5 CCR 1002-33
DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT REGULATION NO. 33 - CLASSIFICATIONS AND NUMERIC STANDARDS FOR UPPER COLORADO RIVER BASIN AND NORTH PLATTE RIVER (PLANNING REGION 12) 5 CCR 1002-33 [Editor’s Notes follow the text of the rules at the end of this CCR Document.] _________________________________________________________________________
33.1 AUTHORITY
These regulations are promulgated pursuant to section 25-8-101 et seq. C.R.S., as amended, and in particular, 25-8-203 and 25-8-204.
33.2 PURPOSE
These regulations establish classifications and numeric standards for the Colorado River, the Yampa River, and the North Platte River, including all tributaries and standing bodies of water as indicated in section 33.6. The classifications identify the actual beneficial uses of the water. The numeric standards are assigned to determine the allowable concentrations of various parameters. Discharge permits will be issued by the Water Quality Control Division to comply with basic, narrative, and numeric standards and control regulations so that all discharges to waters of the state protect the classified uses. It is intended that these and all other stream classifications and numeric standards be used in conjunction with and be an integral part of Regulation No. 31 Basic Standards and Methodologies for Surface Water.
33.3 INTRODUCTION
These regulations and tables present the classifications and numeric standards assigned to stream segments listed in the attached tables (See Appendix 33-1). As additional stream segments are classified and numeric standards for designated parameters are assigned for this drainage system, they will be added to or replace the numeric standards in the tables in Appendix 33-1. Any additions or revisions of classifications or numeric standards can be accomplished only after public hearing by the Commission and proper consideration of evidence and testimony as specified by the statute and the Basic Standards and Methodologies for Surface Water.
33.4 DEFINITIONS
See the Colorado Water Quality Control Act and the codified water quality regulations for definitions.
33.5 BASIC STANDARDS
(1) Temperature All waters of Region 12 are subject to the following standard for temperature. (Discharges regulated by permits, which are within the permit limitations, shall not be subject to enforcement proceedings under this standard). Temperature shall maintain a normal pattern of diurnal and seasonal fluctuations with no abrupt changes and shall have no increase in temperature of a magnitude, rate, and duration deemed deleterious to the resident aquatic life. This standard shall not be interpreted or applied in a manner inconsistent with section 25-8-104, C.R.S.
(2) Qualifiers See Basic Standards and Methodologies for Surface Water for a listing of organic standards at
(3) Uranium
(4) Nutrients See Basic Standards and Methodologies for Surface Water at 31.17 for a listing of chlorophyll a, total nitrogen, and total phosphorus standards for lakes and reservoirs (Table V) and rivers and streams (Table VI). As described in 31.17(2), total nitrogen and total phosphorus standards will be considered for adoption in phases.
Aspen Village Inc c/o Independence COUCRF03a Aspen Village, INC. COG588085 Environmental Services COUCRF03a Riversbend HOA Riverbend Apartments COG588066 COUCRF03a Independence Environmental Services Lazy Glen Homeowners Assoc. COG588049 COUCRF03a Basalt SD Basalt Sanitation District COG588063 Ranch at Roaring Fork c/o COUCRF03a Ranch at Roaring Fork HOA COG588051 Independence Environmental Services COUCRF03a Roaring Fork Water and San District Roaring Fork WSD WWTF CO0044750 COUCRF03a Spring Valley SD Spring Valley SD WWTF CO0046124 COUCRF03a Oak Meadows Service Company Oak Meadows WWTF CO0045802 COUCRF03c Carbondale Town of Carbondale Town of COG588050 COUCRF03c Sunlight Inc Sunlight, INC. CO0038598 COUCRF03c Mid Valley Metro District Mid Valley Metro Dist WWTF COG588105 COUCRF03c Blue Creek Ranch LLC Blue Creek Ranch COG588074 COUCRF03c H Lazy F LLC H Lazy F MHP WWTF COG588035 COUCRF03c El Rocko Mobile Home Park El Rocko MHP COG588029 COUCRF04 Snowmass WSD Snowmass WSD CO0023086 COUCRF08 Sopris Engineering LLC Redstone Castle WWTF COG588115 COUCRF08 Redstone WSD Redstone WSD WWTF CO0046370 