was one of those segments. The data showed that the temperature standard was exceeded in the epilimnion on 7/21/05. An adequate refuge from high temperatures in the epilimnion was not present on that day due to inadequate dissolved oxygen in the lower portion of the lake. Due to confusion that this type of listing caused, the parameter notation in Regulation No. 94 was changed to indicate that the D.O. listing was due to exceedances of the temperature standard. The Commission added Ridgeway Reservoir; segment COGUUN03b, to the M&E List for “D.O. (temperature)”.

7. Fountain Creek segment 2a (COARFO02a): Fountain Creek segment COARFO02a includes the mainstem from its confluence with Monument Creek to the State Highway 47 Bridge. This segment was assigned an ambient-based chronic selenium standard of 8.0 ug/L during the Arkansas River Basin RMH in 2007. The Aquatic Life Use-based acute standard was set at TVS. Two acute exceedances were found during the data assessment for this rulemaking hearing that could place this segment on the 303(d) List. Further investigation of these acute exceedances showed discrepancies in the USGS and the WQCD data. The Division, as well as Colorado Springs, believed that because of the inconsistent nature of this data it may not be representative, and together the parties will investigate the validity of these data. For this reason, the Commission placed this segment on the M&E as opposed to the 303(d) List until further study of selenium in this segment can take place.

8. Upper Colorado segment 2, Shadow Mountain Reservoir (COUCUC02): The Division originally proposed to include Shadow Mountain Reservoir on the 2008 303(d) List for dissolved oxygen. In their RPHS, Northern opposed the listing of Shadow Mountain for dissolved oxygen on the 303(d) List. They stated that the data was not representative because it was not spatially distributed, it did not have temporal variability, and it followed a temporary event, namely fall turn over following a historic drought. The Division disagreed regarding the representative nature of the sampling program but points out that there are questions about the validity of the September 2003 sample profile that was evaluated. For example, the Division believed that D.O. readings taken on September 16, 2003 may have been a calibration error. Moreover, that was the only reading that exceeded the standard during the entire period of record and thus may not have been representative. For these reasons the reservoir was placed on the M&E List as opposed to the 303(d) List until further evaluation can take place.

9. Upper Colorado segments 6 and 8, Camp Cr, Jones Gulch, Keystone Cr, and Mozart Creek (COUCBL06 and COUCBL08): During the 2004 rulemaking process, the four identified tributaries in these two segments were placed on the M&E List based upon measured pH levels during one spring one runoff season when pH levels are expected to be relatively low due to natural causes. Subsequent water quality monitoring conducted over a period of four years has found that these streams meet the pH standards and have 15th percentile values that are above the minimum 6.5 s.u. pH standard. Based upon these findings, the Commission removed segments COUCBL06 and COUCBL08 from the M&E List.

10. Upper Colorado segment 10 (COUCUC10): The Division proposed that segment COUCUC10 be placed on the M&E List for copper based on data from WQCD station 12193, located on the Fraser River at the Town of Fraser. Additional stations were assessed on this segment. The Districts questioned the data used in the assessment and upon reevaluation of data for five stations along the Fraser River, the Division revised its proposal to only list a portion of the segment on the M&E List. The WQCC placed the Fraser River from the Town of Fraser to the confluence with the Colorado River on the M&E List based on this data analysis. The Division will work with the Grand County Districts and the Grand County Water Information Network (GCWIN) to collect more data and look into copper issues on the Fraser River.

1. PARTIES TO THE RULEMAKING HEARING

1. The Metro Wastewater Reclamation District 2. Bear Creek Watershed Association 3. Keystone Resort 4. City of Colorado Springs and Colorado Springs Utilities 5. CAM-Colorado LLC and CAM Mining LLC 6. Colorado Division of Wildlife 7. Southeastern Colorado Water Conservancy District 8. Shell Frontier Oil and Gas, Inc.

9. The Grand County Water and Sanitation District #1, the Winter Park West Water and Sanitation District, the Fraser Sanitation District and the Winter Park Sanitation District 10. Trout Unlimited, Colorado Trout Unlimited, and the Evergreen Chapter of Trout Unlimited 11. Northern Colorado Water Conservancy District 12. Seneca Coal Company 13 Colorado River Water Conservation District 14. U.S. Environmental Protection Agency, Region 8 15. City of Black Hawk and Black Hawk/Central City Sanitation District 16. Cripple Creek & Victor Gold Mining Company 17. Town of Minturn 18. Homestake Mining Company of California 19. CBS Operations Inc

93.13 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND

PURPOSE; FEBRUARY, 2010 RULEMAKING, EFFECTIVE DATE OF APRIL 30, The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.

BASIS AND PURPOSE A. Consolidation of Regulations #93 and #94 Prior to the 2010 listing cycle, Colorado’s list of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads was set forth in this Regulation #93, and Colorado's Monitoring and Evaluation List was set forth in Regulation #94. In this hearing, the Commission has approved the Division staff proposal to combine both lists into Regulation #93, and to repeal the former Regulation #94. The primary benefit of combining the regulations is to make the status of water segments in Colorado easier to understand by setting forth both lists in one table. This new structure will also make it easier to understand proposed revisions to either list during future rulemaking hearings. These benefits will be seen by the Division, the Commission and interested stakeholders.

Both regulations were heard by the Commission at the same rulemaking hearings in the past and decisions were made for both regulations at the same time. One reason for maintaining separate lists in the past is that Colorado’s list of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads is subject to EPA approval, while Colorado's Monitoring and Evaluation List is not. Although the Commission is now combining both lists into one regulation for simplicity and ease of use, it will continue to be only the list of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads that requires EPA approval. In submitting the revised “Section 303(d) List” to EPA, the Commission will note that only that list is submitted for approval and that the separate Colorado Monitoring and Evaluation List is maintained as state-only information.

B. Revisions to 303(d) List 1. Introduction This regulation updates Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (“TMDLs”) to reflect additional water quality information available since the Regulation was promulgated in 2008. This list was prepared to fulfill section 303(d) of the federal Clean Water Act (“Act”) which requires that states submit to the U.S. Environmental Protection Agency (“EPA”) a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.

2. List Development a. Listing Methodology The “Section 303(d) Listing Methodology - 2010 Listing Cycle” contains a description of the listing process, the criteria for listing, and the criteria for determination of TMDL priority. The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission administrative action hearing on May 11, 2009. This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2010 Section 303(d) List and the 2010 M&E List. However, this methodology was not adopted by the Commission as a rule. The Commission therefore has the flexibility to take into account other appropriate factors in making site- specific listing decisions.

b. Information Considered The Commission has considered all existing and readily available information in developing the 2010 Section 303(d) List. In determining whether data and information are existing and readily available, it has taken into account such data and information as the Division has utilized in the preparation of those identification processes, calculations and models referenced in 40 CFR §130.7(a)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and submitted in reports provided to the Division as referenced in 40 CFR §130.7(a)(5)(iii). In addition, the Commission accepted credible data and information that was submitted in accordance with the listing process schedule, whether submitted by EPA or any other interested party. The Division also continues to independently collect and analyze new data on a rotating basin basis as part of its triennial review efforts and will utilize such data and information in making future listing determinations. Existing data which was not brought forward through one of the above mechanisms or otherwise presented to the Commission in accordance with the schedule was not treated as “readily available” for purposes of making the 2010 listing decisions. Such information will be considered in the next listing cycle.

c. Data Quality In the Division's Quality Management Plan 2007 for the Collection and Utilization of Environmental Data, the WQCD states that “It is the expressed goal of the Division to use only those analytical data that are both reliable and have a defined level of quality.” In order to meet this goal, the WQCD required that all information submitted in response to its August 2009 call for data have a certification of quality included with the data. All of the information received for this data call that was utilized to develop assessments for this rulemaking hearing had a quality certification submitted or has been identified as not having this certification. Only a small fraction of the data is not certified.

3. Prioritization The objective of prioritization is to identify those waterbody segments where the Division and the public should concentrate their resources. Priorities of High, Medium and Low were established according to section IV. of the 2010 Section 303(d) Listing Methodology.

4. Fish Consumption Advisory Listings The 2010 Section 303(d) Listing Methodology, states:

1. Fish Consumption Advisories are issued by the Colorado Department of Public Health and Environment (“CDPHE”) in instances where analysis of fish tissue samples provides documentation of a public health risk. Issuance of a FCA by CDPHE indicates impairment of an Aquatic Life Use classification for any waters so classified.

The Commission has included 17 segments on the 2010 303(d) List for non- attainment of the aquatic life use due to mercury fish consumption advisories for 22 lakes or reservoirs. The Commission also included one listing based on non- attainment of the aquatic life use due to a PCE fish consumption advisory in Willow Springs Ponds, Fountain Creek, Segment 7a.

The following segments have been added to the 2010 303(d) List due to new Fish Consumption Advisories:

- Lower Gunnison Segment 4b, Juniata Reservoir - Lower Colorado Segment 20, Rifle Gap Reservoir - San Juan Segment 6a, Echo Canyon Reservoir - Upper Colorado Segment 12, Lake Granby - Yampa River Segment 2b, Elkhead Reservoir, Catamount Lake 5. New Table Value Standards Cadmium and Zinc: As part of the Basic Standards hearing of 2005, new zinc and cadmium table values were adopted. The acute and chronic zinc and cadmium equations in each basin were modified to conform to Regulation No. 31 over the last four years. An increase in cadmium listings were the result of a more stringent cadmium standard.

The following segments were added to the 303(d) List for cadmium: - Big Thompson Segment 2 - Clear Creek Segments 2a, 2b, 2c, 9b, 11, 13b - Cache la Poudre Segment 7 - Upper South Platte Segments 2b, 2c, 5a, 5b, 15 - Blue River Segment 12 - Eagle River Segment 5c - Upper South Platte Segments 3 (Hawkins Gulch), 5a Temperature: As part of the Temperature Standards hearing of 2007, new temperature table values were adopted. The acute and chronic temperature standards in the Upper and Lower Colorado and the South Platte River Basins were modified to conform to Regulation No. 31 over the last two years. The following segments were added to the 303(d) List for temperature: - Upper Colorado Segments 3, 4, 7b and 10c 6. Listings Due to Exceedances of the Secondary Water Supply Standards For the secondary water supply standards of dissolved iron, manganese and sulfate, the less restrictive of the following two options will apply as the numeric standard: existing quality as of January 1, 2000 or the table value criteria in Regulation No. 31, Tables II and III. For dissolved iron this value is 300 ug/l. For manganese this value is 50 ug/l. For sulfate this value is 250 ug/l. The Division evaluated the water quality as of January 1, 2000 to determine in some cases where standards exceeded the water supply criteria in Tables II and III. The following segments were proposed for listing based on exceedances of the standards:

- Lower South Platte Segment 1: Manganese 7. Relisting Segments with Approved TMDLs Due to Standards Changes Once a TMDL has been completed, impaired waters are removed from the 303(d) List and placed into Integrated Reporting Category 4a. TMDLs are written to the adopted standards at the time they are submitted to EPA. As standards are periodically reviewed they may become more stringent. In these cases the TMDL may no longer be protective of the current standards. The Division reviewed segments where both TMDLs have been written and new, more restrictive standards have been adopted by the Commission. The Commission has relisted the following segments:

South Platte Basin:

- Clear Creek Segments 09b, 11, and 13b: Cadmium - Clear Creek Segment 02b: Zinc - Upper South Platte Segments 2b, 2c and 15: Cadmium 8. Delisting of Segments with Recently Approved TMDLs The Division submitted 64 TMDLs to EPA in the last biennium that have been approved. The following segments and parameters have been removed from the 303(d) List:

- Upper Arkansas Segment 2a: Zinc - Upper Arkansas Segments 2b, 2c and 3: Cadmium and Zinc - Upper Arkansas Segment 5: Lead and Cadmium - Upper Arkansas Segment 7: Zinc - Upper Arkansas Segment 11: pH, Aluminum, Cadmium, Copper and Zinc - Upper Arkansas Segment 12a: Lead and Zinc - San Miguel Segment 3a: Zinc - San Miguel Segment 3b: Cadmium and Zinc - San Miguel Segments 6a and 6b: Zinc - Uncompahgre Segments 2, 3a, 6a: Cadmium, Copper, Iron, and Zinc - Rio Grande Segment 4: Cadmium and Zinc - Rio Grande Segment 30, Sanchez Reservoir: Aquatic Life Use (Hg FCA) - Closed Basin Segment 9a: Cadmium - Closed Basin Segment 9b: Copper - Dolores River Segment 9: Cadmium and Zinc - Boulder Creek Segment 4a: pH, Cadmium, Copper and Zinc - Clear Creek Segment 2: Copper and Zinc - Clear Creek Segment 3a: Zinc - Clear Creek Segment 3b: Lead and Zinc - Clear Creek Segment 9a: Copper - Clear Creek Segment 9b: Copper, Lead and Zinc - Clear Creek Segment 11: Lead and Zinc - Clear Creek Segment 13b: Total Recoverable Iron, Manganese, Zinc, and Aquatic Life Use - Upper South Platte Segment 4: Copper - Upper South Platte Segment 5b: Zinc - Blue River Segment 6: pH, Cadmium, Copper, Lead and Zinc - Blue River Segment 7: pH, Cadmium, Copper, Lead, Manganese and Zinc - Blue River Segment 12: Zinc - Eagle River Segment 5a: Copper and Zinc - Eagle River Segment 5b: Zinc - Eagle River Segment 5c: Zinc - Eagle River Segment 7b: Copper and Zinc 9. Delisting of Segments where Water Quality is Currently Meeting Standards As additional water quality data is collected and assessed, new data may show attainment of the standards. The following segments and parameters have been removed from the 303(d) List due to attainment of current water quality standards:

- Upper Arkansas Segment 2a: NO - Uncompahgre River Segment 14, Sweitzer Lake: D.O.

- Lower Colorado Segment 3: Total Recoverable Iron - White River Segment 13b, Corral Creek: Selenium - La Plata Segment 4a: Zinc - Rio Grande Grande Segment 9 (Beaver Creek Reservoir): D.O. - Closed Basin Segment 6, San Luis Lake: D.O.

- Cherry Creek Segment 2, Cherry Creek Reservoir: chlorophyll a - Upper Colorado Segment 7a: Total Recoverable Iron - Yampa River Segment 16: Total Recoverable Iron - Lower Yampa Segment 20: E. coli - Cache La Poudre Segment 14 (Horsetooth Reservoir): D.O. - Upper Colorado Segment 5 (Wolford Reservoir): D.O.

10. Dissolved Oxygen Standard in Lakes and Reservoirs In 2008, the Commission directed the Division to work with outside parties and stakeholders on changes to the Listing Methodology with regards to the assessment of dissolved oxygen in lakes and reservoirs. Refinement of assessment methods were discussed in workgroup meetings and updates to the dissolved oxygen methods were included in the 2010 Listing Methodology. The revised 2010 Listing Methodology states that if the average temperature in the epilimnion of lakes and reservoirs exceeds the temperature standard, temperature and dissolved oxygen below the epilimnion will be evaluated for adequate refuge. Refuge is defined as the concurrent attainment of the temperature and dissolved oxygen standard at lower depths. If adequate refuge is not present in a single profile, the segment is listed as impaired for dissolved oxygen rather than for temperature. The Commission added the following segments to the 303(d) List due to exceedances of the temperature standard where adequate refuge was not found:

- Lower Arkansas Segment 5b, Trinidad Lake - Clear Creek Segment 17a, Arvada Reservoir The Listing Methodology also states that if the average dissolved oxygen concentration in the epilimnion falls below the standard in any profile, the lake will be placed on the 303(d) list. Where the dissolved oxygen standard is not attained in the metalimnion, but it is attained in the epilimnion, the lake may be placed on the M&E list, according to the Listing Methodology. The Commission added 25 new lakes to the M&E list due to exceedances in the dissolved oxygen standard in the metalimnion. The following twelve lakes and reservoirs were added to the 303(d) List due to exceedances in the dissolved oxygen standard in the epilimnion:

- Cache la Poudre Segment 20, Seaman Reservoir - Middle South Platte Segment 4, Milton Reservoir - Middle South Platte Segment 7, Prospect Lake - Upper South Platte Segment 17a, Berkeley Lake, Duck Lake - Upper South Platte Segment 17b, Sloan’s Lake - Upper South Platte Segment 23, Barnum Lake, Garfield Lake, Harvey Lake, Parkfield Lake and Houston Lake - Upper Colorado Segment 2, Shadow Mountain Lake The dissolved oxygen standard is slated for revisions in the 2010 Basic Standards and Methodology, Regulation No. 31, rule-making hearing in June 2010. The attainment decision for these lakes and reservoirs may be different when they are reassessed with the revised standard.

11. Seasonal Listings of E. Coli The 2010 Listing Methodology included a provision to allow assessment of the E. coli standard on a seasonal basis. The Division proposed the following segments be placed on the 303(d) List based on seasonal impairments of the E. coli standard:

- Arkansas River Basin, Fountain Creek Segments 2b and 6 - South Platte Basin, Big Thompson Segment 9 - South Platte Basin, Cache la Poudre Segments 12 and 13a - South Platte Basin, Bear Creek Segment 2 - South Platte, Clear Creek Segment 15 - South Platte, Upper South Platte Segment 16c: Harvard, West Harvard and Lakewood Gulches The Commission adopted all proposed seasonal listings onto the 303(d) List as proposed by the Division.

12. Listing of Segments where Water Quality is not Meeting Standards not Identified Above The following segments were added to the 303(d) List due to exceedances of water quality standards not identified above:

- South Platte, Bear Creek Segment 5: Swede Gulch/Kerr Gulch, E. coli - South Platte, Cherry Creek Segment 3: E. coli and Se - South Platte, Clear Creek Segment 2b: Zn - South Platte, Clear Creek Segment 3a: Cu - South Platte, Clear Creek Segment 9a: Silver Creek, Cu and Pb - South Platte, Clear Creek Segment 9b: pH - Upper Gunnison Segment 29a, Deadman Gulch: pH, Cd, Cu, Mn, Zn, Fe(Trec)

- Lower Colorado Segment 10: Se - Lower Colorado, White River Segment 9d: Se - South Platte, Bear Creek Segment 1c (Bear Creek Reservoir): Chl a, Phosphorus - South Platte, Bear Creek Segment 5: E. coli - South Platte, Boulder Creek Segment 2a, 2b and 3: Cu - South Platte, Boulder Creek Segment 8: Se - South Platte, Boulder Creek Segment 9: As - South Platte, Big Thompson Segment 2: Cu, Zn - South Platte, Big Thompson Segment 3, 6, 7: Cu - South Platte, Big Thompson Segment 4a, 4b: Se - South Platte, Big Thompson Segment 8: D.O - South Platte, Big Thompson Segment 16 (Lake Estes): Cu - South Platte, Cache La Poudre Segment 7: Pb - South Platte, Cache La Poudre Segment 11: Se - South Platte, Lower South Platte Segment 1: Se, Mn - South Platte, Lower South Platte Segment 2b: Se - South Platte, Middle South Platte Segment 1a: E. coli - South Platte, Middle South Platte Segment 1b: Se - South Platte, Middle South Platte Segment 4 (Barr and Milton Reservoirs): NH - South Platte, Middle South Platte Segment 7 (Horse Creek Reservoir and Prospect Lake): pH, NH - South Platte, Republican Segment 4: E. coli - South Platte, St. Vrain Segment 2a: Zn - South Platte, St. Vrain Segment 4c: Cu, As - South Platte, Upper South Platte Segment 2c: Zn - South Platte, Upper South Platte Segment 3 (Hawkins Gulch): Se - South Platte, Upper South Platte Segment 3 (Horse Creek): D.O., Fe(trec) - South Platte, Upper South Platte Segment 3 (West Creek): As, Hg - South Platte, Upper South Platte Segment 3 (Goose Creek): D.O. - South Platte, Upper South Platte Segment 3 (Trail & Wigwam Creeks): Fe(trec)

- South Platte, Upper South Platte Segment 4: pH - South Platte, Upper South Platte Segment 5a: Cu, Zn - South Platte, Upper South Platte Segment 5c: NH - South Platte, Upper South Platte Segment 14: As - South Platte, Upper South Platte Segment 17a (Berkeley Lake): As - South Platte, Upper South Platte Segment 23 (Barnum Lake): E. coli - Upper Colorado,Yampa River Segment 13b: Total Recoverable Iron 13. Segment- Specific Issues a. Upper South Platte Segment 15 and Middle South Platte Segment 1a – Category 4b Demonstration Plan Metro Wastewater Reclamation submitted a Category 4b Demonstration Plan to the Division for two segments on the mainstem of the South Platte: Upper South Platte Segment 15 and Middle South Platte Segment 1a. Category 4b is an alternative to listing an impaired segment on the 303(d) List. A Category 4b Demonstration Plan, when implemented, must ensure attainment with all applicable water quality standards through pollution control mechanisms within a reasonable time period. This plan was accepted by the U.S. Environmental Protection Agency prior to the development of the Division's proposed 303(d) List. As a result, the Division did not include these segments in their proposal. No further discussion or comments were received by other parties. The Commission did not include Upper South Platte Segment 15 and Middle South Platte Segment 1a on the 303(d) List for ammonia and nitrate, for which the Category 4b Demonstration Plan was written. The Commission expects that after a reasonable period of time as defined in the Category 4b Demonstration Plan, water quality will be reexamined on these segments. If water quality standards are not achieved at this time the segment will be considered impaired and placed on the 303(d) List.

b. South Platte River (COSPUS14 and COSPUS15) - Trash Two proposals were originally submitted in prehearing statements by P.U.R.E. and Wild Earth Guardians to list the South Platte River from Bowles Avenue to the confluence of Sand Creek as impaired for trash. Wild Earth Guardians withdrew their proposal but P.U.R.E maintained their proposal. The Division met prior to the Rulemaking hearing with representatives of P.U.R.E and discussed the issue. The Division maintained that a method to determine impairment for trash did not exist and that this must be determined before a decision of impairment can be made. The Division and P.U.R.E agreed to begin to address this issue in the 2012 303d Listing Methodology development stakeholder process that is to begin in the summer of 2010.

1. After listening to all of the testimony on this topic, the Commission took no action on listing these segments for trash at this time. It is expected that P.U.R.E, the Division and other stakeholders will work collaboratively to develop an appropriate methodology for determining impairment for trash through the 2012 303d Listing Methodology development process and other appropriate collaborative processes.

c. Muddy Creek (COUCUC07b) – Temperature The Division proposed to list Muddy Creek (COUCUC07b) on the 303(d) List for temperature. The River Water Conservation District (River District) opposed this listing stating that exceedances at an upper station were due to a temporary construction at the outlet of Wolford Reservoir. Exceedances were still found at the lower station. The Commission adopted the Division’s alternate proposal to include the upper portion from Wolford Reservoir to Cow Gulch on the M&E List the and lower portion from Cow Gulch to the Colorado River on the 303(d) List.

d. Colorado River (COUCUC03) – Temperature The Division proposed to place all of the Colorado River mainstem from Lake Granby to the Roaring Fork River (COUCUC03) on the 303(d) List for temperature exceedances. Northern Colorado River Conservancy District (Northern) proposed an alternative portion of 578 Road bridge to the William Fork confluence. The Commission found that the portion that Northern recommended, omitted sites with exceedances both above and below their recommended portion. To encompass the entire scope of temperature exceedances, the Commission adopted the portion from 578 Road to immediately above the confluence with the Blue River.

e. Lower Colorado Segment 2b – Selenium In 2008, the Commission adopted only the portion at Humphrey Backwaters Area onto the 303(d) List for selenium. For this cycle, the Division proposed to list the entire segment for selenium. The City of Grand Junction and the River District opposed this listing claiming that the Riverwatch data used in the assessment was not representative or of good quality. The Division supported the quality of this data but since the data was older than five years, the Division agreed that additional data collection was needed before a decision to list the entire segment could be made. The Commission placed the remainder of this segment on the M&E List while leaving the Humphrey Backwaters Area on the 303(d) List. Grand Junction and the River District have offered to collect data throughout the segment before the next 303(d) rulemaking hearing in 2012.

f. Upper South Platte Segment 16c Upper South Platte Segment 16c is an all tributary segment and the Division proposed to place the entire segment on the 303(d) List for exceedances of E. coli and selenium.

1. E. coli: Denver Environmental Health (DEH) opposed listing all tributaries for both parameters. DEH put forward an alternative proposal for E. coli on this segment with some tributaries to be included on the 303(d) annually, some listed seasonally and one for the M&E List based on the attainment conclusions for each tributary individually. Those tributaries attaining the standard were not proposed for either list. The Division reviewed their proposal and agreed that it is a reasonable approach for E. coli. The Commission adopted the alternative proposal as presented by DEH. Selenium: DEH also asked that the Commission to only list those tributaries that have selenium data on the 303(d) List. The Division opposed this alternative proposal. The Division pointed out that unlike the data found on E. coli for these tributaries, everywhere that selenium data was collected, exceedances were found. The Commission chose to place the entire segment on the 303(d) List for selenium.

g. Fountain Creek Segments 2a and 2b The Division originally proposed to change the E. coli listing on Segment 2a from annual to seasonal (May through October) and to add Segment 2b to the 303(d) List seasonally. Rocky Mountain Environmental Labor Coalition/Sierra Club and Bill Thiebaut, District Attorney for the 10th Judicial District, asked that the listing be considered for the entire year for both segments as there are recreation uses in Fountain Creek year round. Through further investigation and reassessment of the data by the Division and the parties, data indicates that in Segment 2a, the E. coli standards are exceeded annually as opposed to seasonally as originally thought. In Segment 2b the exceedances were only found from May – October. The Commission chose to retain the listing on Segment 2a for E. coli annually and to add Segment 2b to the 303(d) List from May-October. The Division also originally proposed to remove the selenium listings on Segment 2a and 2b. This proposal also received opposition from RMELC/Sierra Club and Bill Thiebaut as there are ongoing studies regarding selenium in Fountain Creek. Colorado Springs supported the Division’s original proposal. Further investigation of acute selenium exceedances in Segment 2b in July 2005 prompted the Division and EPA to change their position prior to the hearing to retain this segment on the 303(d) List. The Commission agreed that this listing should remain on the 303(d) List until further evidence exist to support delisting. The Commission agreed with the Division that the data is meeting the ambient based standards in Segment 2a and removed the M&E listing for that segment.

h. Bear Creek (COSPBE05) – Swede Gulch and Kerr Gulch - E. coli The Division originally proposed to list only Swede Gulch based on the Division’s sampling at the mouth of the gulch. The Bear Creek Watershed Association (BCWA) identified this sampling location as Kerr Gulch. The Division used USGS and other maps indicating this as Swede Gulch. The Colorado Department of Transportation (CDOT) and residents identify this as Kerr Gulch. The Division met with the BCWA and agreed that the watershed, whatever the name of the stream, may be impacted by septic systems and livestock. The BCWA agreed to the development and implementation of a monitoring plan in the watershed to identify E. coli sources. The Division agreed that if the plan were implemented the priority of the listing should be changed from high to low to allow time for sampling and development of stakeholder involvement. The Commission agreed with the Division and the BCWA’s plan for Swede Gulch and Kerr Gulch.

i. Clear Creek (COSPCL14b) – Manganese The Division proposed to add manganese to the list of impairment parameters of Clear Creek segment 14b. During the 2009 South Platte River Basin RMH a new site-specific manganese standard was established for the segment. In the development of the new site-specific standard for segment 14b, data from both Clear Creek segments 14a and 14b were combined to determine a single standard for both segments. This procedure was used since segment 14a has very limited data and it was felt averaging would establish a more realistic standard. As it turns out when segment 14b only data is assessed against the new standard developed using data from both segments, the few samples from segment 14a with a lower ambient manganese concentration skewed the development of the site-specific standard enough that segment 14b data exceeds the new standard.

1. Based on the fact that the segment 14b site-specific standard was developed using data from the upstream segment it is not possible to evaluate if the segment is in attainment of the manganese standard. The proper site-specific standard indicating ambient conditions should be equivalent to the current assessment value and would not indicate impairment since they are the same dataset.
   1. After reviewing the development of the segment 14b site-specific manganese standard, the Division agreed with MillerCoors that the Clear Creek segment should not be listed for exceeding the manganese standard. The Commission agreed with the Division and MillerCoors that Clear Creek segment 14b should not be listed for manganese.

j. Juniata Reservoir (COGULG04a)

1. The Division originally proposed to list Juniata Reservoir on the 303(d) List for impairment of the Aquatic Life Use due to a Fish Consumption Advisory (FCA). A mercury FCA was issued for Juniata Reservoir in 2009. The Section 303(d) Listing Methodology 2010 Listing Cycle states at III.D.6 “Issuance of a FCA by CDPHE indicates impairment of an Aquatic Life Use classification for any waters so classified.” The City of Grand Junction and Colorado Division of Wildlife proposed to either close the reservoir or change the reservoir to “catch and release” in order for the Division to remove the FCA and therefore remove the basis for inclusion on the 303(d) List. The Division stated that the FCA would not be lifted if the reservoir changed to catch and release and the only way that the FCA could be lifted at Juniata is if the reservoir was completely fenced and fishing access was prohibited. At the time of the hearing, no action had been taken and the FCA was still in effect. Therefore the Commission chose to add this segment to the 303(d) List.

k. Marston Reservoir (COSPUS22)

1. The Division proposed that Marston Reservoir as part of COSPUS22 be placed on the M & E List for non-attainment of the DO standard in the metalimnion. The Denver Water Board argued that Marston was not waters of the state and was not used for aquatic life uses. There was discussion about what constitutes waters of the state and it was decided that that decision was not appropriate for this hearing, since this hearing addresses all waters for which classifications and standards have been adopted. The Commission decided to include Marston Reservoir on the 2010 M & E List because it fits within the description of waters in Upper South Platte segment 22.

C. Revisions to Monitoring and Evaluation List 1. Introduction This regulation updates Colorado’s Monitoring and Evaluation List (M&E List) to reflect additional water quality information available since the Regulation was promulgated in 2008.

2. List Development See the discussion of list development under subsection B.2 above.

3. Prioritization and Scheduling The Division remains committed to establishing a plan for monitoring and evaluating these water bodies prior to the list submission date for the subsequent listing cycle. Further, the Commission has committed to determining their appropriate status (as either impaired or fully supporting) within ten years of their placement on the M&E List.

4. Data Quality See the discussion of data quality under subsection B.2.c above.

5. New Table Value Standards Cadmium and Zinc: As part of the Basic Standards hearing of 2005, new zinc and cadmium table values were adopted. The acute and chronic zinc and cadmium equations in each basin were modified to conform to Regulation No. 31 over the last four years. An increase in cadmium listings were the result of a more stringent cadmium standard.

The following segments were added to the M&E List for cadmium: - Gunnison River, San Miguel Segment 3a - South Platte, Boulder Creek Segment 14, Barker Reservoir - Boulder Creek Segments 2a, 2b, 3, 9 10 and 14 - Clear Creek Segment 6, Hoop Creek - Cache la Poudre Segment 13a - Upper South Platte Segment 3, Hawkins Gulch - Cache La Poudre Segment 9 6. Listings Due to Exceedances of the Secondary Water Supply Standards For the secondary water supply standards of dissolved iron, manganese and sulfate, the less restrictive of the following two options will apply as the numeric standard: existing quality as of January 1, 2000 or the table value criteria in Regulation No. 31, Tables II and III. For dissolved iron this value is 300 ug/l. For manganese this value is 50 ug/l. For sulfate this value is 250 ug/l. The Division evaluated the water quality as of January 1, 2000 to determine in some cases where standards exceeded the water supply criteria in Tables II and III. The following segments were proposed for listing based on exceedances of the standards:

- Upper Colorado, Yampa River Segments 2a: Manganese - Upper Colorado, Yampa River Segments 3: Manganese and Dissolved Iron 7. Delisting of Segments where Water Quality is Currently Meeting Standards As additional water quality data is collected and assessed, new data may show attainment of the standards. The following segments and parameters have been removed from the M&E List due to attainment of current water quality standards: - Fountain Creek Segment 2a: Selenium - Fountain Creek Segment 3, Bear Creek and Cheyenne Creek: Sediment - Middle Arkansas Segment 14: E. coli - Upper Arkansas Segment 5, Turquiose Lake: D.O.

- Upper Arkansas Segment 13: Sediment - Lower Colorado Segment 4a: Selenium - Lower Colorado Segment 11h: Total Recoverable Iron - Lower Colorado Segment 13b: D.O. and E. coli - St. Vrain Segment 2: Sediment - St. Vrain Segment 3: E. coli - Upper South Platte Segment 2a: Sediment - Upper South Platte Segment 3: Sediment and Temperature - Upper South Platte Segment 4 (North Fork South Platte and Buffalo Creek): Sediment - Upper South Platte Segment 6a: Sediment - Upper Colorado, Yampa River Segment 3 (First Creek): Sediment - Upper Colorado, Yampa River Segment 19 (Oliver Creek): Sediment - Upper Colorado, North Platte River Segment 4a: Sediment - Gunnison River, Uncompahgre Segment 3b, Ridgway Reservoir: D.O. - Gunnison River, San Miguel Segment 7a: Total Recoverable Iron - Lower Colorado, White River Segment 22: Sediment - Upper Colorado, Blue River Segment 18: E. coli 8. Segments Moved to the 303(d) List As additional water quality data is collected and assessed, a segment may be moved from the M&E List to the 303(d) List once the non-attainment is confirmed. In general, segments with less than 10 data points will be placed on the M&E List until more data is collected. The following segments and parameters have been moved from the M&E List to the 303(d) List due to additional data collection:

- Lower Arkansas Segment 5b: D.O.

- San Miguel Segment 3a: Cadmium - Upper Gunnison Segment 29a, Deadman Gulch: Cd, Cu, Mn, Zn, Fe(Trec)

- Big Thompson Segment 4b: Selenium - Boulder Creek Segment 8: Selenium - Upper Colorado Segment 12, Shadow Mountain Lake: D.O. - Upper Colorado, Yampa River Segment 3 (Bushy Creek): Sediment - Upper South Platte 5a: Cadmium, copper and zinc 9. Dissolved Oxygen Standard in Lakes and Reservoirs In 2008 the Commission directed the Division to work with parties in 2008 and 2009 on changes to the Listing Methodology in regards to dissolved oxygen. Refinement of assessment methods were discussed in workgroup meetings and included in the 2010 Listing Methodology. The dissolved oxygen standard is slated for revisions in the 2010 Basic Standards and Methodology, Regulation No. 31, RMH in June 2010.

The following segments were added to the M&E List due to exceedances of the dissolved oxygen standard in the metalimnion in at least one profile: - Gunnison River, Uncompahgre Segment 14, Sweitzer Lake - Rio Grande Segment 9, Beaver Creek Reservoir - Big Dry Creek Segment 2, Standley Lake - Boulder Creek Segment 14, Barker Reservoir - Big Thompson Segment 12, Lake Loveland, Horseshoe Lake and Boyd Lake - Big Thompson Segment 14, Lon Hagler Reservoir and Lonetree Reservoir - Cache la Poudre Segment 14, Horsetooth Reservoir - Lower South Platte Segment 3, North Sterling Reservoir - Middle South Platte Segment 4, Barr Lake - Middle South Platte Segment 7, Horse Creek Reservoir - St. Vrain Creek Segment 7, Boulder Reservoir - St. Vrain Segment 9, Union Reservoir - St. Vrain Segment 13, Lake Thomas - Upper South Platte Segment 16b, Aurora Reservoir - Upper South Platte Segment 19, Tarryall Reservoir, Cheesman Reservoir, Elevenmile Reservoir, Spinney Mountain Reservoir - Upper South Platte Segment 22, Marston Reservoir, Quincy Reservoir, - Upper South Platte Segment 23, Vanderbilt Reservoir - Upper Colorado Segment 5, Wolford Mountain Reservoir - Upper Colorado, Yampa River Segment 2b, Stagecoach Reservoir PARTIES TO THE RULEMAKING HEARING 1. Protect Urban River Environments (Confluence Kayaks and Telemark, Colorado Whitewater Association, Denver Trout Unlimited, The Shimoda Group, The Greenway Foundation)

2. Summit Water Quality Committee 3. Northwest Colorado Council of Governments 4. City of Boulder 5. City of Colorado Springs and Colorado Springs Utilities 6. City of Aurora 7. Denver Water 8. City and County of Denver 9. Bear Creek Watershed Association 10. City of Grand Junction 11. Northern Colorado Water Conservancy District 12. Metro Wastewater Reclamation District 13. Alamosa Riverkeeper 14. Bill Thiebaut, District Attorney for 10th Judicial District, Colorado 15. Farmers Reservoir and Irrigation Company 16. Barr Lake and Milton Reservoir Watershed Association 17. Colorado Division of Wildlife 18. City of Black Hawk and Black Hawk/Central City Sanitation District 19. Cherry Creek Basin Water Quality Authority 20. South Platte Coalition for Urban River Evaluation 21. Colorado River Water Conservation District 22. Grand County Water and Sanitation District #1, Winter Park Ranch Water and Sanitation District, Fraser Sanitation District, Winter Park Sanitation District 23. City of Westminster 24. The Rocky Mountain Environmental Labor Coalition and the Sierra Club 25. Colorado Stormwater Council 26. Seneca Coal Company 27. Littleton/Englewood Wastewater Treatment Plant 28. City of Arvada 29. MillerCoors LLC 30. Ute Water Conservancy District, acting by and through the Ute Water Activity Enterprise 31. US Environmental Protection Agency

93.14 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND

PURPOSE; DECEMBER 2011 RULEMAKING, EFFECTIVE DATE OF MARCH 30, The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.

BASIS AND PURPOSE A. Revisions to 303(d) List 1. Introduction This regulation updates Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (TMDLs) to reflect additional water quality information available since the Regulation was revised in 2010. This list was prepared to fulfill section 303(d) of the federal Clean Water Act (Act) which requires that states submit to the U.S. Environmental Protection Agency (EPA) a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards. This regulation also updates Colorado’s Monitoring and Evaluation List (M&E List) to reflect additional water quality information available since the Regulation was revised in 2010.

2. List Development a. Listing Methodology The “Section 303(d) Listing Methodology - 2012 Listing Cycle” contains a description of the listing process, the criteria for listing, and the criteria for determination of TMDL priority. The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission administrative action hearing in March 2011. This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2012 Section 303(d) List and the 2012 M&E List. However, this methodology was not adopted by the Commission as a rule. The Commission therefore has the flexibility to take into account other appropriate factors in making site- specific listing decisions.

b. Information Considered The Commission has considered all existing and readily available information in developing the 2012 Section 303(d) List. In determining whether data and information are existing and readily available, it has taken into account such data and information as the Division has utilized in the preparation of those identification processes, calculations and models referenced in 40 CFR §130.7(a)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and submitted in reports provided to the Division as referenced in 40 CFR §130.7(a)(5)(iii). In addition, the Commission accepted credible data and information that was submitted in accordance with the listing process schedule, whether submitted by EPA or any other interested party. The Division also continues to independently collect and analyze new data on a rotating basin basis as part of its triennial review efforts and will utilize such data and information in making future listing determinations. Existing data which was not brought forward through one of the above mechanisms or otherwise presented to the Commission in accordance with the schedule was not treated as “readily available” for purposes of making the 2012 listing decisions. Such information will be considered in the next listing cycle.

c. Data Quality In the Water Quality Control Division's (WQCD) Quality Management Plan 2011 for the Collection and Utilization of Environmental Data, the WQCD states that “It is the expressed goal of the Division to use only those analytical data that are both reliable and have a defined level of quality.” 3. Prioritization The objective of prioritization is to identify those waterbody segments where the Division and the public should concentrate their resources. Priorities of High, Medium and Low were established according to section IV. of the 2012 Section 303(d) Listing Methodology.

The Division remains committed to establishing a plan for monitoring and evaluating water bodies on the M&E List prior to the list submission date for the subsequent listing cycle. Further, the Commission has committed to determining their appropriate status (as either impaired or fully supporting) within ten years of their placement on the M&E List.

4. Fish Mercury (Hg) Listings The 303(d) Listing Methodology was revised in 2012 for the assessment of Fish Mercury (Hg). The newly adopted methods compare the median fish Hg for each waterbody and species to a 0.3 ppm threshold. A sample size requirement of 30 fish tissue samples per waterbody/species was also introduced in order to list new waterbodies for Fish Hg. Waterbodies can also be listed if there is overwhelming evidence of impairment (>0.45 ppm Hg) and a sample size of at least 10 fish tissue samples.

The Commission retained the following 6 lakes on the 303(d) List because these lakes have a median Hg above the 0.3 ppm threshold and either meet the sample size requirements or show overwhelming evidence of impairment: - Upper South Platte Segment 23, Berkeley Lake (COSPUS23) - Upper Arkansas Segment 27, Brush Hollow Reservoir (COARUA27) - Cache la Poudre Segment 14, Horsetooth Reservoir (COSPCP14) - Upper South Platte Segment 17a, Rocky Mountain Lake (COSPUS17a) - Lower Arkansas Segment 5b, Trinidad Reservoir (COARLA05b) - Los Pinos Segment 3, Vallecito Reservoir (COSJPN03)

The Commission retained the following 10 lakes on the 303(d) List because they were on the 303(d) List prior and have a median Hg of greater than 0.3 ppm. Although the 2012 Listing Methodology requires a minimum sample size of thirty fish, the Commission chose to retain these segments on the 303(d) List as opposed to the Monitoring and Evaluation List:

- Big Thompson Segment 11, Carter Reservoir (COSPBT11)

- Yampa River Segment 2b, Catamount Reservoir (COUCYA02b) - San Juan Segment 6a, Echo Canyon Reservoir (COSJSJ06a) - Yampa River Segment 2b, Elkhead Reservoir (COUCYA02b) - Middle Arkansas Segment 16, Horseshoe Lake– Lathrop (COARMA16) - Dolores River Segment 4, McPhee Reservoir (COSJDO04)

- Los Pinos, Segment 11, Narraguinnep Reservoir (COSJLP11) - Lower Colorado Segment 20, Rifle Gap Reservoir (COLCLC20) - La Plata Segment 11, Totten Reservoir (COSJLP11)

- Upper Arkansas Segment 14b, Teller Reservoir (COARUA14b) The Commission retained the following 2 lakes on the 303(d) List because they were on the 303(d) List prior to the adoption of the new assessment methods. With median Fish Hg concentrations below 0.3 ppm, they will not be removed from the 303(d) List, however, until a minimum of 30 fish are collected: - Big Thompson Segment 12, Boyd Lake (COSPBT12)

- Upper Colorado Segment 12, Lake Granby (COUCUC12)

The Commission added the following 3 lakes on the Monitoring and Evaluation List because they have a median Fish Hg of greater than 0.3 ppm but the sample size is insufficient for Listing:

- North Platte Segment 4a, Big Creek Lake (COUCNP04a)

- Boulder Segment 15, Gross Reservoir (COSPBO15)

- Big Thompson Segment 14, Lonetree Reservoir (COSPBT14) The Commission removed the following lake from the 303(d) List. Additional data was collected meeting the minimum sample size requirement of thirty fish. Median Fish Hg concentrations are below the 0.3 ppm, threshold. - Lower Gunnison Segment 4, Juniata Reservoir (COGULG04) The Commission retained one listing based on non-attainment of the aquatic life use due to a PCE fish consumption advisory in Willow Springs Ponds, Fountain Creek, Segment 7a.