COUCNP05b Walden Town of Walden Town of WWTF CO0020788 COUCYA02a Yampa Town of Yampa WWTF CO0030635 COUCYA02a Routt County Milner Community WWTF CO0047449 COUCYA02b Hayden Town of Hayden Town WWTF CO0040959 COUCYA02b Steamboat Springs City of Steamboat Springs, City of CO0020834 COUCYA03 Whiteman School Whiteman School CO0031062 Routt County Phippsburg/Dept of Envir COUCYA04 Routt CO for Phippsburg Comm WWTF COG589026 Hlth COUCYA07 Oak Creek Town of Oak Creek, Town of CO0041106 Steamboat Lake Water and Sanitation Steamboat Lake Water & Sanitation COUCYA08 CO0035556 Dist Dist WWTF Morrison Creek Metropolitan Water and COUCYA22 Morrison Creek Metro WWTF CO0022969 Sanitation District Steamboat Lake Water and Sanitation Steamboat Lake Water & Sanitation COUCYA22 CO0035556 Dist Dist WWTF Prior to December 31, 2027:
• For segments located entirely above these facilities, total nitrogen and total phosphorus standards apply to the entire segment.
• For segments with portions downstream of these facilities, total nitrogen and total phosphorus standards only apply above these facilities. A note was added to the total phosphorus and total nitrogen standards in these segments. The note references the table of qualified facilities at 33.5(4). • For segments located entirely below these facilities, total nitrogen and total phosphorus standards do not apply.
• Additionally, for segments with portions downstream of these facilities or for segments located entirely below these facilities, total phosphorus standards may apply where special circumstances have been identified by the Commission (31.17(2)(a)(i)(B) and 31.17(2)(a)(ii)(B)).
33.6 TABLES
(1) Introduction The numeric standards for various parameters in this regulation and in the tables in Appendix 33- 1 were assigned by the Commission after a careful analysis of the data presented on actual stream conditions and on actual and potential water uses. For each parameter listed in the tables in Appendix 33-1, only the most stringent standard is shown. Additional, less stringent standards may apply to protect additional uses and can be found in the tables in Regulation No. 31. Numeric standards are not assigned for all parameters listed in the tables in Regulation No. 31. If additional numeric standards are found to be needed during future periodic reviews, they can be assigned by following the proper hearing procedures.
(2) Abbreviations
Manganese = 50 µg/L (dissolved)
Sulfate = 250 mg/L (dissolved)
For all surface waters with a “water supply” classification that are not in actual use as a water supply, no water supply standards are applied for iron, manganese or sulfate, unless the Commission determines as the result of a site-specific rulemaking hearing that such standards are appropriate.
(3) Table Value Standards In certain instances in the tables in Appendix 33-1, the designation “TVS” is used to indicate that for a particular parameter a “table value standard” has been adopted. This designation refers to numerical criteria set forth in the Basic Standards and Methodologies for Surface Water. The criteria for which the TVS are applicable are on the following table. TABLE VALUE STANDARDS (Concentrations in µg/L unless noted)
PARAMETER(1) TABLE VALUE STANDARDS(2)(3)
Aluminum(T) Acute = e(1.3695*ln(hardness)+1.8308)
Chromium VI(7) Acute = 16 Chronic = 11 Copper Acute= e(0.9422*ln(hardness)-1.7408)
Lead Acute= (1.46203-(ln(hardness)*0.145712))*e(1.273*ln(hardness)-1.46) Chronic=(1.46203-(ln(hardness)*0.145712))*e(1.273*ln(hardness)-4.705) Manganese Acute= e(0.3331*ln(hardness)+6.4676)
Nickel Acute= e(0.846*ln(hardness)+2.253)
Nitrogen(6) See 31.17 TVS for Aquatic Life and/or Recreation. Phosphorus(6) See 31.17 TVS for Aquatic Life and/or Recreation. Selenium(8) Acute = 18.4 Chronic = 4.6 PARAMETER(1) TABLE VALUE STANDARDS(2)(3)
Silver Acute= 0.5*e(1.72*ln(hardness)-6.52)
Temperature TEMPERATURE TIER STANDARD (°C)
March Cold Lake(10) CL brook trout, brown trout, April – Dec. 17.0 21.2 cutthroat trout, lake trout, rainbow trout, Arctic grayling, Jan. – March 9.0 13.0 sockeye salmon Cold Large CLL brown trout, lake trout, April – Dec. 18.3 24.2 Lake (>100 rainbow trout acres surface Jan. – March 9.0 13.0 area)(10)
Warm Stream WS-I common shiner, Johnny March –
Tier I darter, orangethroat darter, Nov.
stonecat Dec. – Feb. 12.1 24.6 Warm Stream WS-II brook stickleback, central March – Tier II stoneroller, creek chub, 27.5 28.6 Nov.
longnose dace, Northern redbelly dace, finescale dace, razorback sucker, white Dec. – Feb. 13.8 25.2 sucker, mountain sucker Warm Stream WS-III all other warm-water species March –
Tier III Nov.
Chronic= e(1.1021*ln(hardness)+2.2382)
Zinc Acute = 0.978*e(0.9094*ln(hardness)+0.9095)
(4) Site-specific Standards, Assessment Locations and Assessment Criteria
March-June, Iron(chronic) = 2090(T), median of all data July-February, Iron (chronic) = 1000(T)
Foidel Creek Iron(chronic) = 1000(T), median of all data Iron Assessment Locations:
Middle Creek Site G-MC-2/Site 29: located at 40.396768, -106.980422 Foidel Creek Site 14: located at 40.335154, -107.085973 Foidel Creek Site 8: located at 40.365472, -107.045444 Foidel Creek Site 900: located at 40.390194, -106.994694 (i) Yampa River Segment 13b: Temperature Standards Fish Creek DM = 21.2 and MWAT = 16.9 from 4/1 – 5/31 DM and MWAT = WS-II from 6/1 – 9/30 DM = 21.2 and MWAT = 16.9 from 10/1 – 10/31 DM and MWAT = WS-II from 11/1 – 3/31 All other locations DM and MWAT = WS-II (j) Yampa River Segment 13d: Iron Standards and Assessment Locations Iron Standards:
March-April, Iron (chronic) = 3040(T), snowmelt season median values May-February, Iron (chronic) = 1110(T), no-snowmelt season median values Iron Assessment Locations:
Seneca II-W Stream Site 7 on Hubberson Gulch (WSH7): located in the middle reaches of Hubberson Gulch at 40.386235, -107.269066 Seneca II-W Flume Site 1 on Hubberson Gulch (WSHF1): located on Hubberson Gulch just upstream of its confluence with Dry Creek at 40.393377, -107.272209 Seneca II-W Stream Site 5 on Dry Creek (WSD5): located in the middle reaches of Dry Creek at 40.427817, -107.256629 (k) Yampa River Segment 13e: Iron Standards and Assessment Locations Iron Standards:
Upper Sage Creek: Iron(chronic) = 1250(T), median of all data Lower Sage Creek: Iron(chronic) = 1000(T), median of all data Break between Upper and Lower Sage Creek is at 40.39202, -107.20000 Iron Assessment Locations:
Yoast Stream Site 2 on Sage Creek (YSS2): located at 40.383515, -107.193475 Seneca II-W Stream Site 3 on Sage Creek (WSSF3): located at 40.408001,
107.231974
Mainstem Bond Creek: fish tissue whole body = 8.5 mg/kg dry weight, not to be exceeded. When fish tissues are at steady state, whole body tissue results supersede instream water column results when both representative fish tissue and water column concentrations are measured.