5. Aquatic Life Listings 280 Multimetric Index (MMI) scores were calculated for the 2012 listing cycle, utilizing the Water Quality Control Commission’s (WQCC) Policy 10-1, Aquatic Life Use Attainment. Of the 280 MMI scores generated, 48 segments were found to be not attaining the Aquatic Life Use standard. From those segments, or portions of segments, determined to be in non-attainment, 31 will be provisionally listed, as there is currently no water quality data available to indicate impairment. This is in accordance with the Section 303(d) Listing Methodology for the 2012 Listing Cycle, approved by the WQCC in March 2011. The Commission anticipates that the Division will collect additional data for these segments in the next two years to continue the investigation into potential sources. Because of the site-specific nature of macroinvertebrate data, waterbodies in all tributary segments that were identified as impaired for their Aquatic Life Use were listed individually.

The following segment was 303(d) listed for non-attainment of the Aquatic Life Use based on Policy 10-1:

- White River, Segment 13c, Yellow Creek (COLCWH13c)

The following segments were provisionally 303(d) listed for non-attainment of their Aquatic Life Use based on Policy 10-1:

- Upper Arkansas Segment 21a, Cripple Creek (COARUA21a) - San Miguel Segment 12, Maverick Draw (COGUSM12)

- Upper Gunnison Segment 6b, Cement Creek (COGUUG06b)

- Upper Gunnison Segment 15, S. Beaver Creek (COGUUG15) - Upper Gunnison Segment 24, Cochetopa Creek from Forest Road 3076/Co. Rd 43 to confluence with Tomichi Creek (COGUUG24) - Upper Gunnison Segment 29a, Lake Fork Gunnison River between Cooper and Silver Creek (COGUUG29a)

- Uncompahgre Segment 11, Deer Creek (COGUUN11)

- Lower Yampa Segment 22a, Talamantes Creek COLCLY22a)

- White River Segment 15, Piceance Creek (COLCWH15)

- White River Segment 20, Black Sulphur Creek (COLCWH20) - White River Segment 23, West Douglas Creek (COLCWH23) - Rio Grande Segment 12, Rio Grande River (CORGRG12)

- Bear Creek Segment 1a, Bear Creek from Witter Gulch to inlet to Evergreen Lake (COSPBE01a)

- Boulder Creek Segment 9, Boulder Creek from 107th Street to confluence with Coal Creek (COSPBO09)

- Clear Creek Segment 14a, Clear Creek from Croke Canal diversion to McIntyre Street (COSPCL14a)

- St. Vrain Segment 3, St. Vrain Creek (COSPSV03), from Left Hand Creek confluence to confluence with Boulder Creek - Upper South Platte Segment 3, Horse Creek (COSPUS03)

- Upper South Platte Segment 10a, West Plum Creek (COSPUS10a) - Upper South Platte Segment 11a, Cook Creek (COSPUS11a) - Eagle River Segment 6, Lake Creek (from below the confluence with East and West Lake Creek to the mouth), and Red Sandstone Creek (from north side I-70 Frontage Road to the confluence with Gore Creek) (COUCEA06)

- Eagle River Segment 8, Gore Creek (COUCEA08)

- Roaring Fork Segment 3a, Roaring Fork from Hunter Creek to Brush Creek confluence, Cattle Creek from Bowers Gulch to Mouth, W. Sopris Creek (COUCRF03a)

- Roaring Fork Segment 4, Brush Creek (COUCRF04)

- Roaring Fork Segment 7, South Fork Frying Pan River from transbasin diversion to confluence with unnamed tributary (COUCRF07) - Upper Colorado Segment 10a, Fraser River, Vasquez Creek (COUCUC10a)

- Yampa River Segment 15, Elkhead Creek (COUCYA15)

The following segments were included on the M&E List for possible non- attainment of their Aquatic Life Use based on Policy 10-1: - Bear Creek Segment 1e, Bear Creek (COSPBE01e)

- White River Segment 13b, Duck Creek (COLCWH13b)

- Eagle River Segment 6, Black Gore Creek Beaver Creek (from Wayne Creek to Mouth), Red Sandstone Creek (from USFS boundary to north side I-70 Frontage Road) (COUCEA06)

- Eagle River Segment 9a, Eagle River (from confluence with Berry Creek to confluence with Squaw Creek) (COUCEA09a)

Several segments were found to have data outside of the standard index period for data collection. The Commission included these segments on the Monitoring and Evaluation (M&E) List in order to gather more information within the standard index period. The following segments were listed on the M&E List for possible non-attainment of their Aquatic Life Use based on Policy 10-1: - Fountain Creek Segment 4, Sand Creek (COARFO04)

- Upper Arkansas Segment 5, Lake Fork Creek (COARUA05)

- Upper Gunnison Segment 8, Slate River (COGUUG08)

- Saint Vrain Segment 3, Saint Vrain Creek from Hover Road to the confluence with Left Hand Creek (COSPSV03)

- Boulder Creek Segment 7b, Coal Creek (COSPBO07b)

- Bear Creek Segment 2, Bear Creek (COSPBE02)

- Clear Creek Segment 1, Kearney Gulch, Grizzly Gulch (COSPCL01) Various parties questioned whether or not the data collected below reservoirs should be evaluated as being representative of an entire stream segment. They recommend that listings below reservoirs be placed on the M&E List while the applicability of the current thresholds below reservoirs is investigated. The Division agreed that a study was warranted and changed its proposal to the M&E List. The Commission placed the following segments on the M&E List for possible non-attainment of their Aquatic Life Use:

- COUCBL17, Blue River from outlet of Dillon Reservoir to N. Rock Creek confluence - COARUA05, Lake Fork below Sugarloaf Dam - COSPUS02a, South Fork South Platte River below Antero - COSPUS06a, South Platte River below Cheesman at Cheesman Canyon - COSPUS03, Trout Creek below Manitou Reservoir Dam - COUCUC03, Colorado River from below Windy Gap Reservoir to FR 538 Several segments were found to have data outside of the assessed period of record. Therefore, the Division proposed to remove them from both the 303(d) and M&E Lists. The Commission did not include these segments on either list: - Upper Arkansas Segment 5, S. Cottonwood Creek (COARUA05) - Upper Arkansas Segment 18, Currant Creek (COARUA18)

- San Miguel Segment 2, Howard Fork (COGUSM02)

- Rio Grande Segment 2, South Clear Creek (CORGRG02)

- Animas and Florida Segment 13c, Salt Creek (COSJAF13c) - Big Thompson Segment 2, Big Thompson River (COSPBT02) - Blue River Segment 17, Blue River from N. Rock Creek confluence to Colorado River (COUCBL17)

- North Platte Segment 4a, Snyder Creek (COUCNP04a)

- Upper Colorado Segment 7a, Big Alkali Creek (COUCUC07a) Other issues were raised in this rulemaking hearing in regards to listing decisions based on the assessment of macroinvertebrate data. In October 2010, the Commission adopted the Aquatic Life Use Attainment WQCC Policy 2010-1 which determined that the Colorado MMI is an appropriate tool for the quantitative bioassessment of the health of aquatic communities. The Commission adopted the 2012 Listing Methodology in March 2011. This Regulation No. 93 rulemaking hearing is the first occasion where the policies adopted by the Commission in Policy 2010-1 are being implemented into regulation. The Division followed the policies as defined in the methodologies to the intent for which they were adopted. The Commission recognizes that some of the policy decisions that were questioned by various parties may need additional review. The Commission directs the Division and interested parties to review WQCC Policy 2010-1 and the 2012 Listing Methodology and make appropriate changes in regards to the use of data for the MMI tool.

6. Listings Due to Exceedances of the Secondary Water Supply Standards For the secondary water supply standards of dissolved iron, manganese and sulfate, the less restrictive of the following two options will apply as the numeric standard: existing quality as of January 1, 2000 or the table value criteria in Regulation No. 31, Tables II and III. For dissolved iron this value is 300 ug/l. For manganese this value is 50 ug/l. For sulfate this value is 250 mg/l. The Division evaluated the water quality as of January 1, 2000 to determine in some cases where standards exceeded the water supply criteria in Tables II and III. The following segments were included on the 303(d) listing based on exceedances of the standards:

- Lower Gunnison Segment 4a, Whitewater Creek from below Brandon Ditch to confluence with Gunnison River: Manganese, Sulfate (COGULG04a)

- North Fork Segment 6b, Alum Gulch: Sulfate (COGUNF06b) - Upper Gunnison Segment 11, Coal Creek: Manganese (COGUUG11) - Upper Gunnison Segment 29a, Lake Fork Gunnison River: Manganese (COGUUG29a)

- Upper Gunnison Segment 32, N. Fork Henson Creek: Manganese (COGUUG32)

- Uncompahgre Segment 2, Uncompahgre River: Manganese (COGUUN02)

- Animas and Florida Segment 5a, Animas River: Manganese (COSJAF05a)

- La Plata Segment 4a, E. Mancos River, Manganese (COSJLP04a) - Big Thompson Segment 8, Little Thompson River: Sulfate (COSPBT08) - Clear Creek Segment 15, Clear Creek: Manganese (COSPCL15) - Saint Vrain Segment 5, Left Hand Creek: Manganese (COSPSV05) - Blue River Segment 2a, Blue River: Manganese (COUCBL02a) - Upper Colorado Segment 3, Colorado River: Manganese (COUCUC03) The following segments were included on the M&E List:

- Lower Gunnison Segment 4a, Callow Creek, Cummings Gulch, Peach Valley Creek: Sulfate (COGULG04a)

- Lower Gunnison Segment 4b, Kannah Creek: Sulfate (COGULG04b) - North Fork Segment 6b, Cottonwood Creek: Manganese, Sulfate (COGUNF06b)

- San Miguel Segment 8, S. Fork San Miguel River: Manganese (COGUSM08)

- Upper Gunnison Segment 15, S. Beaver Creek: Manganese, Dissolved Iron (COGUUG15)

- Upper Gunnison Segment 17, Antelope Creek: Manganese (COGUUG17) - Upper Gunnison Segment 23, Cochetopa Creek: Dissolved Iron (COGUUG23)

- Uncompahgre Segment 11, Cow Creek: Sulfate (COGUUN11) - Piedra River Segment 6a, Stollsteimer Creek: Sulfate (COSJPI06a) 7. Delisting of Segments with Recently Approved TMDLs The Division submitted 26 TMDLs to EPA in the last biennium that have been approved. The following segments and parameters have been removed from the 303(d) List:

- Arkansas, Upper Arkansas Segment 10, Lake Creek: Cu (COARUA10) - Gunnison, Lower Gunnison Segment 2, Gunnison River: Se (COGULG02) - Gunnison, Lower Gunnison Segment 4a, Tributaries to Gunnison River: Se (COGULG04a)

- Gunnison, Lower Gunnison Segment 4c, Red Rock Creek: Se (COGULG04c)

- Gunnison, North Fork Segment 3, North Fork Gunnison River: Se (COGUNF03)

- Gunnison, North Fork Segment 5, Leroux Creek, Jay Creek: Se (COGUNF05)

- Gunnison, North Fork Segment 6a, Short Draw: Se (COGUNF06a) - Gunnison, North Fork Segment 6b, Big Gulch, Cottonwood Creek: Se (COGUNF06b)

- Gunnison, San Miguel Segment 3a, San Miguel River: Cd (COGUSM03a) - Gunnison, San Miguel Segment 6a, Ingram Creek: Cd (COGUSM06a) - Gunnison, San Miguel Segment 6b, Marshall Creek: Cd (COGUSM06b) - Gunnison, Upper Gunnison Segment 30, Henson Creek: Cd, Zn(sc) (COGUUG30)

- Gunnison, Upper Gunnison Segment 31, Palmetto Gulch: Cd, Zn (COGUUG31)

- Gunnison, Uncompahgre Segment 4b, Uncompahgre River: Se (COGUUN04b)

- Gunnison, Uncompahgre Segment 4c, Uncompahgre River: Se (COGUUN04c)

- Gunnison, Uncompahgre Segment 12, Tributaries to Uncompahgre River: Se (COGUUN12)

- South Platte, Boulder Segment 2b, Boulder Creek from 13th Street to the confluence with South Boulder Creek: E. coli (COSPBO02b) - South Platte, Boulder Segment 4a, Gamble Gulch: Cd (COSPBO04a) - South Platte, Upper South Platte Segment 5a, Geneva Creek: Cd, Cu, Zn (COSPUS05a)

- South Platte, Upper South Platte Segment 5b, Geneva Creek: Cd (COSPUS05b)

- South Platte, Upper South Platte Segment 15, South Platte River: Cd (COSPUS15)

- Upper Colorado, Blue River Segment 12, Illinois Gulch: Cd (COUCBL12) 8. Delisting of Segments where Water Quality is Currently Meeting Standards As additional water quality data is collected and assessed, new data may show attainment of the standards. The following segments and parameters have been removed from the 303(d) List due to attainment of current water quality standards:

- Arkansas, Fountain Creek Segment 1a, Fountain Creek: Se (COARFO01a)

- Arkansas, Fountain Creek Segment 2b, Fountain Creek: Se (COARFO02b)

- Arkansas, Fountain Creek Segment 6, Monument Creek below Mesa Road: Se (COARFO06)

- Arkansas, Lower Arkansas Segment 4, Lorencito Canyon: Se (COARLA04)

- Arkansas, Lower Arkansas Segment 5a, Purgatoire River: Se (COARLA05a)

- Gunnison, Lower Dolores Segment 1, Dolores River: Fe(Trec) (COGULD01)

- Gunnison, Lower Gunnison Segment 2, Gunnison River: SO (COGULG02)

- Gunnison, Lower Gunnison Segment 8, Kannah Creek: Se (COGULG08) - Gunnison, Upper Gunnison Segment 11, Coal Creek: Pb (COGUUG11) - Lower Colorado, Lower Colorado Segment 3, Colorado River mainstem: Se (COLCLC03)

- South Platte, Middle South Platte Segment 4, Barr Lake: NH (COSPMS04)

- South Platte, Upper South Platte Segment 23, Barnum Lake: E. coli (COSPUS23)

The following segments and parameters have been removed from the M&E List due to attainment of current water quality standards:

- Arkansas, Upper Arkansas Segment 20, North Fork Wilson Creek: Cu (COARUA20)

- Arkansas, Upper Arkansas Segment 27, Brush Hollow Reservoir: pH (COARUA27)

- Gunnison, Lower Gunnison Segment 7, Surface Creek: Fe(Trec) (COGULG07)

- Gunnison, Lower Gunnison Segment 7, Ward Creek: Se (COGULG07) - Gunnison, San Miguel Segment 2, Bilk Creek: Cd (COGUSM02) - Gunnison, Upper Gunnison Segment 7, Slate River: Cd (COGUUG07) - Gunnison, Upper Gunnison Segment 16, Ohio Creek: Zn(sculpin) (COGUUG16)

- Upper Gunnison Segment 17, Antelope Creek: Dissolved Oxygen (COGUUG17)

- Gunnison, Upper Gunnison Segment 18, Tomichi Creek: E. coli (COGUUG18)

- Gunnison, Upper Gunnison Segment 32, N. Fork Henson Creek: Pb, Zn(sculpin) (COGUUG32)

- Gunnison, Uncompahgre Segment 8, Mineral Creek: Cd (COGUUN08) - Lower Colorado, Lower Colorado Segment 2b, Colorado River mainstem: Se (COLCLC02b)

- Rio Grande, Alamosa Segment 11, La Jara Reservoir: Cu, Se, Zn (CORGAL11)

- South Platte, Big Thompson Segment 11, Carter Lake: Cu (COSPBT11) - South Platte, Big Thompson Segment 16, Lake Estes: As (COSPBT16) - South Platte, Cache la Poudre Segment 14, Horsetooth Reservoir: D.O. (COSPCP14)

- South Platte, Lower South Platte Segment 3, N. Sterling and Jumbo Reservoirs: pH (COSPLS03)

9. Dissolved Oxygen Standard in Lakes and Reservoirs Twenty-eight lakes were previously on the M&E List due to low dissolved oxygen (DO) in the metalimnion. With the adoption of a revised DO standard in 2011, the Division proposed to remove 24 of these lakes from the M&E list because the lakes are now in attainment. Barr Lake was proposed for the 303(d) List for DO because recent data show non-attainment. The Division proposed that Horse Creek Reservoir, North Sterling Reservoir and Lake Thomas remain on the M&E list for DO either because of a minimal sample size (n=1) or due to concerns of the representative nature of the data. The Commission supported the Division’s proposal.

Lakes now in attainment with the revised DO standard:

- Upper South Platte Segment 16b, Aurora Reservoir (COSPUS16b) - Boulder Segment 14, Barker Reservoir (COSPBO14)

- Bear Creek Segment 1c, Bear Creek (COSPBE01C)

- Rio Grande Segment 9, Beaver Creek Reservoir (CORGRG09) - St. Vrain Segment 7, Boulder Reservoir (COSPSV07)

- Big Thompson Segment 12, Boyd Lake (COSPBT12)

- Upper South Platte Segment 19, Cheesman Reservoir (COSPUS19) - Cherry Creek Segment 2, Cherry Creek Reservoir (COSPCH02) - Upper South Platte Segment 19, Elevenmile Reservoir (COSPUS19) - Big Thompson Segment 12, Horseshoe (Loveland) Lake (COSPBT12) - Cache la Poudre Segment 14, Horsetooth Reservoir (COSPCP14) - Big Thompson Segment 14, Lon Hagler Reservoir (COSPBT14) - Big Thompson Segment 14, Lonetree Reservoir (COSPBT14) - Big Thompson Segment 12, Lake Loveland (COSPBT12)

- Upper South Platte Segment 22, Marston Reservoir (COSPUS22) - Now identified as Bear Creek Segment 11 (COSPBE11)

- Upper South Platte Segment 16c, Quincy Reservoir (COSPUS16c) - Upper South Platte Segment 19, Spinney Mountain Reservoir (COSPUS19)

- Yampa River Segment 2b, Stagecoach Reservoir (COUCYA02b) - Big Dry Segment 2, Standley Lake (COSPBD02)

- Uncompahgre River Segment 14, Sweitzer Reservoir (COGUUN14) - Upper South Platte Segment 2a, Tarryall Reservoir (COSPUS02a) - St. Vrain Segment 9, Union Reservoir (COSPSV09)

- Upper South Platte Segment 23, Vanderbilt Lake, Harvey Lake, Duck Lake (COSPUS23)

- Upper Colorado Segment 5, Wolford Mountain Reservoir (COUCUC05) The Commission moved the following lakes to the 303(d) List for D.O.: - Middle South Platte Segment 4, Barr Lake (COSPMS04)

- Middle South Platte Segment 7, Horse Creek Reservoir (COSPMS07) - Upper South Platte Segment 23, Vanderbilt Lake (COSPUS23) The Commission retained the following lakes on the M&E List for D.O.: - Lower South Platte Segment 3, North Sterling Reservoir (COSPLS03) - St. Vrain Segment 7, Thomas Reservoir (COSPSV07)

10. Listing of Segments where Water Quality is not Meeting Standards not Identified Above The following segments or parameters were added to the 303(d) List due to exceedances of water quality standards not identified above: - Arkansas, Upper Arkansas Segment 20, North Fork Wilson Creek: As (COARUA20)

- Gunnison River, Lower Gunnison Segment 3, Eggleston Reservoir: Fe(Trec) (COGULG03)

- Gunnison River, Lower Gunnison Segment 7, Tongue Creek: Fe(Trec) (COGULG07)

- Gunnison River, Lower Gunnison Segment 13, Crawford Reservoir: D.O. (temperature) (COGULG13)

- Gunnison River, North Fork Gunnison Segment 4, East Muddy Creek: Fe(Trec) (COGUNF04)

- Gunnison River, North Fork Gunnison Segment 6b, Alum Gulch: SO , Fe(Trec) (COGUNF06b)

- Gunnison River, San Miguel Segment 2, Bear Creek: Cd, Zn(sc) (COGUSM02)

- Gunnison River, San Miguel Segment 2, Howard Fork abv Swamp Gulch: pH, D.O. (COGUSM02)

- Gunnison River, San Miguel Segment 11, Miramonte Reservoir: D.O. (temperature) (COGUSM11)

- Gunnison River, Upper Gunnison Segment 9, Coal Creek: As (COGUUG09)

- Gunnison River, Upper Gunnison Segment 11, Elk Creek: As (COGUUG11)

- Gunnison River, Upper Gunnison Segment 11, Coal Creek: Cd, Zn, As (COGUUG11)

- Gunnison River, Upper Gunnison Segment 12, Coal Creek: Cu (COGUUG12)

- Gunnison River, Upper Gunnison Segment 26, Blue Creek: Cu (COGUUG26)

- Gunnison River, Uncompahgre Segment 4c, Uncompahgre River: Fe(Trec) (COGUUN04c)

- Gunnison River, Uncompahgre Segment 6a, Red Mountain Creek: Ag, Cu (COGUUN06a)

- Gunnison River, Uncompahgre Segment 7, Gray Copper Gulch: Cu (COGUUN007)

- Gunnison River, Uncompahgre Segment 9, Sneffels Creek: Cd, (COGUUN09)

- Gunnison River, Uncompahgre Segment 12, Dry Creek: Fe(Trec) (COGUUN12)

- Gunnison River, Uncompahgre Segment 12, Loutzenhizer Arroyo: Fe(Trec) (COGUUN12)

- Gunnison River, Lower Dolores Segment 5, Roc Creek: Cu, Fe(Trec) (COGULD05)

- Lower Colorado, Lower Colorado Segment 13b, Leach Creek: E. coli, Fe(Trec) (COLCLC013b)

- Lower Colorado, White River Segment 13c, Yellow Creek: Fe(Trec) (COLCWH13c)

- Lower Colorado, White River Segment 14a, Piceance Creek from Willow Creek to Hunter Creek: Fe(Trec) (COLCWH14a)

- San Juan/Dolores Rivers, Animas and Florida Segment 3c, Arrastra Gulch: Cd, Zn COSJAF03c)

- San Juan/Dolores Rivers, Animas and Florida Segment 4a, Animas River: Al(Trec) (COSJAF04a)

- San Juan/Dolores Rivers, La Plata Segment 1, La Plata River: Ag (COSJLP01)

- San Juan/Dolores Rivers, La Plata Segment 4a, E. Mancos River: D.O. (COSJLP04a)

- San Juan/Dolores Rivers, La Plata Segment 4a, Mancos River: D.O. (COSJLP04a)

- San Juan/Dolores Rivers, La Plata Segment 7a, McElmo Creek: Fe(Trec),

1. E. coli (COSJLP07a)

- San Juan/Dolores Rivers, La Plata Segment 8a, Mud Creek: Se (COSJLP08a)

- San Juan/Dolores Rivers, La Plata Segment 8a, Trail Canyon: Fe(Trec) (COSJLP08a)

- San Juan/Dolores Rivers, San Juan Segment 6a, Echo Canyon Reservoir: DO (Temperature) (COSJSJ06a)

- South Platte, Bear Creek Segment 1a, Bear Creek: Temperature (COSPBE01a)

- South Platte, Bear Creek Segment 1e, Bear Creek: Temperature (COSPBE01e)

- South Platte, Cherry Creek Segment 3, Cherry Creek: Fe(Trec) (COSPCH03)

- South Platte, Clear Creek Segment 17b, Ralston Creek: U (COSPCL17b) - South Platte, Upper South Platte Segment 17a, Smith Lake: NH (COSPUS17a)

- South Platte, St. Vrain River Segment 5, Left Hand Creek: Cu (COSPSV05)

- Upper Colorado, Eagle River Segment 9a, Eagle River from Ute Creek to Rube Creek: Temperature (COUCEA09a)

- Upper Colorado, Eagle River Segment 9a, Eagle River from Berry Creek to Squaw Creek: Sediment (COUCEA09a)

- Upper Colorado, North Platte Segment 9, Lake John: D.O. (COUCNP09) - Upper Colorado, Upper Colorado Segment 2, Willow Creek Reservoir: Mn (COUCUC02)

The following segments or parameters were added to the M&E List where there is a reason to suspect water quality problems, but there is also uncertainty.: - Arkansas River, Fountain Creek Segment 2a, Fountain Creek: Fe(Trec) - Gunnison River, Lower Gunnison Segment 3, Eggleston Reservoir: pH, Zn, Fe(Trec) (COGULG03)

- Gunnison River, Lower Gunnison Segment 4a, Callow Creek: E. coli (COGULG04a)

- Gunnison River, Lower Gunnison Segment 4a, Peach Valley Creek: Fe(Trec) (COGULG04a)

- Gunnison River, Lower Gunnison Segment 4a, Wells Gulch: pH (COGULG04a)

- Gunnison River, Lower Gunnison Segment 7, Ward Creek: Se (COGULG07)

- Gunnison River, Lower Gunnison Segment 7, Surface Creek: Pb (COGULG07)

- Gunnison River, Lower Gunnison Segment 12, Muddy Creek: E. coli (COGULG12)

- Gunnison River, North Fork Gunnison Segment 4, East Muddy Creek: Pb, Se (COGUNF04)

- Gunnison River, North Fork Gunnison Segment 4, Muddy Creek: E. coli (May-Oct) (COGUNF04)

- Gunnison River, North Fork Gunnison Segment 4, Island Reservoir: pH, Zn (COGUNF04)

- Gunnison River, North Fork Gunnison Segment 5, Leroux Creek: E. coli (COGUNF05)

- Gunnison River, North Fork Gunnison Segment 6a, Unnamed Tributary: Se (COGUNF06a)

- Gunnison River, North Fork Gunnison Segment 6b, Alum Gulch: Fe(Trec) (COGUNF06b)

- Gunnison River, North Fork Gunnison Segment 7, Paonia Reservoir: Zn (COGUNF07)

- Gunnison River, San Miguel Segment 2, Bear Creek: Pb (COGUSM02) - Gunnison River, San Miguel Segment 2, Cornet Creek: Pb (COGUSM02) - Gunnison River, San Miguel Segment 3b, San Miguel River: Pb (COGUSM03b)

- Gunnison River, San Miguel Segment 4a, San Miguel River: Pb (COGUSM04a)

- Gunnison River, San Miguel Segment 7a, Chapman Creek: Fe(Trec) (COGUSM07a)

- Gunnison River, San Miguel Segment 7a, Iron Bog Creek: pH, D.O. (COGUSM07a)

- Gunnison River, San Miguel Segment 10, Naturita Creek: E. coli, D.O. (COGUSM10)

- Gunnison River, San Miguel Segment 12, Mesa Creek: Se (COGUSM12) - Gunnison River, San Miguel Segment 12, Calamity Draw: D.O. (COGUSM12)

- Gunnison River, San Miguel Segment 12, Specie Creek: D.O. (COGUSM12)

- Gunnison River, Upper Gunnison Segment 4, Taylor River: Pb (COGUUG04)

- Gunnison River, Upper Gunnison Segment 10, Redwell Creek: pH (COGUUG10)

- Gunnison River, Upper Gunnison Segment 15, S. Beaver Creek: Fe(Trec) (COGUUG15)

- Gunnison River, Upper Gunnison Segment 16, Ohio Creek: E. coli (COGUUG16)

- Gunnison River, Upper Gunnison Segment 17, Antelope Creek: E. coli (COGUUG17)

- Gunnison River, Upper Gunnison Segment 23, Stewart Creek: Fe(Trec) (COGUUG23)

- Gunnison River, Upper Gunnison Segment 26, Mesa Creek: Cu (COGUUG26)

- Gunnison River, Upper Gunnison Segment 31, Palmetto Gulch: Ag (COGUUG31)

- Gunnison River, Uncompahgre Segment 2, Uncompahgre River: Pb (COGUUN02)

- Gunnison River, Uncompahgre Segment 3b, Ridgway Reservoir: Pb, Zn (COGUUN03b)

- Gunnison River, Uncompahgre Segment 4c, Uncompahgre River: Pb (COGUUN04c)

- Gunnison River, Uncompahgre Segment 7, Gray Copper Gulch: pH (COGUUN007)

- Gunnison River, Lower Dolores Segment 2, Dolores River: E. coli (COGULD02)

- Gunnison River, Lower Dolores Segment 3a, Disappointment Creek: Se,

1. E. coli (COGULD03a)

- Gunnison River, Lower Dolores Segment 4, West Paradox Creek: E. coli, Fe(Trec) (COGULD04)

- Gunnison River, Lower Dolores Segment 5, Roc Creek: E. coli (COGULD05)

- Lower Colorado, Lower Colorado Segment 4b, South Canyon Hot Springs: Pb (COLCLC04b)

- San Juan/Dolores Rivers, Animas and Florida Segment 3c, Arrastra Gulch: Pb (COSJAF03c)

- San Juan/Dolores Rivers, Animas and Florida Segment 12a, Electra Reservoir: Ag, Zn (COSJAF12a)

- San Juan/Dolores Rivers, Animas and Florida Segment 13a, Junction Creek: Ag, E. coli (COSJAF13a)

- San Juan/Dolores Rivers, Upper Dolores Segment 11, Lost Canyon Creek: E. coli (COSJDO11)

- San Juan/Dolores Rivers, La Plata Segment 3a, Cherry Creek: Cu (COSJLP03a)

- San Juan/Dolores Rivers, La Plata Segment 4a, E. Mancos River: Pb (COSJLP04a)

- San Juan/Dolores Rivers, La Plata Segment 4a, Mancos River: Cu, Pb (COSJLP04a)

- San Juan/Dolores Rivers, La Plata Segment 8a, Tribs to McElmo Creek:

1. E. coli (COSJLP08a)

- San Juan/Dolores Rivers, Piedra Segment 5, Williams Creek Reservoir: pH, Zn, Fe(Trec), D.O. (COSJPI05)

- San Juan/Dolores Rivers, Piedra Segment 8a, Williams Creek: pH, Cu (COSJPI05)

- San Juan/Dolores Rivers, Piedra Segment 6a, Stollsteimer Creek: Fe(Trec), E. coli (COSJPI06a)

- San Juan/Dolores Rivers, San Juan Segment 1, Navajo River: E. coli (COSJSJ01)

- San Juan/Dolores Rivers, San Juan Segment 5, San Juan River: Pb, (COSJSJ05)

- San Juan/Dolores Rivers, San Juan Segment 6a, San Juan River: Pb, Cu (COSJSJ06a)

- San Juan/Dolores Rivers, San Juan Segment 6a, Echo Canyon Reservoir: pH (COSJSJ06a)

- San Juan/Dolores Rivers, San Juan Segment 9a, Rio Blanco: Ag, Pb (COSJSJ09a)

- San Juan/Dolores Rivers, San Juan Segment 10, Rito Blanco: E. coli (COSJSJ10)

- South Platte, Upper South Platte Segment 17a, Rocky Mountain Lake: Cu, DO (COSPUS17a)

- South Platte, Upper South Platte Segment 23, Huston Lake: E. coli (COSPUS23)

- Upper Colorado, Eagle River Segment 9a, Eagle River from Berry Creek to Ute Creek: Temperature (COUCEA09a)

- Upper Colorado, Eagle River Segment 9a, Eagle River from Gore Creek to Berry Creek and from Squaw Creek to Rube Creek: Sediment (COUCEA09a)

- Upper Colorado, Upper Colorado Segment 10c, Fraser River: Pb (COUCUC10c)

11. Segments Moved to the 303(d) List As additional water quality data is collected and assessed, a segment may be moved from the M&E List to the 303(d) List once the non-attainment is confirmed. In general, segments with less than 10 data points will be placed on the M&E List until more data is collected. The following segments and parameters have been moved from the M&E List to the 303(d) List due to additional data collection:

- Arkansas, Upper Arkansas Segment 10, Twin Lake West Cu (COARUA10)

- Gunnison, Lower Gunnison Segment 7, Tongue Creek: Se (COGULG07) - Gunnison, Uncompahgre Segment 9, Sneffels Creek: Zn (COGUUN09) - Lower Colorado, White River Segment 11, Rio Blanco Reservoir: pH (COLCWH11)

- South Platte, Boulder Creek Segment 9, Boulder Creek: Aquatic Life Use (COSPBO09)

- South Platte, Big Thompson Segment 11, Carter Lake: As (COSPBT11) - South Platte, Big Thompson Segment 16, Lake Estes: Pb (COSPBT16) - South Platte, Cache la Poudre Segment 14, Horsetooth Reservoir: Cu, As (COSPCP14)

- South Platte, Lower South Platte Segment 3, Jackson Reservoir: pH (COSPLS03)

- South Platte, Middle South Platte Segment 4, Barr Lake: D.O. (COSPMS04)

- South Platte, Middle South Platte Segment 7, Horse Creek Reservoir: D.O. (COSPMS07)

- South Platte, St. Vrain Segment 3, St. Vrain Creek from Left Hand Creek confluence to confluence with Boulder Creek: Aquatic Life Use (COSPSV03)

- South Platte, Upper South Platte Segment 17a, Rocky Mountain Lake: pH, Cu (COSPUS17a)

- South Platte, Upper South Platte Segment 17a, Ferril Lake, Smith Lake: pH (COSPUS17a)

- South Platte, Upper South Platte Segment 17a, Duck Lake: pH, NH (COSPUS17a)

- South Platte, Upper South Platte Segment 23, Aqua Golf, Overland, Parkfield, and Huston Lakes: pH (COSPUS23)

- South Platte, Upper South Platte Segment 23, Vanderbilt Lake: DO (COSPUS23)

12. E. coli Listings In June of 2010, the Commission adopted a two-month averaging period for the existing E. coli criteria. Evaluation of the E. coli standard is over fixed two-month intervals. Where adequate data were available two-month intervals were assessed. Where adequate data were not available data were assessed either seasonally or for the entire period of record.

13. Lakes and Reservoirs D.O. (temperature) listings For lakes and reservoirs, the MWAT is assumed to be equivalent to the maximum WAT. When a lake or reservoir is stratified, the upper portion may exceed the applicable temperature standards in the basin regulations, provided that an adequate refuge exists in water below the upper portion. Adequate refuge depends on concurrent attainment within a given profile of the temperature standard and applicable dissolved oxygen standards. Attainment of the temperature standard below the upper portion is based on comparison with individual depths because of the need to verify concurrent attainment with the DO standard. If the refuge is not adequate because of low dissolved oxygen levels, the lake or reservoir will be listed as impaired for dissolved oxygen rather than for temperature.

14. Site-specific decisions made by the Commission are discussed below. Eagle River Segments 6, 8 and 9a:

The Division originally proposed to list the following segments in the Eagle River Basin: the mainstem of Eagle River Segment 9a for sediment, temperature, and Aquatic Life Use impairment, and several tributaries to the Eagle River for impairment of the Aquatic Life Use (Provisional) including Black Gore Creek, Beaver Creek, Lake Creek, Red Sandstone Creek and Gore Creek. Division staff worked with stakeholders in the Eagle River watershed to examine the data and further narrow the issues potentially in dispute. Through this work additional data was made available. Based upon the additional data received and reviewed by Division staff, the Division revised its proposal. In general, parties agreed with the Division’s refined proposal for the Aquatic Life Listings in the Eagle River Subbasin. Eagle River stakeholders opposed the Division’s proposal to list the mainstem of the Eagle River (Segment COUCEA09a) for temperature. They presented an alternative proposal to M & E list a 6-mile long portion of the segment from Berry Creek to Ute Creek. Evidence presented by the Eagle River Water & Sanitation District showed that the only temperature excursions in this stream reach occurred in the early part of the winter shoulder season and wastewater effluent did not cause the excursions. The District will continue collecting data and will work with the Division to complete additional analysis to determine whether the temperature excursions are a result of anthropogenic activities in the watershed. The Commission adopted the Eagle River Basin stakeholders’ proposal.

Upper Colorado River Segment 3 (COUCUC03):

Trout Unlimited referenced a report prepared by the Division of Parks and Wildlife (Nehring 2011) which contained significant site-specific macroinvertebrate and other aquatic life information and analysis for the portion of the Colorado River mainstem between Windy Gap Reservoir and its confluence with the Blue River. The Commission finds that given the fact that there are conflicting MMI scores on this segment, said portion of this segment should be placed on the Monitoring and Evaluation list at this time. Western Resource Advocates White River Basin:

WRA proposed the addition of White River Segments COLCWH13b, COLCWH13c, COLCWH14a, COLCWH14b, COLCWH15 and COLCWH20 on either the 303(d) or M&E Lists for selenium (COLCWH13b) or total recoverable iron. Following additional data that was submitted by Shell in its Responsive Prehearing Statement, WRA modified its proposal. WRA supported listing a portion of COLCWH13b, Duck Creek, on the 303(d) List for selenium. However, the Commission agreed with the Division that the 2008 Statement of Basis and Purpose language in Regulation #37, Classifications and Numeric Standards for the Lower Colorado River Basin, identifies that the four sites used to create the ambient selenium standard should be assessed in aggregate. The Commission supports the Division’s position to include COLCWH13c and a portion of COLCWH14a (the mainstem Piceance Creek from Willow Creek to Hunter Creek) for inclusion on the 303(d) List for total recoverable iron. Southwestern Water Conservation District E. coli:

The Commission has placed several stream segments (COGULD02, COGULD03a, COGULD04, COGULD05, COSJAF13a, COSJDO11, COSJLP08a, COSJPI06a, COSJSJ10, and COSJSJ03) on the M&E List for E. coli based on data from four or fewer measurements as outlined in the Listing Methodology. Because of the limited number of data points, the listings were based on either a seasonal or annual geometric mean, rather than the two-month averaging period. As a result, the Commission has concluded that the data at these sites indicate potential impairment of the E. coli standard, warranting listing on the M&E List so that additional measurements can be collected. Lower Colorado Segment 3 (COLCLC03):

Lower Colorado Segment 3 was proposed to be removed from the 303(d) List for selenium impairment due to attainment of standards. USFWS opposed its removal from the list because the segment is critical habitat for the endangered Colorado pikeminnow and razorback sucker. The Commission acknowledges the significance of this issue, but given the fact that the segment is in attainment of its selenium standard, the segment should be removed from the list. If the USFWS feels that the standard is not protective of endangered fish species, the Commission recommends they pursue an alternative standard in the next Colorado basin rulemaking hearing.

Animas River (COSJAF05a):

La Plata Energy Council expressed concern with listing segment COSJAF05a as impaired for manganese. In segment COSJAF05a there is an actual water supply use in the upper portion of the segment. However, there is no actual water supply use in the lower reach below the intake to the Animas-La Plata Project. In 2000, when the Commission adopted the table value criteria for manganese based on secondary water supply standards, the Commission adopted Statement of Basis and Purpose language in Section 31.37(iv)(H) indicating that its action could result in the situation facing La Plata – that is, a segment with a water supply classification but where the only actual water supply use is upstream of point source dischargers. The Commission determined in 2000 that the appropriate course of action is for the Commission to consider resegmentation of that stream. Accordingly the Commission encourages La Plata to pursue resegmentation in the Regulation #34 basin rulemaking hearing if they believe it is warranted. Marston Forebay (COSPUS22 or COSPBE11):

Marston Forebay was listed as Segment COSPUS22 in the 2010 version of Regulation #93, when in fact, it is correctly included in COSPBE11. Marston Forebay was originally placed on the M&E List in 2010 because dissolved oxygen (DO) concentrations were below the standard in the metalimnion (middle layer of the reservoir). In 2010, the DO standard was revised in Regulation 31. The current DO standard only applies to the top 0.5-2 meters of the water column, unless assessing for refuge with regards to the temperature standard. When assessing against the revised standard, Marston is now attaining the DO standard, as DO readings are above 6 mg/L in the top 2 meters of the water column on all dates. As a result, the Division proposed to remove Marston from the M&E List. The Commission agreed with the Division’s recommendation and removed Marston from the M&E List for this reason.

Denver Water also requested a finding that Marston is not “waters of the state”. The Commission believes that a Regulation #38 rulemaking hearing is the appropriate forum in which to consider any formal regulatory conclusion regarding this issue.

Ralston Creek (COSPCL17b):

The Division originally placed Ralston Creek on the 303(d) List for impairment of its Water Supply Use-based uranium standard. Cotter Corporation opposed this listing and its high priority listing due to ongoing cleanup work at the Schwartzwalder Mine Site. The Division recognizes that Cotter Corporation is actively addressing non-attainment of the primary drinking water uranium standard in Ralston Creek, and the Division anticipates continued cooperation during development of a Category 4b Plan. However, pending revisions to the standard, the Commission finds that COSPCL17b should be retained on the 303(d) List in the interim with a high priority.