Mainstem Bond Creek: chronic water column = 9.0 µg/L dissolved total selenium (i.e., all species of selenium that are dissolved into the water column and would be measured in a water sample after passing through a 0.45 µm membrane filter). Monthly average, not to be exceeded more than once in three years on average. The instream water column value is the applicable standard in the absence of representative fish tissue data or when fish tissues have not reached steady-state. No acute water column standard applies.
Mainstem Cow Camp Creek: fish tissue whole body = 8.5 mg/kg dry weight, not to be exceeded. When fish tissues are at steady-state, whole body tissue results supersede instream water column results when both representative fish tissue and water column concentrations are measured.
Mainstem Cow Camp Creek: chronic water column = 8.5 µg/L dissolved total selenium (i.e., all species of selenium that are dissolved into the water column and would be measured in a water sample after passing through a 0.45 µm membrane filter). Monthly average, not to be exceeded more than once in three years on average. The instream water column value is the applicable standard in the absence of representative fish tissue data or when fish tissues have not reached steady-state. No acute water column standard applies. See 33.73(B)(4) for more information.
Assessment Locations for Site-specific Selenium Standards: Bond Creek - Site G-BC-3 (40.412050°, -107.019250°)
Cow Camp Creek - Upper Site G-CC-1 (40.392790°, -107.092050°) Cow Camp Creek - Lower Site G-CC-2 (40.397690°, -107.020360°) All other waterbodies in Segment 13g: chronic and acute selenium = TVS (n) Yampa River Segment 22: Temperature Standards All locations DM and MWAT = CL, CLL from 1/1 – 3/31 Pearl Lake DM = CLL and MWAT = 19.6 from 4/1 – 12/31 Steamboat Reservoir DM = CLL and MWAT = 21.6 from 4/1 – 12/31 Stagecoach Reservoir DM = CLL and MWAT = 21.7 from 4/1 – 12/31 All other locations DM and MWAT = CL,CLL from 4/1-12/31
(5) Stream Classifications and Water Quality Standards Tables The stream classifications and water quality standards tables in Appendix 33-1 are incorporated herein by reference.
(6) Discharger-specific Variances
33.7 - 33.9 RESERVED
33.10 STATEMENT OF BASIS AND PURPOSE
(1) Introduction These stream classifications and water quality standards for state waters in Eagle, Grand, Jackson, Pitkin, Routt, and Summit Counties implement requirements of the Colorado Water Quality Control Act, C.R.S. 1973, 25-8-101 et seq. They also represent the implementation for Planning Region 12 of the Commission's Regulations Establishing Basic Standards and an Antidegradation Standard and Establishing a System for Classifying State Waters, for Assigning Standards, and for Granting Temporary Modifications (the “basic standards”). The basic regulations establish a system for the classification of state waters according to the beneficial uses for which they are suitable or are to become suitable, and for assigning specific numerical water quality standards according to such classifications. Because these stream classifications and standards implement the basic regulations, that statement of basis and purpose (Section 3.1.16) must be referred to for a complete understanding of the underlying basis and purpose of the regulations adopted herein; therefore, that statement of basis and purpose is addressed to the scientific and technological rationale for the specific classifications and standards developed from information in the record established in the administrative process. Public participation was a significant factor in the development of these regulations. A lengthy record has been built through public hearings, and this record establishes a substantial basis for the specific classifications and standards adopted. Public hearings were commenced on August 20, 1979, to receive a testimony, and were continued on September 5, October 9, October 10, and November 5, 1979. A total of twenty-two persons requested and were granted party status by the Commission in accordance with C.R.S. 1973, 24-4-101 et seq.
(2) General Considerations
(3) Definition of Stream Segments
(4) Use Classifications -- Generally
The “goal” qualifier (Section 3.1.13(2)(a), basic regulations) has been used in specific cases where waters are presently not fully suitable for the classified use, but are intended to become so. In all such cases, water quality standards have been assigned to protect the classified uses and temporary modifications have been granted for specific parameters.