Wildhorse Creek – Segment COARMA04a:

Bill Thiebaut, District Attorney for the Tenth Judicial District, Colorado submitted an alternative proposal to add selenium to the existing listing for E.coli for Wildhorse Creek. After review of the data submitted, the Division agreed with the alternative proposal. Pueblo West opposed this listing as data for the middle portion of the segment attains the ambient based selenium chronic standard of 597 ug/L as well as the ambient based acute standard of 708 ug/L. It has generally not been the practice of the Commission to 303(d) list the majority of a segment except for a portion in the middle. In addition, there was discussion in regards to the appropriateness of the adopted ambient based standard. Pueblo West has expressed interest in reviewing this standard in a future rulemaking hearing. Until revisions to the standard can be made, the Commission has added the entire segment to the 303(d) List for selenium.

Pueblo West raised concerns about whether the current ambient based selenium standard for Middle Arkansas segment 4a is still the appropriate standard. This issue was discussed and it was determined that revising the ambient based standard based on new data is not appropriate for this rulemaking but could be addressed in the next basin hearing for Regulation #32 in June 2013. If the ambient based standard is modified during that proceeding, the appropriateness of the 303(d) listing for this segment would be revisited in the next rulemaking hearing for Regulation #93 in December 2013. The Commission does not expect that the Division would proceed with development of a TMDL between now and the Regulation #32 hearing in June 2013.

1. PARTIES TO THE RULEMAKING HEARING

1. Western Resource Advocates 2. Bill Thiebaut, District Attorney for the 10th Judicial District 3. Colorado Division of Parks and Wildlife 4. Town of Avon 5. City of Grand Junction 6. Eagle River Watershed Council Inc 7. Town of Vail 8. Shell Frontier Oil and Gas Inc.

9. Denver Water 10. Roaring Fork Conservancy 11. City of Aurora 12. Northern Colorado Water Conservancy District 13. City and County of Denver 14. City of Colorado Springs and Colorado Springs Utilities 15. Cripple Creek & Victor Gold Mining Co 16. MillerCoors, LLC 17. Seneca Coal Company 18. Tri-State Generation & Transmission Association 19. Xcel Energy 20. Eagle County 21. City of Boulder 22. Grand County Districts 23. Gunnison County 24. Eagle River Water and Sanitation District 25. Upper Eagle Regional Water Authority 26. Vail Corporation 27. Northwest Colorado Council of Governments 28. Littleton/Englewood Wastewater Treatment Plant 29. Southeastern Colorado Water Conservancy District 30. Colorado Department of Transportation 31. Pitkin County 32. Upper Gunnison River Water Conservancy District 33. Metro Wastewater Reclamation District 34. Bear Creek Watershed Association 35. Colorado River Water Conservation District 36. Cotter Corporation (N.S.L.)

37. Colorado Oil & Gas Association 38. Gunnison County Stockgrowers Association, Inc.

39. Trout Unlimited 40. Pioneer Natural Resources USA, Inc.

41. XTO Energy, Inc.

42. U.S. Fish and Wildlife Service 43. Colorado Petroleum Association 44. La Plata County Energy Council 45. Dolores Water Conservancy District 46. Southwestern Water Conservation District 47. Pueblo West Metropolitan District 48. Greeley Water & Sewer Department 49. City of Pueblo 50. Environmental Protection Agency 51. North Front Range Water Quality Planning Association 52. Board of County Commissioners of Montrose County 53. Wright Water Engineers, Inc 54. South Platte Coalition for Urban River Evaluation 55. Garfield County 56. Ruedi Water and Power Authority 57. Vail Recreation District 58. National Park Service 59. Town of Norwood, Norwood Water Commission and Norwood Sanitation District

93.15 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND

PURPOSE; DECEMBER 2015 RULEMAKING, FINAL ACTION JANUARY 11, 2016, EFFECTIVE DATE OF MARCH 1, 2016 The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.

BASIS AND PURPOSE A. Revisions to 303(d) List 1. Introduction This regulation updates Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (TMDLs) to reflect additional water quality information available since the Regulation was promulgated in 2006. This list was prepared to fulfill section 303(d) of the federal Clean Water Act (Act) which requires that states submit to the U.S. Environmental Protection Agency (EPA) a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards. This regulation also updates Colorado’s Monitoring and Evaluation List (M&E List) to reflect additional water quality information available since the Regulation was last promulgated in 2012.

2. List Development a. Listing Methodology The Section 303(d) Listing Methodology - 2016 Listing Cycle (“Listing Methodology”) provides the listing process, the criteria for listing, and the criteria for determination of TMDL priority. The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission (Commission) administrative action hearing in March 2015.

1. This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2016 Section 303(d) List and the 2016 M&E List. However, this methodology was not adopted by the Commission as a rule. The Commission therefore has the flexibility to take into account other appropriate factors in making site- specific listing decisions.

b. Information Considered To determine the final segments and parameters that would be included on the 303(d) list and M&E list, the Commission considered all existing and readily available information that relates to the segments included in the Notice of Rulemaking (published August 10, 2015).The Commission considered existing and readily available data, which includes the data used to prepare the identification processes, calculations and models referenced in 40 CFR §130.7(a)(5)(i), (ii) and (iv), and data that was presented in a readily usable format and submitted in conformance with 40 CFR §130.7(a)(5)(iii). In addition, the Commission accepted credible data and information that was submitted in accordance with the listing process schedule. The Division will continue to independently collect and analyze new data on a rotating basin basis as part of its triennial review efforts, and the Commission will utilize such data and information in making future listing determinations. Existing data which was not brought forward through one of these mechanisms or otherwise presented to the Commission in accordance with the schedule was not treated as “readily available” for purposes of making the 2016 listing decisions. Such information will be considered in the next listing cycle if the information is provided through a proper mechanism.

c. Data Quality In the Division's Quality Management Plan 2011 for the Collection and Utilization of Environmental Data, the Division states that “[i]t is the expressed goal of the Division to use only those analytical data that are both reliable and have a defined level of quality.”

3. Segment Prioritization The objective of prioritization is to identify those segments where the Division and the public should concentrate their resources. Priorities of High, Medium and Low were established according to section IV of the 2016 Section 303(d) Listing Methodology.

The Division remains committed to establishing a plan for monitoring and evaluating water bodies on the M&E List prior to the list submission date for the subsequent listing cycle. Further, the Commission has committed to determining their appropriate status (as either impaired or fully supporting) within ten years of their placement on the M&E List.

4. Impaired Segments Not Requiring TMDLs In the 2016 listing cycle, the Commission has added a list of impaired waters where a TMDL is not required. There are three primary reasons why the Commission did not require a TMDL for an impaired segment: (1) a TMDL has already been completed, but the classified uses are not yet attained but will be in the foreseeable future; (2) there is a required control mechanism in place that is expected to address all segment-pollutant combinations and the segment will attain water quality standards in a reasonable period of time; or (3) the Commission determined that the impairment is not caused by a pollutant. These segments have been included in section 93.4.

5. Fish Mercury (Hg) Listings The 303(d) Listing Methodology was revised in 2014 for the assessment of Fish Mercury (Hg). The methods compare the weighted average fish Hg for each waterbody and species (and size class, where appropriate) to a 0.3 ppm threshold. The sample size must meet or exceed 30 fish tissue samples per waterbody/species to list new waterbodies for Fish Hg. Waterbodies can also be listed if there is overwhelming evidence of impairment (>0.45 ppm Hg) and a sample size of at least 10 fish tissue samples.

The Commission retained the following 15 lakes on the 303(d) List: • Lower Arkansas segment 15, Trinidad Reservoir (COARLA15) • Middle Arkansas segment 26, Horseshoe Lake (COARMA26) • Upper Arkansas segment 40, Brush Hollow Reservoir (COARUA40) • Lower Colorado segment 20, Rifle Gap Reservoir (COLCLC20) • Dolores River segment 4b, McPhee Reservoir (COSJDO04b) • La Plata segment 11, Narraguinnep Reservoir (COSJLP11) • La Plata segment 11, Totten Reservoir (COSJLP11)

• Los Pinos segment 3, Vallecito Reservoir (COSJPN03)

• San Juan segment 8, Echo Canyon Reservoir (COSJSJ08)

• Big Thompson segment 11, Carter Lake (COSPBT11)

• Cache la Poudre segment 14, Horsetooth Reservoir (COSPCP14) • Upper South Platte segment 17a, Berkeley Lake (COSPUS17a) • Upper South Platte segment 17a, Rocky Mountain Lake (COSPUS17a) • Yampa River segment 23, Catamount Reservoir (COUCYA22) • Yampa River segment 22, Elkhead Reservoir (COUCYA23)

The Commission retained the following 3 lakes on the M&E List: • Middle Arkansas segment 27, Teller Reservoir (COARMA27) • San Juan segment 8, Navajo Reservoir (COSJSJ08)

• Boulder Creek segment 18, Gross Reservoir (COSPBO18)

The Commission moved the following lake from the M&E List to the 303(d) List: • North Platte segment 9, Big Creek Reservoir (COUCNP09) The Commission added the following lake to the M&E List: • Upper South Platte segment 19, Cheesman Reservoir (COSPUS19) The Commission removed the following lakes from the 303(d) List or the M&E List:

• Big Thompson segment 12, Boyd Lake (COSPBT12)

• Big Thompson segment 14, Lonetree Reservoir (COSPBT14) • Upper Colorado segment 12, Lake Granby (COUCUC12)

6. Aquatic Life Listings In October 2010, the Commission adopted Policy 10-1, Aquatic Life Use Attainment Commission’s Policy (“Policy 10-1”), which established that the Colorado multi-metric index (“MMI”) is an appropriate tool for the quantitative bioassessment of the health of aquatic communities. Utilizing the Commission Policy 10-1, the Division calculated over 750 MMI scores for the 2016 listing cycle. Based on this assessment, the Commission determined that 53 new segments were not attaining, with an additional 14 new segments included on the M&E List. These segments are in addition to 23 segments that were previously included on the 2012 303(d) List, and 5 segments that were previously included on the 2012 M&E List. For 50 of these segments that are not attaining for aquatic life a specific pollutant could not be identified as the cause of non-attainment, accordingly these 50 segments were listed as provisional. Several segments had data outside of the standard index period for data collection. The Commission included these segments on the M&E List in 2012 to allow the Division and parties to gather additional information within the standard index period. The 2016 Listing Methodology allowed additional flexibility to include additional data that was collected four weeks after the October deadline to be considered in the index period. This resulted in the Commission moving some segments from the M&E List to the 303(d) List. Any data collected outside of the standard index period was not used for the 2016 listing cycle. The Commission added the following segments to the 303(d) List for non- attainment of their Aquatic Life Use based on Policy 10-1: • White River segment 7 (COLCWH07)

• White River segment 23, East Douglas Creek (COLCWH23) • Closed Basin segment 2a, North Fork Carnero Creek (CORGCB02a) • Closed Basin segment 2b, La Garita Creek (CORGCB02b)

• Rio Grande segment 11 (CORGRG11)

• Rio Grande segment 20a (CORGRG20a)

• Big Thompson segment 2 (COSPBT02)

• Upper Gunnison segment 01, Stewart Creek (COGUUG01)

• Upper Gunnison segment 4, Taylor River (COGUUG04 The Commission provisionally added the following segments to the 303(d) List for non-attainment of their Aquatic Life Use based on Policy 10-1: • Fountain Creek segment 3a, West Monument Creek (COARFO03a) • Fountain Creek segment 6 (COARFO06)

• Lower Arkansas segment 6a, Apache Canyon (COARLA06a)

• San Miguel segment 12a, MaKenzie Creek (COGUSM12a)

• Upper Gunnison segment 2, Willow Creek (COGUUG02)

• Upper Gunnison segment 18b (COGUUG18b)

• Upper Gunnison segment 19, Razor Creek (COGUUG19)

• Upper Gunnison segment 26, Crystal Creek (COGUUG26)

• Closed Basin/San Luis Valley segment 9b, Kerber Creek from U S Gulch to the confluence with San Luis Creek (CORGCB09b)

• La Plata segment 5a (COSJLP05a)

• La Plata segment 6a (COSJLP06a)

• Piedra River segment 6a (COSJPI06a)

• Bear Creek segment 2 (COSPBE02)

• Boulder Creek segment 7a (COSPBO07a)

• Cache la Poudre segment 2a (COSPCP02a)

• Lower South Platte segment 2b, Kiowa Creek (COSPLS02b) • Upper South Platte segment 3, Pine Creek, Fourmile Creek and West Creek (COSPUS03)

• Upper South Platte segment 10a, East Plum Creek (COSPUS10a) • Upper South Platte segment 11b, Spring Creek (COSPUS11b) • Blue River segment 1 (COUCBL01)

• Blue River segment 2b, Blue River to the confluence with Swan River (COUCBL02b)

• Blue River segment 2c (COUCBL02c)

• Blue River segment 5 (COUCBL05)

• North Platte segment 4a, Little Grizzly Creek (COUCNP04a) • Yampa segment 12, Wolf Creek (COUCYA12)

The Commission retained the following segments on the 303(d) List for non- attainment of their Aquatic Life Use:

• White River segment 13c, Yellow Creek from Barcus Creek to the White River (COLCWH13c)

• Clear Creek segment 14b (COSPCL14b)

• Clear Creek segment 15 (COSPCL15)

• Big Thompson segment 9, Little Thompson River (COSPBT09) The Commission retained the following segments provisionally on the 303(d) List for non-attainment of their Aquatic Life Use:

• Upper Arkansas segment 21a, Squaw Gulch to a point 1.5 miles upstream of the confluence with Fourmile Creek (COARUA21a)

• San Miguel segment 12a, Maverick Draw (COGUSM12a)

• Upper Gunnison segment 24, Cochetopa Creek from Forest Rd 43 to Tomichi Creek (COGUUG24)

• Uncompahgre segment 11, Deer Creek (COGUUN11)

• Lower Yampa/Green River segment 22a, Talamantes Creek (COLCLY22a)

• White River segment 15, Piceance Creek (COLCWH15)

• White River segment 20, Black Sulphur Creek (COLCWH20) • Rio Grande segment 12 (CORGRG12)

• Boulder Creek segment 9, From 107th Street to the confluence with Coal Creek (COSPBO09)

• Upper South Platte segment 10a, West Plum Creek (COSPUS10a) • Upper South Platte segment 11a, Cook Creek (COSPUS11a) • Eagle River segment 6, Mainstem of Lake Creek from confluence with East and West Lake Creek to the mouth (COUCEA06)

• Eagle River segment 6, Red Sandstone Creek to confluence with Gore Creek (COUCEA06)

• Eagle River segment 8 (COUCEA08)

• Roaring Fork segment 3a, Roaring Fork from Hunter Creek to Trentaz Gulch (COUCRF03a)

• Roaring Fork segment 3a, West Sopris Creek (COUCRF03a) • Roaring Fork segment 3d, Cattle Creek from Bowers Gulch (COUCRF03d)

• Roaring Fork segment 7, South Fork of Frying Pan River from diversion to unnamed tributary (COUCRF07)

• Upper Colorado segment 10a, Fraser River and Vasquez Creek (COUCUC10a)

The Commission added the following segments to the M&E List for possible non- attainment of their Aquatic Life Use:

• Upper Arkansas segment 14c, North Hardscrabble Creek (COARUA14c) • Upper Arkansas segment 15 (COARUA15)

• Rio Grande segment 7 (CORGRG07)

• Lower Yampa/Green River segment 3i (COLCLY03i)

• La Plata/Mancos/McElmo/San Juan segment 4a (COSJLP04a) • San Juan segment 5, Mainstem San Juan River (COSJSJ05) • Clear Creek segment 2c (COSPCL02c)

The Commission retained the following segments on the M&E List for possible non-attainment of their Aquatic Life Use:

• Upper Arkansas segment 5, Lake Fork below Sugarloaf Dam (COARUA05)

• White River segment 13b, Duck Creek (COLCWH13b)

• Boulder Creek segment 7b (COSPBO07b)

• Clear Creek segment 1, Kearney Gulch and Grizzly Gulch (COSPCL01) • Upper South Platte segment 2a, South Fork of South Platte below Antero Reservoir (COSPUS02a)

• Upper South Platte segment 3, Trout Creek (COSPUS03)

• Blue River segment 17 (COUCBL17)

• Eagle River segment 6, Black Gore Creek (COUCEA06)

• Eagle River segment 6, Red Sand Stone Creek from USFS Boundary to northside of I-70 frontage road (COUCEA06)

• Upper Colorado segment 3, Colorado River from Windy Gap Reservoir to Derby Creek (COUCUC03)

The Commission expanded the portion of Upper Colorado segment 3 that is on the M&E List to include the portion from the outlet of Windy Gap Reservoir to Derby Creek. Despite improving MMI scores in the upper reach, the Commission was concerned about declining taxa in the upper reach, and feels the stream would benefit from additional investigation.

The Commission removed the following segments from the 303(d) List for attainment of their Aquatic Life Use:

• Upper Arkansas segment 21a, Cripple Creek from source to above Squaw Gulch (COARUA21a)

• Upper Gunnison segment 6b, Cement Creek (COGUUG06b)

• Upper Gunnison segment 29a, Lake Fork of the Gunnison River between Cooper and Silver Creek (COGUUG29a)

• White River segment 23, West Douglas Creek (COLCWH23) • Bear Creek segment 1a, Bear Creek (COSPBE01a)

• St. Vrain segment 3, From the confluence with Left Hand Creek to the confluence with Boulder Creek (COSPSV03)

• Roaring Fork segment 4, Mainstem Brush Creek (COUCRF04) • Yampa River segment 15, Elkhead Creek (COUCYA15)

The Commission removed the following segments from the M&E List for attainment of the Aquatic Life Use standard:

• Fountain Creek segment 4, Sand Creek (COARFO04)

• Upper Gunnison segment 8, Slate River (COGUUG08)

• Bear Creek segment 1e, All (COSPBE01e)

• Bear Creek segment 2, Below Kipling Parkway (CO 391) (COSPBE02) • Boulder Creek segment 10 (COSPBO10)

• Lower South Platte segment 1 (COSPLS01)

• St. Vrain segment 3, From Hover Road to the confluence of Left Hand Creek (COSPSV03)

• Upper South Platte segment 11b, Bear Creek (COSPUS11b) • North Platte segment 4a, Grizzly Creek (COUCNP04a)

The Commission moved the following segments from the M&E List to the 303(d) List, provisionally:

• Upper South Platte segment 6a, South Platte from Cheeseman Reservoir to Lazy Gulch (COSPUS06a)

• Upper South Platte segment 01a, South Platte River from the outlet of Elevenmile Reservoir to the Idlewilde picnic area (COSPUS01a) • Upper South Platte segment 11b, Spring Creek (COSPUS11b) • Eagle River segment 6, Beaver Creek from Wayne Creek to mouth (COUCEA06)

• Eagle River segment 9a, Eagle River from confluence with Berry Creek to confluence with Squaw Creek (COUCEA09a)

• North Platte segment 4a, Little Grizzly Creek (COUCNP04a) The Commission removed the provisional qualifier for the non-attainment of the Aquatic Life Use standard for the following segments:

• Upper Gunnison segment 15a, South Beaver Creek (COGUUG15a) • Clear Creek segment 14a, Clear Creek from Croke Canal to McIntyre Street (COSPCL14a)

• Upper South Platte segment 3, Horse Creek (COSPUS03)

7. Narrative Sediment Standard Listings The Commission adopted a new approach in the 2016 Listing Methodology to evaluate impairment of the narrative sediment standard. This methodology, which is described in the Commission’s Policy 98-1, Guidance for the Implementation of Colorado’s Narrative Stream Standard Regulation #31, Section 31.11(1)(a)(i), includes assessment of the macroinvertebrate population using a sediment tolerance indicator score and the percent fines as compared to a regional threshold. An impairment listing is further supported by a review of the watershed for differences of the sampling site from the range of conditions used to establish the expected condition for the sediment region, as well as the presence of likely anthropogenic sources of sediment.

The Commission added the following segments to the 303(d) List for non- attainment of the narrative sediment standard:

• White River segment 13b (COLCWH13b)

• White River segment 23, East Douglas Creek from just below Tommy’s Draw to the confluence with Douglas Creek (COLCWH23)

• Closed Basin segment 12a, East Pass Creek (CORGCB12a) The Commission added the following segments to the M&E List for potential non- attainment of the narrative sediment standard:

• Yampa River segment 13b (COUCYA13b)

• North Platte segment 4a, Sand Creek (COUCNP04a)

The Commission removed the following segment from the 303(d) List for attainment of the narrative sediment standard:

• Upper South Platte segment 3, Trout Creek and its tributaries on USFS land (COSPUS03)

The Commission removed the following segments from the M&E List for attainment of the narrative sediment standard:

• Lower Yampa segment 2 (COLCLY02)

• Upper South Platte segment 3, Sugar Creek on USFS land (COSPUS03) • Upper South Platte segment 3, Pine Creek on USFS land (COSPUS03) The Commission retained these segments on the 303(d) List for non-attainment of the narrative sediment standard as no new data was available: • Lower Colorado segment 13b, Salt Creek (COLCLC13b)

• White River segment 22, West Evacuation Wash, Douglas Creek (COLCWH22)

• Eagle River segment 6, Black Gore Creek, adjacent to I-70 (COUCEA06) • Eagle River segment 9a, Eagle River from confluence with Berry Creek to confluence with Squaw Creek (COUCEA09a)

• Yampa River segment 3, Bushy Creek (COUCYA03)

• Clear Creek segment 14b (COSPCL14b)

• Clear Creek segment 15 (COSPCL15)

The Commission retained these segments on the M&E List for non-attainment of the narrative sediment standard as no new data was available: • Lower Arkansas segment 7 (COARLA07)

• Lower Gunnison segment 2 (COGULG02)

• Lower Gunnison segment 11b, Lunch Creek (COGULG11b)

• Uncompahgre River segment 4a (COGUUN04a)

• Uncompahgre River segment 4b (COGUUN04b)

• Uncompahgre River segment 4c (COGUUN04c)

• Uncompahgre River segment 15b, Dry Creek Watershed (COGUUN15b) • Lower Colorado segment 1 (COLCLC01)

• Lower Colorado segment 2a (COLCLC02a)

• Lower Colorado segment 2b (COLCLC02b)

• Lower Yampa segment 16 (COLCLY16)

• Rio Grande segment 13 (CORGRG13)

• Los Pinos segment 6a, Stollsteimer Creek above Southern Ute boundary (COSJPI06a)

• Eagle River segment 9a, Eagle River from Gore Creek to confluence with Berry Creek (COUCEA09a)

8. Listings Due to Exceedances of the Temperature Standards The 2016 Listing Methodology requires that the party proposing a temperature listing is responsible for investigating the temperature excursions as defined in Regulation No. 31, Footnote 5c, Table 1. This footnote includes four allowable excursions to exceedances of the temperature standard. These include an air temperature excursion, a low flow excursion, an excursion for the upper portion of a lake or reservoir and a winter shoulder season excursion. For the 2016 listing cycle the Division analyzed water temperature data from more than 240 stations in more than 100 segments. In cases where the excursions were evaluated and exceedances of the temperature standards remained, the Commission included these segments on the 303(d) List. In cases where the excursions were not fully evaluated and exceedances of the temperature standards remained, the Commission included these segments on the M&E List. The Commission added the following segments to the 303(d) List for exceedances of the temperature standards (portions are indicated where appropriate):

• Fountain Creek segment 6 (COARFO06)

• Lower Arkansas segment 3a (COARLA03a)

• Middle Arkansas segment 2 (COARMA02)

• Lower Dolores segment 2 (COGULD02)

• Upper Gunnison segment 8 (COGUUG08)

• Lower Colorado segment 1 (COLCLC01)

• White River segment 7 (COLCWH07)

• White River segment 13c, Yellow Creek below Greasewood Creek (COLCWH13c)

• White River segment 15, Piceance Creek from 3 miles above the confluence with the White River, to the confluence with the White River. (COLCWH15)

• White River segment 23 (COLCWH23)

• Rio Grande segment 4b (CORGRG04b)

• Bear Creek segment 1b (COSPBE01b)

• Bear Creek segment 1e (COSPBE01e)

• Bear Creek segment 3 (COSPBE03), Vance Creek • Big Thompson segment 2, From Cedar Creek to Home Supply Canal (COSPBT02)

• Clear Creek segment 11 (COSPCL11)

• Clear Creek segment 13b, Mainstem of North Clear Creek (COSPCL13b) • Clear Creek segment 14a (COSPCL14a)

• Clear Creek segment 15 (COSPCL15)

• Upper South Platte segment 3, Goose Creek (COSPUS03)

• Blue River segment 17, Blue River downstream of Green Mtn Reservoir (COUCBL17)

• Roaring Fork segment 3c (COUCRF03c)

• Upper Colorado segment 2, Colorado River from Shadow Mountain Reservoir to Granby Reservoir (COUCUC02)

• Upper Colorado segment 2, Willow Creek, Stillwater Creek and Arapaho Creek (COUCUC02)

• Upper Colorado segment 7a, mainstem of Muddy Creek (COUCUC07a) • Yampa River segment 2a, Yampa River below Stagecoach Reservoir (COUCYA02a)

• Yampa River segment 2b (COUCYA02b)

The Commission added the following segments to the M&E List for exceedances of the temperature standards (where portions are not indicated the entire segment was listed):

• Lower Arkansas segment 5b (COARLA05b)

• Lower Arkansas segment 6a, Reilly Canyon and Sarcillo Canyon(COARLA06a)

• Lower Arkansas segment 6b (COARLA06b)

• Middle Arkansas segment 7b (COARMA07b)

• Upper Arkansas segment 4a (COARUA04a)

• Lower Gunnison segment 8 (COGULG08)

• Closed Basin segment 12a (CORGCB12a)

• San Miguel segment 10, Naturita Creek (COGUSM10)

• San Miguel segment 12b (COGUSM12b)

• Lower Colorado segment 4a (COLCLC04a)

• Alamosa River segment 11b (CORGAL11b)

• Los Pinos River segment 4a, East Mancos River (COSJLP04a) • Piedra River segment 5 (COSJPI05)

• San Juan River segment 6a (COSJSJ06a)

• San Juan River segment 10 (COSJSJ10)

• Bear Creek segment 6a, Turkey Creek below Parmelee Gulch (COSPBE06a)

• Bear Creek segment 6b (COSPBE06b)

• Clear Creek segment 14b (COSPCL14b)

• Clear Creek segment 17b (COSPCL17b)

• Upper South Platte segment 3, Trout Creek and tributaries on USFS property (COSPUS03)

• Upper South Platte segment 10a, Plum Creek (COSPUS10a) • Upper South Platte segment 15 (COSPUS15)

• Upper South Platte segment 16g (COSPUS16g)

• Yampa River segment 13e (COUCYA13e)

The Commission retained the following segments on the 303(d) List for exceedances of the temperature standards:

• Bear Creek segment 1a, Bear Creek below the confluence with Yankee Creek (COSPBE01a)

• Cache la Poudre segment 10a (COSPCP10a)

• Saint Vrain segment 2b (COSPSV02b)

• Upper Colorado segment 3, From 578 Road Bridge (COUCUC03) • Upper Colorado segment 7b, Muddy Creek and tributaries (COUCUC07b) • Upper Colorado segment 10a, Ranch Creek (COUCUC10a)

The Commission retained the following segment on the M&E List for exceedances of the temperature standards:

• Upper South Platte segment 2a, Twin Creek, on USFS Land (COSPUS02a)

The Commission delisted the following segments from the 303(d) List or the M&E List for exceedances of the temperature standards:

• Bear Creek segment 1e, Bear Creek from the outlet of Evergreen Lake to Kerr/Swede Gulch (COSPBE01e)

• Upper South Platte segment 2a, Salt Creek (COSPUS02a) • Eagle River segment 9a, Eagle River from Berry Creek to confluence with Ute Creek (COUCEA09a)

• Eagle River segment 9a, Eagle River from Ute Creek to confluence with Rube Creek (COUCEA09a)

• Upper Colorado segment 10c (COUCUC10c)

• Yampa River segment 2c (COUCYA02c)

• Bear Creek segment 1a, Bear Creek from Witter Gulch to Evergreen Lake (COSPBE01a)

The Commission moved the following segment from the 303(d) List to the M&E List for exceedances of the temperature standards:

• Big Thompson segment 8 (COSPBT08)

9. Listings Due to Exceedances of the Secondary Water Supply Standards For the secondary water supply standards of dissolved iron, manganese and sulfate, the less restrictive of the following two options apply as the numeric standard: existing quality as of January 1, 2000 or the table value criteria in Regulation No. 31, Tables II and III. For dissolved iron, the table value standard (TVS) is 300 ug/l. For dissolved manganese, the TVS is 50 ug/l. For sulfate, the TVS is 250 mg/l.

In the 2016 303(d) Listing Methodology, the Commission included additional language regarding the determination of existing quality from the year 2000. This included a minimum data requirement of ten data points, and the ability to use data collected after the year 2000 when characterizing existing quality from 2000. However, pursuant to section 31.11(6) of Regulation 31, the use of data collected after 2000 may only be used upon a showing that there are no new or increased sources of these pollutants in the segment being assessed since 2000. Some issues were raised regarding whether the data should be assessed station by station when comparing concentrations from 2000 to current conditions or can data be aggregated for the entire segment (or a portion of the segment). The Commission determined that unless a good reason was presented to assess station to station, data should be combined and assessed to characterize water quality as of 2000 and current conditions for manganese, dissolved iron and sulfate.

In the following segments, the TVS was less restrictive than water quality as of the year 2000. Therefore, the TVS was used as the standard for these listing decisions. The Commission added the following segments to the 303(d) List: • Middle Arkansas segment 2, mainstem of the Arkansas River from Pueblo Reservoir to Blue Ribbon Creek: manganese (COARMA02)

• Lower Yampa/Green River segment 3c, Wilson Creek: sulfate (COLCLY03c)

• Boulder Creek segment 2a, Como Creek to the confluence of North Boulder Creek: dissolved iron (COSPBO02a)

• Big Thompson segment 8, From source to St Vrain Supply Canal: sulfate (COSPBT08)

• Cache la Poudre segment 7: manganese (COSPCP07)

• Cache la Poudre segment 13a, Dry Creek: manganese and sulfate (COSPCP13a)

• Middle South Platte segment 1b: manganese (COSPMS01b) • Upper Colorado segment 7a, Alkali Slough: sulfate (COUCUC07a) In the following segments, the existing quality as of 2000 was greater (less restrictive) than the TVS. Therefore, the water quality representative of 2000 was used as the standard for these listing decisions. The Commission added the following segments to the 303(d) List:

• Fountain Creek segment 1a, Mainstem: manganese (COARFO01a) • Lower Arkansas segment 1b: manganese (COARLA01b)

• Lower Arkansas segment 1c: manganese (COARLA01c)

• Lower Arkansas segment 4a: sulfate (COARLA04a)

• Middle Arkansas segment 6b: manganese and sulfate (COARMA06b) • Lower Colorado segment 14c: manganese (COLCLC14c)

• Lower Yampa segment 3c, Stinking Gulch: sulfate (COLCLY03c) • Clear Creek segment 2c, Turkey Gulch below Rockford Tunnel: manganese and dissolved iron (COSPCL02c)

• Upper South Platte segment 3, Trout Creek and tributaries on USFS property: manganese (COSPUS03)

• Upper South Platte segment 5b, Geneva Creek: manganese (COSPUS05b)

• Blue River segment 06a: manganese (COUCBL06a)

• Eagle River segment 5c: dissolved iron (COUCEA05c)

• North Platte segment 4a, Snyder Creek: manganese and dissolved iron (COUCNP04a)

• Upper Colorado segment 10c, below Fraser Canyon: dissolved iron (COUCUC10c)

In the following segments, the TVS was less restrictive than water quality as of the year 2000. Therefore, the TVS was used as the standard for these listing decisions. The Commission added the following segments to the M&E List: • Middle Arkansas segment 6a: manganese (COARMA06a)

• Upper Arkansas segment 38, Skagway Reservoir: dissolved iron (COARUA38)

• Upper Gunnison segment 29a, Lake Fork of the Gunnison upstream of Cottonwood Creek: manganese (COGUUG29a)

• Lower Colorado segment 4a: sulfate (COLCLC04a)

• Lower Yampa/Green River segment 3c, Wilson Creek: manganese (COLCLY03c)

• Lower Yampa/Green River segment 6: sulfate (COLCLY06) • Lower White segment 9b: manganese (COLCWH09b)

• Lower White segment 13b, Corral Gulch: manganese (COLCWH13b) • Alamosa River segment 20: dissolved iron (CORGAL20)

• Closed Basin segment 12a, Ford Creek: manganese (CORGCB12a) • Rio Grande segment 2, South Clear Creek: dissolved iron (CORGRG02) • Rio Grande segment 38, Big Meadows Reservoir: dissolved iron and manganese (CORGRG38)

• Rio Grande segment 38, Road Canyon Reservoir: dissolved iron (CORGRG38)

• Boulder Creek segment 2a, North Boulder Creek from Caribou Creek to the confluence with Como Creek: dissolved iron (COSPBO02a) • Big Thompson segment 7, Buckhorn Creek: manganese (COSPBT07) • Boulder Creek segment 2a, from the outlet of Barker Reservoir to Longitude: 105.475577°Latitude: 39.971275°: manganese (COSPBO02a) • Cherry Creek segment 1: manganese (COSPCH01)

• Clear Creek segment 3b, Leavenworth Creek: manganese (COSPCL03b) • Clear Creek segment 6, North Empire Creek: sulfate (COSPCL06) • Clear Creek segment 12a, Gilson Gulch and tributaries: dissolved iron, manganese, and sulfate (COSPCL12a)

• Cache la Poudre segment 7: dissolved iron (COSPCP07)

• Laramie River segment 2a: manganese (COSPLA02a)

• St. Vrain segment 4a, (Hwy 72 to James Creek): manganese (COSPSV04a)

• North Platte segment 3: dissolved iron (COUCNP03)

• Yampa River segment 18, South Fork Little Snake River: dissolved iron (COUCYA18)

In the following segments, the existing quality as of 2000 was greater (less restrictive) than the TVS. Therefore, the water quality representative of 2000 was used as the standard for these listing decisions. The Commission added the following segments to the M&E List:

• Lower Arkansas segment 2a: manganese and sulfate (COARLA02a) • Middle Arkansas segment 6b: sulfate (COARMA06b)

• Upper Arkansas segment 5, Lake Fork below Sugarloaf Dam to the confluence with the Arkansas River and Colorado Gulch: manganese (COARUA05)

• Upper Arkansas segment 38, Skagway Reservoir: manganese (COARUA38)

• Lower Colorado segment 2b, Humphrey Backwater area: manganese and sulfate (COLCLC02b)

• Lower Yampa/Green River segment 3e: sulfate (COLCLY03e) • Lower Yampa/Green River segment 6: manganese (COLCLY06) • White River segment 13b, Stake Springs: sulfate (COLCWH13b) • Alamosa River segment 2: dissolved iron and manganese (CORGAL02) • Closed Basin segment 9a, Squirrel Creek: manganese (CORGCB09a) • Rio Grande segment 4c: manganese (CORGRG04c)

• Clear Creek segment 6, North Empire Creek: dissolved iron (COSPCL06) • Lower South Platte segment 1: sulfate (COSPLS01)

• Middle South Platte segment 1a: manganese (COSPMS01a) • Blue River segment 12: manganese (COUCBL12)

• North Platte segment 4a, Canadian River: manganese (COUCNP04a) • North Platte segment 4a, Illinois River: dissolved iron (COUCNP04a) • North Platte segment 4b, Illinois River: manganese (COUCNP04b) • North Platte segment 5b: dissolved iron and manganese (COUCNP05b) In the following segments, there was not enough data available to characterize the water quality representative of the year 2000. Until additional information can be gathered to make a determination on the water quality as a 2000, the Commission added the following segments to the M&E List: • Middle Arkansas segment 6a: sulfate (COARMA06a)

• Middle Arkansas segment 9: manganese (COARMA09)

• Middle Arkansas segment 11b: manganese (COARMA11b)

• Closed Basin segment 2a, North Fork Carnero Creek: manganese (CORGCB02a)

• Closed Basin segment 2a, South Fork Carnero Creek: dissolved iron and manganese (CORGCB02a)

• Closed Basin segment 2b, La Garita Creek: dissolved iron and manganese (CORGCB02b)

• Closed Basin segment 2c: manganese (CORGCB02c)

• Clear Creek segment 14b: dissolved iron (COSPCL14b)

• Boulder Creek segment 14, Barker Reservoir: dissolved iron, manganese (COSPBO14)

• Blue River segment 20, Spruce Creek: dissolved iron (COUCBL20) • Upper Colorado segment 7a, Alkali Slough: manganese (COUCUC07a) • Yampa River segment 3, Little Morrison Creek: manganese (COUCYA03) For the following segments, existing 303(d) and M&E listings for exceedances of the secondary water supply standards were retained:

• Coal Creek segment 11: manganese (COGUUG11)

• Clear Creek segment 14b: manganese (COSPCL14b)

• Lower South Platte segment 1: manganese (COSPLS01)

• St. Vrain segment 5, Left Hand Creek below US 36 to a point above the Lefthand Feeder Canal: manganese (COSPSV05)

• North Platte segment 4a, Canadian River: dissolved iron (COUCNP04a) • Yampa segment 2a, Yampa River below Stagecoach: manganese (COUCYA02a)

10. Listings Due to Exceedances of the Water Supply Standards for Arsenic and Nitrite The 2016 303(d) Listing Methodology was modified to reflect changes in Regulation #31 for the assessment of arsenic, nitrite and nitrate. Previously, the assessment of arsenic, nitrite and nitrate water supply standards was solely conducted at the point of intake for a water supply. This provision was removed in the Regulation #31, resulting in the assessment of these standards throughout the entire segment.

Based on comments received from parties regarding the arsenic listings the Commission reiterates the following Commission decisions. The source of a pollutant is not considered during the listing analysis, and the Commission recommends that parties who believe that impairments are the result of high background levels of arsenic consider site-specific regulatory changes, such as site-specific standards or removal of a classified use through a use attainability analysis. Attainment is assessed against the underlying standard, not against a temporary modification. Data for dissolved arsenic may be used in determining attainment of total arsenic.

For arsenic listings the Commission determined that the Division may use “j data” in its assessment. “J data” is an analytical result that falls between the method detection limit (“MDL”) and the minimum level (“ML”). The arsenic water supply standard (0.02µg/L) is below the MDL for arsenic (with the lowest MDL in data assessed for this rulemaking hearing at 0.022 µg/L). J data may be used in assessing arsenic because a j data result means that the lab is 99% certain arsenic is present in the sample at a level higher than the MDL, which is higher than the standard for arsenic.