The Commission has considered appending the “interrupted flow” qualifier to numerous stream segments in accordance with Section 3.1.13(2) 8 of the basic regulations; however, numerous questions have arisen as to its meaning and applicability. The intention of the provision is to allow the Commission to classify certain stream segments according to their water quality, despite the existence of flow problems. It has not been included in order to eliminate confusion as to its applicability to diminished, as opposed to interrupted, flows. It has also been eliminated in order to avoid any misimpression regarding benefits to dischargers. This qualifier is essentially a statement of the obvious, particularly in view of the provision regarding low flow exceptions (Section 3.1.9(1), basic regulations).
In addition, where flow characteristics permanently impair the suitability of the stream segment to provide a habitat for a wide variety of aquatic life, the “Class 2 - Cold Water Aquatic Life” classification has been assigned.
(5) Water Quality Standards -- Generally
Consistent with the basic regulations, the Commission has not assumed that the table values have presumptive validity or applicability in Region 12. This accounts for the extensive data in the record of ambient water quality; however, the Commission has found that the table values are generally sufficient to protect the use classifications. They have, therefore, been applied in the situations outlined in the preceding paragraph, as well as in those cases where there is insufficient data in the record to justify the establishment of different standards. The documentary evidence forming the basis for the table values is included in the record.
Levels that were determined to be below the detectable limits of the sampling methodology employed were averaged in as zero rather than at the detectable limit. This moves the mean down; but since zero is also used when calculating wasteload allocations, this method is not unfair to dischargers. A number of different statistical methods could have been used. All of them have pros and cons and the approach used is reasonable.
Metals present in water samples may be tied up in turbidity when the water is present in the stream. In this form they are not “available” to fish and may not be detrimental to aquatic life. Because the data of record does not distinguish as to availability, some deviation from table values, as well as the use of (x̄+ s) is further justified, because it is unlikely that the total value in the samples analyzed is in available form.
Section 3.1.14(5) of the basic regulations states that “dischargers will not be required to regularly monitor for any parameters that are not identified by the division as being of concern”. Generally, there is not requirement for monitoring unless a parameter is in the effluent guidelines for the relevant industry.
(6) Classification and Standards -- Special Cases Except as indicated above and below, the Commission accepts and incorporates herein the rationale for specific stream segments of the Water Quality Control Division developed in conjunction with the proposed classifications and standards, and made part of the record as Water Quality Control Division Exhibits 2 and 3 at the hearing on October 4, 1979. In order to properly correlate these documents with the proposals themselves, the Division's revised proposals must be consulted. This is Water Quality Control Division Exhibit 3 of the hearing on October 4, 1979 (23 pages).
The mainstem of the Blue River has been broken down into two segments because of current problems associated with the Breckenridge treatment plant. The Commission endorses the rationale of the staff located at pages 10 and 11 of the Water Quality Control Division Exhibit 2, except as to fecal coliform and ammonia. The change as to fecal coliform conforms to the reasoning outlined above. The evidence is compelling regarding the need for a temporary modification for ammonia. The standard for unionized ammonia of 0.02 mg/l may be met now, but not consistently. Because of growth pressures in the area, more consistent violations of the standard in the near future are imminent.
A new plant is coming on line in the fall of 1981 or the winter of 1982. Significant questions presently exist regarding the location of the discharge and the kind of treatment that will be installed to meet the ammonia standard. Pending the completion of the new facility, a temporary modification is appropriate. The Breckenridge Sanitation District has recommended a temporary modification to 0.05 mg/l NH3 on the basis that phosphorus removal is presently capable of reducing the ammonia to this level. The Commission accepts this alternative proposal.
Because of the importance of this segment as a spawning area, close monitoring of these waters is necessary, and the Commission may have to re-examine this decision in the near future.
At the very least, the Commission recognizes its obligation to re-examine its decision with regard to the temporary modification within three years.