The Commission added the following segments to the 303(d) List for exceedances of the arsenic standard:

• Fountain Creek segment 1a, Mainstem (COARFO01a)

• Lower Arkansas segment 1b (COARLA01b)

• Lower Arkansas segment 1c (COARLA01c)

• Lower Arkansas segment 5a (COARLA05a)

• Lower Arkansas segment 5b (COARLA05b)

• Lower Arkansas segment 9a (COARLA09a)

• Middle Arkansas segment 3 (COARMA03)

• Middle Arkansas segment 9 (COARMA09)

• Upper Arkansas segment 2c (COARUA02c)

• Upper Arkansas segment 05, Colorado Gulch (COARUA05)

• Upper Arkansas segment 15 (COARUA15)

• North Fork of the Gunnison segment 4, Ruby Anthracite Creek (COGUNF04)

• Upper Gunnison segment 12, Coal Creek (COGUUG12)

• Lower Colorado segment 1, Colorado River from Roaring Fork confluence to confluence with Paradise Creek (COLCLC01)

• Lower Colorado segment 4c (COLCLC04c)

• Lower Colorado segment 10 (COLCLC10)

• Lower Colorado segment 15a (COLCLC15a)

• Lower Colorado segment 15c (COLCLC15c)

• Lower Yampa segment 3c, Stinking Gulch (COLCLY03c)

• White River segment 7, White River below Meeker (COLCWH07) • White River segment 12 (COLCWH12)

• White River segment 14a, Piceance Creek (COLCWH14a)

• White River segment 20, Black Sulphur Creek (COLCWH20) • White River segment 21 (COLCWH21)

• Closed Basin segment 2a, North Fork Carnero Creek and South Fork Carnero Creek (CORGCB02a)

• Closed Basin segment 2b, La Garita Creek (CORGCB02b)

• Closed Basin segment 2c (CORGCB02c)

• Closed Basin segment 4 (CORGCB04)

• Closed Basin segment 9b (CORGCB09b)

• Closed Basin segment 12a (CORGCB12a)

• Rio Grande segment 4b, South Fork Rio Grande to Del Norte (CORGRG04b)

• Rio Grande segment 4c (CORGRG04c)

• Rio Grande segment 09, North Branch of Pass Creek (CORGRG09) • Rio Grande segment 11 (CORGRG11)

• Rio Grande segment 19 (CORGRG19)

• Bear Creek segment 2 (COSPBE02)

• Boulder Creek segment 2a (COSPBO02a)

• Boulder Creek segment 2b (COSPBO02b)

• Boulder Creek segment 3 (COSPBO03)

• Boulder Creek segment 4b (COSPBO04b)

• Boulder Creek segment 9 (COSPBO09)

• Boulder Creek segment 10 (COSPBO10)

• Boulder Creek segment 14, Barker Reservoir (COSPBO14) • Big Thompson segment 1 (COSPBT01)

• Big Thompson segment 2 (COSPBT02)

• Big Thompson segment 3 (COSPBT03)

• Big Thompson segment 7, Buckhorn Creek and North Fork of Big Thompson (COSPBT07)

• Big Thompson segment 8 (COSPBT08)

• Cache la Poudre segment 2a (COSPCP02a)

• Cache la Poudre segment 6 (COSPCP06)

• Cache la Poudre segment 9 (COSPCP09)

• Cache la Poudre segment 10a (COSPCP10a)

• Cache la Poudre segment 10b (COSPCP10b)

• Middle South Platte segment 1b (COSPMS01b)

• Republican Basin segment 1 (COSPRE01)

• St. Vrain segment 2b (COSPSV02b)

• Saint Vrain segment 7, Boulder Reservoir (COSPSV07)

• Upper South Platte segment 2c, South Mosquito Creek (COSPUS02c) • Upper South Platte segment 10a, East Plum Creek (COSPUS10a) • Blue River segment 2c (COUCBL02c)

• Blue River segment 4a, Gold Run Gulch below Jessie Mine (COUCBL04a)

• Blue River segment 20, Spruce Creek (COUCBL20)

• Eagle River segment 2 (COUCEA02)

• Eagle River segment 5c (COUCEA05c)

• Eagle River segment 6 (COUCEA06)

• Eagle River segment 9a (COUCEA09a)

• Eagle River segment 9c (COUCEA09c)

• North Platte segment 1, South Fork Big Creek (COUCNP01) • North Platte segment 4a, Illinois River, South Fork Big Creek and Snyder Creek (COUCNP04a)

• North Platte segment 4b, Illinois River (COUCNP04b)

• North Platte segment 5b (COUCNP05b)

• North Platte segment 09, Lake John and North Delaney Lake (COUCNP09)

• Upper Colorado segment 7a, Muddy Creek (COUCUC07a)

• Upper Colorado segment 7b, Muddy Creek (COUCUC07b)

• Upper Colorado segment 10c (COUCUC10c)

• Upper Colorado segment 12, Shadow Mountain Reservoir (COUCUC12) • Yampa River segment 2a, Yampa River above Stagecoach Reservoir (COUCYA02a)

• Yampa River segment 2b (COUCYA02b)

• Yampa River segment 3, Little Morrison Creek and Gunn Creek (COUCYA03)

• Yampa River segment 15, Elkhead Creek (COUCYA15)

The Commission added the following segments to the M&E List for potential non- attainment of the arsenic standard:

• Middle Arkansas segment 11b (C)OARMA11b)

• Lower Arkansas segment 10, Adobe Creek Reservoir (COARLA10) • Upper Arkansas segment 35 (COARUA35)

• Upper Arkansas segment 38, Skagway Reservoir (COARUA38) • Lower Dolores segment 5, Mesa Creek and tributaries (COGULD05) • Lower Colorado segment 2b, Humphrey Backwater area (COLCLC02b) • Lower Colorado segment 14c (COLCLC14c)

• Lower Colorado segment 20, Rifle Gap Reservoir (COLCLC20) • Bear Creek segment 11, Harriman Reservoir (COSPBE11)

• Cache la Poudre segment 7 (COSPCP07)

• Laramie segment 2a (COSPLA02a)

• Laramie segment 2b (COSPLA02b)

• Alamosa River segment 20 (CORGAL20)

• Rio Grande segment 37 (CORGRG37)

• Upper South Platte segment 12, Jackson Creek (COSPUS12) • Blue River segment 12 (COUCBL12)

• Eagle River segment 9b (COUSEA09b)

• North Platte segment 4a, Grizzly Creek and Little Grizzly Creek (COUSNP04a)

• Upper Colorado segment 3, Lake Granby to Gore Canyon (COUCUC03) • Upper Colorado segment 12, Willow Creek Reservoir (COUCUC12) • Yampa River segment 18, South Fork of the Little Snake River (COUCYA18)

• Upper Gunnison segment 29a, Lake Fork of the Gunnison River Upstream of Cotonwood Creek (COGUUG29a)

• Yampa River segment 8, Lost Dog Creek (COUCYA08)

The Commission retained the following segments on the 303(d) List for exceedances of the arsenic standard:

• Upper Gunnison segment 09, Coal Creek (COGUUG09)

• Upper Gunnison segment 11, Elk Creek (COGUUG11)

• Upper Gunnison segment 11, Coal Creek (COGUUG11)

• Big Thompson segment 11 (COSPBT11)

• Cache la Poudre segment 14 (COSPCP14)

• Upper South Platte segment 3, Fourmile Creek (COSPUS03) • Upper South Platte segment 3, Pine Creek (COSPUS03)

• Upper South Platte segment 14 (COSPUS14)

• Upper South Platte segment 17a, Berkeley Lake (COSPUS17a) The Commission retained the following segment on the M&E List for exceedances of the arsenic standard:

• Upper South Platte segment 03, West Creek (COSPUS03)

The Commission retained the following segment on the M&E List for exceedances of the nitrite standard:

• Middle Arkansas segment 4a (COARMA04a)

The Commission added the following segment to the M&E List for exceedances of the nitrite standard:

• Lower Colorado segment 2b, Humphrey Backwater Area (COLCLC02b) The Commission delisted the following segments as they are attaining the arsenic standard:

• Upper Arkansas segment 20, North Fork Wilson Creek below Independence Mine (COARUA20)

• Saint Vrain segment 4c (COSPSV04c)

11. Listings Due to Exceedances of the Total Phosphorus Standards In May 2012, the Commission adopted nutrient control management regulations, as detailed in Regulation 85 and Regulation 31. Interim total nitrogen and total phosphorus values were included in Regulation 31, and as the Commission revises basin regulations, the interim value for total phosphorus is adopted as a numeric standard in waters upstream of domestic wastewater treatment facilities. A list of such dischargers has been included in each of the basin regulations. At the time of this hearing, the total phosphorus standard has been adopted in the upstream waters of the following basins: Upper Colorado, Lower Colorado, Arkansas, and Rio Grande.

For the 2016 303(d) Listing Methodology, the Commission outlined the assessment methodology for numeric nutrient standards. The ambient annual median is assessed against the numeric standard, with an allowable exceedance frequency of one in five years. If the annual median nutrient concentration exceeds the standard but fewer than five samples are available for a specific year, the segment should be included on the M&E until additional data can be collected.

The following segments have been included on the M&E list for exceeding the numeric total phosphorus standard but not meeting sample size requirements. • Lower Colorado segment 4a (COLCLC04a)

• Closed Basin segment 2a, North Fork Carnero Creek (CORGCB02a) • Closed Basin segment 2a, South Fork Carnero Creek (CORGCB02a) • Closed Basin segment 2b, La Garita Creek (CORGCB02b)

• Closed Basin segment 2c (CORGCB02c)

• Closed Basin segment 12a (CORGCB12a)

• Rio Grande segment 11 (CORGRG11)

• Rio Grande segment 19 (CORGRG19)

• Rio Grande segment 20a (CORGRG20a)

• Rio Grande segment 20b (CORGRG20b)

12. Delisting of Segments with Recently Approved TMDLs The Division submitted 11 TMDLs to EPA since the approval of the 2012 303(d) List that have been approved. The Commission has removed the following segments from the 303(d) List:

• Upper Arkansas segment 8b, Iowa Gulch: cadmium, lead, and zinc (COARUA08b)

• Lower Gunnison segment 9, Fruitgrowers Reservoir: dissolved oxygen (COGULG09)

• Alamosa segment 8, Terrace Reservoir: total recoverable iron (CORGAL08)

• La Plata segment 4a, East Mancos: copper and manganese (COSJLP04a)

• Middle South Platte segment 4, Barr Lake and Milton reservoir: pH and DO (COSPMS04)

• Saint Vrain segment 4a, Left Hand Creek from Hwy 72 to James Creek: copper, zinc, and pH (COSPSV04a)

• Saint Vrain segment 4b: copper and lead (COSPSV04b)

• Saint Vrain segment 4c: copper (COSPSV04c)

13. Delisting of Segments where Water Quality is Currently Meeting Standards As additional water quality data is collected and assessed, new data may show attainment of the standards. The Commission removed the following segments and parameters from the 303(d) List due to attainment of current water quality standards:

• Fountain Creek segment 7a, Willow Springs Ponds #1 & #2: Aquatic life use (tetrachloroethylene fish tissue) (COARFO07a)

• Lower Arkansas segment 1a: selenium, sulfate (COARLA01a) • Lower Arkansas segment 4a, Timpas Creek: total recoverable iron (COARLA04a)

• Lower Arkansas segment 7: selenium (COARLA07)

• Lower Arkansas segment 9b, Chicosa Creek: total recoverable iron, selenium (COARLA09b)

• Middle Arkansas segment 6a: selenium (COARMA06a)

• Middle Arkansas segment 14: selenium (COARMA14)

• Upper Arkansas segment 20, Wilson Creek below Independence Mine: arsenic (COARUA20)

• Upper Arkansas segment 40: dissolved oxygen (COARUA40) • Lower Gunnison segment 9: dissolved oxygen (COGULG09) • Upper Gunnison segment 29a, Lake Fork between Cooper and Silver Creeks: aquatic life (provisional) (COGUUG29a)

• Lower Colorado segment 10: selenium (COLCLC10)

• Lower Colorado segment 13b, Adobe Creek, Leach Creek: total recoverable iron (COLCLC13b)

• Lower Yampa segment 2: total recoverable iron (COLCLY02) • Lower Yampa segment 5: selenium (COLCLY05)

• White River segment 14a, Willow Creek to Hunter Creek: total recoverable iron (COLCWH14a)

• Alamosa segment 3b, Alamosa River above Jasper Creek: cadmium (CORGAL03b)

• Alamosa segment 8, Terrace Reservoir: total recoverable iron (CORGAL08)

• Rio Grande segment 7, Nelson Creek, West Willow Creek below Nelson Creek to East Willow Creek: pH (CORGRG07)

• Rio Grande segment 37: dissolved oxygen (CORGRGR37)

• Big Dry segment 1: selenium (COSPBD01)

• Bear Creek segment 2, below Kipling Parkway: E. coli (COSPBE02) • Bear Creek segment 5, Swede/Kerr Gulch: E. coli (COSPBE05) • Big Thompson segment 2: cadmium, zinc, copper (from downstream of the UTSD discharge) (COSPBT02)

• Big Thompson segment 8: dissolved oxygen (COSPBT08)

• Big Thompson segment 9: copper (COSPBT09)

• Big Thompson segment 10, Big Hollow: selenium (COSPBT10) • Cherry Creek segment 3: selenium (COSPCH03)

• Cherry Creek segment 3, Cherry Creek from Holly Street to the South Platte River: total recoverable iron (COSPCH03)

• Clear Creek segment 2b: cadmium (COSPCL02b)

• Clear Creek segment 6, Mad Creek: zinc (COSPCL06)

• Clear Creek segment 15: manganese (COSPCL15)

• Cache la Poudre segment 8: arsenic (COSPCP08)

• Cache la Poudre segment 10a: copper (COSPCP10a)

• Cache la Poudre segment 11: selenium (COSPCP11)

• Cache la Poudre segment 12: selenium (COSPCP12)

• Cache la Poudre segment 13a: selenium (COSPCP13a)

• Cache la Poudre segment 14: copper (COSPCP14)

• Middle South Platte segment 1b: selenium (COSPMS01b)

• Middle South Platte segment 7, Prospect Lake: dissolved oxygen (COSPMS07)

• Republican River segment 4: E.coli (COSPRE04)

• St. Vrain segment 2a: zinc (COSPSV02a)

• St. Vrain segment 2b: copper (COSPSV02b)

• St. Vrain segment 6: selenium (COSPSV06)

• Upper South Platte segment 17a, Duck Lake: dissolved oxygen (COSPUS17a)

• Upper South Platte segment 17b, Sloan’s Lake: dissolved oxygen (COSPUS17b)

• Upper South Platte segment 23, Garfield and Huston Lakes: dissolved oxygen (COSPUS23)

• North Platte segment 4b, Illinois River: total recoverable iron (COUCNP04b)

• North Platte segment 9, Lake John: dissolved oxygen (COUCNP09) • Upper Colorado segment 3, from 578 Rd Bridge to Blue River: manganese (COUCUC03)

• Yampa River segment 13d, Below Seneca sample location 8 (WSD5): selenium (COUCYA13d)

The Commission removed the following segments and parameters from the M&E List due to attainment of current water quality standards: • Middle Arkansas segment 6a: uranium (COARMA06a)

• Middle Arkansas segment 6b: uranium (COARMA06b)

• Middle Arkansas segment 7b: copper, zinc (COARMA07b)

• Middle Arkansas segment 9: selenium (COARMA09)

• San Miguel segment 12a, Calamity Draw: dissolved oxygen (COGUSM12a)

• Lower Colorado segment 4a, Alkali Creek: E. coli , copper, total recoverable iron, lead, zinc (COLCLC04a)

• Lower Colorado segment 4c: copper and selenium (COLCLC04c) • Lower Colorado segment 13b, Indian Wash: total recoverable iron (COLCLC13b)

• Lower Colorado segment 15a, Plateau Creek: selenium (COLCLC15a) • Lower Yampa segment 3c, Stinking Gulch: copper, zinc (COLCLY03c) • Lower Yampa segment 3c, Wilson Creek: selenium (COLCLY03c) • Lower Yampa segment 18: E .coli, total recoverable iron, selenium (COLCLY18)

• White River segment 7, White River below Meeker: copper (COLCWH07) • White River segment 9a, Strawberry Creek: copper, zinc (COLCWH09a) • White River segment 23, East Douglas Creek: total recoverable iron (COLCWH23)

• White River segment 10b, Coal Creek below Ninemile Gulch: selenium (COLCWH10b)

• Closed Basin segment 9a, Squirrel Creek: cadmium, copper, zinc, total recoverable iron (CORGCB09a)

• Blue River segment 20, Spruce Creek: total recoverable iron (COUCBL20) • Boulder Creek segment 1: lead, zinc (COSPBO01)

• Boulder Creek segment 2a: cadmium, copper (COSPBO02a) • Boulder Creek segment 2b: cadmium, copper (COSPBO02b) • Boulder Creek segment 3: cadmium, copper (COSPBO03)

• Boulder Creek segment 9: cadmium (COSPBO09)

• Boulder Creek segment 10: cadmium (COSPBO10)

• Boulder Creek segment 14, Boulder Reservoir: cadmium (COSPBO14) • Big Thompson segment 2: sulfide (COSPBT02)

• Big Thompson segment 6, Dry Creek: E. coli (COSPBT06) • Cherry Creek segment 6, Lollipop Lake: selenium (COSPCH06) • Clear Creek segment 6, Mad Creek: pH (COSPCL06)

• Clear Creek segment 6, Hoop Creek: cadmium, lead, zinc (COSPCL06) • Clear Creek segment 9a, Fall River: zinc, dissolved oxygen (COSPCL09a) • Clear Creek segment 15: lead (COSPCL15)

• Cache la Poudre segment 6: copper (COSPCP06)

• Cache la Poudre segment 9: cadmium, lead (COSPCP09)

• Lower South Platte segment 3, Jackson Reservoir: selenium (COSPLS03) • North Platte segment 1, South Fork Big Creek: copper, E. coli (COUCNP01)

• North Platte segment 4a, Little Grizzly Creek: E. coli, total recoverable iron (COUCNP04a)

• North Platte segment 4a, Grizzly Creek, Little Grizzly Creek: Aquatic Life Use (COUCNP04a)

• North Platte segment 4a, Lake Creek: pH (COUCNP04a)

• Roaring Fork segment 3a, Capitol Creek: selenium (COUCRF03a) • Roaring Fork segment 10, Thompson Creek: total recoverable iron (COUCRF10)

• St. Vrain segment 13, Lake Thomas: dissolved oxygen (COSPSV13) • Upper Colorado segment 10c, Fraser River: copper, lead (COUCUC10c) • Upper Colorado segment 10c, from Town of Fraser to Colorado River: copper (COUCUC10c)

• Upper Colorado segment 10c, from Town of Tabernash to Town of Granby: lead (COUCUC10c)

• Upper South Platte segment 12, Jackson Lake: lead (COSPUS12) • Upper South Platte segment 17a, Rocky Mountain Lake and Grasmere Lake: copper (COSPUS17a)

• Upper South Platte segment 17b, Sloan’s Lake: total recoverable iron (COSPUS17b)

• Upper South Platte segment 23, Aqua Golf: total recoverable iron (COSPUS23)

• Yampa segment 2a, Yampa River below Stagecoach: selenium (COUCYA02a)

• Yampa segment 3, Little Morrison Creek: zinc, dissolved iron (COUCYA03)

• Yampa segment 3, Walton Creek: manganese (COUCYA03)

• Yampa River segment 13d, Dry Creek below Routt County Rd 53: lead and E.coli (COUCYA13d)

14. Delisting of Segments where Water Quality is Currently Meeting Ambient Based Standards The Commission adopted a new assessment methodology in the 2016 Listing Methodology to evaluate ambient based standards. This methodology uses a statistical approach based on the concept of the confidence interval to minimize uncertainty of assessment conclusions. The following segments were delisted due to attainment of ambient based standards using the new assessment methodology for ambient based standards:

• Middle Arkansas segment 4a: selenium (COARMA04a)

• Middle Arkansas segment 6a: selenium (COARMA06a)

15. Listing of Segments where Water Quality is not Meeting Standards not identified above The following segments or parameters were added to the 303(d) List due to exceedances of water quality standards not identified above: • Fountain Creek segment 3b: copper (COARFO03b)

• Fountain Creek segment 4, Sand Creek: selenium (COARFO04) • Lower Arkansas segment 1a, E. coli (COARLA01a)

• Lower Arkansas segment 9b, Big Sandy Creek: total recoverable iron (COARLA09b)

• Lower Arkansas segment 10, Nee Gronda: selenium (COARLA10) • Lower Arkansas segment 12, Lake Meredith: selenium (COARLA12) • Middle Arkansas segment 3: selenium (COARMA03)

• Middle Arkansas segment 14: total recoverable iron (COARMA14) • Upper Arkansas segment 4a: copper (COARUA04a)

• Upper Arkansas segment 5, Lake Fork below Sugarloaf Dam: zinc (COARUA05)

• Upper Arkansas segment 5, Colorado Gulch: cadmium, copper, zinc (COARUA05)

• Upper Arkansas segment 12a: cadmium (COARUA12a)

• Uncompahgre segment 9, Imogene Creek: cadmium and zinc (COGUUN09)

• Lower Colorado segment 4a, Mamm Creek: total recoverable iron (COLCLC04a)

• Lower Colorado segment 4a, South Canyon Creek above Hot Springs: total recoverable iron (COLCLC04a)

• Lower Colorado segment 13b: total recoverable iron (COLCLC13b) • Lower Colorado segment 14c, Roan Creek: total recoverable iron (COLCLC14c)

• Lower Yampa segment 3c, Wilson Creek: total recoverable iron (COLCLY03c)

• Lower Yampa segment 3c, Stinking Gulch: selenium (COLCLY03c) • Closed Basin segment 3, Willow Creek: copper (CORGCB03) • Closed Basin segment 12a: total recoverable iron (CORGCB12a) • Rio Grande segment 2, South Clear Creek: total recoverable iron (CORGRG02)

• Rio Grande segment 4a: lead (CORGRG04a)

• Rio Grande segment 4c: copper (CORGRG04c)

• Rio Grande segment 7: cadmium, lead, zinc (CORGRG07)

• Rio Grande segment 9, North Branch of Pass Creek: zinc (CORGRG09) • Big Dry Creek segment 1, Big Dry Creek downstream of Weld County Road 8: total recoverable iron (COSPBD01)

• Boulder Creek segment 2a, North Boulder Creek from Caribou Creek to the confluence with Como Creek: copper (COSPBO02a)

• Boulder Creek segment 2a, Como Creek to the confluence of North Boulder Creek: total recoverable iron (COSPBO02a)

• Boulder Creek segment 2a, North Boulder Creek to confluence of Caribou Creek: copper and lead (COSPBO02a)

• Boulder Creek segment 4a: copper (COSPBO04a)

• Boulder Creek segment 4b: copper (COSPBO04b)

• Boulder Creek segment 7b, below Rock Creek: selenium (COSPBO07b) • Boulder Creek segment 9: E. coli (COSPBO09)

• Boulder Creek segment 10: pH (COSPBO10)

• Boulder Creek segment 14, Barker Reservoir: copper (COSPBO14) • Big Thompson segment 2, from RMNP to above UTSD discharge: copper (CPSPBT02)

• Cherry Creek segment 2: chlorophyll and dissolved oxygen (COSPCH02) • Cherry Creek segment 4a, Goldsmith Gulch: E. coli and selenium (COSPCH04a)

• Cherry Creek segment 4a, McMurdo Gulch: dissolved oxygen (COSPCH04a)

• Cherry Creek segment 4b, Upper Windmill Creek: selenium (COSPCH04b)

• Clear Creek segment 2c, Turkey Gulch below Rockford Tunnel: copper, nickel, total recoverable iron, zinc (COSPCL02c)

• Clear Creek segment 5, from Hoop Creek to confluence with Clear Creek: copper (COSPCL05)

• Clear Creek segment 6, Mad Creek: copper (COSPCL06)

• Clear Creek segment 6, North Empire Creek: copper (COSPCL06) • Clear Creek segment 12a, Gilson Gulch and tributaries: cadmium, copper, nickel, lead, selenium and zinc (COSPCL12a)

• Clear Creek segment 12a, all tributaries except Gilson Gulch: cadmium, copper, and zinc (COSPCL12a)

• Clear Creek segment 15: ammonia (COSPCL15)

• Cache la Poudre segment 11: E. coli (COSPCP11)

• Cache la Poudre segment 13b: E. coli (COSPCP13b)

• Laramie segment 2b: copper (COSPLA02b)

• Lower South Platte segment 1: uranium (COSPLS01)

• Lower South Platte segment 3, North Sterling: dissolved oxygen and selenium (COSPLS03)

• Middle South Platte segment 1b: E. coli (COSPMS01b)

• St. Vrain segment 3: E. coli (COSPSV03)

• St. Vrain segment 5, Left Hand Creek: pH (COSPSV05)

• St. Vrain segment 6, Dry Creek: selenium (COSPSV06)

• Upper South Platte segment 2c, South Mosquito Creek: cadmium (COSPUS02c)

• Upper South Platte segment 3, Trout Creek and tributaries: dissolved oxygen and pH(COSPUS03)

• Upper South Platte segment 5b, Geneva Creek: pH(COSPUS05b) • Upper South Platte segment 10a, Plum Creek: E. coli(COSPUS10a) • Upper South Platte segment 16c: E. coli(COSPUS16c)

• Upper South Platte segment 16i: E. coli(COSPUS16i)

• Upper South Platte segment 16i, Sand Creek from Westerly Creek to the South Platte River: selenium (COSPUS16i)

• Upper South Platte segment 17a, Rocky Mountain Lake: dissolved oxygen (COSPUS17a)

• Upper South Platte segment 17a, Smith Lake: pH (COSPUS17a) • Upper South Platte segment 17a, Grasmere Lake: ammonia (COSPUS17a)

• Upper South Platte segment 23, Garfield Lake: dissolved oxygen (COSPUS23)

• Upper South Platte segment 23, Aqua Gulf: pH (COSPUS23) • Upper South Platte segment 23, Parkfield Lake: pH (COSPUS23) • Blue River segment 2a, above South Barton Gulch: zinc (COUCBL02a) • Blue River segment 4a, Gold Run Gulch below Jessie Mine: zinc (COUCBL04a)

• Blue River segment 4a, Meadow Creek: copper (COUCBL04a) • Blue River segment 6a: zinc (COUCBL06a)

• Blue River segment 12: zinc (COUCBL12)

• North Platte segment 4a, Snyder Creek: total recoverable iron (COUCNP04a)

• North Platte segment 9, Lake John: pH (COUCNP09)

• Upper Colorado segment 2, north inlet to Grand Lake: copper (COUCUC02)

• Upper Colorado segment 10a, Vasquez Creek: copper (COUCUC10a) • Yampa segment 3, Little Morrison Creek: total recoverable iron (COUCYA03)

• Yampa segment 3, Gunn Creek: zinc (COUCYA03)

• Yampa segment 13h: selenium (COUCYA13h)

The following segments or parameters were added to the M&E List due to exceedances of water quality standards not identified above: • Fountain segment 4, Little Fountain Creek below Deadman Canyon: selenium (COARFO04)

• Lower Arkansas segment 3a: E. coli (COARLA03a)

• Lower Arkansas segment 7: E. coli (COARLA07)

• Lower Arkansas segment 9a, Adobe Creek: total recoverable iron (COARLA09a)

• Lower Arkansas segment 12, Lake Henry: total recoverable iron (COARLA12)

• Middle Arkansas segment 11b: total recoverable iron (COARMA11b) • Upper Arkansas segment 5, Lake Fork below Sugarloaf Dam: cadmium (COARUA05)

• Upper Arkansas segment 5, Colorado Gulch: silver, lead (COARUA05) • Upper Gunnison segment 29a, Lake Fork of the Gunnison upstream of Cottonwood Creek: zinc and cadmium (COGUUG29a)

• Uncompahgre segment 9, Imogene Creek: copper (COGUUN09) • Lower Colorado segment 3: selenium (COLCLC03)

• Lower Colorado segment 4e: total recoverable iron, copper, selenium and cadmium (COLCLC04e)

• Lower Colorado segment 13a, Sulphur Gulch: total recoverable iron, copper and lead (COLCLC13a)

• Lower Colorado segment 16: total recoverable iron (COLCLC16) • Lower Yampa segment 3c, Wilson Creek: selenium (COLCLY03c) • Lower Yampa segment 3e: selenium (COLCLY03e)

• White River segment 7, White River below Meeker: total recoverable iron (COLCWH07)

• Alamosa River segment 10: total recoverable iron (CORGAL10) • Alamosa River segment 12: total recoverable iron (CORGAL12) • Closed Basin segment 3, Cottonwood Creek: copper (CORGCB03) • Closed Basin segment 3, Major Creek: total recoverable iron (CORGCB03)

• Closed Basin segment 5: copper (CORGCB05)

• Closed Basin segment 10, Sand Creek: copper (CORGCB10) • Closed Basin segment 12a, Ford Creek: cadmium and zinc (CORGCB12a)

• Rio Grande segment 3: total recoverable iron (CORGRG03) • Rio Grande segment 9, North Branch of Pass Creek: copper (CORGRG09)

• Rio Grande segment 25: copper (CORGRG25)

• Rio Grande segment 28, Upper Rito Seco below Battle Mountain: copper (CORGRG28)

• Rio Grande segment 33, Alberta Park: silver (CORGRG33) • Rio Grande segment 38, Road Canyon: silver (CORGRG38) • Boulder Creek segment 14, Barker Reservoir: silver (COSPBO14) • Big Thompson segment 5: E. coli (COSPBT05)

• Big Thompson segment 10: dissolved oxygen (COSPBT10)

• Clear Creek segment 3b: cadmium (COSPCL03b)

• Clear Creek segment 6, North Empire Creek: cadmium, total recoverable iron, zinc (COSPCL06)

• Clear Creek segment 12a, Gilson Gulch and tributaries: pH (COSPCL12a) • Clear Creek segment 12a, all tributaries except Gilson Gulch: dissolved oxygen (COSPCL12a)

• Clear Creek segment 14b: ammonia (COSPCL14b)

• Clear Creek segment 17b: E. coli (COSPCL17b)

• Cache la Poudre segment 7: silver (COSPCP07)

• Cache la Poudre segment 9: pH (COSPCP09)

• Cache la Poudre segment 12: pH (COSPCP12)

• St. Vrain segment 2b: silver(COSPSV02b)

• Upper South Platte segment 1a, Middle South Platte: pH (COSPUS01a) • Upper South Platte segment 3, West Creek: total recoverable iron, dissolved oxygen (COSPUS03)

• Upper South Platte segment 23, Aqua Gulf: ammonia (COSPUS23) • Upper South Platte segment 23, Harvey Lake: total recoverable iron (COSPUS23)

• Blue River segment 4a, Meadow Creek: zinc (COUCBL04a) • Blue River segment 12: copper (COUCBL12)

• North Platte segment 4a, Illinois River: copper (COUCNP04a) • North Platte segment 5b: copper (COUCNP05b)

• North Platte segment 6: copper (COUCNP06)

• Roaring Fork segment 2: copper (COUCRF02)

• Upper Colorado segment 8, below Kinney: copper (COUCUC08) • Yampa segment 13j: selenium (COUCYA13j)

16. Site-specific decisions made by the Commission are discussed below.

a. Segments COARF001a, COARF002a, COARF002b, COARF003a COARF004 and COARF006 – Waldo Canyon Fire and Storm Events The Arkansas Fountain Coalition for Urban River Evaluation (“AF CURE”) raised site-specific issues with listing segments that are within the geographic area that was affected by the Waldo Canyon Fire in 2012 and with using samples that are collected during or soon after storm events. Data collected after the Waldo Canyon Fire was appropriately used to assess segments COARF001a, COARF002a, COARF002b, COARF003a COARF004 and COARF006. Any variability in data was alleviated through application of the nonparametric statistical analysis as included in the Listing Methodology; removal of data that was collected by USGS as part of a special study specifically looking at the effects of the fire; or by comparing attainment of water quality standards before and after the fire event, and where available listing those segments on the 303(d) list that were out of attainment prior to the fire event and out of attainment after the fire event (segments that were in attainment prior to the fire event were listed on the M&E list). Additionally, the Commission was uncertain whether two years is a sufficient period of time for macroinvertebrate communities to recover from the impacts of sedimentation that result from forest fires, and the time may vary based on the proximity to the fire, the amount of water flowing through the waterway, and other factors. The Commission anticipates that the next iteration of the Listing Methodology will address the complexity of listing fire, flood, or other catastrophic event impacts on streams to provide further guidance for these types of decisions, and also acknowledges that there may be many case specific determinations.

1. Condition Prior to Condition After Recommended Listing Fire Fire Out of Attainment Out of Attainment List on 303(d) List In Attainment Out of Attainment List on M & E List Out of Attainment In Attainment Do not list Based on USGS standard operating procedure, the Commission determined that sampling should not be conducted for four weeks following a significant flushing event. However, the data on the record for these segments was collected outside of the four week window, and therefore was appropriately included in the assessment.

b. Portion of segment COSPCL03a (South Clear Creek downstream of Lower Cabin Creek Reservoir to Clear Lake) - Category 4b Plan for Nonattainment of the Aquatic Life Use Public Service Company of Colorado (PSCo) submitted a Category 4b Demonstration Plan (the Plan) to the Division for Clear Creek segment 3a in the South Platte River Basin, for the portion of the segment of South Clear Creek downstream of Lower Cabin Creek Reservoir to Clear Lake. Category 4b is an alternative to listing an impaired segment on the 303(d) list. A Category 4b Demonstration Plan, when implemented, must ensure attainment of all applicable water quality standards through pollution control mechanisms within a reasonable time period. The Plan was accepted by the U.S. Environmental Protection Agency prior to the rulemaking hearing. The Commission approved Public Service Company of Colorado’s Category 4b Plan for segment COSPCL03a (South Clear Creek downstream of Lower Cabin Creek Reservoir to Clear Lake) and as a result, the Commission did not include Clear Creek segment 3a, South Clear Creek downstream of Lower Cabin Creek Reservoir to Clear Lake, on the 303(d) List for the aquatic life use, for which the Category 4b Demonstration Plan was written. PSCo will provide updates on the implementation of the Plan to the Commission in future 303(d) rulemaking hearings. The Commission expects that after a reasonable period of time as defined in the Category 4b Demonstration Plan, the aquatic life use be reexamined on this portion of Clear Creek segment 3a. If the aquatic life use is not attained by this time, the segment will be considered impaired and placed on the 303(d) List.

c. Segment COLCLC03 – Chronic Aquatic Life Use-based Selenium Standard In 2012, the Commission removed Lower Colorado segment 3 from the 303(d) List for selenium impairment due to attainment of standards. At that time, USFWS opposed its removal from the list because the segment is critical habitat for the endangered Colorado pike minnow and razorback sucker. The Commission acknowledged the significance of this issue and recommended USFWS pursue an alternative standard in the next Colorado basin rulemaking; however, USFWS did not submit a proposal in 2014. In this rulemaking there was consensus that the acute selenium standard was attained; however, there was disagreement among the parties regarding whether the chronic selenium standard is attained due to uncertainty regarding the representativeness of a portion of the data set used in the assessment.

1. During 2012-2014, EPA and USFWS collected samples in segment 3 targeting critical habitat for the endangered fish. These samples were collected during low-flow periods from August to October. Colorado River Water Conservation District and the Colorado Stone, Sand and Gravel Association disagreed about whether the tributary-influenced sample locations and time periods are representative of conditions in the mainstem. Specifically, these parties argued that the majority of the data comes from poorly mixed sites located downstream of tributaries, and therefore is not representative of the spatial and temporal variability. When the Commission adopts a standard it applies to the entire segment including areas of the segment that are under the influence of tributaries. The Listing Methodology excludes data collected within the mixing zone of a discharge (as defined by Regulation 31), however it does not exclude data collected at the confluences of tributaries and river mainstems. Because selenium bio-accumulates in fish, the chronic selenium standard is designed to protect fish from cumulative life-long exposure. The default from the Listing Methodology is that data from the entire segment (including data at the confluences) is representative because the data represents the levels of selenium that aquatic food chain is exposed to through the segment.
   1. However, where a sampling study targets a particular constituent in a portion of a segment, the data from that study may be skewed and may not be representative of the spatial and temporal nature of the whole segment. Here the Commission determined that it is unclear whether the data collected in the EPA and USFWS’s study was representative of the entire segment, and therefore included segment 3 (COLCLCO3) on the 2016 M&E List for selenium.
      1. The River District and the Colorado Stone Sand and Gravel Association have agreed to work with the Division, the Selenium Task Force, and other stakeholders to evaluate whether an alternative approach to a TMDL may be a more effective approach to achieving load reductions

d. COUCEA05c – Upstream Sources of Loading Segment 5c on the Eagle River is located downstream of the Eagle Mine superfund site with a history of being impacted by the mine. Remedial activities conducted at the Eagle Mine superfund site beginning in the late 1980s resulted in reductions in metals loading and improved water quality in the Eagle River in the vicinity of the superfund site. At the 2005 Regulation No. 33 rulemaking hearing (Reg. 33 RMH), the Commission adopted resegmentation of Eagle River segment 5 into segments 5a, 5b, and 5c, based on recognized changes in water quality, hardness, and use. In this rulemaking hearing, the Commission placed segment 5c on the 303(d) list for dissolved iron and total recoverable arsenic. Although it was argued that the upstream segments (segments 5a and 5b) should also be included on the 303(d) list as the primary source of contamination in segment 5c, segments 5a and 5b were not included in the Notice for this Rulemaking. The Commission finds that data collected in segment 5c which consisted of 123 total arsenic values with lower detection limits were representative of water quality conditions. The majority of data submitted to assess segments 5a and 5b, however, used a reporting limit of 15 ug/L for the water quality standard of 0.02 ug/L, and all such data were reported as non-detect (43 of the 65 values for segment 5a, and 79 of the 98 values for segment 5b). It is the Commission’s intent that TMDLs for this segment 5c will consider upstream sources of loading occurring in the Eagle River as is the division’s typical practice for TMDL development.

e. COUCNP04b – Total Recoverable Iron Jackson County Water Conservancy District (District) proposed to remove the Illinois River (COUCNP04b) from the 303(d) List for total recoverable iron. The division assessed total recoverable iron for the Illinois River portion of the segment. After locational issues with sampling sites were resolved, the division concluded that the segment was in attainment of the total recoverable iron standard. The 50th percentile of the 10 total recoverable iron values for the portion was found to be 746 ug/L, a value less than the aquatic life standard of 1000 ug/L. Therefore, the data supported delisting of this portion and the Commission removed this segment from the 303(d) List for total recoverable iron.

f. COSPUS06a – Aquatic Life Several parties raised issues with the representative nature of the aquatic life data for Upper South Platte segment 6a. Specifically they state that one data point is not enough to make a listing decision, that the location of the data point collected was not representative of the segments and that the 2003 EPA Standard Operating Procedure (SOP) for collecting benthic macroinvertebrate samples were not used. All of these issues are inconsistent with the Listing Methodology.

1. The Listing Methodology establishes the standard procedure for collecting macroinvertebrate data, which is the procedure established in Policy 10-1. The Commission reiterates that one data point is sufficient to include or remove a segment on the 303(d) List. Appendix B of the Listing Methodology ensures that samples are collected in stream reaches that are representative but does not necessarily prohibit sampling near areas of human disturbance. The Commission determined that both stations used in the assessment of segment 6a are located at a substantial and sufficient distance upstream from the nearest road or bridge crossing, which in this instance is a highway. Finally, the Commission determined that following the procedures in Policy 10-1 is the appropriate methodology, or standard operating procedure for collecting macroinvertebrate data.
   1. The Commission determined that the data was representative and that segment 6a should be included on the 303(d) List provisionally. The Commission directs the division and interested parties to study this segment to determine the stressors and pollutants that are impacting aquatic life in this segment.

g. Indian Reservations The Commission intends that the list of water quality-limited segments requiring total maximum daily loads shall apply to waters within the external boundaries of the Southern Ute Indian Reservation only to the extent that the state has jurisdiction, and is not attempting to resolve that jurisdictional issue here.

h. COSPUS10a E. coli Chatfield Watershed Authority will continue its proactive monitoring program, including current E. coli data collection efforts. The Authority is in the early stages of the data analysis and interpretation. Any potential control measures will be based on data and science.

i. COSPUS16h – Selenium in Toll Gate Creek, East Toll Gate Creek and West Toll Gate Creek Toll Gate Creek, East Toll Gate Creek, and West Toll Gate Creek are meeting adopted ambient selenium standards. Toll Gate Creek, East Toll Gate Creek, and West Toll Gate Creek were resegmented from Upper South Platte segment 16c to segment 16h at the 2008 Temporary Modifications RMH but never formally delisted from the 303(d) List.

j. COUCNP04a – Sand Creek State Line Ranch submitted a proposal as part of written public comment proposing that Sand Creek be listed as impaired for sediment due to impacts to a beneficial use. While the Commission found the evidence submitted to be persuasive and compelling evidence of impairment, the Commission was reluctant to list the segment as impaired in this hearing for a number of reasons. One reason was that the proposal was made late in the process and therefore the Division had not had an opportunity to thoroughly review and evaluate the proposal. In addition, potentially affected parties, such as the BLM and the affected local community, were not able to participate in the process. Also, because this would be the first time a segment would be listed for sediment impairing a beneficial use, the Commission would like to proceed thoughtfully to establish appropriate precedent about the factors to be considered in such a decision. Therefore, the Commission included the segment on the M&E List. A proposal may be made for a special hearing to consider this proposal, or that it may be proposed to be included on the 303(d) List as part the next 303(d) listing cycle.

1. PARTIES TO THE RULEMAKING HEARING

1. Public Service Company of Colorado 2. Jackson County Water Conservancy District 3. Bear Creek Watershed Association 4. Climax Molybdenum Company 5. Colorado Parks and Wildlfie 6. Cripple Creek and Victor Gold Mining Company 7. U.S. Environmental Protection Agency 8. Eagle River Water and Sanitation District 9. Town of Fraser 10. Silverthorne/Dillon Joint Sewer Authority 11. Suncor Energy (U.S.A.) Inc.

12. Upper Blue Sanitation District 13. Upper Thompson Sanitation District 14. Upper Clear Creek Watershed Association 15. Cherry Creek Basin Water Quality Authority 16. Eagle River Watershed Council 17. Centennial Water and Sanitation District 18. City of Colorado Springs and Colorado Springs Utilities 19. Tri-State Generation and Transmission Association, Inc.

20. City of Boulder 21. Metro Wastewater Reclamation District 22. Barr Lake and Milton Reservoir Watershed Association 23. Colorado Stone, Sand and Gravel Association 24. MillerCoors, LLC 25. Town of Castle Rock 26. City of Steamboat Springs 27. Cottonwood Water and Sanitation District 28. Trapper Mining Company 29. Seneca Coal Company; Peabody-Sage Creek Mining Company; and Twentymile Coal, LLC 30. Plum Creek Water Reclamation Authority 31. POC-1, LLC 32. City of Aurora 33. Northwest Colorado Council of Governments Water Quality/Quantity Committee 34. City of Black Hawk 35. Tri-Lakes Wastewater Treatment Facility 36. Northern Colorado Water Conservancy District 37. County of Pueblo 38. Colorado River Water Conservation District 39. Dominion Water and Sanitation District 40. Parker Water and Sanitation District 41. Trout Unlimited 42. Chatfield Watershed Authority 43. South Platte Coalition for Urban River Evaluation 44. Arkansas Fountain Coalition for Urban River Evaluation

93.16 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND

PURPOSE; AUGUST 2016 RULEMAKING, FINAL ACTION OCTOBER 11, 2016, EFFECTIVE DATE OF NOVEMBER 30, 2016 The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.

BASIS AND PURPOSE A. Revisions to 303(d) List 1. Introduction This regulation updates Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (TMDLs) to reflect additional water quality information available since the Regulation was last updated. This change was prepared to fulfill section 303(d) of the federal Clean Water Act (Act) which requires that states submit to the U.S. Environmental Protection Agency (EPA) a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.

2. List Development a. Listing Methodology The Section 303(d) Listing Methodology - 2016 Listing Cycle (“Listing Methodology”) provides the listing process, the criteria for listing, and the criteria for determination of TMDL priority. The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission (Commission) administrative action hearing in March 2015.

1. This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2016 Section 303(d) List and the 2016 M&E List. However, this methodology was not adopted by the Commission as a rule. The Commission therefore has the flexibility to take into account other appropriate factors in making site- specific listing decisions.

b. Information Considered To determine whether Sand Creek, a portion of segment COUCNP04a, should be included on the 303(d) List rather than the M&E List, the Commission considered existing and readily available data, which includes the data used to prepare the identification processes, calculations and models referenced in 40 CFR §130.7(a)(5)(i), (ii) and (iv), and data that was presented by Cody Resources LP/State Line Ranch.

3. Sand Creek, a Portion of Segment COUCNP04a Cody Resources LP/State Line Ranch proposed that Sand Creek be listed as impaired for sediment due to impacts to a beneficial use at the Commission’s December 2015 303(d) Rulemaking. The Commission, however, placed Sand Creek on the Monitoring & Evaluation List effective March 1, 2016 based on the State Line Ranch’s proposal submitted as part of written public comment. While the Commission found the evidence submitted to be persuasive and compelling evidence of impairment, the Commission was reluctant to list the segment as impaired because the proposal was made late in the process and the Division had not had an opportunity to review and evaluate the proposal. In addition, potentially affected parties were not able to participate in the process. This was the first time a segment has been listed for sediment impairing a beneficial use, and so the Commission wanted to proceed thoughtfully to establish precedent about the factors considered in such a decision. The Commission, however, stated that a proposal could be made for a special hearing to consider the sediment listing proposal. State Line Ranch subsequently requested and the Commission granted and scheduled this special hearing.

In support of listing Sand Creek as impaired, State Line Ranch submitted engineering reports prepared by Hydros Consulting, work logs from the Ranch’s irrigator, and presented testimony of the Ranch President and Ranch Manager. The Commission found that Hydros appropriately analyzed the four factors required to find sediment impairment using Policy 98-1, and that State Line Ranch established with clear and convincing evidence:

1. The represented expected condition in terms of sediment deposition for Sand Creek;

2. The actual observed sediment condition for Sand Creek is significantly different than the expected condition;

3. The sediment is attributable to an anthropogenic source, which is Off- Highway Vehicle use at North Sand Hills;

4. There is a beneficial irrigation use at State Line Ranch to which the excess sediment is a determent.

The Commission has accordingly updated Colorado’s List of Water-Quality- Limited Segments to move Sand Creek, a portion of Segment COUCNP04a, onto its 303(d) list from its M&E list.

The Commission considered the Division’s recommendation to establish quantitative benchmarks to assess conditions on Sand Creek for future listing/delisting decisions. The Commission adopted the benchmarks proposed by Cody Resources/State Line Ranch:

1. Reduction in Sand Deposition in Blankenship Meadow – State Line Ranch has and is now experiencing the formation of long sediment “fingers” in the meadow. The extent of these “fingers” should be quantified each year on the same date and compared to previous years. Quantification could occur using LandSat imagery (based on sand-related parameters such as emissivity and albedo measurements) and / or on-the-ground field measurements. This benchmark would seek to verify that sand deposition in the meadow is no longer increasing and quantify a return to pre-2011 conditions when sand deposition was not inundating additional meadowlands.

2. Return to Historical Maintenance Activities – Historical irrigation activities at State Line Ranch did not include the use of heavy equipment such as excavators or backhoes. This benchmark would track whether and when the Ranch could consistently return to those practices. For both of these recommended benchmarks, the period of assessment will need to cover several years (due to movement of existing sediment downstream and past the headgate) and include years with wet hydrologic conditions. The Commission anticipates that the Division will work with Cody Resources/State Line Ranch to implement these benchmarks because this is the first instance in which the Commission has applied Section V of Policy 98-1 since it made revisions in November 2014.

The Commission recommends that the Bureau of Land Management evaluate the impacts of off highway vehicle use in the North Sand Hills Special Recreational Management Area to water quality and sediment impairment during the next update to the Kremmling Resource Management Plan and any related Environmental Impact Statement.

1. PARTIES TO THE RULEMAKING HEARING

1. Cody Resources, LP/State Line Ranch

93.17 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND

PURPOSE; DECEMBER 2017 RULEMAKING, EFFECTIVE DATE OF MARCH 1, The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; provide the specific statutory authority for adoption of these regulatory amendments. The commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.

BASIS AND PURPOSE A. Revisions to 303(d) List 1. Introduction This regulation updates Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (TMDLs) to reflect additional water quality information available since the Regulation was promulgated in 2006. This list was prepared to fulfill section 303(d) of the federal Clean Water Act (Act) which requires that states submit to the U.S. Environmental Protection Agency (EPA) a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.

This regulation also updates Colorado’s Monitoring and Evaluation List (M&E List) to reflect additional water quality information available since the Regulation was promulgated in 2012.

For the draft proposal of the 2018 Regulation #93, the format of the 303(d) and M&E List tables was changed substantially. The division developed a new format generated directly from the state’s assessment tracking database (ATTAINS). The new 303(d) and M&E tables can be directly linked to the state’s GIS segmentation layer and the standard’s database. This new format will streamline the development of the 303(d) and M&E Lists throughout the hearing process by eliminating the need to track and change listings in two places (an assessment database and a Word table). The new format will also allow for queries and reports to be easily generated and will make for efficient and accurate reporting to EPA at the conclusion of each listing cycle as well as an automated generation of the Integrated Report.

The division studied 303(d) lists from many other states to come up with the new format. The division modeled the new tables after the State of Virginia’s 303(d) List. In speaking with staff from Virginia, the division learned about the efficiencies associated with using a format generated out of the tracking database and decided that Colorado should use a similar model.

2. List Development a. Listing Methodology The “Section 303(d) Listing Methodology - 2018 Listing Cycle” contains a description of the listing process, the criteria for listing, and the criteria for determination of TMDL priority. The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission (commission) administrative action hearing in March 2017.

1. This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2018 Section 303(d) List and the 2018 M&E List. However, this methodology was not adopted by the commission as a rule. The commission therefore has the flexibility to take into account other appropriate factors in making site- specific listing decisions.
   1. b. Information Considered The commission considered all existing and readily available information in developing the 2018 Section 303(d) List. In determining whether data and information are existing and readily available, it has taken into account such data and information as the division has utilized in the preparation of those identification processes, calculations and models referenced in 40 CFR §130.7(a)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and submitted in reports provided to the division as referenced in 40 CFR §130.7(a)(5)(iii). In addition, the commission accepted credible data and information that was submitted in accordance with the listing process schedule, whether submitted by EPA or any other interested party. The division also independently collected and analyzed new data on a rotating basin basis as part of its triennial review efforts. This data and information was utilized in making listing proposals. Existing data which was not brought forward through one of the above mechanisms or otherwise presented to the commission in accordance with the schedule was not treated as “readily available” for purposes of making the 2018 listing decisions. The commission determined that such information will be considered in the next listing cycle.

c. Data Quality In the division's “Quality Management Plan 2016 for Surface Water Monitoring and Assessment”, the division states that “It is the expressed goal of the division to use only those analytical data that are both reliable and have a defined level of quality.”

3. Prioritization The objective of prioritization is to identify those segments where the division and the public should concentrate their resources. Priorities of High, Medium and Low were established according to section VI. of the 2018 Section 303(d) Listing Methodology. The division is directed to establish a plan for monitoring and evaluating water bodies on the M&E List prior to the next listing cycle. Further, the commission has committed to determining their appropriate status (as either impaired or fully supporting) within ten years of their placement on the M&E List.

4. Impaired Segments Not Requiring TMDLs Below the 303(d) and M&E Lists, the regulation includes a table in Section 93.4 with waterbodies that are impaired but that do not require a TMDL. A TMDL may not be required for three main reasons: a TMDL has already been completed but uses are not yet attained; there is a required control mechanism in place that is expected to address all segment-pollutant combinations and will attain water quality standards in a reasonable period of time; or it has been determined that the impairment is not caused by a pollutant.

5. Listings Due to Exceedances of the Temperature Standards In 2016, the commission adopted a new definition of existing quality for temperature which specifies a 1 in 3 year average recurrence frequency of a “warming event”. The 2018 303(d) Listing Methodology defines an allowable cumulative impact during this once in three year period. This method relies on the concept of “degree-days” which integrates both the magnitude of temperatures over the standard, as well the duration, in days, experienced by the aquatic community. Temperature excursions (air, low flow and shoulder season) are evaluated after the warming event is considered. If temperatures exceed the number of ‘degree-days’ specified, and the dates that exceed temperature standards do not have applicable excursions, the segment is placed on the 303(d) List as impaired for temperature.

The party proposing a temperature listing is responsible for investigating the temperature excursions as defined in Regulation No. 31, Footnote 5c, Table 1. This footnote includes three allowable excursions to exceedances of the temperature standard. These include an air temperature excursion, a low flow excursion and a winter shoulder season excursion. For the 2018 listing cycle, the division analyzed water temperature data from more than 68 stations in more than 43 segments. In cases where the excursions were evaluated and exceedances of the temperature standards remained, the commission included these segments on the 303(d) List. In cases where the excursions were not fully evaluated and exceedances of the temperature standards remained, the commission included these segments on the M&E List.

6. Listings Due to Exceedances of the Secondary Water Supply Standards For the secondary water supply standards of dissolved iron, dissolved manganese and sulfate, the less restrictive of the following two options apply as the numeric standard: existing quality as of January 1, 2000 or the table value criteria in Regulation No. 31, Tables II and III. For dissolved iron, the table value standard (TVS) is 300 ug/l. For dissolved manganese, the TVS is 50 ug/l. For sulfate, TVS is 250 mg/l. For the 2016 303(d) Listing Methodology, the commission included additional language regarding the determination of existing quality from the year 2000. This includes a minimum data requirement and the ability to use data collected after the year 2000 when characterizing existing quality from 2000. The utilization of data collected past the year 2000 is contingent upon there being no known new or increased sources of these parameters in the segment being assessed since 2000.

The following table summarizes the values that were used for the assessment of dissolved iron, manganese and sulfate for those waterbodies being proposed for the 303(d) or M&E List:

Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese and Sulfate Water Supply Standards Period Sample of Analyt TVS or Valu Unit size of Portion ID List Record e 2000 e s 2000 for 2000 dataset data set COARFO02a_A Fe-D 303(d) TVS 300 ug/L COARFO02b_A Fe-D 303(d) TVS 300 ug/L COGUNF06b_C Fe-D 303(d) TVS 300 ug/L COGUUG01_A Fe-D M&E TVS 300 ug/L COGUUG01_B Fe-D M&E TVS 300 ug/L COSJAF09_A Fe-D M&E 2000 95- 99 3200 ug/L 7 3 COSJLP05_B Fe-D M&E TVS 300 ug/L OARFO04_C Mn-D 303(d) 2000 95-09 66.6 ug/L 84 COARFO06_B Mn-D 303(d) 2000 95-09 60 ug/L 175 COARFO06_C Mn-D 303(d) 2000 95-09 60 ug/L 175 COARLA09a_A Mn-D 303(d) 2000 95- 99 204 ug/L 4 7 COGULG02_A Mn-D 303(d) TVS 50 ug/L COGULG12_B Mn-D 303(d) 2000 95-04 94.3 ug/L 18 COGUNF03_B Mn-D 303(d) 2000 95-99 72 ug/L 59 COGUNF03_C Mn-D 303(d) 2000 95-99 72 ug/L 59 COGUNF06b_C Mn-D 303(d) 2000 95- 99 87.5 ug/L 3 6 COGUUG19_B Mn-D 303(d) TVS 50 ug/L COGUUG29a_F Mn-D 303(d) TVS 50 ug/L COGUUN03a_A Mn-D 303(d) 2000 95-99 573. ug/L 54 COGUUN03b_A Mn-D 303(d) 2000 95-99 412. ug/L 67 Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese and Sulfate Water Supply Standards Period Sample of Analyt TVS or Valu Unit size of Portion ID List Record e 2000 e s 2000 for 2000 dataset dataset COGUUN03c_A Mn-D 303(d) 2000 95- 99 180 ug/L 8 7 COGUUN04b_A Mn-D 303(d) TVS 50 ug/L COGUUN05_C Mn-D 303(d) TVS 50 ug/L COGUUN05_E Mn-D 303(d) TVS 50 ug/L CORGRG04b_B Mn-D 303(d) TVS 50 ug/L CORGRG04b_C Mn-D 303(d) TVS 50 ug/L CORGRG04b_D Mn-D 303(d) TVS 50 ug/L COSJAF03a_A Mn-D 303(d) site- 2571 ug/L specific /217 std. 9 COSJAF09_A Mn-D 303(d) 2000 95-99 507. ug/L 60 COARFO04_B Mn-D M&E 2000 95-09 66.6 ug/L 84 COARUA04b_A Mn-D M&E TVS 50 ug/L COGULG04a_E Mn-D M&E 2000 95-99 85.4 ug/L 12 COSJAF04b_A Mn-D M&E 2000 95-99 259. ug/L 369 COSJLP04c_B Mn-D M&E TVS 50 ug/L COSJSJ06a_C Mn-D M&E TVS 50 ug/L COSJDO04b_A Mn-D M&E TVS 50 ug/L Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese and Sulfate Water Supply Standards Period Sample of Analyt TVS or Valu Unit size of Portion ID List Record e 2000 e s 2000 for 2000 dataset data set COARFO04_B SO4 303(d) TVS 250 mg/L COARFO04_C SO4 303(d) TVS 250 mg/L COGULG02_A SO4 303(d) 2000 95-99 298 mg/L 94 COGULG12_B SO4 303(d) 2000 95-04 555 mg/L 18 COGUUN04b_A SO4 303(d) 2000 95-99 664 mg/L 106 COSJLP08a_A SO4 303(d) 2000 95-99 3000 mg/L 65 COSJLP08a_B SO4 303(d) 2000 95-99 3000 mg/L 65 COSJLP08a_C SO4 303(d) 2000 95-99 3000 mg/L 65 COSJLP08a_D SO4 303(d) 2000 95-99 3000 mg/L 65 COSJLP08a_E SO4 303(d) 2000 95-99 3000 mg/L 65 COARLA09a_C SO4 M&E 2000 95-99 1701 mg/L 34 COGULD03a_B SO4 M&E 2000 95- 09 275 mg/L 1 4 COGUUN04a_B SO4 M&E TVS 250 mg/L COSJLP05_B SO4 M&E 2000 95-04 739 mg/L 22 7. Delisting of Segments with Recently Approved TMDLs The division submitted 3 TMDLs to EPA since the approval of the 2016 303(d) List that have been approved. The commission has removed the following segments from the 303(d) List:

• COARMA18a –Mainstem of Boggs Creek from the source to Pueblo Reservoir (Selenium, Uranium)

• COSPBD01 - Mainstem of Big Dry Creek, including all tributaries and wetlands, from the source to the confluence with the South Platte River (E. coli)

• COSPUS15 - South Platte, Burlington Ditch to Big Dry Creek (E. coli) 8. Segments with TMDLs Currently under EPA Review:

• COARMA04a – Mainstem of Wildhorse Creek from the source to the confluence with the Arkansas River (E. coli).

9. Delisting of Segments Where Water Quality is Currently Meeting Standards As additional water quality data are collected and assessed, new data may show attainment of the standard. The commission removed the following segments and parameters from the 303(d) List due to a recent assessment of water quality data: Table 2. Water Bodies Removed from 303(d) List Assessment Assessment Unit ID Parameter Unit ID Parameter CO ARMA02 Di l d COGUUG08 A Di l d d i The commission removed the following segments and parameters from the M&E List: Table 3. Water Bodies Removed from M&E List Assessment Assessment Parameter Parameter Unit ID Unit ID COARFO01a_B Total iron CORGCB02a_C Dissolved iron Dissolved Dissolved COARLA04a_B manganese CORGCB02a_C manganese COARMA04a_A Nitrite CORGCB02a_C Total phosphorus Dissolved COARMA06a_A manganese CORGCB02b_B Dissolved iron Dissolved COARMA06a_A Sulfate CORGCB02b_B manganese COARMA07b_A Temperature CORGCB02b_B Total phosphorus Dissolved Dissolved COARMA09_A manganese CORGCB02c_A manganese Dissolved COARMA11b_A Total iron CORGCB09a_B manganese Dissolved COARMA11b_A manganese CORGCB12a_C Temperature Dissolved COARMA18a_A manganese CORGCB12a_C Total phosphorus Dissolved Dissolved COARUA24_B manganese CORGRG04c_A manganese COARUA38_B Dissolved iron CORGRG11_A Total phosphorus Dissolved COARUA38_B manganese CORGRG19_A Total phosphorus COGULD02_B E. coli CORGRG20a_B Total phosphorus COGULD02_C E. coli CORGRG20a_C Total phosphorus COGULD02_D E. coli CORGRG20b_A Total phosphorus COGULD02_E E. coli CORGRG37_A Dissolved Table 3. Water Bodies Removed from M&E List Assessment Assessment Parameter Parameter Unit ID Unit ID manganese COGULD03a_B E. coli CORGRG38_D Dissolved silver COGULG04a_B Sulfate CORGRG38_D Dissolved iron COGULG04b_B Sulfate COSJLP03c_A Dissolved copper COGULG07a_A Dissolved selenium COSJLP04c_C Temperature COGULG07b_D Dissolved lead COSJLP04c_D Temperature COGULG08a_A Temperature COSJPI05a_A Temperature COGULG08b_A Temperature COSJPI05a_B Dissolved copper COGUSM02_B Dissolved lead COSJPI05a_B pH COGUSM02_C Dissolved lead COSJPI05a_B Temperature COGUSM03b_A Dissolved lead COSJPI05b_A Temperature COGUSM04a_B Dissolved lead COSJPI06a_C Total iron COGUSM12a_D Dissolved oxygen COSJPI06a_C Sulfate COGUSM12a_F Dissolved selenium COSJPI06a_E Total iron COGUSM12b_C Temperature COSJPI06a_E Sulfate COGUSM12b_D Temperature COSJPI06a_G Total iron COGUSM12b_F Temperature COSJPI06a_G Sulfate COGUSM12c_A Temperature COSJPI06c_A E. coli COGUUG01_B Total iron COSJPI06c_A Total iron COGUUG04_B Dissolved lead COSJPI06c_A Sediment COGUUG16a_A E. coli COSJPI06c_A Sulfate COGUUG23_B Dissolved iron COSJPI08_A Dissolved oxygen Table 3. Water Bodies Removed from M&E List Assessment Assessment Parameter Parameter Unit ID Unit ID COGUUG26_B Dissolved copper COSJPI08_A Dissolved zinc COGUUN04c_A Dissolved lead COSJSJ05_D Dissolved lead COGUUN07_A Total iron COSJSJ05_E Dissolved lead COGUUN09_C Dissolved lead COSJSJ06a_C Dissolved copper COGUUN10a_C Sulfate COSJSJ06a_C Dissolved lead COGUUN11_E Sulfate COSJSJ06a_C Temperature COGUUN11_H Dissolved selenium COSJSJ06a_D Dissolved lead COGUUN11_J Dissolved selenium COSJSJ06b_B Temperature CORGAL02_B Dissolved iron COSJSJ06b_C Temperature CORGAL02_B pH COSJSJ08_B pH CORGAL02_C Dissolved iron COSJSJ09a_A Dissolved silver CORGAL02_C pH COSJSJ09a_A Dissolved lead CORGAL03b_B Dissolved selenium COUCEA09a_A Sediment CORGAL03c_A Ammonia COUCEA09b_B Sediment CORGAL10_A Total iron COUCEA09b_C Sediment Dissolved CORGCB02a_B manganese COLCLC04e Total iron 10. Below is a table that summarizes segments or portions of segments that were added to, removed or retained on both the 303(d) and M&E Lists, by analyte. Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs Delist from M&E CORGRG38_D; COSJSJ09a_A New listing COGUUG10b_A; COSJAF03a_A;

1. on M&E COSJAF03a_B Dissolved Silver COARUA05_C; COGUUG31_A;
   1. CORGRG33_B; COSJAF13a_B;
      1. Retain on 10 COSJAF22_B; COSPBO14_B;
         1. M&E List COSPCP07_B; COSPCP07_C;

            COSPSV02b_A; COSPSV02b_B Retain on 4a List due to approved Dissolved Silver TMDL CORGCB09a_A; CORGCB09a_B New listing on 303(d) COGUNF04c_A Retain on 303(d) List COGUUN06a_A; COSJLP01_A Retain on 4a List due to Dissolved Aluminum 1 approved TMDL COARUA12a_A COARUA11_A; CORGAL03a_A;

            Retain on 4a CORGAL03b_A; CORGAL03b_B;

            List due to CORGAL03c_A; COSJAF02_B;

            approved COSJAF03a_B; COSJAF03b_A;

            TMDL COSJAF06_B; COSJAF07_A;

            COSJAF08_A Total Aluminum New listing on 303(d) COSJAF09_A Retain on 303(d) List CORGAL03d_A; COSJAF04a_A Delist from 303(d) COARLA05a_A; CORGCB12a_C Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs Delist due to extent of impairment refined CORGCB12a_B; CORGCB12a_E COARUA04b_A; COARUA12a_A;

Total Arsenic COARUA20b_A; COGULG16_C;

1. COGUSM12b_F; COGUSM12b_H;
   1. COGUUG04_B; COGUUG05a_A;
      1. COGUUG18b_A; COGUUG30_B;
         1. COGUUG30_C; CORGRG05_B;

            New listing 25 COSJAF10a_A; COSJDO04b_A;

            on M&E COSJDO05a_B; COSJDO05a_C;

            COSJDO10b_A; COSJLP05_B;

            COSJLP11_B; COSJPI08_A;

            COSJPN02a_A; COSJPN05_A;

            COSJSJ06b_B; COSJSJ08_B;

            COSJSJ09a_A COARLA09a_C; COARMA11b_A;

            COARUA38_B; COGUUG29a_C;

            COGUUG29a_D; COGUUG29a_E;

            COLCLC02b_B; COLCLC14c_B;

            COLCLC14c_C; COLCLC20_B;

            CORGAL20_A; CORGRG37_A;

            COSPBE11_B; COSPCP07_B;

            Retain on COSPCP07_C; COSPLA02a_A;

            M&E List COSPLA02b_A; COSPUS03_F;

            COSPUS12_B; COUCBL12_B;

            COUCBL12_C; COUCEA09b_B;

Total Arsenic COUCEA09b_C; COUCNP04a_C;

1. COUCNP04a_D; COUCUC03_A;
   1. COUCUC03_B; COUCUC03_C;
      1. COUCUC12_D; COUCYA08_C;
         1. COUCYA18_B Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COARLA11_A; COARLA15_B;

            COARMA07b_A; COARMA13a_B;

            COARMA18a_A; COARMA26_B;

            COARMA26_C; COARUA02a_A;

            COARUA05_B; COARUA07_A;

            COGUNF04b_B; COGUNF04b_C;

            COGUNF06b_C; COGUSM02_C;

            COGUSM08_A; COGUSM12a_D;

            COGUSM12b_G; COGUUG01_B;

            COGUUG01_C; COGUUG07_A;

            COGUUG16a_B; COGUUG19_B;

            COGUUG21_A; COGUUG23_A;

            COGUUG23_B; COGUUG24_A;

            New listing 54 COGUUG24_B; COGUUG26_B;

            on 303(d)

            COGUUG26_D; COGUUG26_E;

            COGUUG29b_C; COGUUN04a_B;

            COGUUN04b_A; COGUUN10a_C;

            COGUUN11_C; COGUUN11_E;

            COGUUN11_G; COGUUN11_H;

            COGUUN11_I; COGUUN11_J;

            CORGAL02_B; CORGAL02_C;

            CORGAL14a_B; CORGRG02_A;

            CORGRG02_B; CORGRG04b_B;

            CORGRG05_C; CORGRG38_D;

            CORGRG38_E; COSJLP04c_C;

            COSJPI05a_A; COSJPI05a_B;

            COUCEA05a_A; COUCEA05b_A Moved from M&E to 3 COARLA10_B; COARUA35_A;

Total Arsenic 303(d) COGULD05_D COARFO01a_B; COARLA01b_A;

1. COARLA01c_A; COARLA05b_A;
   1. COARLA05b_B; COARLA09a_A;
      1. Retain on 130 COARLA09a_B; COARMA03_A;
         1. 303(d) List COARMA09_A; COARUA02c_A;

            COARUA05_C; COARUA15_B;

            COARUA15_C; COGUNF04a_B;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COGUUG09_B; COGUUG09_C;

1. COGUUG09_D; COGUUG11_B;
   1. COGUUG11_D; COGUUG12_C;
      1. COLCLC01_B; COLCLC04c_A;
         1. COLCLC10_A; COLCLC10_B;

            COLCLC15a_A; COLCLC15c_A;

            COLCLY03c_C; COLCWH07_B;

            COLCWH12_A; COLCWH14a_A;

            COLCWH14a_B; COLCWH20_B;

            COLCWH20_C; COLCWH21_A;

            CORGCB02a_B; CORGCB02a_C;

            CORGCB02b_B; CORGCB02c_A;

            CORGCB04_A; CORGCB09b_A;

            CORGCB09b_B; CORGCB12a_D;

            CORGRG04b_C; CORGRG04b_D;

            CORGRG04c_A; CORGRG09_B;

            CORGRG11_A; CORGRG19_A;

            COSPBE02_A; COSPBE02_B;

            COSPBE02_C; COSPBO02a_A;

            COSPBO02a_B; COSPBO02a_C;

            COSPBO02a_D; COSPBO02a_E;

            COSPBO02a_F; COSPBO02b_B;

Total Arsenic COSPBO02b_C; COSPBO03_A;

1. COSPBO03_B; COSPBO04b_B;
   1. COSPBO09_A; COSPBO09_B;
      1. COSPBO10_A; COSPBO14_B;
         1. COSPBT01_A; COSPBT02_A;

            COSPBT02_B; COSPBT02_C;

            COSPBT02_D; COSPBT03_A;

            COSPBT07_A; COSPBT07_B;

            COSPBT08_A; COSPBT08_B;

            COSPBT11_A; COSPCP02a_A;

            COSPCP06_A; COSPCP09_A;

            COSPCP10a_A; COSPCP10b_A;

            COSPCP14_A; COSPMS01b_A;

            COSPRE01_A; COSPSV02b_A;

            COSPSV02b_B; COSPSV07_B;

            COSPUS02c_C; COSPUS02c_D;

            COSPUS03_C; COSPUS03_D;

            COSPUS10a_C; COSPUS14_B;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COSPUS14_C; COSPUS17a_D;

1. COUCBL02c_A; COUCBL04a_B;
   1. COUCBL20_B; COUCEA02_A;
      1. COUCEA05c_A; COUCEA06_A;
         1. COUCEA06_C; COUCEA06_D;

            COUCEA06_E; COUCEA06_F;

            COUCEA06_G; COUCEA06_H;

            COUCEA09a_A; COUCEA09a_B;

            COUCEA09c_A; COUCNP01_B;

            COUCNP04a_F; COUCNP04a_G;

            COUCNP04a_H; COUCNP04b_B;

            COUCNP05b_A; COUCNP09_C;

            COUCNP09_D; COUCUC07a_C;

            COUCUC07b_C; COUCUC10c_A;

            COUCUC10c_B; COUCUC10c_C;

            COUCUC12_B; COUCYA02a_A;

            COUCYA02b_A; COUCYA03_D;

            COUCYA03_E; COUCYA15_B Delist due to extent of impairment refined COSJSJ05_D Aquatic Life COARLA06a_F; COARMA04b_B;

            New listing COGULD02_B; COGULD02_C;

            on M&E COGULD02_D; COGULD02_E;

            COGUUN09_B; COSJLP04c_C Added to M&E due to database correction COSJLP04c_D COARUA05_B; COARUA14c_B;

            COARUA15_B; COARUA15_C;

            Retain on COLCLY03i_A; COLCWH13b_D;

            M&E List CORGRG07_A; CORGRG07_B;

            COSJSJ05_E; COSPBO07b_A;

            COSPBO07b_B; COSPCL01_B;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COSPCL02c_B; COSPCL02c_C;

1. COSPCL02c_D; COSPUS01a_D;
   1. COSPUS02a_C; COSPUS03_B;

Aquatic Life COUCBL17_A; COUCBL17_B;

1. COUCEA06_E; COUCEA06_G;
   1. COUCUC03_B; COUCUC03_C;
      1. COUCUC03_D Retain on 4b List due to 4b 1 Plan COSPCL03a_C New listing COGUUG10a_A; COGUUG10b_A;
         1. on 303(d) COSJLP07a_C; COSJLP07b_B COGUUG01_B; COGUUG04_B;

            COGUUG15a_B; COLCLY22a_B;

            COLCWH07_A; COLCWH07_B;

            COLCWH13c_A; COLCWH13c_B;

            COLCWH23_C; CORGCB02a_B;

            CORGCB02b_B; CORGRG11_A;

            Retain on 26 CORGRG20a_B; CORGRG20a_C;

            303(d) List COSPBT02_A; COSPBT02_B;

            COSPBT02_C; COSPBT02_D;

            COSPCL14a_B; COSPUS01a_C;

            COSPUS03_D; COSPUS03_E;

            COSPUS03_F; COSPUS11a_B;

            COUCRF03a_C; COGUUN05_E Delist from COARUA21a_B; COGUUG02_B;

            303(d) CORGCB09b_B; COSJPI06c_A Delist due to new 2 segmentation COSJLP05_C; COSJLP06b_B Aquatic Life Retain on (Provisional) 1 M&E List COUCEA06_H Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COARLA06a_E; COGULD05_E;

            COGUSM07_A; COGUSM07_B;

            COGUSM07_C; COGUUG26_D;

            New listing CORGAL09_A; CORGAL10_A;

            on 303(d) CORGRG23a_B; CORGRG23b_A;

            COSJAF05a_B; COSJAF05a_C;

            COSJLP05_B; COSJLP08_E;

            COSJLP09_B; COUCRF03a_E Moved from M&E to 1 303(d) COSJSJ05_D COARFO03a_B; COARFO06_B;

            COARFO06_C; COARLA06a_B;

            COGUSM12a_E; COGUSM12b_D;

            COGUUG18b_A; COGUUG19_B;

            COGUUG24_B; COGUUG26_C;

            COGUUN11_C; COLCWH15_B;

            COLCWH15_C; COLCWH20_B;

            COLCWH20_C; CORGRG12_A;

Aquatic Life COSJLP06a_B; COSJPI06a_E;

(Provisional)

1. COSJPI06a_F; COSJPI06d_A;
   1. COSPBE02_A; COSPBE02_B;
      1. COSPBE02_C; COSPBO02a_D;
         1. Retain on COSPBO03_B; COSPBO07a_A;

            303(d) List COSPBO09_B; COSPCP02a_A;

            COSPLS02b_C; COSPUS01a_A;

            COSPUS03_C; COSPUS06a_B;

            COSPUS10a_B; COSPUS10a_C;

            COSPUS11b_B; COUCBL01_A;

            COUCBL02b_A; COUCBL02c_A;

            COUCBL05_A; COUCEA06_C;

            COUCEA06_D; COUCEA06_F;

            COUCEA08_A; COUCEA09a_B;

            COUCNP04a_D; COUCRF03a_B;

            COUCRF03d_B; COUCRF07_B;

            COUCUC10a_C; COUCUC10a_D;

            COUCYA12_B Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs Delist from COGUSM02_B; COGUUG08_A;

            303(d) COGUUG11_D Delist due to approved 3 COARUA02b_A; COARUA02c_A;

            TMDL COARUA05_D New listing COARUA07_A; COGUUG07_B;

            on M&E COGUUN05_B; CORGRG06_B Dissolved Cadmium COGUUG29a_C; COGUUG29a_D;

            COGUUG29a_E; COLCLC04e_A;

            CORGAL03c_A; CORGAL20_A;

            Retain on 14 CORGCB12a_C; CORGRG05_B;

            M&E List CORGRG07_A; CORGRG07_B;

            COSPCL03b_A; COSPCL06_C;

            COSPUS01b_C; COUCBL04a_B COARUA03_A; COARUA04a_A;

            COARUA04b_A; COARUA08b_A;

            COARUA11_A; COGUSM03a_A;

            COGUSM03b_A; COGUSM06a_A;

            COGUSM06b_A; COGUUG30_B;

            COGUUG31_A; COGUUN02_A;

            COGUUN03a_A; COGUUN03b_A;

            COGUUN03c_A; COGUUN03d_A;

            COGUUN03e_B; COGUUN03e_C;

            Retain on 4a COGUUN03f_A; CORGCB09a_A;

            List due to 44 CORGCB09b_A; CORGCB09b_B;

            approved CORGRG04a_A; CORGRG04b_B;

            TMDL CORGRG04b_C; CORGRG04b_D;

            COSJAF02_B; COSJAF03a_B;

            COSJAF03b_A; COSJAF06_B;

            COSJAF07_A; COSJAF08_A;

            COSJDO09_A; COSPBO04a_B;

            COSPCL13b_A; COSPSV04a_A;

            COSPSV04a_B; COSPSV04b_B;

Dissolved Cadmium COSPUS05a_A; COSPUS15_B;

1. COSPUS15_C; COUCBL06a_B;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COUCBL07_A; COUCBL12_B COGUNF04c_A; COGUUN05_C;

1. New listing COGUUN05_E; COGUUN08_A;
   1. on 303(d) CORGAL03a_A; CORGRG04c_A;
      1. COSJAF04a_A Moved from M&E to 1 303(d) COARUA05_B COARUA05_C; COARUA12a_A;
         1. COGUUG10a_A; COGUUG10b_A;

            COGUUG11_B; COGUUG12_C;

            COGUUG29a_B; COGUUN09_B;

            COGUUN09_D; COSJAF03c_A;

            COSPCL02a_A; COSPCL02c_B;

            Retain on 26 COSPCL02c_C; COSPCL02c_D;

            303(d) List COSPCL09b_A; COSPCL11_A;

            COSPCL12a_A; COSPCL12a_B;

            COSPCL13b_B; COSPCP07_B;

            COSPCP07_C; COSPUS02b_A;

            COSPUS02c_A; COSPUS02c_C;

            COSPUS02c_D; COUCEA05c_A New listing Total Cadmium 1 on M&E COARFO01a_B Retain on Chlorophyll a 2 303(d) List COSPBE01c_A; COSPCH02_A New listing Chloride 1 on 303(d) COGULD02_C Delist from 4 COGUUG26_B; COSJLP03c_A;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs M&E COSJPI05a_B; COSJSJ06a_C Dissolved Copper Delist from COARFO03b_A; COARUA04a_A;

1. 303(d) COGUUG12_C; CORGRG04c_A Delist due to approved 1 TMDL COSJAF06_B COARMA04b_B; COGUUN05_B;
   1. New listing 6 CORGRG07_A; CORGRG07_B;
      1. on M&E COSJDO05a_C; COSJLP01_A M&E listing due to new 2 segmentation COSJLP04c_C; COSJSJ06b_C COGUUN09_D; COLCLC04e_A;
         1. COLCLC13a_B; COLCLY07_A;

            CORGAL20_A; CORGCB03_B;

            CORGCB05_A; CORGCB10_B;

            Retain on CORGRG05_B; CORGRG09_B;

            M&E List CORGRG25_A; CORGRG28_B;

            COUCBL12_B; COUCBL12_C;

            COUCNP04a_F; COUCNP05b_A;

            COUCNP06_A; COUCRF02_A;

            COUCUC08_B; COUCYA18_A Added to 4a Dissolved Copper List due to database correction COSJLP04a_E COARUA10_A; COARUA11_A;

            Retain on 4a COGUUN02_A; COGUUN03a_A;

            List due to COGUUN03b_A; COGUUN03c_A;

            approved COGUUN03d_A; COGUUN03e_B;

            TMDL COGUUN03e_C; COGUUN03f_A;

            CORGAL03a_A; CORGAL03b_A;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs CORGAL03b_B; CORGAL03c_A;

1. CORGAL03d_A; CORGAL08_A;
   1. CORGAL09_A; CORGCB09b_A;
      1. CORGCB09b_B; COSJAF02_B;
         1. COSJAF03a_B; COSJAF03b_A;

            COSJAF04a_A; COSJAF07_A;

            COSJAF08_A; COSJAF09_A;

            COSJLP04c_D; COSJLP04c_E;

            COSPBO04a_B; COSPCL02a_A;

            COSPCL02b_B; COSPCL02c_C;

            COSPCL09a_C; COSPCL09b_A;

Dissolved Copper COSPSV04a_B; COSPSV04b_B;

1. COSPSV04c_A; COSPUS04_C;
   1. COSPUS04_E; COSPUS05a_A;
      1. COSPUS05b_A; COUCBL06a_B;
         1. COUCBL07_A; COUCEA05a_A;

            COUCEA05b_A; COUCEA05c_A;

            COUCEA07b_A New listing COARUA05_A; COARUA05_B;

            on 303(d) COGUUN05_C; COSJDO04a_B Moved from M&E to 4 COGUSM06a_A; COGUSM06b_A;

            303(d) COGUUG31_A; COGUUN08_A COARUA05_C; COARUA30_B;

            COGULD05_B; COGUUG10a_A;

            COGUUG10b_A; COGUUG29a_B;

            COGUUN06a_A; COGUUN07_A;

            CORGCB03_D; CORGRG04b_B;

            COSPBE01e_B; COSPBO02a_B;

            Retain on COSPBO02a_C; COSPBO04a_A;

            303(d) List COSPBO04b_B; COSPBO14_B;

            COSPBT01_A; COSPBT02_C;

            COSPBT03_A; COSPBT07_B;

            COSPBT16_B; COSPCL02c_B;

            COSPCL03a_B; COSPCL03b_A;

            COSPCL05_B; COSPCL06_C;

            COSPCL09a_B; COSPCL10_A;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COSPCL12a_A; COSPCL12a_B;

1. COSPLA02b_A; COSPSV02b_B;
   1. COSPSV05_A; COSPSV05_B;
      1. COUCBL04a_C; COUCUC02_D;
         1. COUCUC10a_D Delist from 303(d) COGULG13_A Dissolved Oxygen (Temperature)

            New listing on 303(d) CORGRG38_E Delist from M&E COGUSM12a_D; COSJPI08_A Delist from 303(d) COSJSJ08_B; COSPCH04a_C COGUNF04c_A; COGUSM02_E;

            New listing Dissolved Oxygen 6 COGUSM14_B; CORGRG02_B;

            on M&E CORGRG20a_B; CORGRG23b_A COGUSM07_C; COGUSM10b_B;

            COLCLC04b_A; CORGCB05_A;

            Retain on COSPBT10_A; COSPCL12a_A;

            M&E List COSPUS03_E; COSPUS03_F;

            COSPUS03_H; COSPUS09_B;

            COUCUC06b_A; COUCYA04_A Retain on 4a List due to COGULG09_A; COSPMS04_A;

            approved COSPMS04_B; COSPUS15_B;

Dissolved Oxygen TMDL COSPUS15_C; COSPUS15_D Added to 303d List due to database correction COSJLP04c_D Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs 303d listing due to new 1 segmentation COSJLP04c_C COARUA10_A; COARUA35_A;

1. COGUSM02_D; CORGAL25_B;
   1. COSPCH02_A; COSPCH06_B;
      1. COSPCL17a_A; COSPCP20_B;
         1. Retain on COSPLS03_B; COSPUS03_B;

            303(d) List COSPUS17a_D; COSPUS17a_E;

            COSPUS23_B; COSPUS23_C;

            COSPUS23_D; COUCNP07b_A;

            COUCUC12_B; COARLA15_B;

            COGUSM20_B COGULD02_B; COGULD02_C;

            Delist from COGULD02_D; COGULD02_E;

E.coli M&E COGULD03a_B; COGUUG16a_A;

1. COSJPI06c_A Delist due to extent of impairment refined COSJPI06a_C; COSJPI06a_G Delist due to new 1 segmentation COSJDO11a_A New listing COARMA04c_A; COARMA04g_A;
   1. on M&E COARUA15_B; COGUUG26_B COARLA03a_A; COARLA07_A;
      1. COGULD04_B; COGULD05_B;
         1. COGULG04a_B; COGULG12_B;

            Retain on 34 COGUSM10b_B; COGUUG16a_B;

            M&E List COGUUG16b_A; COGUUG17a_A;

            COGUUG17b_A; COLCLC10_A;

            COLCLC10_B; COLCLC14b_A;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COLCLY22c_A; COLCWH16b_B;

1. COSJAF13a_B; COSJDO11b_A;
   1. COSJLP08_A; COSJLP08_B;
      1. COSJLP08_C; COSJLP08_D;
         1. COSJLP08_E; COSJPI06a_E;

            COSJSJ01b_B; COSJSJ03_A;

            COSJSJ10_A; COSPBO08_B;

            COSPBT05_A; COSPCL17b_A;

            COSPCP08_A; COSPRE05_A;

            COUCNP04a_B; COUCYA13b_B Delist due to COSPBD01_A; COSPBD01_B;

            approved 5 COSPUS15_B; COSPUS15_C;

            TMDL COSPUS15_D

E. coli Retain on 4a List due to approved TMDL COSPBO02b_B; COSPUS14_B New listing COARFO02b_A; COARFO06_C;

1. on 303(d) COARMA03_A; COGULG04c_A COARFO01a_B; COARFO02a_A;
   1. COARFO04_B; COARFO04_D;
      1. COARFO04_G; COARLA01a_A;
         1. COARLA09a_C; COARMA04a_A;

            COGULG02_A; COGULG02_B;

            COLCLC13b_C; CORGRG28_B;

            COSJLP07a_C; COSPBO07b_A;

            COSPBO07b_B; COSPBO10_A;

            Retain on 34 COSPCH03_A; COSPCH03_B;

            303(d) List COSPCH04a_B; COSPCL18a_A;

            COSPCP11_A; COSPCP13b_A;

            COSPLS02b_B; COSPMS01a_A;

            COSPMS01b_A; COSPSV03_B;

            COSPSV03_C; COSPSV03_D;

            COSPSV03_E; COSPSV06_B;

            COSPUS16a_A; COSPUS16i_A;

            COSPUS16i_B; COUCYA08_B;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COSPBE02_C, COSPBO09_A, COSPBO09_B, COSPBT09_A, Retain on 10 COSPCL15_A, COSPCP12_A, 303(d) List COSPCP13a_C, COSPUS10a_D, COSPUS16c_A, COARFO06_B E. coli (seasonal)

1. Retain on M&E List COGUNF04b_C; COLCLC04c_A Delist from 303(d) COARFO06_C COARUA38_B; COGUUG23_B;
   1. Delist from CORGAL02_B; CORGAL02_C;
      1. M&E CORGCB02a_C; CORGCB02b_B;
         1. CORGRG38_D New listing COARFO02a_A; COGUUG01_B;

            on M&E COGUUG01_C; COSJLP05_B Dissolved Iron COLCLC10_B; CORGAL20_A;