The staff has recommended standards based on instream values and “goals” based on the “pilot plant data” i.e., data accumulated during the first six months of operation of the new treatment plant, while it was operating at the 50 percent of rated capacity. The staff's opinion is that these “goals” should be met with operation of the new plant. If the Commission were to adopt this approach, it would use the recommended “goals” as the standards, and set the recommended standards as temporary modifications (for copper, lead, and zinc); however, this approach was not taken because the data with respect to the new plant is not wholly adequate in determining what it will produce. This is an important concern since a significant portion of the flow of the stream goes through the plant. Therefore, instream values sufficient to protect the uses have been established and no temporary modifications have been granted.
The standards for metals are based on a hardness of less than 100 derived from the water quality data measured downstream. Basing the standards on a hardness of 400 which derives from effluent data would be unreasonable since ambient water quality for purposes of these standards is not to be measured at the point of discharge. The water supply classification has been removed because there is not water supply use, and standards have been assigned from table values in accordance with the appropriate classifications, except in the metals categories.
The reasoning contained in the Water Quality Control Division Exhibit 2 on this stream segment is generally acceptable.
The water supply classification has been included because water quality is sufficient to protect this use.
The standards reflect instream water quality. Only cadmium and zinc represent values higher than the table values.
The Commission takes the same approach here with respect to the possibility of improved water quality as it does for the upper segment of Tenmile Creek.
Although there is conflict in the evidence before the Commission regarding the “Aquatic Life - Class 1 - Cold” use, the Commission finds that the evidence is sufficient to show the presence of a variety of cold water aquatic life, although their numbers may be impacted. In addition, flow and streambed characteristics indicate that a variety of aquatic life can be supported and that the “Class 1” category is appropriate. The “Water Supply” classification has been included because even though such use is not present within this segment, the classification is necessary to protect the Eagle-Vail water supply downstream, immediately below Gore Creek.
Inactive mines are at least partially responsible for water quality degradation in this segment. Some of these sites are of undermined ownership, and therefore, control of these sources cannot be predicted with any certainty. The control of some sources of pollution on this segment and the planned removal of the Cross Creek discharge by the New Jersey Zinc Company is expected but the extent of favorable impact of these efforts on water quality is unknown. Under no circumstances is water quality expected to improve beyond upstream quality, and therefore, some standard reflect those values (cadmium, copper, lead and zinc), and temporary modifications are not assigned. Manganese and iron levels are set to protect the downstream water supply, and reflect table values.
The manganese problem on the Eagle River originates upstream of Gore Creek. For the reasons indicated above, the standard reflects the value necessary to protect the water supply use. That standard is not currently being met; however, control measures by the New Jersey Zinc Company are deemed sufficient to allow the standard to be met in the future. Therefore, a temporary modification has been granted. Standards for the other metals reflect instream values.
The record shows a conflict in the evidence concerning the data on ambient water quality which is the basis for the standards here. New Jersey Zinc Company presently discharges into Cross Creek, although an NPDES permit application is currently pending to move the discharge point to the Eagle River. The company's data indicates higher instream values than found by the Division. The Commission has adopted the Division's recommended standards because its analysis includes the most recent data, which was not used by the company. Also, difference sampling methods currently in use are found to be more accurate and they indicate lower values.
Although there is a conflict in the evidence regarding the existence of aquatic life downstream of th Snowmass Sanitation District discharge, the record supports the finding that a fishery is present. However, because the discharge sometimes constitutes the entire flow of the stream in the summer months, it is considered intermittent and assigned an “Aquatic Life - Class 2” classification. Nevertheless, standards have been assigned to protect the existing fishery.
The Snowmass Sanitation District has been funded for tertiary treatment but the technology is untested; therefore, a temporary modification has been assigned for ammonia.
Otherwise, ambient water quality data indicates that the table values are bing met and standards have been assigned accordingly.