            CORGRG38_C; COSPBO02a_B;

            COSPBO14_B; COSPCL06_C;

            COSPCL12a_B; COSPCL14b_A;

            Retain on 17 COSPCP07_B; COSPCP07_C;

            M&E List COUCBL20_B; COUCNP03_A;

            COUCNP04a_B; COUCNP04a_F;

            COUCNP05b_A; COUCUC10c_A;

            COUCYA18_B COSJAF02_B; COSJAF03a_B;

            COSJAF03b_A; COSJAF04a_A;

            Retain on 4a COSJAF06_B; COSJAF07_A;

            List due to 13 COSJAF08_A; COSPCL13b_A;

            approved COSPCL13b_B; COSPSV04b_B;

            TMDL COSPUS02c_A; COSPUS02c_C;

            COSPUS02c_D New listing 3 COARFO02b_A; COGUNF06b_C;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs on 303(d) COSJDO04b_A Moved from M&E to 2 303(d) COGUUG15a_B; CORGRG02_B COARUA05_C; COGUUG29a_B;

1. COSPBO02a_F; COSPCL02c_B;
   1. Retain on 9 COUCEA05c_A; COUCNP04a_H;
      1. 303(d) List COUCUC10c_B; COUCUC10c_C;
         1. COUCUC12_D COARFO01a_B; COARMA11b_A;

            COGUUG01_B; COGUUN07_A;

            Delist from 10 COLCLC04e_A, CORGAL10_A;

            M&E COSJPI06a_C; COSJPI06a_E;

Total Recoverable COSJPI06a_G; COSJPI06c_A Iron Delist from COGUUN04c_A; CORGCB12a_C;

1. 303(d) COSJLP03c_A Delist due to extent of impairment refined CORGCB12a_B; CORGCB12a_E COARMA04b_B; COGULD03a_B;
   1. COGULD05_E; COGUSM12b_H;
      1. New listing 10 COGUUN11_H; CORGRG23a_C;
         1. on M&E COSJLP08_A; COSJLP08_B;

            COSJLP08_C; COSJLP08_E COARFO02a_A; COARFO05_A;

            COARLA09a_C; COARLA12_B;

            COGULD04_B; COGULG04a_F;

            Retain on COGUNF06a_C; COGUSM07_B;

            M&E List COGUUG15a_B; COLCLC10_B;

            COLCLC13a_B; COLCLC14b_A;

Total Recoverable COLCLC15a_A; COLCLC16_A;

Iron COLCLY03c_C; COLCLY22c_A;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COLCWH07_B; CORGAL02_B;

1. CORGAL02_C; CORGAL12_A;
   1. CORGAL20_A; CORGCB03_C;
      1. CORGRG03_A; COSJPI08_A;
         1. COSPCL06_C; COSPUS01b_B;

            COSPUS03_E; COSPUS03_F;

            COSPUS03_G; COSPUS07_B;

            COSPUS11a_A; COSPUS23_E;

            COUCNP04a_E; COUCRF03b_B COGUUN03a_A; COGUUN03b_A;

            Retain on 4a COGUUN03c_A; COGUUN03d_A;

            List due to 9 COGUUN03e_B; COGUUN03e_C;

            approved COGUUN03f_A; CORGAL08_A;

            TMDL COSJAF09_A COARFO02b_A; COARLA04a_A;

            COARLA04a_B; COARLA09b_A;

            COGULG02_A; COGULG02_B;

            COGULG04a_C; COGULG12_B;

            New listing 17 COGUNF04b_C; COGUSM12b_G;

            on 303(d)

            COGUUG19_B; COGUUG31_A;

            COGUUN04a_B; COSJSJ06b_B;

            COSJSJ09a_A; COGUSM12b_F;

            COGUSM12b_I Moved from M&E to 3 COGUNF06b_B; COGUNF06b_C;

            303(d) CORGCB02b_B COARLA09a_B; COARLA09b_B;

            COARMA10_A; COARMA14_A;

            Retain on COGULD02_B; COGULD02_C;

Total Recoverable 303(d) List COGULD02_D; COGULD02_E;

Iron COGULD05_B; COGULG07b_C;

1. COGULG15_B; COGUNF04b_B;
   1. COGUUG29a_B; COGUUN12_C;
      1. COGUUN12_D; COLCLC04a_B;
         1. COLCLC04a_D; COLCLC13b_A;

            COLCLC13b_B; COLCLC13b_C;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COLCLC13b_D; COLCLC14c_C;

1. COLCLY03c_B; COLCWH13c_A;
   1. COLCWH13c_B; CORGAL13_A;
      1. CORGCB12a_D; CORGCB19_A;
         1. CORGRG02_B; COSJLP07a_C;

            COSJLP07b_B; COSJLP08_D;

            COSPBD01_B; COSPBO02a_F;

            COSPCL02c_B; COSPUS03_D;

            COUCNP04a_H; COUCUC07a_B;

            COUCYA03_D; COUCYA13d_A;

            COUCYA13d_B Retain on the 41 303(d) list Retain on COARMA27_A; COSJSJ08_C;

            M&E List COSPBO18_A; COSPUS19_B Delist due to approved 1 TMDL COSJLP11_B Retain on 4a List due to approved TMDL CORGRG37_A; COSJDO04b_B Fish Tissue Mercury New listing on 303(d) COSJLP11_A COARLA15_B; COARMA26_B;

            COARUA40_A; COLCLC20_B;

            COSJLP11_C; COSJPN03_A;

            Retain on 14 COSJSJ08_B; COSPBT11_A;

            303(d) List COSPCP14_A; COSPUS17a_D;

            COSPUS17a_E; COUCNP09_B;

            COUCYA22_B; COUCYA23_A Retain on M&E List COSPUS03_F; COUCYA08_C Dissolved Mercury Retain on 1 COSPUS03_D Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs 303(d) List COARLA04a_B; COARMA06a_A;

            COARMA09_A; COARMA11b_A;

            COARMA18a_A; COARUA24_B;

            Delist from 14 COARUA38_B; CORGCB02a_B;

            M&E Dissolved Manganese CORGCB02a_C; CORGCB02b_B;

            CORGCB02c_A; CORGCB09a_B;

            CORGRG04c_A; CORGRG37_A Delist from 303(d) COARMA02_B; COGUUG11_D COARUA04b_A; COGULG04a_E;

            New listing 5 COSJAF04b_A; COSJDO04b_A;

            on M&E COSJSJ06b_B COARLA05b_B; COARLA09b_A;

            COARLA09b_B; COGUSM08_A;

            COGUUG17a_A; COGUUG17b_A;

            COGUUG29a_D; COGUUG29a_E;

            COLCLC02b_B; COLCLY03c_B;

            COLCLY06_A; COLCWH09b_A;

Dissolved Manganese COLCWH13b_B; CORGAL02_B;

1. CORGAL02_C; CORGAL20_A;
   1. CORGCB04_A; CORGCB12a_C;
      1. CORGRG05_B; CORGRG38_C;
         1. Retain on COSPBO02a_D; COSPBO14_B;

            M&E List COSPBT07_A; COSPCH01_A;

            COSPCL03b_A; COSPCL09b_A;

            COSPCL12a_A; COSPCL12a_B;

            COSPCL14b_A; COSPCL16a_A;

            COSPLA02a_A; COSPMS01a_A;

            COSPSV04a_B; COUCBL12_B;

            COUCBL12_C; COUCNP04a_B;

            COUCNP04a_E; COUCNP04b_B;

            COUCNP05b_A; COUCUC07a_B;

            COUCYA02a_A; COUCYA03_D;

            COUCYA04_A Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COSJLP04a_E; COSJLP04c_D;

            Retain on 4a COSJLP04c_E; COSPCL13b_A;

            List due to COSPCL13b_B; COSPSV04b_B;

            approved COSPUS02c_A; COSPUS02c_C;

            TMDL COSPUS02c_D; COSPUS05a_A;

            COUCBL07_A COARFO06_B; COARFO06_C;

            COARLA01a_A; COARLA09a_A;

            COGULG02_A; COGULG02_B;

Dissolved Manganese COGULG12_B; COGUNF03_B;

1. COGUNF03_C; COGUNF06b_C;
   1. COGUUG02_D; COGUUG12_C;
      1. New listing 25 COGUUG19_B; COGUUG31_A;
         1. on 303(d)

            COGUUN03a_A; COGUUN03b_A;

            COGUUN03c_A; COGUUN04b_A;

            COGUUN05_C; COGUUN05_E;

            CORGRG04b_C; CORGRG04b_D;

            COSJAF03a_A; COSJAF03a_B;

            COSJAF04a_A;

            COARLA02a_A; COARLA09a_B;

            Moved from COARUA05_B; COGUNF06b_B;

            M&E to 8 COGUSM06a_A; COGUUG15a_B;

            303(d)

            CORGRG02_B; CORGRG38_D COARFO01a_B; COARLA01b_A;

            COARLA01c_A; COARMA06b_A;

            COARUA05_C; COGULG04a_D;

            COGUUG29a_B; COGUUG29a_C;

            COGUUG32_A; COGUUN02_A;

            COLCLC14c_B; COLCLC14c_C;

            Retain on 32 COSJAF05a_B; COSJAF05a_C;

            303(d) List COSPCL02c_B; COSPCP07_B;

            COSPCP07_C; COSPCP13a_B;

            COSPLS01_A; COSPMS01b_A;

            COSPSV05_B; COSPSV06_A;

            COSPSV06_B; COSPUS03_B;

            COSPUS05b_B; COUCBL02a_A;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COUCBL02a_B; COUCBL06a_B;

1. COUCBL06a_C; COUCNP04a_H;
   1. COUCUC07b_C; COUCUC12_D Delist from M&E CORGAL03c_A Retain on M&E List COSPCL14b_A; COSPUS23_F Retain on 4a Ammonia List due to COSPBO09_A; COSPBO09_B;
      1. approved COSPBO10_A; COSPSV03_B;
         1. TMDL COSPSV03_E; COUCUC06c_A Retain on 4b List due to 4b 3 COSPUS15_B; COSPUS15_C;

            Plan COSPUS15_D New listing on 303(d) COARMA04c_A CORGCB19_A; COSPCL15_A;

            COSPMS04_B; COSPMS07_B;

            Retain on 9 COSPMS07_C; COSPUS05c_B;

            303(d) List COSPUS17a_B; COSPUS17a_F;

            COSPUS17a_G New listing on M&E CORGAL07_A Dissolved Nickel Retain on 303(d) List COSPCL02c_B; COSPCL12a_B Delist from M&E COARMA04a_A Nitrite Retain on 1 COLCLC02b_B Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs M&E List New listing on M&E COGULD03a_B Retain on 4a List due to approved TMDL COSPUS14_B Retain on 4b List due to 4b 4 COSPMS01a_A; COSPUS15_B;

            Plan COSPUS15_C; COSPUS15_D Dissolved Lead COGULG07b_D; COGUSM02_B;

            COGUSM02_C; COGUSM03b_A;

            COGUSM04a_B; COGUUG04_B;

            Delist from 13 COGUUN04c_A; COGUUN09_C;

            M&E COSJSJ05_D; COSJSJ05_E;

            COSJSJ06a_C; COSJSJ06a_D;

            COSJSJ09a_A Delist from 303(d) COGUUG11_B Delist due to approved 2 TMDL COARUA05_D; COARUA08b_A COARUA05_B; COGUSM06b_A;

            New listing COGUUN05_B; COGUUN05_D;

            on M&E CORGRG04b_B; CORGRG04b_C;

            CORGRG04b_D; CORGRG06_B Added to M&E due to database correction COSJLP04c_D Dissolved Lead M&E listing 2 COSJLP04c_C; COSJSJ06b_C Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs due to new segmentation COARUA05_C; COGUNF04b_B;

            COGUUN02_A; COGUUN19_A;

            Retain on 10 COLCLC04b_A; COLCLC13a_B;

            M&E List CORGRG05_B; CORGRG07_A;

            CORGRG07_B; COSJAF03c_A COARUA01b_A; COARUA12a_A;

            CORGCB09a_A; CORGCB09a_B;

            COSJAF02_B; COSJAF03a_B;

            Retain on 4a COSJAF03b_A; COSJAF06_B;

            List due to COSJAF07_A; COSJAF08_A;

            approved COSPCL02a_A; COSPCL02b_B;

            TMDL COSPCL02c_C; COSPCL03b_A;

            COSPCL09b_A; COSPCL11_A;

            COSPSV04b_B; COSPUS02b_A;

            COUCBL06a_B; COUCBL07_A COGUUG07_B; COGUUN05_C;

            New listing 6 COGUUN05_E; COGUUN07_A;

            on 303(d)

            COGUUN09_B; CORGRG04c_A COGUUG10a_A; COGUUG10b_A;

            CORGRG04a_A; COSPBO02a_C;

            Retain on 10 COSPBT16_B; COSPCL09a_B;

            303(d) List COSPCL12a_B; COSPCP07_B;

            COSPCP07_C; COSPRE01_A New listing Total Lead 2 on M&E COARFO01a_B; COARFO02a_A Delist from CORGAL02_B; CORGAL02_C;

            M&E COSJPI05a_B; COSJSJ08_B pH Delist from 303(d) COGUNF09_B New listing 2 COGUUG31_A; CORGAL07_A Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs on M&E COGULG04a_E; COGUSM07_C;

            COGUUG10b_A; CORGAL13_A;

            CORGAL25_B; CORGAL30_A;

            Retain on 14 CORGRG05_B; CORGRG38_B;

            M&E List COSPCL12a_B; COSPCP09_A;

            COSPCP12_A; COSPLA02a_A;

            COSPUS01a_B; COSPUS11a_A COARUA11_A; COARUA12a_A;

            CORGAL03a_A; CORGAL03b_A;

            CORGAL03b_B; CORGAL03c_A;

pH Retain on 4a CORGAL03d_A; CORGAL05_A;

1. List due to 18 COSJAF04a_A; COSJAF09_A;
   1. approved COSPBO04a_B; COSPMS04_A;
      1. TMDL COSPMS04_B; COSPSV04a_A;
         1. COSPSV04a_B; COSPSV04b_B;

            COUCBL06a_B; COUCBL07_A New listing on 303(d) COGUUN02_A; COGUUN03a_A Moved from M&E to 3 COGULG15_B; COGUUN07_A;

            303(d) COSJPI08_A COARUA10_A; COGUSM02_D;

            COGUUG29a_B; COLCWH11_B;

            CORGAL20_A; COSPBO10_A;

            COSPBT02_B; COSPCL09b_A;

            COSPLS03_D; COSPMS07_B;

            Retain on COSPMS07_C; COSPSV05_B;

            303(d) List COSPUS03_B; COSPUS04_C;

            COSPUS04_E; COSPUS05b_B;

            COSPUS17a_B; COSPUS17a_C;

            COSPUS17a_E; COSPUS17a_F;

            COSPUS23_F; COSPUS23_G;

            COUCNP09_D Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COGULG07a_A; COGUSM12a_F;

            Delist from 5 COGUUN11_H; COGUUN11_J;

            M&E CORGAL03b_B Dissolved Selenium Delist from 303(d) COGULG16_C Delist due to new 1 segmentation COLCLC19_C New listing COARLA09a_C; COARUA20b_A;

            on M&E COGUUN04a_B Moved from 303(d) to 1 M&E COARFO04_B COARFO04_G; COGULD03a_B;

            COGULG16_B; COGULG16_D;

            COGUNF04b_B;

            COGUNF06a_B;COGUUN10a_B;

            Retain on COLCLC03_A; COLCLC04e_A;

            M&E List COLCLC13a_B; COLCLY03c_B;

            COLCLY03e_A; COSPLS03_C;

            COSPRE05_A; COSPUS01b_C;

            COSPUS07_B; COUCEA10a_B;

            COUCYA13j_A Delist due to approved 1 TMDL COARMA18a_A COGULG01_C; COGULG02_A;

            Retain on 4a COGULG02_B; COGULG04a_B;

            List due to COGULG04a_B; COGULG04a_C;

Dissolved Selenium approved COGULG04a_C; COGULG04a_D;

1. TMDL COGULG04a_D; COGULG04a_E;
   1. COGULG04a_E; COGULG04a_F;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COGULG04a_I; COGULG04a_I;

1. COGULG04b_B; COGULG04b_B;
   1. COGULG04c_A; COGULG04c_A;
      1. COGUNF03_C; COGUNF05a_C;
         1. COGUNF05b_B; COGUNF06b_B;

            COGUNF06b_D; COGUNF06b_E;

            COGUNF06b_F; COGUUN04b_A;

            COGUUN04c_A; COGUUN12_C;

            COGUUN12_D; COGUUN12_E;

            COGUUN12_F COARFO04_E; COARMA02_A;

            New listing 5 COARMA02_B; COARMA09_A;

            on 303(d)

            COGUNF06b_A COARLA01b_A; COARLA01c_A;

            COARLA04a_A; COARLA04a_B;

            COARLA09a_A; COARLA09a_B;

            COARLA09b_A; COARLA09b_B;

            COARLA10_B; COARLA10_C;

            COARLA11_A; COARLA12_A;

            COARLA12_B; COARMA03_A;

            Retain on 51 Dissolved Selenium COARMA10_A; COARMA12_A;

            303(d) List COGULG07b_C; COGUUG29a_B;

            COGUUN20_A; COLCLC02b_B;

            COLCLC04a_A; COLCLC04a_B;

            COLCLC04a_C; COLCLC04a_D;

            COLCLC13b_A; COLCLC13b_B;

            COLCLC13b_C; COLCLC13b_D;

            COLCLC14c_B; COLCLC19_B;

            COLCLY03c_C; COLCWH09d_A;

            COSJLP08_B; COSPBO07b_B;

            COSPBO08_B; COSPBT04b_A;

            COSPBT05_A; COSPBT09_A;

            COSPCH04a_B; COSPCH04b_B;

            COSPCL12a_B; COSPCP13b_A;

            Retain on COSPLS01_A; COSPLS02b_B;

            303(d) List 51 COSPLS03_B; COSPSV06_B;

            COSPUS16a_A; COSPUS16c_A;

            COUCUC07a_B; COUCYA13e_B;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COUCYA13h_A Delist from COSJPI06c_A; COUCEA09a_A;

1. M&E COUCEA09b_B; COUCEA09b_C Sediment Delist from 303(d) COUCEA09a_B Delist due to extent of impairment COSJPI06a_C; COSJPI06a_G;
   1. refined COUCEA06_H Delist due to approved 1 COUCBL18_B TMDL Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COARLA07_A; COGULG02_A;
      1. COGULG02_B; COGULG11b_B;
         1. COGUUN04a_B; COGUUN04a_C;

            COGUUN04b_A; COGUUN04c_A;

            Retain on COGUUN15b_A; COLCLC01_A;

            M&E List COLCLC01_B; COLCLC02a_A;

            COLCLC02b_A; COLCLC02b_B;

            COLCLY16_A; CORGRG13_A;

            COSJPI06a_E; COUCYA13b_A;

            COUCYA13b_B Sediment Retain on 4a List due to COGUSM03b_A; COSJLP04a_D;

            approved COSPCP07_C; COSPUS01a_A;

            TMDL COSPUS01a_C; COSPUS01a_E New listing on 303(d) CORGRG09_C COLCLC13b_B; COLCWH13b_A;

            COLCWH13b_B; COLCWH13b_C;

            COLCWH13b_D; COLCWH22_B;

            Retain on COLCWH23_B; CORGCB12a_B;

            303(d) List 13 COSPCL14b_A; COSPCL15_A;

            COUCEA06_G; COUCNP04a_I;

            COUCYA03_B COARMA06a_A; COARMA06b_A;

            COGULG04a_B; COGULG04b_B;

            Delist from 10 COGUUN10a_C; COGUUN11_E;

            M&E COSJPI06a_C; COSJPI06a_E;

            COSJPI06a_G; COSJPI06c_A Delist from Sulfate 1 303(d) COGUNF05b_B COARFO04_E; COGULD03a_B;

            New listing 5 COGULG12_B; COGUUN04a_B;

            on M&E COSJLP05_B Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COARLA09a_B; COARLA09b_A;

            COARLA09b_B; COGULG04a_F;

            COLCLC02b_B; COLCLC04a_A;

            COLCLC04a_B; COLCLC04a_C;

            Retain on 17 COLCLC04a_D; COLCLC10_B;

            M&E List COLCLY03e_A; COLCLY06_A;

            COLCWH09b_A; COLCWH13b_C;

            COSPCL06_C; COSPCL12a_B;

            COSPLS01_A COARLA01a_A; COGULG02_A;

            New listing COGULG02_B; COGULG07b_C;

            on 303(d) COSJLP08_A; COSJLP08_B;

            COSJLP08_C; COSJLP08_E Moved from M&E to 4 COARLA02a_A; COARMA18a_A;

            303(d) COGULG04a_C; COGUNF06b_B COARLA04a_A; COARLA04a_B;

            COGULG04a_D; COGUNF06b_C;

            Retain on 9 COLCLY03c_B; COLCLY03c_C;

            303(d) List COSPBT08_B; COSPCP13a_B;

            COUCUC07a_B COARMA07b_A; COGULG08a_A;

            COGULG08b_A; COGUSM12b_C;

            COGUSM12b_D; COGUSM12b_F;

            Delist from COGUSM12c_A; CORGCB12a_C;

            M&E COSJLP04c_C; COSJLP04c_D;

            COSJPI05a_A; COSJPI05a_B;

            COSJPI05b_A; COSJSJ06a_C;

            COSJSJ06b_B; COSJSJ06b_C COGULD02_D; COGULD02_E;

            Delist from 5 COGUSM10b_B; COGUSM12b_G 303(d)

            COGUSM12b_H Delist due to 2 CORGCB12a_B; CORGCB12a_E Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs extent of Temperature impairment refined Moved from 303(d) to 2 M&E COGULD02_B; COGULD02_C;

            COARFO02a_A; COARLA01a_A;

            COARLA01c_A; COARLA09b_A;

            COARLA09b_B; COARUA14c_B;

            New listing COARUA15_B; COGUNF04b_C;

            on M&E COGUSM03b_A; COGUSM14_B;

            COGUUG02_D; COGUUG09_C;

            COGUUG23_A; COGUUG23_B;

            COGUUN11_G COARLA05b_A; COARLA05b_B;

            COARLA06a_C; COARLA06a_D;

            COARLA06b_A; COARUA04a_A;

            COLCLC04a_A; COLCLC04a_B;

            COLCLC04a_C; COLCLC04a_D;

            CORGAL11b_A; CORGCB12a_D;

            Retain on COSJSJ10_A; COSPBE06a_B;

            M&E List COSPBE06b_A; COSPBT08_A;

            COSPBT08_B; COSPCL14b_A;

            COSPCL17b_A; COSPUS02a_B;

            COSPUS03_B; COSPUS10a_D;

            COSPUS15_B; COSPUS15_C;

Temperature COSPUS15_D; COSPUS16g_A;

1. COUCYA13e_A COARFO02b_A; COARLA01b_A;
   1. New listing COARMA26_C; COGUNF03_B;
      1. on 303(d) COGUNF03_C; COGUUG18b_A;
         1. COGUUN03e_B; COGUUN03e_C Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COARFO06_B; COARFO06_C;

            COARLA03a_A; COARMA02_A;

            COARMA02_B; COGUUG08_A;

            COLCLC01_A; COLCLC01_B;

            COLCWH07_A; COLCWH07_B;

            COLCWH13c_B; COLCWH15_C;

            COLCWH23_A; COLCWH23_B;

            COLCWH23_C; CORGRG04b_B;

            CORGRG04b_C; CORGRG04b_D;

            COSPBE01a_B; COSPBE01b_A;

            COSPBE01e_A; COSPBE01e_B;

            Retain on 45 COSPBE03_B; COSPBT02_D;

            303(d) List COSPCL11_A; COSPCL13b_B;

            COSPCL14a_A; COSPCL14a_B;

            COSPCL15_A; COSPCP10a_A;

            COSPSV02b_A; COSPSV02b_B;

            COSPUS03_H; COUCBL17_B;

            COUCRF03c_A; COUCUC02_B;

            COUCUC02_C; COUCUC03_C;

            COUCUC03_D; COUCUC03_E;

            COUCUC07a_C; COUCUC07b_B;

            COUCUC07b_C; COUCUC10a_B;

            COUCYA02b_A CORGCB02a_C; CORGCB02b_B;

            Delist from CORGCB12a_C; CORGRG11_A;

Total Phosphorus M&E CORGRG19_A; CORGRG20a_B;

1. CORGRG20a_C; CORGRG20b_A Delist due to extent of impairment refined CORGCB12a_B; CORGCB12a_E New listing on M&E COARUA14d_B Retain on COLCLC04a_A; COLCLC04a_B;
   1. M&E List COLCLC04a_C; COLCLC04a_D;

Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs CORGCB02a_B; CORGCB02c_A;

1. CORGCB12a_D Moved from M&E to 1 303(d) COARUA35_A Retain on 303(d) List COSPBE01c_A New listing on M&E COARLA09a_B Retain on M&E List COARFO01a_B Total Uranium Delist due to approved 1 TMDL COARMA18a_A Retain on 303(d) List COARLA01c_A; COSPLS01_A Retain on 4a List due to Zinc (sculpin) 1 approved TMDL COGUUN06a_A Delist from M&E COSJPI08_A Delist from COARMA18a_A; COGULG15_B;
   1. 303(d) COGUNF09_B; COGUSM02_B Dissolved Zinc Delist due to approved 1 TMDL COARUA02c_A New listing CORGRG06_B; COSJAF03a_A;
      1. on M&E COSJAF03a_B Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COGUNF07_B; COGUUG29a_C;
         1. COGUUG29a_D; COGUUG29a_E;

            COGUUN19_A; COLCLY07_A;

            Retain on CORGAL20_A; CORGCB12a_C;

            M&E List CORGRG05_B; CORGRG07_A;

            CORGRG07_B; COSJAF22_B;

            COSPCL06_C; COUCBL04a_C;

            COUCYA08_C COARUA01b_A; COARUA02a_A;

            COARUA02b_A; COARUA03_A;

            COARUA04a_A; COARUA04b_A;

            COARUA07_A; COARUA08b_A;

            COARUA11_A; COARUA12a_A;

            COGUSM03a_A; COGUSM03b_A;

            COGUSM06a_A; COGUSM06b_A;

            COGUUG30_B; COGUUG31_A;

            COGUUN02_A; CORGAL03a_A;

            CORGAL03b_A; CORGAL03b_B;

            CORGAL03c_A; CORGAL03d_A;

            CORGCB09b_A; CORGCB09b_B;

            CORGRG04a_A; CORGRG04b_B;

            Retain on 4a CORGRG04b_C; CORGRG04b_D;

            List due to 58 COSJAF04a_A; COSJAF04b_A;

            approved COSJAF05a_B; COSJAF09_A;

            TMDL COSJDO09_A; COSPBO04a_B;

            COSPCL02a_A; COSPCL02c_C;

            COSPCL03a_A; COSPCL03a_B;

            COSPCL03a_C; COSPCL03b_A;

            COSPCL09b_A; COSPCL11_A;

            COSPCL13b_A; COSPCL13b_B;

            COSPSV04a_A; COSPSV04a_B;

Dissolved Zinc COSPSV04b_B; COSPUS02b_A;

1. COSPUS02c_C; COSPUS02c_D;
   1. COSPUS05a_A; COSPUS05b_A;
      1. COSPUS05b_B; COUCBL07_A;
         1. COUCEA05a_A; COUCEA05b_A;

            COUCEA05c_A; COUCEA07b_A Table 4. Summary of Water Bodies Added, Removed and Retained on the 303(d) and M&E Lists by Analyte # of Parameter Action Portion s Assessment Unit IDs COARFO01b_A; COARUA05_A;

            COGUNF04c_A; COGUUN03a_A;

            New listing 10 COGUUN05_B; COGUUN05_C;

            on 303(d)

            COGUUN05_E; COGUUN07_A;

            COGUUN09_C; CORGRG04c_A Moved from M&E to 1 303(d) COGUUN08_A COARUA05_B; COARUA05_C;

            COGUUG07_B; COGUUG08_A;

            COGUUG10a_A; COGUUG10b_A;

            COGUUG11_B; COGUUG11_D;

            COGUUG12_C; COGUUG29a_B;

            COGUUN09_B; COGUUN09_D;

            Retain on CORGRG09_B; COSJAF03c_A;

            303(d) List COSPCL02b_B; COSPCL02b_C;

            COSPCL02c_B; COSPCL12a_A;

            COSPCL12a_B; COSPUS02c_A;

            COUCBL02a_B; COUCBL04a_B;

            COUCBL06a_B; COUCBL06a_C;

            COUCBL12_B; COUCBL12_C;

            COUCYA03_E

11. Site-specific decisions made by the commission are discussed below.

a) COUCEA09a_B – Sediment Eagle River Water and Sanitation District proposed that a portion of the Eagle River from Berry Creek to Squaw Creek be removed from the 303(d) List for a few reasons. In this portion, the gradient of the Eagle River flattens and as flow velocities decrease the river channel and floodplain broaden. Under the Sediment Policy 98-1, Sediment Region 3 for mid-elevation mountain streams include slopes that range from 0.4% to 10%, with percent fines that range from 9% to 41%. The questionable area for this portion has a slope of 0.12 %, which is below the range of slopes used to establish the expected condition of Sediment Region 3. The portion of Segment 9a above the deposition zone (Segment 9a from Gore Creek to Berry Creek), and Segment 9b downstream of the deposition zone (Squaw Creek to Rube Creek), have stream slopes within the slope ranges for Sediment Region 3 and attain the TIVSED and percent fines for Sediment Region 3. Therefore the increased sediment is limited to the low gradient depositional zone. The division recommended not to use the thresholds in Sediment Region 3 for the lower slope depositional zone and therefore based on data upstream and downstream that show attainment, the commission decided to remove segment COUCEA09a_B from the 303(d) List as impaired for sediment.

1. b) COGULD02 – Temperature The division proposed that the Dolores River from Big Gypsum Creek to the San Miguel River (COGULD02) be placed on the 303(d) List due to exceedances in the aquatic life use based temperature standards. The Dolores Water Conservancy District (DWCD) raised an issue regarding whether the cause of the temperature impairment had been considered and whether the waterbody should be placed into Category 4c instead of the 303(d) List. When reviewing the topic of Category 4c in the 2018 Listing Methodology, some inconsistent language was noticed between Regulation #93 and the 2018 Listing Methodology. The introduction in Regulation #93 states that “Water bodies that are impaired, but it is unclear whether the cause of impairment is attributable to pollutants as opposed to pollution, are also placed on the Monitoring and Evaluation List.” The 2018 303(d) Listing Methodology states that “Before placing impaired waterbody segments into Category 4c, thorough monitoring and assessment needs to be performed on the segment to confirm that no pollutants are contributing to the waterbody’s failure to meet water quality standards. If adequate monitoring and assessment is not performed to rule out pollutant(s) as a cause, then the impaired waterbody should be placed on the 303(d) List (Category 5)”.
   1. The most recent policy decisions that relate to impairment decisions for temperature are reflected in the Listing Methodology and not Regulation #93. However, the division recognizes that where there is a conflict between the regulation and the listing methodology, the language in the regulation would prevail and must be followed. Therefore the commission placed segment COGULD02 on the M&E List for temperature until 2020 when the language in the regulation can be changed to better reflect recent policy decisions. The inconsistency was not noticed until after the submittal of the responsive prehearing statement by DWCD and therefore the division could not propose a change to the regulation as it would be outside of the scope of this rulemaking hearing.

c) COSJAF09 – Fe, Mn, SO4 Water Supply Standards The commission adopted an alternative methodology for assessing ambient based water quality standards in the 2016 Listing Methodology (Appendix B). This assessment methodology incorporates confidence intervals into the assessment of ambient standards. The confidence interval is a more statistically sound approach in determining impairments in situations when an impairment is slightly above the standard because it takes into account the “normal variability in the available concentration of the data” (Appendix B, 2018 LM).

1. For segment COSJAF09 (Mineral Creek), the 85th percentiles of dissolved manganese and dissolved iron were exceeding the standard, that was based on the ambient conditions of the stream from the year 2000. The Animas River Stakeholder Group proposed to re-assess both dissolved manganese and iron using the ambient-based approach to determine the level of confidence that the parameters were exceeding the standards. Based on the information provided by the Animas River Stakeholders Group, using the confidence interval approach, both dissolved manganese and iron are attaining standards. The commission concluded that dissolved iron, dissolved manganese and sulfate water supply standards based on 2000 conditions are in essence, ambient standards and should be assessed as such. The commission did not include Mineral Creek on the 303(d) list for manganese and iron.

d) Multiple segments in Fountain Creek - Storm Events The second paragraph in § III.B.7 of the 2018 Listing Methodology states that data collected during or immediately after temporary events influencing the waterbody that are not representative of normal conditions shall typically be discounted in making the listing decision. For example, scouring storm flows which lead to diminished aquatic life use or accidental spills of toxic chemicals would not be a basis upon which to list the affected segment. However, such events may be considered as a basis for listing in instances where nonattainment of standards arises from a reversible source of pollutants.

1. The commission maintains that storms are a normal part of the hydrologic cycle. If samples collected during a storm event are obtained using established procedures and analyzed using standard methods, those results are representative of conditions within the stream at that time. The commission acknowledges that changes in the volume of stream flow, such as those caused by precipitation events, can affect water quality indicators. However, assessment procedures are in place to deal with the variation, including those values that might be perceived as outliers within the data set. These procedures include bias removal, the averaging of daily and weekly samples, the use of percentiles to determine ambient concentrations for total and dissolved constituents, and the calculation of the geometric mean for the observed E. coli concentrations. In the latter case, the geometric mean is a statistical description of the central tendency of a set of results and serves to mute the effect of outliers. The commission concluded that not all high flow events can be automatically considered to be either a substantial storm or scouring event. If such instances are known to exist, then the associated data would be removed. However, a blanket removal of such data should not be expected.

e) All tributary segments The commission requested that in the next listing methodology work group, that the division further explore the listing of “all tributary” segments, particularly for E.coli, and also consider what happens to “all tributary” segments that are on the 303(d) list when they are resegmented. PARTIES TO THE RULEMAKING 1. Colorado Parks and Wildlife 2. Colorado Stone, Sand & Gravel Association 3. Eagle River Water and Sanitation District 4. U.S. Environmental Protection Agency 5. Dolores Water Conservancy District 6. Montezuma Valley Irrigation Company 7. Southwestern Water Conservation District 8. Arkansas Fountain Coalition for Urban River Evaluation 9. City of Black Hawk and Black Hawk Central City Sanitation District 10. Animas River Stakeholders Group 11. Cripple Creek and Victor Gold Mining Company 12. City of Fort Collins 13. Public Service Company of Colorado 14. Tri-Lakes Wastewater Treatment Facility 15. Tri-State Generation and Transmission Association, Inc.

16. Colorado Springs Utilities 17. Ouray Silver Mines, Inc.

93.18 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND

PURPOSE; DECEMBER 2019 RULEMAKING, EFFECTIVE DATE OF MARCH 1, 2020.

The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; provide the specific statutory authority for adoption of these regulatory amendments. The commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.

BASIS AND PURPOSE A. Revisions to 303(d) List 1. Introduction This regulation updates Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (TMDLs) to reflect additional water quality information available since the regulation was promulgated in 2006. This list was prepared to fulfill section 303(d) of the federal Clean Water Act (Act) which requires that states submit to the U.S. Environmental Protection Agency (EPA) a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.

This regulation also updates Colorado’s Monitoring and Evaluation List (M&E List) to reflect additional water quality information available since the regulation was promulgated in 2012.

2. List Development a. Listing Methodology The “Section 303(d) Listing Methodology - 2020 Listing Cycle” contains a description of the listing process, the criteria for listing, and the criteria for determination of TMDL priority. The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission (commission) administrative action hearing in March 2019. This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2020 Section 303(d) List and the 2020 M&E List. However, this methodology was not adopted by the commission as a rule. The commission, therefore, has the flexibility to take into account other appropriate factors in making site-specific listing decisions.

b. Information Considered The commission has considered all existing and readily available information in developing the 2020 Section 303(d) List. In determining whether data and information are existing and readily available, it has taken into account such data and information as the division has utilized in the preparation of those identification processes, calculations and models referenced in 40 CFR §130.7(b)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and submitted in reports provided to the Water Quality Control Division (division) as referenced in 40 CFR §130.7(ab)(5)(iii). In addition, the commission accepted credible data and information that was submitted in accordance with the listing process schedule, whether submitted by EPA or any other interested party. The division also continues to independently collect and analyze new data on a rotating basin basis as part of its triennial review efforts and will utilize such data and information in making future listing determinations. Existing data which was not brought forward through one of the above mechanisms or otherwise presented to the commission in accordance with the schedule was not treated as "readily available" for purposes of making the 2020 listing decisions. Such information will be considered in the next listing cycle.

c. Data Quality In the division's “Quality Management Plan 2016 for Surface Water Monitoring and Assessment", the division states that "It is the expressed goal of the division to use only those analytical data that are both reliable and have a defined level of quality."

3. Prioritization The objective of prioritization is to identify those segments where the division and the public should concentrate their resources. Priorities of High, Medium, and Low were established according to section IV. of the 2020 Section 303(d) Listing Methodology. The division remains committed to establishing a plan for monitoring and evaluating water bodies on the M&E List prior to the list submission date for the subsequent listing cycle. Further, the commission has committed to determining their appropriate status (as either impaired or fully supporting) within ten years of their placement on the M&E List.

4. Regulation #93 Introductory Language Regarding Pollution and Pollutants During the 2018 303(d) listing cycle, the division identified inconsistent language between Regulation #93 and the 2018 Listing Methodology. The introduction in Regulation #93.2(2) states:

“Water bodies that are impaired, but it is unclear whether the cause of impairment is attributable to pollutants as opposed to pollution, are also placed on the Monitoring and Evaluation List.”

The 2018 303(d) Listing Methodology section II.f stated: “Before placing impaired waterbody segments into Category 4c, thorough monitoring and assessment needs to be performed on the segment to confirm that no pollutants are contributing to the waterbody’s failure to meet water quality standards. If adequate monitoring and assessment is not performed to rule out pollutant(s) as a cause, then the impaired waterbody should be placed on the 303(d) List (Category 5)”.

In the 2018 rulemaking hearing for Regulation #93, the commission’s approach to a temperature listing was to defer to the regulation language even though it was in conflict with the language in the listing methodology. Based on this approach, the commission moved the existing Lower Dolores segment 02 temperature 303(d) listing to the M&E List because the cause of the impairment had not been determined. The commission then directed the division to propose changes to the regulatory language during the 2020 Regulation #93 rulemaking hearing process to better reflect the current commission policy decision and provide consistency between the regulatory language and the 303(d) Listing Methodology.

In 2018, the EPA partially approved the 2018 303(d) List. The EPA cited the change from the 303(d) List to the M&E List for segment COGULD02 as a reason for this partial approval, instead of full approval. The 2020 Listing Methodology workgroup considered this topic. The division proposed to remove language in Regulation #93.2(2): “Colorado’s Monitoring and Evaluation List identifies water bodies where there is reason to suspect water quality problems, but there is also uncertainty regarding one or more factors, such as the representative nature of the data. Water bodies that are impaired, but it is unclear whether the cause of impairment is attributable to pollutants as opposed to pollution, are also placed on the Monitoring and Evaluation List. This Monitoring and Evaluation list is a state-only document that is not subject to EPA approval. These segments are included in Section 93.3 with parameters included in the Colorado’s Monitoring and Evaluation column.” When the removal of this language was discussed in the 2020 Listing Methodology workgroup, there was no opposition to this proposal. The division proposed this change to Regulation #93 during the 2020 Rulemaking Hearing process and the commission adopted this language modification to align Regulation #93 with the most recent policy decisions, as reflected in the Listing Methodology.

5. Temperature Assessments The 2020 303(d) Listing Methodology requires that the party proposing a temperature listing is responsible for investigating the temperature excursions defined in Regulation #31, Table 1, Footnote 5c. This footnote includes three allowable excursions to exceedances of the temperature standard. These include an air temperature excursion, a low flow excursion, and a winter shoulder season excursion. These excursions require a significant investment in resources to assess. Due to resource limitations, the division deprioritized temperature assessments and no excursions were investigated. Therefore, the commission carried existing temperature 303(d) and M&E listings forward to the 2020 303(d) List. Segment COGULD02 is an exception. This segment was reassessed to address EPAs concerns cited in their partial approval of the 2018 303(d) List.

6. Assessment Values Used for Secondary Water Supply Standards For the secondary water supply standards of dissolved iron, dissolved manganese and sulfate, the less restrictive of the following two options apply as the numeric standard: existing quality as of January 1, 2000, or the table value criteria in Regulation #31, Tables II and III. For dissolved iron, the table value standard (TVS) is 300 ug/l. For dissolved manganese, the TVS is 50 ug/l. For sulfate, TVS is 250 mg/l. For the 2016 303(d) Listing Methodology, the commission included additional language regarding the determination of existing quality from the year 2000 (EQ 2000). This includes a minimum data requirement and the ability to use data collected after the year 2000 when characterizing existing quality from 2000. The utilization of data collected past the year 2000 is contingent upon there being no known new or increased sources of these parameters in the segment being assessed since 2000. Table 1 summarizes the secondary water supply assessment values used for dissolved iron, manganese, and sulfate for 303(d) or M&E Listing actions: Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

1. Sampl POR Listin e Size Categor for Analyt g TVS or of Portion ID y 2000 Value Units e Actio 20001 2000 / List Datas n Datas et et COLCLC02b_ Retai Mn-D M&E 2000 95-99 34 87.16 ug/L B n COLCLC02b_ Retai 1109.
   1. SO4 M&E 2000 95-99 82 mg/L B n 5 COLCLC04a_ Retai SO4 M&E TVS N/A N/A 250 mg/L A n M&E COLCLC04a_ to SO4 303(d) TVS N/A N/A 250 mg/L B 303(d )

COLCLC04a_ Retai SO4 M&E TVS N/A N/A 250 mg/L C n COLCLC04a_ Retai SO4 M&E TVS N/A N/A 250 mg/L D n Attainin M&E COLCLC10_B Fe-D TVS N/A N/A 300 ug/L g Delist Attainin M&E COLCLC10_B SO4 2000 95-04 25 590 mg/L g Delist COLCLC14c_ Retai Mn-D 303(d) 2000 95-99 59 52.6 ug/L B n COLCLC14c_ Retai Mn-D 303(d) 2000 95-99 59 52.6 ug/L C n COLCLY03c_ Retai Mn-D M&E TVS N/A N/A 50 ug/L B n COLCLY03c_ Retai SO4 303(d) 2000 95-99 13 406 mg/L B n Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

1. Sampl POR Listin e Size Categor for Analyt g TVS or of Portion ID y 2000 Value Units e Actio 20001 2000 / List Datas n Datas et et COLCLY03c_ Retai SO4 303(d) 2000 95-99 13 406 mg/L C n COLCLY03e_ Retai SO4 M&E 2000 95-99 17 720 mg/L A n Retai COLCLY06_A Mn-D M&E TVS N/A N/A 50 ug/L n Retai COLCLY06_A SO4 M&E TVS N/A N/A 250 mg/L n COLCWH09b_ Retai Mn-D M&E TVS N/A N/A 50 ug/L A n COLCWH09b_ Retai SO4 M&E TVS N/A N/A 250 mg/L A n COLCWH13b_ Retai Mn-D M&E TVS N/A N/A 50 ug/L B n COLCWH13b_ Retai SO4 M&E 2000 95-99 18 416.8 mg/L C n COLCWH20_ SO4 303(d) List 2000 N/A N/A N/A mg/L B COSPBO02a_ Attainin M&E Fe-D 2000 95-09 20 341.5 ug/L B g Delist COSPBO02a_ Retai Mn-D M&E TVS N/A N/A 50 ug/L D n COSPBO02a_ Retai Fe-D 303(d) 2000 95-09 20 341.5 ug/L F n COSPBO02b_ SO4 M&E List TVS N/A N/A 250 mg/L Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.
   1. Sampl POR Listin e Size Categor for Analyt g TVS or of Portion ID y 2000 Value Units e Actio 20001 2000 / List Datas n Datas et et E COSPBO02b_ Mn-D M&E List TVS N/A N/A 50 ug/L F COSPBO07b_ Mn-D 303(d) List TVS N/A N/A 50 ug/L B M&E to COSPBO14_B Fe-D 303(d) TVS N/A N/A 300 ug/L 303(d )
      1. M&E to COSPBO14_B Mn-D 303(d) TVS N/A N/A 50 ug/L 303(d )

COSPBO14_D Mn-D 303(d) List TVS N/A N/A 50 ug/L COSPBT04a_ Mn-D 303(d) List TVS N/A N/A 50 ug/L A COSPBT04b_ Mn-D 303(d) List 2000 95-04 105 79.48 ug/L A Attainin M&E COSPBT07_A Mn-D TVS N/A N/A 50 ug/L g Delist COSPBT08_A Mn-D 303(d) List TVS N/A N/A 50 ug/L Retai COSPBT08_B SO4 303(d) TVS N/A N/A 250 mg/L n COSPBT09_A Mn-D 303(d) List 2000 95-99 23 89.7 ug/L M&E COSPCH01_A Mn-D 303(d) 2000 95-99 46 86.95 ug/L to Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

1. Sampl POR Listin e Size Categor for Analyt g TVS or of Portion ID y 2000 Value Units e Actio 20001 2000 / List Datas n Datas et et 303(d )

COSPCH04a_ Fe-D M&E List TVS N/A N/A 300 ug/L A COSPCH04a_ Mn-D M&E List TVS N/A N/A 50 ug/L A COSPCH04a_ Mn-D 303(d) List TVS N/A N/A 50 ug/L B COSPCL02c_ Retai Mn-D 303(d) 2000 95-99 165 203.1 ug/L B n COSPCL02c_ Retai 442.2 Fe-D 303(d) 2000 95-99 68 ug/L B n 5 COSPCL02c_ SO4 303(d) List TVS N/A N/A 250 mg/L E COSPCL02c_ 442.2 Fe-D M&E List 2000 95-99 68 ug/L E 5 No COSPCL03a_ Attainin Fe-D Action 2000 95-14 29 792 ug/L C g No COSPCL03a_ Attainin Mn-D Action 2000 95-14 29 174 ug/L C g COSPCL03b_ Retai Mn-D M&E TVS N/A N/A 50 ug/L A n COSPCL05_B Mn-D M&E List 2000 95-99 67 431 ug/L COSPCL06_C Fe-D Attainin M&E 2000 95-99 58 9995 ug/L Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

1. Sampl POR Listin e Size Categor for Analyt g TVS or of Portion ID y 2000 Value Units e Actio 20001 2000 / List Datas n Datas et et g Delist M&E to COSPCL06_C SO4 303(d) TVS N/A N/A 250 mg/L 303(d )

COSPCL09b_ Attainin M&E 507.0 Mn-D 2000 95-09 14 ug/L A g Delist 2 COSPCL10_A Mn-D M&E List TVS N/A N/A 50 ug/L COSPCL12a_ Retai Mn-D M&E TVS N/A N/A 50 ug/L A n M&E COSPCL12a_ to SO4 303(d) TVS N/A N/A 250 mg/L B 303(d )

1. M&E COSPCL12a_ to Fe-D 303(d) TVS N/A N/A 300 ug/L B 303(d )
   1. M&E COSPCL12a_ to Mn-D 303(d) TVS N/A N/A 50 ug/L B 303(d )

COSPCL13a_ Fe-D M&E List TVS N/A N/A 300 ug/L C COSPCL14a_ Fe-D M&E List 2000 95-99 15 397 ug/L A COSPCL14b_ Fe-D 303(d) M&E TVS N/A N/A 300 ug/L Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

1. Sampl POR Listin e Size Categor for Analyt g TVS or of Portion ID y 2000 Value Units e Actio 20001 2000 / List Datas n Datas et et A to 303(d )
   1. M&E Site COSPCL14b_ to Specific Mn-D 303(d) N/A N/A 244 ug/L A 303(d Standar ) d COSPCL15_B Mn-D 303(d) List 2000 95-99 31 315 ug/L COSPCL15_B Fe-D M&E List TVS N/A N/A 300 ug/L COSPCL15_C Mn-D 303(d) List 2000 95-99 31 315 ug/L COSPCL16a_ Retai Mn-D M&E TVS N/A N/A 50 ug/L A n COSPCL17b_ Mn-D 303(d) List TVS N/A N/A 50 ug/L A Retai COSPCP07_B Fe-D M&E TVS N/A N/A 300 ug/L n Retai COSPCP07_B Mn-D 303(d) TVS N/A N/A 50 ug/L n Retai COSPCP07_C Fe-D M&E TVS N/A N/A 300 ug/L n Retai COSPCP07_C Mn-D 303(d) TVS N/A N/A 50 ug/L n COSPCP09_B Fe-D 303(d) List TVS N/A N/A 300 ug/L 303(d COSPCP13a_ Attainin Mn-D ) TVS N/A N/A 50 ug/L B g Delist Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.
      1. Sampl POR Listin e Size Categor for Analyt g TVS or of Portion ID y 2000 Value Units e Actio 20001 2000 / List Datas n Datas et et 303(d COSPCP13a_ Attainin SO4 ) 2000 95-04 17 2708 mg/L B g Delist COSPCP13a_ Mn-D 303(d) List TVS N/A N/A 50 ug/L E COSPLA02a_ Retai Mn-D M&E TVS N/A N/A 50 ug/L A n 303(d Attainin COSPLS01_A Mn-D ) TVS N/A N/A 50 ug/L g Delist M&E to COSPLS01_A SO4 303(d) 2000 95-99 46 553 mg/L 303(d )

COSPMS01a_ Attainin M&E Mn-D 2000 95-04 248 240 ug/L A g Delist 303(d COSPMS01b_ Attainin Mn-D ) TVS N/A N/A 50 ug/L A g Delist COSPSV04a_ Attainin M&E Mn-D 2000 95-18 28 188.2 ug/L B g Delist COSPSV04b_ Mn-D 303(d) List 2000 95-99 107 57.6 ug/L A COSPSV04b_ Attainin TMDL Fe-D TVS N/A N/A 300 ug/L B g Delist COSPSV04b_ Mn-D 303(d) List 2000 95-99 107 57.6 ug/L B Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

1. Sampl POR Listin e Size Categor for Analyt g TVS or of Portion ID y 2000 Value Units e Actio 20001 2000 / List Datas n Datas et et COSPSV04b_ SO4 303(d) List TVS N/A N/A 250 mg/L B COSPSV05_A Mn-D 303(d) List TVS N/A N/A 50 ug/L Retai COSPSV05_B Mn-D 303(d) TVS N/A N/A 50 ug/L n 303(d COSPSV06_A Attainin Mn-D ) N/A N/A N/A N/A N/A 2 g Delist 303(d COSPSV06_C Attainin Mn-D ) N/A N/A N/A N/A N/A 2 g Delist 303(d COSPSV06_D Attainin Mn-D ) N/A N/A N/A N/A N/A 2 g Delist COSPUS02c_ Retai Fe-D TMDL TVS N/A N/A 300 ug/L A n COSPUS02c_ Retai Mn-D TMDL 2000 95-99 31 235 ug/L A n COSPUS02c_ Retai Fe-D TMDL TVS N/A N/A 300 ug/L C n COSPUS02c_ Retai Mn-D TMDL 2000 95-99 31 235 ug/L C n COSPUS02c_ Retai Fe-D TMDL TVS N/A N/A 300 ug/L D n COSPUS02c_ Retai Mn-D TMDL 2000 95-99 31 235 ug/L D n Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.
   1. Sampl POR Listin e Size Categor for Analyt g TVS or of Portion ID y 2000 Value Units e Actio 20001 2000 / List Datas n Datas et et Retai COSPUS03_B Mn-D 303(d) 2000 95-99 45 170 ug/L n COSPUS04_E Mn-D 303(d) List 2000 95-99 95 100 ug/L COSPUS05b_ Retai Mn-D 303(d) 2000 95-99 153 151.8 ug/L B n No COSPUS06b_ Attainin Mn-D Action 2000 95-18 30 62.9 ug/L A4 g COSPUS15_B SO4 303(d) List TVS N/A N/A 250 mg/L COUCBL02a_ Retai Mn-D 303(d) TVS N/A N/A 50 ug/L A n COUCBL02a_ Retai Mn-D 303(d) TVS N/A N/A 50 ug/L B n 303(d COUCBL06a_ Attainin Mn-D ) 2000 95-99 88 665 ug/L B g Delist 303(d COUCBL06a_ Attainin Mn-D ) 2000 95-99 88 665 ug/L C g Delist Retai COUCBL12_B Mn-D M&E 2000 95-04 15 199 ug/L n Retai COUCBL12_C Mn-D M&E 2000 95-04 15 199 ug/L n Retai COUCBL20_B Fe-D M&E 2000 N/A N/A N/A ug/L n Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.
      1. Sampl POR Listin e Size Categor for Analyt g TVS or of Portion ID y 2000 Value Units e Actio 20001 2000 / List Datas n Datas et et COUCEA05a_ Fe-D 303(d) List TVS N/A N/A 300 ug/L C COUCEA05c_ Retai Fe-D 303(d) TVS N/A N/A 300 ug/L A n COUCEA10a_ SO4 303(d) List TVS N/A N/A 250 mg/L B Retai COUCNP03_A Fe-D M&E TVS N/A N/A 300 ug/L n COUCNP04a_ Retai Fe-D M&E TVS N/A N/A 300 ug/L B n COUCNP04a_ Retai Mn-D M&E TVS N/A N/A 50 ug/L B n COUCNP04a_ Retai Mn-D M&E TVS N/A N/A 50 ug/L E n M&E COUCNP04a_ to Fe-D 303(d) TVS N/A N/A 300 ug/L F 303(d )

COUCNP04a_ Retai Fe-D 303(d) TVS N/A N/A 300 ug/L H n COUCNP04a_ Retai Mn-D 303(d) TVS N/A N/A 50 ug/L H n COUCNP04b_ Attainin M&E Mn-D 2000 95-04 19 479 ug/L B g Delist COUCNP05b_ M&E Fe-D 303(d) 2000 95-04 28 359 ug/L A to Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

1. Sampl POR Listin e Size Categor for Analyt g TVS or of Portion ID y 2000 Value Units e Actio 20001 2000 / List Datas n Datas et et 303(d )

COUCNP05b_ Attainin M&E Mn-D 2000 95-04 28 109.5 ug/L A g Delist COUCUC02_ Mn-D 303(d) List TVS N/A N/A 50 ug/L H COUCUC05_ Mn-D 303(d) List TVS N/A N/A 50 ug/L B COUCUC07b_ Retai Mn-D M&E TVS N/A N/A 50 ug/L E n COUCUC07b_ Retai SO4 303(d) TVS N/A N/A 250 mg/L E n COUCUC07b_ SO4 M&E List TVS N/A N/A 250 mg/L D COUCUC07b_ Mn-D M&E List TVS N/A N/A 50 ug/L D COUCUC07b_ Fe-D M&E List TVS N/A N/A 300 ug/L D COUCUC07d_ Retai Mn-D 303(d) TVS N/A N/A 50 ug/L B n 303(d COUCUC07e_ Attainin Mn-D ) N/A N/A N/A N/A N/A A2 g Delist COUCUC10c_ Attainin M&E Fe-D TVS N/A N/A 300 ug/L A g Delist Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

1. Sampl POR Listin e Size Categor for Analyt g TVS or of Portion ID y 2000 Value Units e Actio 20001 2000 / List Datas n Datas et et 303(d COUCUC10c_ Attainin Fe-D ) TVS N/A N/A 300 ug/L B g Delist 303(d COUCUC10c_ Attainin Fe-D ) TVS N/A N/A 300 ug/L C g Delist 303(d COUCUC12_ Attainin 426.2 Fe-D ) 2000 95-18 18 ug/L D g 5 Delist 303(d COUCUC12_ Attainin 877.0 Mn-D ) 2000 95-18 12 ug/L D g 5 Delist COUCYA02a_ Attainin M&E Mn-D 2000 95-99 45 128 ug/L A g Delist Attainin M&E COUCYA03_D Mn-D TVS N/A N/A 50 ug/L g Delist Attainin M&E COUCYA18_B Fe-D TVS N/A N/A 300 ug/L g Delist COUCYA22_E Fe-D 303(d) List TVS N/A N/A 300 ug/L Footnotes

1) Where this column indicates that the appropriate standard is the existing quality as of the year 2000 (as indicated with ‘2000’ in this column), information for the subsequent columns is only reported where 10 or more samples are available.

2) The water supply use classification was removed from COSPSV06 and from COUCUC07e during the 2015 and 2019 rulemaking hearings, respectively. Therefore there are no standards to memorialize.

3) During the hearing process, it was determined that the 303(d) listing was not appropriate. Assessment values are memorialize for future assessment cycles.

4) Assessment value memorialized in this table applies only to the epilimnion.

7. Policy 10-1 Aquatic Life Use Attainment Update In 2017, the commission updated Policy 10-1, Aquatic Life Use Attainment, Methodology to Determine Use Attainment for Rivers and Streams. Policy 10-1 provides the commission with a methodology for determining if the Aquatic Life Use is attaining in wadeable streams and rivers. The policy describes a bioassessment Multi-Metric Index (MMI) tool, which provides a direct measurement and characterization of the health of the benthic macroinvertebrate community. The MMI calculates a unitless score that ranges from 0-100. These MMI scores are then compared to biological thresholds, which are located in Table 1 of Policy 10-1.

For the 2017 update of Policy 10-1, the MMI (4.0) tool was updated to provide more precise MMI scores as well as new metrics that describe more detailed attributes of the benthic macroinvertebrate community. The MMI tool was recalibrated with a more robust reference and stressed site dataset. As a result, the MMI scores for reference sites were recalculated, which led to new biotype thresholds. The three biotypes are Biotype 1 (Transition), Biotype 2 (Mountain) and Biotype 3 (Xeric and Plains). During the 2020 303(d) listing cycle, the division utilized the recalibrated tool to assess MMI scores against the new biotype thresholds. This included newly provided and previously submitted data. These assessments were completed within the South Platte and Upper and Lower Colorado basins.

For the 2020 listing cycle the commission placed 27 new segments on the 303(d) List, removed 18 segments from the 303(d) List, and retained 26 segments on the 303(d) List.

8. Site-specific decisions made by the commission are discussed below a) COSPCH01 – Dissolved Manganese Segment COSPCH01 was placed on the M&E List for dissolved manganese at the 2016 Regulation #93 rulemaking. In the current assessment, sampling data shows that Segment COSPCH01 is not in attainment of the water supply standard for dissolved manganese, as the current concentration (101.55 μg/L) exceeds the existing water quality as of January 1, 2000 (86.95 μg/L). Although the division considered the existence of facilities as of January 1, 2000,including Parker Water and Sanitation District’s water reclamation facilities, the updated attainment analysis found no evidence of increased sources of dissolved manganese from these facilities between 1999 and 2010. The Division is making no conclusion as to whether such facilities are the source of impairment.

b) COSPUS06b –Total Arsenic Chatfield Reservoir was placed on the 303(d) List for arsenic, but was assigned a low priority for TMDL development. Statewide, compliance problems are evident, and there is uncertainty regarding the appropriate standard to protect the water supply use for arsenic and the extent to which ambient levels of arsenic are natural/irreversible. Additionally, there has been a delay in the release of the EPA Integrated Risk Information System (IRIS) report for arsenic that is necessary for standards revisions. Therefore, as it relates to arsenic, the division will focus efforts on evaluating feasibility information and revising the arsenic standards. The division will deprioritize the development of TMDL's for arsenic listings until other work has been accomplished.

c) COUCEA05 In the case of the acute and chronic dissolved metal standards for Eagle River Segments 5a, 5b and 5c the division considered available data and used the approach described in the 2020 303(d) Listing Methodology to determine attainment of water quality standards. The commission approved several listing actions within these segements. This included adding paramaters to the 303(d) List, removing paramaters from the 303(d) List and changing listing categories from 4a (approved TMDL) to 1(attaining). Under CERCLA, the EPA determines the nature and extent of contamination (Remedial Investigation), considers cleanup alternatives in a Feasibility Study, and then selects a Final Remedy in a Record of Decision. In the 2013 Focused Feasibility Study, the EPA considered data from 2009 to 2012 and any exceedance of water quality standards resulted in the identification of remediation actions to achieve water quality standards attainment year-round. The 303(d) and CERCLA water quality assessment processes differ slightly and it is possible that they result in differing analysis and conclusions for Eagle River Segment 5. Therefore, some segments that are deemed attaining standards in 303(d) assessment process may still indicate that additional water quality improvements are needed as a part of the Superfund process. In this hearing, the commission decided not to move the upper portion of segment 5a from Category 4a into Category 1 for zinc and instead decided to keep all three of these segments in Category 4a. The commission found that there were factors specific to these circumstances that warranted deviating from the Listing Methodology and exercising best professional judgment. These factors include the unique access constraints associated with a Superfund site designation, such as the fact that only the Hazardous Materials and Waste Management Division is able to collect data from the upper portion of segment 5a, and therefore it is challenging to collect paired data reflecting conditions in the upper portion and the lower portion of this segment on the same day. Another factor was that there was more data available for the lower portion than for the upper portion, and the data for the lower portion demonstrated impairment. The commission was not convinced that if there had been paired data the upper portion would still have been assessed as in attainment. Therefore the commission determined to keep the upper portion of segment 5a in Category 4a for zinc.

d) COUCYA13e_A – Macroinvertebrates The commission decided to place this segment on the monitoring and evaluation list instead of the 303(d) List for macroinvertebrates because there was only one data point and it was from 2008. While the Listing Methodology indicates that in these circumstances a 303(d) listing is appropriate, in these circumstances the commission determined that a deviation from the Listing Methodology was warranted because when the segment was first evaluated using the prior version of the MMI tool it was considered attaining but when the same data was assessed using the newer version of the MMI tool, it was not in attainment. Therefore, the commission determined that placing this segment on the Monitoring and Evaluation list for macroinvertebrates was warranted in this unique instance.

9. Parties to the rulemaking hearing

93.19 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND

PURPOSE; MAY 2021 RULEMAKING; FINAL ACTION JUNE 15, 2021; EFFECTIVE DATE OF AUGUST 14, 2021.

The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; provide the specific statutory authority for adoption of these regulatory amendments. The commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.

BASIS AND PURPOSE A. Revisions to 303(d) List 1. List Development

1. a. Listing Methodology The “Section 303(d) Listing Methodology - 2022 Listing Cycle” contains a description of the listing process and the criteria for listing. This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2022 Section 303(d) List and the 2022 Monitoring & Evaluation List (M&E list). This document was adopted in May of 2020 with limited changes from the previous Section 303(d) Listing Methodology. Changes included modifying the Regulation #93 rulemaking hearing from occurring in December of odd numbered years to May of odd numbered years.
   1. This methodology was not adopted by the commission as a rule. The commission, therefore, has the flexibility to take into account other appropriate factors in making site-specific listing decisions.
      1. b. Information Considered The commission has considered all existing and readily available information in developing the 2022 Section 303(d) List. In determining whether data and information are existing and readily available, it has taken into account such data and information as the division has utilized in the preparation of those identification processes, calculations and models referenced in 40 CFR §130.7(b)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and submitted in reports provided to the division as referenced in 40 CFR §130.7(ab)(5)(iii). In addition, the commission accepted credible data and information that was submitted in accordance with the listing process schedule, whether submitted by EPA or any other interested party. The division also continues to independently collect and analyze new data on a rotating basin basis as part of its triennial review efforts and will utilize such data and information in making future listing determinations. Existing data which were not brought forward through one of the above mechanisms or otherwise presented to the commission in accordance with the schedule were not treated as "readily available" for purposes of making the 2022 listing decisions. Such information will be considered in the next listing cycle.

         This Regulation #93 rulemaking hearing cycle focused on the San Juan and Dolores River Basins (Regulation #34) and the Gunnison, Lower Dolores River Basins (Regulation #35), and where there were outstanding issues statewide. This approach follows the rotating basin structure described in the 2022 303(d) Listing Methodology.

2. Incorporation of TMDLs into Table 93.3 of Regulation #93 The commission incorporated category 4 waterbodies (impaired but where a TMDL is not needed) into the main table within Regulation #93, instead of in a separate table at the end of the regulation as they have been in previous versions of this regulation. This organizes all impaired waterbodies and waterbodies under investigation of being impaired into one table. Table 93.3 now includes the following category 4 listings:

1. 1. Category 4a - Impaired waterbodies with a completed TMDL 2. Category 4b - Impaired waterbodies where other pollution control requirements are reasonably expected to result in the attainment of the water quality standard in the near future.
   1. 3. Category 4c - Impaired waterbodies where the impairment is not caused by a pollutant.
      1. Combining these tables eliminates the need for section 93.4 (Impaired Water Bodies Not Requiring TMDLs), and therefore, this section was deleted from the regulation. Additionally, combining these tables required a title change to table 93.3. The commission changed the title from “Water Bodies Requiring TMDLs or Identified for Monitoring and Evaluation” to “Waterbodies That Are Impaired or Identified for Monitoring and Evaluation.”

3. New Sub Categories 1a (Attaining) and 1b (Attaining with TMDL) Two new reporting subcategories were created for classifying the attainment status of waterbody segments in order to distinguish between waterbodies in attainment of water quality standards (category 1a) and waterbodies in attainment of water quality standards with approved TMDLs (category 1b). This distinction is important because even after a waterbody is reclassified for a given analyte from 4a (TMDL completed) to 1 (attaining), the TMDL remains in effect. The TMDL remains in place so that the practices that were implemented to improve water quality maintain the restored level of water quality. As more waterbodies with TMDLs are no longer impaired, it is helpful to have a subcategory to quickly locate attaining waterbodies with TMDLs. This will help:

1. • Potential and existing dischargers understand the locations where waste load allocations may exist.
   1. • Division permit writers find TMDLs on waterbodies in attainment. • Watershed groups dedicate resources to support continued pollution reduction efforts.
      1. During the Regulation #93 rulemaking hearing, subcategories 1a (attaining) and 1b (attaining with TMDL) are visible within the division’s proposal to indicate the proposed action to be taken by the commission to change the attainment status of a waterbody. However, because Regulation #93 reports on waterbodies that are impaired or identified for the M&E List, attaining waterbodies (i.e., subcategories 1a, and 1b) are removed from the final Regulation #93 document. These subcategories will be presented in Colorado’s Integrated Water Quality Monitoring and Assessment Report (IR), which is approved by the commission every even numbered year, in an administrative action hearing.

         While subcategories 1a and 1b are useful to the state of Colorado as described above, the EPA recognizes them both as category 1. This is similar to other instances in which Colorado developed subcategories such as 3a (no water quality data has been collected), and 3b (waterbody placed on M&E List). In these cases, the EPA recognizes each as simply category 3, insufficient data to determine whether or not the classified uses are being attained.

4. Removal of Adequate Refuge Clause from Regulation #31 In 2016, the commission removed footnote 5(c)(iii) from Regulation #31 which allowed lake and reservoir surface water temperatures to exceed the applicable temperature standards if adequate refuge existed in deeper layers of the water column. Adequate refuge was defined as concurrent attainment of the temperature and dissolved oxygen standard below the surface of the lake or reservoir in deeper layers. The footnote was proposed for removal by the division because an elevation based temperature standard was being considered for adoption by the commission. Although the commission did not adopt the elevation based standard, the footnote allowing for adequate refuge as a part of the lake temperature standard was deleted in error.

1. Due to the removal of this footnote, data assessed for the 2020 and 2022 Regulation #93 listing cycles were compared to the lakes and reservoir temperature standards without consideration for adequate refuge. This resulted in numerous lakes and reservoirs with exceedances of the temperature standard in the surface layer more than once in 3 years. These lakes and reservoirs would have otherwise been considered attaining temperature standards if the refuge footnote was still in place. For the 2020 303(d) List, the following 7 lakes and reservoirs were added to the 303(d) List as impaired for temperature because adequate refuge was not considered: Lake Avery (COLCWH25_A), Big Creek Reservoir (COUCNP09_B), North Delaney Lake (COUCNP09_C), Lake John (COUCNP09_D), South Delaney Lake (COUCNP09_E), Pearl Lake (COUCYA22_D) and Steamboat Lake (COUCYA22_E). For the 2022 303(d) List, the following 7 new lakes and reservoirs were added to the 303(d) List as impaired for temperature because adequate refuge was not considered: Blue Mesa Reservoir (COGUUG38_C), Grand Lake (COUCUC12_E), McPhee Reservoir (COSJDO04b_B), Lake Nighthorse (COSJAF22_A), Ridgway Reservoir (COGUUN19_A), Vallecito Reservoir (COSJPN03_A) and Willow Creek Reservoir (COUCUC12_D).
   1. For the June 2021 Regulation #31 rulemaking hearing, the commission is considering a proposal by the division to reinstate language that would allow for adequate refuge when assessing temperature for lakes and reservoirs. Reinstatement of the adequate refuge provision is expected to result in attainment of the temperature standards for all of the lakes and reservoirs listed above. In light of this proposed change, the division proposed that the lakes and reservoirs above be included on the 303(d) List with low priority for TMDL development. If the adequate refuge provision is added to the lake temperature standard in June of 2021, the division will prioritize the assessment of the lakes and reservoirs listed above for the 2024 303(d) List, regardless of the division’s basin of focus.

5. For the secondary water supply standards of dissolved iron, dissolved manganese and sulfate, the less restrictive of the following two options apply as the numeric standard: existing quality as of January 1, 2000, or the table value criteria in Regulation #31, Tables II and III. For dissolved iron, the table value standard (TVS) is 300 ug/l. For dissolved manganese, the TVS is 50 ug/l. For sulfate, the TVS is 250 mg/l.

1. The 303(d) Listing Methodology, includes language regarding the determination of existing quality from the year 2000 (EQ 2000). This includes a minimum data requirement and the ability to use data collected after the year 2000 when characterizing existing quality from 2000. The utilization of data collected past the year 2000 is contingent upon there being no new or increased sources of these parameters in the segment being assessed since 2000.
   1. Table 1. summarizes the secondary water supply assessment values used for dissolved iron, manganese, and sulfate for 303(d) or M&E listing actions:

Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

1. Sampl POR e Size TVS for Analyt Categor Listing of Valu Portion ID or 2000 Units e y / List Action 2000 e 20001 Datase Datase t t SO4 ME Delist 2000 1995- 10 891.5 mg/l COGULD03a_ B COGULG02_A Mn-D 303d Delist TVS N/A N/A 50 ug/l Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.
   1. Sampl POR e Size TVS for Analyt Categor Listing of Valu Portion ID or 2000 Units e y / List Action 2000 e 20001 Datase Datase t t SO4 303d Retain 2000 1995- 92 297 mg/l COGULG02_A COGULG02_B Mn-D 303d Retain TVS N/A N/A 50 ug/l SO4 303d Delist 2000 1995- 92 297 mg/l COGULG02_B Mn-D 303d Retain 2000 1995- 13 84.4 ug/l COGULG04a_ D SO4 303d Retain 2000 1995- 59 4160 mg/l COGULG04a_ D Mn-D ME Retain 2000 1995- 13 84.4 ug/l COGULG04a_ E SO4 303d Delist 2000 1995- 24 617.2 mg/l COGULG07b_ C Mn-D 303d Retain 2000 1995- 18 94.35 ug/l COGULG12_B COGULG12_B SO4 ME Retain 2000 1995- 18 962.5 mg/l Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.
      1. Sampl POR e Size TVS for Analyt Categor Listing of Valu Portion ID or 2000 Units e y / List Action 2000 e 20001 Datase Datase t t Mn-D 303d Retain 2000 1995- 57 72 ug/l COGUNF03_B Mn-D 303d Retain 2000 1995- 57 72 ug/l COGUNF03_C COGUNF04b_ Mn-D ME List TVS N/A N/A 50 ug/l E SO4 303d Retain 2000 1995- 48 1585. mg/l COGUNF06b_ B Mn-D 303d Delist 2000 1995- 20 783 ug/l COGUNF06b_ B SO4 303d Retain 2000 1995- 48 1585. mg/l COGUNF06b_ C COGUNF06b_ Fe-D 303d Retain TVS N/A N/A 300 mg/l C Mn-D 303d Retain 2000 1995- 20 783 ug/l COGUNF06b_ C COGUSM02_D Mn-D ME List TVS N/A N/A 50 ug/l COGUSM02_F SO4 ME List TVS N/A N/A 250 mg/l COGUSM02_F Mn-D 303d List TVS N/A N/A 50 ug/l Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.
         1. Sampl POR e Size TVS for Analyt Categor Listing of Valu Portion ID or 2000 Units e y / List Action 2000 e 20001 Datase Datase t t COGUSM02_F Fe-D 303d List TVS N/A N/A 300 ug/l COGUSM04a_ Mn-D ME List TVS N/A N/A 50 ug/l B SO4 ME List 2000 1995- 32 377.5 mg/l COGUSM07_B SO4 ME List 2000 1995- 32 377.5 mg/l COGUSM07_C COGUSM07_C Fe-D 303d List TVS N/A N/A 300 ug/l COGUSM07_C Mn-D 303d List TVS N/A N/A 50 ug/l COGUSM08_A Mn-D ME List TVS N/A N/A 50 ug/l Fe-D ME Delist 2000 1995- 15 456 ug/l COGUUG01_B Fe-D ME Retain 2000 1995- 15 456 ug/l COGUUG01_C COGUUG02_D Mn-D 303d Delist TVS N/A N/A 50 ug/l COGUUG09_ Mn-D 303d List TVS N/A N/A 50 ug/l G COGUUG09_ Fe-D 303d List TVS N/A N/A 300 ug/l G Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

            Sampl POR e Size TVS for Analyt Categor Listing of Valu Portion ID or 2000 Units e y / List Action 2000 e 20001 Datase Datase t t Mn-D 303d Delist Site- N/A N/A 191 ug/l COGUUG12_C Specific Fe-D 303d Retain 2000 1995- 16 745 ug/l COGUUG15a_ B Mn-D 303d Retain 2000 1995- 25 66.4 ug/l COGUUG15a_ B Mn-D ME Retain 2000 1995- 13 162 ug/l COGUUG17b_ A COGUUG19_B Mn-D 303d Retain TVS N/A N/A 50 ug/l COGUUG19_B Fe-D ME List TVS N/A N/A 300 ug/l COGUUG24_B Fe-D ME List TVS N/A N/A 300 ug/l Fe-D 303d Retain 2000 1995- 52 2181. ug/l COGUUG29a_ B COGUUG29a_ Mn-D 303d Retain TVS N/A N/A 50 ug/l C COGUUG29a_ Mn-D ME Retain TVS N/A N/A 50 ug/l D COGUUG29a_ Mn-D ME Retain TVS N/A N/A 50 ug/l I COGUUG30_B Mn-D ME List TVS N/A N/A 50 ug/l Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

            Sampl POR e Size TVS for Analyt Categor Listing of Valu Portion ID or 2000 Units e y / List Action 2000 e 20001 Datase Datase t t Mn-D 303d Retain 2000 1995- 13 170.6 ug/l COGUUG32_A Mn-D 303d Retain 2000 1995- 27 119.8 ug/l COGUUN02_B 9 Mn-D 303d Delist 2000 1995- 27 119.8 ug/l COGUUN02_C 9 Mn-D 303d Retain 2000 1995- 39 588.7 ug/l COGUUN03a_ A Mn-D 303d Retain 2000 1995- 44 413.6 ug/l COGUUN03b_ A Mn-D 303d Delist 2000 1995- 85 180 ug/l COGUUN03c_ A SO4 ME Retain 2000 1995- 13 266 ug/l COGUUN04a_ B SO4 ME List 2000 1995- 13 266 ug/l COGUUN04a_ C COGUUN04b_ Mn-D 303d Retain TVS N/A N/A 50 ug/l A COGUUN05_C Mn-D 303d Retain TVS N/A N/A 50 ug/l Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

            Sampl POR e Size TVS for Analyt Categor Listing of Valu Portion ID or 2000 Units e y / List Action 2000 e 20001 Datase Datase t t COGUUN05_E Mn-D 303d Retain TVS N/A N/A 50 ug/l COGUUN05_G Mn-D ME List TVS N/A N/A 50 ug/l COGUUN08_A Mn-D ME List TVS N/A N/A 50 ug/l Mn-D ME Delist 2000 1995- 24 635.4 ug/l COSJAF04b_A 5 Mn-D 303d Retain 2000 1995- 360 177.7 ug/l COSJAF05a_B 5 Mn-D 303d Retain 2000 1995- 360 177.7 ug/l COSJAF05a_C 5 Fe-D 303d List 2000 1995- 276 2902 ug/l COSJAF09_A Mn-D 303d List 2000 1995- 285 479.4 ug/l COSJAF09_A COSJDO04b_ Fe-D ME Retain TVS N/A N/A 300 ug/l A COSJDO04b_ Mn-D ME Retain TVS N/A N/A 50 ug/l A Mn-D TMDL Retain 2000 1995- 12 582 ug/l COSJLP04a_E Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

            Sampl POR e Size TVS for Analyt Categor Listing of Valu Portion ID or 2000 Units e y / List Action 2000 e 20001 Datase Datase t t COSJLP04a_E SO4 303d List TVS N/A N/A 250 ug/l COSJLP04a_E Fe-D 303d List TVS N/A N/A 300 ug/l Mn-D TMDL Correctio 2000 1995- 12 582 ug/l COSJLP04a_F n Mn-D TMDL Delist 2000 1995- 16 78 ug/l COSJLP04c_D Mn-D 303d List 2000 1995- 16 78 ug/l COSJLP04c_G COSJLP05_B Fe-D ME Delist TVS N/A N/A 300 ug/l COSJLP05_B Mn-D 303d List TVS N/A N/A 50 ug/l SO4 ME Retain 2000 1995- 146 966.1 mg/l COSJLP05_B 8 SO4 303d Retain 2000 1995- 64 3000 mg/l COSJLP08_A SO4 303d Retain 2000 1995- 64 3000 mg/l COSJLP08_B SO4 303d Retain 2000 1995- 64 3000 mg/l COSJLP08_C Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

            Sampl POR e Size TVS for Analyt Categor Listing of Valu Portion ID or 2000 Units e y / List Action 2000 e 20001 Datase Datase t t SO4 303d Retain 2000 1995- 64 3000 mg/l COSJLP08_E COSJSJ06b_B Mn-D ME Retain TVS N/A N/A 50 ug/l Table 1. Footnotes:

      2. 1) Where this column indicates that the appropriate standard is the existing quality as of the year 2000 (as indicated with ‘2000’ in this column), information for the subsequent columns is only reported where 10 or more samples are available.
      3. 2) The appropriate assessment value for dissolved manganese in COGUUG12_C is a site-specific standard established in the 2012 rulemaking hearing for Regulation #35. See 5 CCR § 1002- 35.34(L).

6. Parties to the rulemaking hearing:

93.20 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND

PURPOSE; MAY 2023 RULEMAKING; FINAL ACTION JUNE 24, 2021; EFFECTIVE DATE OF SEPTEMBER 14, 2023.

The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; provide the specific statutory authority for adoption of these regulatory amendments. The commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.

BASIS AND PURPOSE A. Revisions to 303(d) List 1. List Development

1. a. Listing Methodology The “Section 303(d) Listing Methodology - 2024 Listing Cycle” contains a description of the listing process and the criteria for listing. This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2024 Section 303(d) List and the 2024 Monitoring & Evaluation List (M&E List). This document was adopted by the commission in March of 2022. This methodology was not adopted as a rule. The commission, therefore, has the flexibility to take into account other appropriate factors in making site-specific listing decisions.
   1. b. Information Considered The commission has considered all existing and readily available information in developing the 2024 Section 303(d) List. In determining whether data and information are existing and readily available, the commission has taken into account data and information that the division has utilized in the preparation of those identification processes, calculations, and models referenced in 40 CFR §130.7(b)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and provided to the division as referenced in 40 CFR §130.7(b)(5)(iii). In addition, the commission accepted credible data and information that was submitted in accordance with the listing process schedule. The division continues to collect and analyze new data on a rotating basin basis and will utilize such data and information in making future listing determinations. Existing data that were not brought forward through one of the above mechanisms or otherwise presented to the commission in accordance with the schedule were not treated as "readily available" for purposes of making the 2024 listing decisions. Such information will be considered in the next listing cycle.
      1. This Regulation #93 hearing cycle focuses on the Arkansas River and Rio Grande Basins (Regulations #32 and #36) and the Upper and Lower Colorado River Basins (Regulations #33 and #37). This approach follows the rotating basin structure described in the 2024 303(d) Listing Methodology.

2. Reinstatement of Adequate Refuge Clause into Regulation #31 In 2016, the commission removed footnote 5(c)(iii) from Regulation #31, which allowed lake and reservoir surface water temperatures to exceed the applicable temperature standards if adequate refuge existed in deeper layers of the water column. Adequate refuge was defined as concurrent attainment of the temperature and dissolved oxygen standard below the surface of the lake or reservoir in deeper layers. The footnote was proposed for removal by the division because an elevation-based temperature standard was being considered for adoption by the commission. Although the commission did not adopt the elevation-based standard, the footnote allowing for adequate refuge as a part of the lake temperature standard was deleted in error.

1. Due to the removal of this footnote, data assessed for the 2020 and 2022 Regulation #93 listing cycles were compared to the lakes and reservoir temperature standards without consideration for adequate refuge. This resulted in numerous lakes and reservoirs exceeding the temperature standard in the surface layer. Many of these lakes and reservoirs would have otherwise been considered attaining temperature standards if the refuge footnote was still in place.
   1. The adequate refuge footnote was reinstated by the commission during the 2021 Regulation #31 rulemaking hearing. All lakes and reservoirs placed on the 303(d) List for temperature without the use of the adequate refuge footnote were reevaluated during the 2024 listing cycle to determine whether a temperature listing was still appropriate. The following lakes were removed from the 303(d) List because the temperature standard was attained when adequate refuge was considered: Lake Avery (COLCWH25_A), Big Creek Reservoir (COUCNP09_B), North Delaney Lake (COUCNP09_C), Lake John (COUCNP09_D), South Delaney Lake (COUCNP09_E), Willow Creek Reservoir (COUCUC12_D), Grand Lake (COUCUC12_E), Pearl Lake (COUCYA22_D), Steamboat Lake (COUCYA22_E), Blue Mesa Reservoir (COGUUG38_C), Ridgway Reservoir (COGUUN19_A), Lake Nighthorse (COSJAF22_A), and McPhee Reservoir (COSJDO04b_B).

3. Health equity and environmental justice (HE/EJ) are priorities for the division and the Colorado Department of Public Health and Environment. The division worked to develop and implement HE/EJ strategies within the water quality assessment and Regulation #93 development process. For this listing cycle the division utilized various EJ concepts into the division’s monitoring, assessment and listing processes. The division developed an Integrated Report storymap to help communicate the 303(d) assessment and listing process to the public in plain language. The division is allocating monitoring resources to collect water quality data from disproportionately impacted communities (DI communities) that lack current water quality information. To reduce the barrier to providing data during the 303(d) assessment process, the division posted physical, biological and chemical data submission training sessions on its website. In the future, the division will continue to strategize ways to incorporate health equity and environmental justice into the 303(d) assessment process. Future efforts may include increased communication, outreach, and monitoring through close coordination with the Office of Health Equity. These efforts may also include efforts regarding data sharing, data quality and filling data gaps in DI communities and exploring options to translate the storymap into other languages.

4. Assessment Values Used for Secondary Water Supply Standards For the secondary water supply standards of dissolved iron, dissolved manganese and sulfate, the less restrictive of the following two options apply as the numeric standard: existing quality as of January 1, 2000, or the table value criteria in Regulation #31, Tables II and III. For dissolved iron, the table value standard (TVS) is 300 ug/l. For dissolved manganese, the TVS is 50 ug/l. For sulfate, the TVS is 250 mg/l.

1. The 303(d) Listing Methodology includes language regarding the determination of existing quality from the year 2000 (EQ 2000). This includes a minimum data requirement and the ability to use data collected after the year 2000 when characterizing existing quality from 2000. The utilization of data collected past the year 2000 is contingent upon there being no new or increased sources of these parameters in the segment being assessed since 2000.
   1. Table 1. summarizes the secondary water supply assessment values used for dissolved iron, manganese, and sulfate for 303(d) or M&E Listing actions:

Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

1. Sampl e Size of POR for 2000 Categor Listing TVS or 2000 Datase Portion ID Analyte y/ List Action 20001 Dataset t Value Units COARFO01a_ B Mn-D 303d Retain TVS 50 ug/l COARFO01a_ C Mn-D 303d Delist TVS 50 ug/l COARFO01a_ D Mn-D 303d Retain TVS 50 ug/l COARFO02a_ 3bDelis B Fe-D M&E t TVS 300 ug/l Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.
   1. Sampl e Size of POR for 2000 Categor Listing TVS or 2000 Datase Portion ID Analyte y/ List Action 20001 Dataset t Value Units COARFO02a_ 3bDelis C Fe-D M&E t TVS 300 ug/l COARFO02a_ D SO4 M&E 3bList 2000 1995-1999 198 250 mg/L COARFO02a_ D Fe-D M&E Retain TVS 300 ug/l COARFO02b_ A Fe-D 303d Retain TVS 300 ug/l COARFO04e_ A SO4 303d List TVS 250 mg/L COARFO04e_ C SO4 M&E Retain TVS 250 mg/L COARFO06_ B Mn-D 303d Retain 2000 1995-1999 175 60 ug/l COARFO06_ C Mn-D 303d Delist 2000 1995-1999 175 60 ug/l COARLA01a_ A Mn-D 303d Retain TVS 50 ug/L COARLA01a_ A Fe-D 303d List TVS 300 ug/L COARLA01b_ A Mn-D 303d Delist 2000 1995-1999 270 58 ug/L COARLA01c_ A Mn-D 303d Retain 2000 1995-1999 50 174 ug/L Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.
      1. Sampl e Size of POR for 2000 Categor Listing TVS or 2000 Datase Portion ID Analyte y/ List Action 20001 Dataset t Value Units COARLA02a_ B Mn-D 303d Retain 2000 1995-1999 11 71 ug/L COARLA02a_ B SO4 303d Retain 2000 1995-2004 20 1278.5 mg/L COARLA04a_ A SO4 303d Delist 2000 1995-1999 18 1145 mg/L COARLA04a_ B SO4 303d Retain 2000 1995-1999 18 1145 mg/L COARLA05b_ B Mn-D 303d List TVS 50 ug/L COARLA07_A Mn-D 303d List 2000 93 ug/L COARLA09a_ B SO4 M&E Retain 2000 1995-1999 34 1903.5 mg/L COARLA09a_ B Mn-D 303d Retain 2000 1995-1999 46 202.5 ug/L COARLA09a_ D Mn-D 303d Retain 2000 1995-1999 46 202.5 ug/L COARLA09a_ E Mn-D 303d Retain 2000 1995-1999 46 202.5 ug/L COARLA09a_ F Mn-D 303d Retain 2000 1995-1999 46 202.5 ug/L COARLA09b_ A Mn-D M&E Retain 2000 1995-1999 11 115 ug/L COARLA09b_ A SO4 M&E Retain 2000 1995-2004 16 958 mg/L Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.
         1. Sampl e Size of POR for 2000 Categor Listing TVS or 2000 Datase Portion ID Analyte y/ List Action 20001 Dataset t Value Units COARLA09b_ B Fe-D 303d List TVS 300 ug/L COARLA09b_ B Mn-D M&E Retain 2000 1995-1999 11 115 ug/L COARLA09b_ B SO4 M&E Retain 2000 1995-2004 16 958 mg/L COARMA03_ A Fe-D 303d List TVS 300 ug/L COARMA03_ A Mn-D 303d List TVS 50 ug/L COARMA03_ A SO4 303d List TVS 250 mg/L COARMA06b _A Mn-D 303d Retain 2000 1995-1999 11 114.5 ug/L COARMA12_ A Mn-D 303d List TVS 50 ug/L COARMA13c_ A Mn-D 303d Retain 2000 1995-1999 11 71 ug/L COARMA13c_ A SO4 303d Retain 2000 1995-2004 20 1278.5 mg/L COARMA18a _A Mn-D 303d List TVS 50 ug/L COARMA18a _A SO4 303d Retain 2000 1995-2009 12 2500 mg/L Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

            Sampl e Size of POR for 2000 Categor Listing TVS or 2000 Datase Portion ID Analyte y/ List Action 20001 Dataset t Value Units COARUA04a_ A Fe-D M&E 3bList TVS 300 ug/L COARUA04b_ A Mn-D M&E Retain TVS 50 ug/L COARUA05a_ C Fe-D 303d Retain TVS 300 ug/L COARUA05a_ 1995-1999 C Mn-D 303d Retain 2000 37 105.4 ug/L COARUA05a_ 1995-1999 E Mn-D 303d Retain 2000 37 105.4 ug/L COARUA05a_ 1995-1999 F Mn-D 303d Retain 2000 37 105.4 ug/L COLCLC02b_ B Mn-D 303d List TVS 50 ug/L COLCLC02b_ B SO4 303d List TVS 250 mg/L COLCLC04a_ A SO4 M&E Retain TVS 250 mg/L COLCLC04a_ B SO4 303d Retain TVS 250 mg/L COLCLC04a_ C SO4 M&E Retain TVS 250 mg/L COLCLC04a_ D SO4 303d List TVS 250 mg/L Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

            Sampl e Size of POR for 2000 Categor Listing TVS or 2000 Datase Portion ID Analyte y/ List Action 20001 Dataset t Value Units COLCLC07a_ C Mn-D 303d List TVS 50 ug/L COLCLC14c_ 1995-1999 B Mn-D 303d Retain 2000 59 52.6 ug/L COLCLC14c_ 1995-1999 C Mn-D 303d Retain 2000 59 52.6 ug/L COLCLY03c_ B Mn-D M&E Retain TVS 50 ug/L COLCLY03c_ B SO4 303d Retain 2000 1995-1999 13 406 mg/L COLCLY03c_ C Mn-D M&E 3bList TVS 50 ug/L COLCLY03c_ C SO4 303d Retain 2000 1995-1999 13 406 mg/L COLCLY03e_ A SO4 M&E Retain 2000 1995-1999 17 720 mg/L COLCWH13b _B Mn-D M&E Retain TVS 50 ug/L COLCWH13b _C SO4 M&E Retain 2000 1995-1999 18 383 mg/L CORGAL02_B Mn-D M&E Retain 2000 1995-2004 21 427.6 ug/L CORGAL02_ C Mn-D M&E Retain 2000 1995-2004 21 427.6 ug/L CORGAL02_ D Mn-D M&E Retain 2000 1995-2004 21 427.6 ug/L Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

            Sampl e Size of POR for 2000 Categor Listing TVS or 2000 Datase Portion ID Analyte y/ List Action 20001 Dataset t Value Units CORGAL02_ D Fe-D M&E Retain 2000 1995-2004 21 1051 ug/L CORGCB04_ 1995-2014 A Mn-D M&E Retain 2000 15 422 ug/L CORGCB12a _C Mn-D M&E Retain TVS 50 ug/L CORGRG02_ B Fe-D 303d Retain TVS 300 µg/L CORGRG02_ B Mn-D 303d Retain 2000 1995-1999 16 82.25 µg/L CORGRG04b _C Mn-D 303d Delist TVS 50 µg/L CORGRG04b _D Mn-D 303d Retain TVS 50 µg/L CORGRG05a _A Mn-D M&E Retain 2000 1995-2004 12 476.21 µg/L CORGRG38_ C Fe-D M&E Retain TVS 300 µg/L CORGRG38_ C Mn-D M&E Retain TVS 50 µg/L CORGRG38_ D Mn-D 303d Retain TVS 50 µg/L COUCBL02a_ A Mn-D 303d Retain TVS 50 µg/L Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

            Sampl e Size of POR for 2000 Categor Listing TVS or 2000 Datase Portion ID Analyte y/ List Action 20001 Dataset t Value Units COUCBL02a_ B Mn-D 303d Retain TVS 50 µg/L COUCBL06a_ B Mn-D 303d List 2000 1995-1999 54 511 µg/L COUCBL12_B Mn-D M&E Retain 2000 1995-2004 15 199 µg/L COUCBL12_C Mn-D M&E Retain 2000 1995-2004 18 199 ug/L COUCEA05a_ C Fe-D 303d Retain TVS2 µg/L COUCEA05c_ A Fe-D 303d Retain TVS 300 µg/L COUCEA10a_ B SO4 303d Retain TVS 250 mg/L COUCNP03_ A Fe-D M&E Retain TVS 300 µg/L COUCNP04a_ B Fe-D M&E Retain 2000 1995-2004 152 427 µg/L COUCNP04a_ B Mn-D M&E Retain 2000 1995-2004 153 98.4 µg/L COUCNP04a_ E Mn-D M&E Retain 2000 1995-2004 153 98.4 µg/L COUCNP04a_ F Fe-D 303d Retain 2000 1995-2004 152 427 µg/L COUCNP04a_ H Fe-D 303d Retain 2000 1995-2004 152 427 µg/L Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

            Sampl e Size of POR for 2000 Categor Listing TVS or 2000 Datase Portion ID Analyte y/ List Action 20001 Dataset t Value Units COUCNP04a_ H Mn-D 303d Retain 2000 1995-2004 153 98.4 µg/L COUCNP05b_ A Fe-D 303d Retain 2000 1995-2004 28 359 µg/L COUCUC02_ L Fe-D M&E 3bList TVS 300 µg/L COUCUC02_ L Mn-D 303d Retain TVS 50 µg/L COUCUC05_ B Mn-D 303d Retain TVS 50 µg/L COUCUC07b _D SO4 M&E Retain TVS 250 mg/L COUCUC07b _D Mn-D M&E Retain TVS 50 ug/L COUCUC07b _D Fe-D M&E Retain TVS 300 ug/L COUCUC07b _E Mn-D M&E Retain 2000 1995-1999 31 55 ug/L COUCUC07b _E SO4 303d Retain 2000 1995-1999 27 1507 mg/L COUCUC07d _B Mn-D 303d Retain TVS 50 ug/L COUCUC10a _B Fe-D M&E 3bList TVS 300 ug/L Table 1. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards.

            Sampl e Size of POR for 2000 Categor Listing TVS or 2000 Datase Portion ID Analyte y/ List Action 20001 Dataset t Value Units COUCYA18_ B Fe-D M&E 3bList TVS 300 µg/L COUCYA22_ E Fe-D 303d Retain TVS 300 ug/L Table 1. Footnotes:

      2. 1) Where this column indicates that the appropriate standard is the existing quality as of the year 2000 (as indicated with ‘2000’ in this column), information for the subsequent columns is only reported where 10 or more samples are available.
      3. 2) At this time, it is inappropriate to set an existing quality as of the year 2000 value on this waterbody because an unauthorized mine discharge located directly upstream of this waterbody that existed prior to 1995, is undergoing Comprehensive Environmental Response, Compensation, and Liability Act remediation efforts with anticipated improved water quality upon completion.

5. Site-specific decisions made by the commission are discussed below.

1. a. COUCEA09c - Temperature Segment COUCEA09c (Mainstem of the Eagle River from a point immediately below the confluence with Rube Creek to the confluence with the Colorado River) was placed on the 303(d) List due to exceedances of the aquatic life use-based cold stream tier II temperature standards. Since the data record for this segment had 4-6 years of data, an allowance of one warming event in one season was permitted. Regulation 31.16, Table 1, Footnote 5(c)(ii). Even with the allowance of one warming event in 2018, temperatures exceeded standards again in 2021, so the commission determined that placing this segment on the 303(d) List for temperature was warranted.
   1. The commission determined that the division’s application of the warming event allowance for 303(d) temperature assessments is consistent with Regulation #31 and the framework outlined in the 303(d) Listing Methodology. Furthermore, the commission determined that the warming event methodology applied to the 2024 temperature assessments is not a new interpretation and that no changes have been made to the warming event language defined in Regulation #31 and the 303(d) Listing Methodology since these documents were revised by the commission in 2016 and 2018.
      1. The commission considers an exceedance of the temperature standard as any DM/WAT above the temperature standard (chronic and acute). In addition, the commission considers the warming event to be the methodology for applying the 1-in-3-year exceedance frequency, by considering the extent of the allowable exceedances above the standard applied in units of degree-days. The recurrence frequency of these warming events is limited to once every 3 years.
      2. b. COSPUS16c - E. coli and Selenium The commission concluded that segment COSPUS16c (All tributaries to the South Platte River, including all wetlands, from the outlet of Chatfield Reservoir, to a point immediately below the confluence with Big Dry Creek) includes the tributaries to Second Creek and that the 303(d) listings for selenium and E. coli on these tributaries should be retained. The City and County of Denver suggested that the division’s interpretation of the segmentation for segment COSPUS16c was incorrect and that the tributaries to Second Creek should instead be included in the mainstem segments for these waterbodies (COSPUS16d). However, because description of segment 16d in Regulation #38 does not have the language ‘including all tributaries’ in the description, the commission agreed that the division was required to implement the description of segment 16d as it was adopted in Regulation #38, without including the tributaries to Second Creek. The commission encouraged the City and County of Denver to work with the division on evaluating the segment descriptions for Second Creek as a part of the next Regulation #38 rulemaking hearing. The commission also encouraged the City and County of Denver to address concerns regarding the 303(d) listings for selenium and E. coli on the tributaries to Second Creek by providing evidence of standards attainment or other supporting information as a part of the next Regulation #93 rulemaking hearing that focuses on the South Platte River Basin.
      3. c. COUCBL14 - Sulfate The division had originally proposed to add segment COUCBL14 to the M&E List for sulfate based on aggregation of data from West Tenmile Creek and data from the bottom of the mainstem of Tenmile Creek. Given the variability in sulfate data in these two portions of the segment, the division reassessed segment COUCBL14 and calculated the water supply standard for sulfate to be the table value standard of 250 mg/L for West Tenmile Creek (and 337 mg/L for the bottom of the mainstem of Tenmile Creek. Segment COUCBL14 attained for sulfate when these values were used, and the data from these two portions were not aggregated. The commission did not include segment COUCBL14 on the M&E List for sulfate.

         In establishing water quality concentrations that represent conditions from the year 2000, the division utilizes a historical database that is maintained and updated on a regular basis. Assessment and permitting actions utilize the best available data at the time of the action and are re-evaluated when water quality assessments are being conducted, resulting in potentially different values. Historical data may be aggregated at different geographic scales for different program purposes. However, while the numbers resulting for each purpose may be different, the historical database and the same general processes are used. The commission recognizes that assessment values for the secondary water supply standards that were utilized in this hearing for COUCBL14 may differ from values used in permitting and/or other contexts.

6. Parties to the rulemaking hearing:

1. 1. Arkansas and Fountain Coalition for Urban River Evaluation 2. City and County of Denver 3. City of Pueblo 4. Climax Molybdenum Company 5. Colorado Parks and Wildlife 6. Cripple Creek & Victor Gold Mining Company 7. Eagle River Water and Sanitation District 8. Environmental Protection Agency Region 8 9. Fortius Capital 10. Northern Colorado Water Conservancy District 11. Public Service Company of Colorado 12. Rio Grande Silver, Inc.
   1. 13. Town of Eagle 14. Town of Fraser as operator of Upper Fraser Valley Wastewater Treatment Plant 15. Town of Gypsum 16. Tri-State Generation and Transmission Association, Inc.
      1. 17. Twentymile Coal, LLC, Seneca Coal Company, Peabody Sage Creek Mining, LLC 18. Upper Blue Sanitation District

93.21 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND

PURPOSE; FEBRUARY, 9, 2026 RULEMAKING; EFFECTIVE DATE OF MARCH 30, 2026.

The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.

BASIS AND PURPOSE A. Revisions to 303(d) List 1. List Development

1. a. Listing Methodology The “Section 303(d) Listing Methodology - 2026 Listing Cycle” outlines the listing process and the criteria for listing. This Listing Methodology sets forth the criteria generally used to determine which waters to include on the 2026 Section 303(d) List and the 2026 Monitoring & Evaluation List (M&E List). This document was adopted by the commission in March of 2024. This methodology was not adopted as a rule. The commission, therefore, has the flexibility to take into account other appropriate factors in making site-specific listing decisions.
   1. b. Information Considered The commission has considered all existing and readily available information in developing the 2026 Section 303(d) List. In determining whether data and information are existing and readily available, the commission has taken into account data and information that the division has utilized in the preparation of those identification processes, calculations, and models referenced in 40 CFR §130.7(b)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and provided to the division as referenced in 40 CFR §130.7(b)(5)(iii). In addition, the commission accepted credible data and information that was submitted in accordance with the listing process schedule. The division continues to collect and analyze new data on a rotating basin basis and will utilize such data and information in making future listing determinations. Existing data that were not brought forward through one of the above mechanisms or otherwise presented to the commission in accordance with the schedule were not treated as “readily available” for purposes of making the 2026 listing decisions. Such information will be considered in the next listing cycle. This Regulation #93 hearing cycle focuses on the South Platte River Basin (Regulation #38). This approach follows the rotating basin structure described in the 2026 303(d) Listing Methodology.

2. Updates to Policy 10-1 The commission approved revisions to Policy 10-1 Aquatic Life Use Attainment Methodology to Determine Use Attainment for Rivers and Streams on August 11, 2025. The policy describes a bioassessment Multi- Metric Index (MMI) tool, which provides a direct measurement and characterization of the health of the benthic macroinvertebrate community. The MMI calculates a score that ranges from 0 to 100. These MMI scores are then compared to biological thresholds for three different biotypes: 1) transition, 2) mountains, and 3) plains & xeric.

1. Through the revised Policy 10-1, and updated MMI tool (5.0), the commission:
   1. a. Updated MMI scores, and attainment, and impairment thresholds for each biotype;
      1. b. Updated the auxiliary metric thresholds for the Hilsenhoff Biotic Index (HBI) and the Shannon Diversity Index (SDI); and c. Reduced the allowable decline for High Score Waters. During the 2026 303(d) listing cycle, the division applied the new MMI scores and Policy 10-1 thresholds to prior South Platte River basin listing decisions. Based on the MMI 5.0 tool, the commission removed the macroinvertebrate 303(d) Listing for AUID COSPBO04b_D - Mainstem of South Boulder Creek, including all tributaries and wetlands, from below the Community Ditch diversion structure (39°55'56.82”N, 105°16'50.56”W), to South Boulder Road, except for specific listings in Segments 4c and 4d.

3. Ensuring the Use of Credible Data in Current and Past Water Quality Assessments The commission rescheduled the 2026 Regulation #93 rulemaking hearing from May 2025 to February 2026 to provide additional time to ensure that recalled data were expunged from the commission’s waterbody attainment determinations.

1. Some of these recalled data were used in previous Regulation #93 rulemaking hearings. The division reviewed past listings across all watershed regulatory basins and identified which decisions were potentially affected by the recalled data. The division then removed the recalled data and reassessed those waterbodies. This resulted in four AUIDs with different conclusions from what were initially adopted. Based on those revisions, the commission adopted the changes described in Table 1. Revised Listing Decisions.

Table 1. Revised Listing Decisions Basin Waterbody Analyte Listing Cycle Previous Action Proposed New AUID Action 33 COUCYA22_D Dissolved 2024 M&E Delisting M&E List copper 36 CORGCB13_A Total iron 2024 M&E Listing M&E Remove 37 COLCLC07a_C Total iron 2024 M&E Delisting M&E List Table 1. Revised Listing Decisions 37 COLCLC16_A Total iron 2024 M&E Delisting M&E List 4. Assessment Values Used for Secondary Water Supply Standards For the secondary water supply standards of dissolved iron, dissolved manganese and sulfate, the less restrictive of the following two options apply as the numeric standard: existing quality as of January 1, 2000, or the table value criteria in Regulation #31, Tables II and III. For dissolved iron, the table value standard (TVS) is 300 ug/l. For dissolved manganese, the TVS is 50 ug/l. For sulfate, the TVS is 250 mg/l.

1. The 303(d) Listing Methodology includes language regarding the determination of existing quality from the year 2000 (EQ 2000). This includes a minimum data requirement and the ability to use data collected after the year 2000 when characterizing existing quality from 2000. The utilization of data collected past the year 2000 is contingent upon there being no new or increased sources of these parameters in the segment being assessed since 2000.
   1. Table 2. summarizes the secondary water supply assessment values used for dissolved iron, manganese, and sulfate for 303(d) or M&E Listing actions:

Table 2. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards. (Information to be entered in Division’s prehearing statement submission)

Portion ID Analyte Category Listing TVS POR Sample Value Units / List Action or for Size of 20001 2000 2000 Dataset Dataset COSPBO02a_D Mn-D M&E Retain TVS 50 ug/L COSPBO02a_F Fe-D 303(d) Retain 2000 1995- 20 341.5 ug/L COSPBO02b_E SO4 M&E Retain TVS 250 mg/L COSPBO02b_F Mn-D M&E Retain TVS 50 ug/L COSPBO07b_A Mn-D M&E 3bList TVS 50 ug/L COSPBO07b_B Mn-D 303(d) Retain TVS 50 ug/L COSPBO08_B Mn-D 303(d) List TVS 50 ug/L COSPBO14_B Fe-D 303(d) Retain TVS 300 ug/L COSPBO14_B Mn-D 303(d) Retain 2000 1995- 1315.56 ug/L COSPBO14_D Mn-D 303(d) Delist TVS 50 ug/L C OSPBT02_G Mn-D 303(d) Retain TVS 50 ug/L COSPBT03_B Mn-D 303(d) Retain 2000 1995- 106 74.125 ug/L Table 2. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards. (Information to be entered in Division’s prehearing statement submission)

Portion ID Analyte Category Listing TVS POR Sample Value Units / List Action or for Size of 20001 2000 2000 Dataset Dataset COSPBT06_A Mn-D M&E 3bList TVS 50 ug/L COSPBT06_A SO4 303(d) List TVS 250 mg/L COSPBT07_A Fe-D 303(d) List TVS 300 ug/L COSPBT07_A Mn-D 303(d) List TVS 50 ug/L COSPBT09_A Mn-D 303(d) Retain 2000 1995- 23 89.7 ug/L COSPCH01_A Mn-D 303(d) Retain 2000 1995- 55 99.9 ug/L COSPCH03_A Mn-D 303(d) List 2000 1995- 34 55.1 ug/L COSPCH04a_A Fe-D 303(d) List TVS 300 ug/L COSPCH04a_A Mn-D M&E Retain TVS 50 ug/L COSPCH04a_B Mn-D 303(d) Retain TVS 50 ug/L COSPCH04a_B SO4 303(d) List TVS 250 mg/L Table 2. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards. (Information to be entered in Division’s prehearing statement submission)

Portion ID Analyte Category Listing TVS POR Sample Value Units / List Action or for Size of 20001 2000 2000 Dataset Dataset C OSPCL02c_B Fe-D 303(d) Retain TVS 300 ug/L COSPCL02c_B Mn-D 303(d) Retain 2000 1995- 177 195.6 ug/L COSPCL02c_B SO4 303(d) List TVS 250 mg/L COSPCL02c_E Fe-D M&E Retain TVS 300 ug/L COSPCL02c_E SO4 303(d) Retain TVS 250 mg/L COSPCL03b_A Mn-D M&E Retain TVS 50 ug/L COSPCL05_B Mn-D M&E Retain 2000 1995- 82 399.85 ug/L COSPCL06_C SO4 303(d) Retain TVS 250 mg/L C OSPCL10_A Mn-D M&E Retain TVS 50 ug/L C OSPCL12a_A Mn-D M&E Retain 2000 1995- 27 317000 ug/L COSPCL12a_B Fe-D 303(d) Retain 2000 1995- 27 4048 ug/L COSPCL12a_B Mn-D 303(d) Retain 2000 1995- 27 317000 ug/L Table 2. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards. (Information to be entered in Division’s prehearing statement submission)

Portion ID Analyte Category Listing TVS POR Sample Value Units / List Action or for Size of 20001 2000 2000 Dataset Dataset COSPCL12a_B SO4 303(d) Retain 2000 1995- 21 2180 mg/L COSPCL12b_A Fe-D 303(d) List TVS 300 ug/L COSPCL12b_A Mn-D 303(d) List TVS 50 ug/L COSPCL13a_C Fe-D M&E Retain TVS 300 ug/L COSPCL13b_B Fe-D 303(d) Delist TVS 300 ug/L COSPCL13b_F SO4 303(d) List 2000 1995- 53 254.84 mg/L COSPCL14a_A Fe-D M&E Retain 2000 1995- 15 397 ug/L COSPCL14b_A Fe-D 303(d) Delist TVS 300 ug/L COSPCL14b_A Mn-D 303(d) Retain Site 244 ug/L Specific COSPCL15_B Fe-D M&E Retain TVS 300 ug/L COSPCL15_B Mn-D 303(d) Delist 2000 1995- 35 330 ug/L Table 2. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards. (Information to be entered in Division’s prehearing statement submission)

Portion ID Analyte Category Listing TVS POR Sample Value Units / List Action or for Size of 20001 2000 2000 Dataset Dataset COSPCL15_C Mn-D 303(d) Retain 2000 1995- 35 330 ug/L COSPCL16a_A Mn-D M&E 3bDelist 2000 1995- 6 132.5 ug/L COSPCL17b_A Mn-D 303(d) Retain TVS 50 ug/L COSPCP07_C Fe-D 303(d) Retain TVS 300 ug/L COSPCP07_C Mn-D 303(d) Retain TVS 50 ug/L COSPCP07_F Mn-D 303(d) Retain TVS 50 ug/L C OSPCP07_G Fe-D 303(d) Retain TVS 300 ug/L COSPCP13a_E Mn-D M&E 3bList TVS 50 ug/L COSPCP14_A Mn-D 303(d) List TVS 50 ug/L COSPLA02a_A Mn-D M&E 3bDelist TVS 50 ug/L COSPLS01a_A SO4 303(d) Retain 2000 1995- 1000 646.05 mg/L COSPLS01b_A SO4 303(d) Retain TVS 250 mg/L Table 2. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards. (Information to be entered in Division’s prehearing statement submission)

Portion ID Analyte Category Listing TVS POR Sample Value Units / List Action or for Size of 20001 2000 2000 Dataset Dataset COSPRE01_A Mn-D 303(d) List TVS 50 ug/L COSPSV04b_A Mn-D 303(d) Retain TVS 50 ug/L COSPSV04b_B Mn-D 303(d) Delist TVS 50 ug/L COSPSV04b_B SO4 303(d) Retain TVS 250 mg/L COSPSV05_A Mn-D 303(d) Retain TVS 50 ug/L COSPSV05_B Mn-D 303(d) Retain TVS 50 ug/L COSPSV06b_A SO4 M&E 3bList TVS 250 mg/L COSPUS03_B Mn-D 303(d) Retain 2000 1995- 45 170 ug/L COSPUS04_E Mn-D 303(d) Retain 2000 1995- 120 110 ug/L COSPUS05b_B Mn-D 303(d) Retain 2000 1995- 116 156.75 ug/L COSPUS07_B Mn-D 303(d) List TVS 50 ug/L COSPUS10_B Fe-D 303(d) List 2000 1995- 46 2725 ug/L Table 2. Values Used for the Assessment of Dissolved Iron, Dissolved Manganese, and Sulfate Water Supply Standards. (Information to be entered in Division’s prehearing statement submission)

Portion ID Analyte Category Listing TVS POR Sample Value Units / List Action or for Size of 20001 2000 2000 Dataset Dataset COSPUS15_B SO4 303(d) Delist TVS 250 mg/L COSPUS16k_A Mn-D 303(d) List TVS 50 ug/L Table 2. Footnotes:

1) Where this column indicates that the appropriate standard is the existing quality as of the year 2000 (as indicated with ‘2000’ in this column), information for the subsequent columns is only reported where 10 or more samples are available.

5. Site-specific decisions made by the commission are discussed below.

1. a. Upper South Platte Segment 15 and Middle South Platte Segment 1a – Category 4b Demonstration Plan In 2010, Metro Wastewater Reclamation submitted a Category 4b Demonstration Plan (Metro Category 4b Plan) for ammonia and nitrate to the division for two segments on the mainstem of the South Platte: Upper South Platte Segment 15 and Middle South Platte Segment 1. A category 4b is an alternative to listing an impaired segment on the 303(d) List, and can be appropriate when there are other required control mechanisms that are expected to address all waterbody- pollutant combinations and will attain water quality standards in a reasonable time. A Category 4b Demonstration Plan, when implemented, must ensure attainment with all applicable water quality standards through pollution control mechanisms within a reasonable period of time. This plan was accepted by the U.S. Environmental Protection Agency and these waterbodies were classified as Category 4b for ammonia and nitrate.

During previous Regulation #93 cycles, COSPUS15 was determined to be in attainment of the nitrate water quality standard and COSPMS01a, was determined to be in attainment of ammonia and nitrate water quality standards and the commission changed the category for these waterbodies from 4b to 1a for these parameters. During the 2026 (current) cycle, ammonia data demonstrated attainment of the aquatic life use standard on COSPUS15. Therefore, the commission changed this waterbody to category 1a, attaining for ammonia.

Both the Upper South Platte Segment 15 and Middle South Platte Segment 1a are currently attaining the applicable nitrate and ammonia standards. Therefore, these waters are no longer classified as category 4b for nitrate and ammonia.

1. b. Clear Creek Segment 3a (COSPCL03a) Category 4B Plan In 2015, Public Service Company of Colorado (PSCo) submitted a Category 4b Demonstration Plan (PSCo 4b plan) to the division for Clear Creek segment 3a in the South Platte River Basin. This plan covers the portion of South Clear Creek downstream of Lower Cabin Creek Reservoir to Clear Lake (COSPCL03a_C). A Category 4b Demonstration plan serves as an alternative to listing an impaired segment on the 303(d) List and can be appropriate when there are other required control mechanisms that are expected to address all waterbody-pollutant combinations and will attain water quality standards in a reasonable time. A Category 4b plan when implemented, must ensure attainment with all applicable water quality standards through pollution control mechanisms within a reasonable period of time. The U.S. Environmental Protection Agency accepted the PSCo 4b Plan, and based on a revised 4b Demonstration Plan dated November 2015, the commission classified this waterbody as Category 4b due to impairment of aquatic life, as indicated by the macroinvertebrate community. PSCo’s 4b plan was based on a 2014 Water Quality Adaptive Management Plan (WQAMP) for its Cabin Creek Pumped Storage Hydroelectric Project, which is licensed by the Federal Energy Regulatory Commission (FERC). The WQAMP was developed with input from the U.S. Forest Service (USFS), Colorado Parks and Wildlife (CPW), and the division, and is required and enforceable by FERC and USFS as part of PSCo’s FERC license. The PSCo Category 4b plan outlined a 10-year period as the WQAMP as the reasonable timeframe to meet water quality standards. The PSCo 4b plan included a Schedule for Implementing Pollution Controls, with final project results reported in 2024. At the conclusion of Year 10 (2023), PSCo would choose a course of action on the two possible outcomes of the actions taken pursuant to the WQAMP (see 4b Plan, pp. 41–42):
   1. Success, defined as attainment of the MMI threshold at Sites D, E, and F on Clear Creek Segment 3a; statistically significant improvement over baseline at Sites D, E, and F of the four individual macroinvertebrate metrics listed above and in WQAMP, Section 3.5.2, with recognition that flexibility is reserved for discussion of minor misses of this goal among consulting parties at the time of WQAMP review; brook trout mean population relative weight of 100 for fish over 130 mm in Year 10 and increase in brook trout biomass over baseline with Confidence Intervals that do not overlap. Success will also include continued attainment of the aquatic-life. Under this outcome, the WQAMP will conclude. Failure, defined as not meeting the goals identified for macroinvertebrate scores and metrics, and fish metrics, and thus failing to bring the identified portion of Clear Creek Segment 3a into attainment. Under this outcome, PSCo will consult with USFS, CPW, and WQCD to develop a mutually agreed-upon off-site mitigation program to support fish habitat, or water quality restoration efforts in the Clear Creek basin, including petitioning the WQCC for site-specific standards, if necessary.
      1. PSCo will submit any such off-site mitigation proposal to FERC for approval and thereafter implement the proposal as directed by FERC. An estimated cost for this effort is a one-time capital cost of $100,000 to $500,000, based on the assumptions that the off-site measure will be a PSCo contribution to an ongoing effort in the Clear Creek drainage and that PSCo’s contribution will be commensurate with any improvements achieved on-site under the WQAMP (i.e., if the WQAMP goals were nearly met, then PSCo’s offsite contribution would be at the lower end of the contribution range, and vice versa). PSCo understands that this outcome may require listing of Segment 3a on the 303(d) list as Category 5 if site- specific standards are not adopted. If the segment is listed as Category 5, a TMDL would need to be developed for Clear Creek Segment 3a. Despite PSCo’s full implementation and adherence to the WQAMP schedule of activities and adaptive changes implemented throughout the 10-year plan, and despite demonstrated improvements in the now-sustaining brook trout population, PSCo did not meet the goals identified for macroinvertebrate scores and metrics, and fish metrics.

Because the success criteria metrics were not met, the commission reclassified this waterbody from Category 4b to Category 5 - Impaired for aquatic life as measured through the macroinvertebrate community.

1. c. TMDLs in Development Over the Next Two Years:

The EPA stated that Section 303(d) of the Clean Water Act (CWA) and its implementing regulations require states to include a priority ranking for all listed waters requiring TMDLs. Specifically, the ranking must include an identifier highlighting the waterbodies where the TMDL will be developed in the next two years.

Historically, the division has provided the list of TMDLs to be developed in a two- year window during the ATTAINS (Assessment, Total Maximum Daily Load, and Tracking & Implementation System) submission to the EPA. However, the division understands the EPA’s position that federal regulations (40 C.F.R. § 130.7(b)(4)) require this identification to be part of the state's priority ranking within the 303(d) list itself.

In response to the EPA's feedback, the division is providing a list of TMDLs to be developed over the next two years. Furthermore, in future iterations of Regulation #93, the division will consider applying an indicator within the TMDL prioritization for Assessment Unit ID (AUID)-pollutant combinations targeted for TMDL development over the next two years.

Table 3. TMDLs to be developed in two years.

1. AUID Pollutant Estimated Completion Year COARLA01b_A selenium 2026 COARLA04a_A selenium 2026 COARLA04a_B selenium 2026 COARLA09a_B selenium 2026 COARLA09a_C selenium 2026 COARMA12_A selenium 2026 COSPBE01c_A phosphorus, chl-a 2026 COSPCP11_B, 2027 12a_B, 12a_A, 12b_A E. coli COSPCP13a_D E. coli 2027 COSPCP13a_E E. coli 2027 AUID Pollutant Estimated Completion Year COSPCP13b_C, 2027 13c_B E. coli COSPBE02_C E. coli 2028 Dissolved Oxygen and COARUA15_A phosphorus 2028 COSPCL02a,b,c _B,C,F Cd, Zn 2028 COSPCL02c_B Cd, Zn, Cu, Fe, Mn, Ni 2028 COSPCL03b_A Cd, Cu 2028 COSPCL05_B Cu 2028 COSPCL06_C Cd, Zn, Cu, Fe, Mn, Ni, Pb 2028 COSPCL09a_B Pb, Cu 2028 COSPCL09a_C Zn 2028 COSPCL10_A Cu 2028 COSPCL12a_B Cd, Cu, Fe, Pb, Mn, Ni, Zn 2028 COSPCL13b_C Cd 2028 d. Evergreen Lake Chlorophyll-a 303(d) Listing The division proposed to add Evergreen Lake (COSPBE01d_A) to the 303(d) List for an exceedance of the chronic Direct Use Water Supply (DUWS) chlorophyll-a standard. This is based on two exceeding seasons with a sample size of six for each season within a period of five years. The Bear Creek Watershed Association (BCWA) opposed the listing, contending that the exceedances observed in 2018 and 2020 occurred during atypical drought years and did not represent normal hydrologic conditions. BCWA argued that drought should be treated as a “catastrophic event” under the Listing Methodology, necessitating the exclusion of data collected during those periods.

The commission determined that the Listing Methodology Section III.B.7 Representative Data/Information provision for excluding data due to “catastrophic events” applies to localized, short-term events such as fires, floods, or chemical spills, and does not apply to drought, which is a widespread and recurrent meteorological event. Furthermore, the chlorophyll-a standard allows for an exceedance frequency of once in five years to account for varying hydrological conditions.

Additionally, evidence presented indicated that chlorophyll-a exceedances in Evergreen Lake were not limited to years with low inflow. Seasonal averages for 2016 and 2022 also exceeded the 5 ug/L DUWS standard, despite those years having normal or above-median seasonal inflows. Consequently, the commission determined the data were representative and consistent with the Listing Methodology. Evergreen Lake was placed on the 303(d) List for chlorophyll-a based on two exceeding seasons within a five-year period.

1. e. Upper South Platte Segment 14 (COSPUS14) – South Platte River The division proposed the South Platte River portion from the outlet of Chatfield Reservoir to Bowles Avenue (COSPUS14_C) for the 303(d) List for non- attainment of the acute water-supply-based nitrate standard. Highlands Ranch Water opposed this listing and argued that assessment data were not representative of current watershed conditions due to upgrades completed at the Marcy Gulch Wastewater Treatment Plant in July 2024. Additionally, they argued that the nitrate exceedances within the period of record were five to eight years old.

The 2026 Listing Methodology provides guidelines for what data is considered representative in Section III.B.7. Factors to consider include the spatial distribution of sampling locations within the waterbody/segment, temporal variability of the data, changes in the watershed (e.g., changes in predominant land use, presence of new discharges, source removal or remediation projects), age of the data, method detection limits, and bias in sampling design. The commission agrees that the upgrades made at the Marcy Gulch WWTP in July of 2024 could constitute a change in the watershed. Based on this, the commission considered the provided information and data to determine if they were sufficient to characterize the expected ongoing condition of the waterbody, therefore making the data collected prior to the upgrade non-representative. The commission acknowledges and appreciates the significant financial investment and all of the hard work by Highlands Ranch Water to upgrade the treatment capabilities of the Marcy Gulch WWTF. This is a tremendous accomplishment, which will result in improved water quality in Colorado. The commission determined that the 303(d) listing was appropriate. While Highlands Ranch Water provided data to demonstrate water quality improvements following the treatment plant upgrades, the data indicated that acute nitrate exceedances occurred as recently as March 2023. And, although the commission acknowledges that there have been no exceedances of the nitrate standard in COSPUS14_C since treatment upgrades were completed, the commission found the 1.5 years of data collected after the July 2024 upgrades represented a limited time period and were insufficient to demonstrate consistent attainment of the standard across the wide range of hydrologic conditions typically represented in a five-year period of record. Consequently, the commission adopted the division’s proposed 303(d) listing for nitrate on COSPUS14_C.

The commission supports the reassessment of this waterbody if additional data are provided during the next Regulation #93 rule-making hearing in May of 2027, understanding that this will be outside of the San Juan, Gunnison, Arkansas and Rio Grande Watershed basins. For data to be considered it shall be provided to the division by its next data call deadline in September of 2026. Based on the listing methodology, the division believes it is feasible to consider all data before the 2024 upgrades to Marcy Gulch WWTF as nonrepresentative. The commission understands that the division will assess the available data, and if warranted, the division would propose a delisting.

Currently, the division is engaging with stakeholders on how to prioritize individual permit renewals through the Permit Performance Improvement and Reporting workgroup, and this will be reflected in an annual permit work plan. The federal fiscal year (FFY) 2026 Permit Work Plan guides the work this year, and the division regularly shares its progress during the quarterly Clean Water webinars. The FFY 2027 Permit Work Plan has not been developed yet. The division is willing to delay the renewal of this permit (CO0037966 for Marcy Gulch WWTF) until after May 2027 in order to evaluate new data collected for nitrate on COSPUS14_C at the planned May 2027 Regulation 93 hearing.

6. Parties to the rulemaking hearing:

1. 1. Bear Creek Watershed Association 2. Big Dry Creek Watershed Association 3. Black Hawk Central City Sanitation District 4. Central Clear Creek Sanitation District 5. Chatfield Watershed Authority 6. Cherry Creek Basin Water Quality Authority 7. City of Greeley 8. City of Lakewood 9. Climax Molybdenum Company 10. Colorado Parks and Wildlife 11. Environmental Protection Agency 12. Highlands Ranch Water 13. North Front Range Water Quality Planning Association 14. Parker Water and Sanitation District 15. Plum Creek Water Reclamation Authority 16. Public Service Company of Colorado 17. St. Mary’s Glacier Water and Sanitation District 18. Suncor Energy (U.S.A.) Inc.
   1. 19. Town of Berthoud 20. Town of Erie Editor’s Notes History Entire rule eff. 04/30/2008.

Entire rule eff. 04/30/2010.

Rules 93.1, 93.2, 93.3, 93.14 eff. 03/30/2012.

Rules 93.2-93.4, 93.15 eff. 03/01/2016.

Rules 93.3, 93.16 eff. 11/30/2016.

Rules 93.3, 93.4, 93.15 eff. 03/02/2018.

Rules 93.3, 93.18 eff. 03/01/2020.

Rules 93.2, 93.3, 93.4 eff. 06/14/2020.

Rules 93.2, 93.3, 93.19, rule 93.4 repealed eff. 08/14/2021. Rules 93.3, 93.20 eff. 09/14/2023.

Rules 93.21 eff. 03/30/2026.