Although the “Aquatic Life - Class 1 - Cold” classification is appropriate, there is a limited variety of aquatic life below Oak Creek Drain. Because of this and because of the short distance between the Oak Creek discharge and the Oak Creek Drain, it is inappropriate to establish an ammonia standard at this time.
F I S C A L S T A T E M E N T Stream Classifications and Water Quality Standards for the Upper Colorado River, the headwaters of the North Platte River, and the Upper Yampa River (Essentially those streams and water bodies in Eagle, Grand, Jackson, Pitkin, Routt and Summit Counties)
The Water Quality Control Commission is charged with the responsibility to conserve, protect, and improve the quality of state waters pursuant to C.R.S. 1973, 25-8-101 et seq. The Commission is further charged to classify all waters of the State and to promulgate standards for any measurable characteristic of the water. (25-8-203 and 25-8-204). The above-titled document assigns use classifications and standards for the state waters in the listed areas in accordance with the “basic regulations” adopted May 22, 1979.
The measurable fiscal impacts which may be caused by these regulation are as follows: - Cost of construction of increased capacity of municipal waste treatment facilities; - Cost of construction of increased capacity of industrial waste treatment facilities; - Cost of Operation & Maintenance of municipal enlargements; - Cost of Operation & Maintenance of industrial enlargements; and - Cost of instream monitoring and lab analysis for new parameters added by the standards. Dischargers will not be required to do stream monitoring. Only those parameters which are limited by a discharge permit will be monitored. The state, federal, and local agencies now doing instream monitoring will have some increased cost; however, any additional frequency should be done to improve state surveillance and would be needed regardless of standard changes. The Division has reviewed these regulations and determined that the following municipalities may need to construct additional facilities because of more stringent water quality standard and may have additional annual operation costs in the amounts shown:
Persons who benefit from standards which will protect existing and future anticipated uses can be identified as all persons benefiting from recreation, municipal water supply, and agriculture. These benefits are directly economic for agriculture, industry and municipalities who health benefit costs are reduced by having clean water, and are both economic and nonquantifiable for some uses such as fishing, recreation, and the aesthetic value of clean waters. Furthermore, benefits will result from human health protection and lack of debilitating disease. Figures have been developed for a recreation/fishing day which can be applied to that aspect of a water use; however, figures which have been developed for total recreation/fishing day uses have been developed statewide and could not be applied region-by- region or stream-by-stream.
The uses of water in this region are adequately protected by these standards. Most municipal treatment facilities and industrial facilities are currently adequate, or are already being upgraded, in order to meet previous requirements. Any additional facilities or expansions in this region will generally be caused by increased capacity required because of pollution growths or industrial enlargement. Industries are required by federal statute to meet effluent limitations described as “best available technology” by 1983 or 1984. For all major industries in this region, the water quality standards should not require treatment beyond these limitations.
No attempt can be made to identify future development costs as this type of data is not readily available.
33.11 STATEMENT OF BASIS AND PURPOSE FOR SEGMENT 13 and 14, TEN MILE CREEK
Use Classification The evidence in this proceeding as well as prior proceedings have established that the Climax discharge, Segment 13, does not have sufficient flow to sustain a classification of aquatic life, Cold Water Class 1 on a year round basis. It is contemplated that Climax will not discharge during the period December 25 through February 28. These months are generally low flow months of the year. Hence, the flow conditions are not present to support an aquatic life, Cold Water Class 1 designation on a year round basis on Segment 13.
The Commission has received testimony and exhibits in this and previous hearings concerning Ten Mile Creek which establish that the number and kind of aquatic species in Segment 13 is limited and that few, if any, sensitive species are found in Segment 13. The Commission believes that the Water Quality standards for Segment 13 that it is adopting today will protect existing species and encourage the establishment of more sensitive species which are compatible with the flow and streambed characteristics of Segment 13.
Testimony has also been presented in a previous hearing on Ten Mile Creek as to the cost of achieving a Class 1 Classification for Segment 13. In weighing these costs together with the cost already expended to improve the water quality of Ten Mile Creek against the low flow and limited aquatic life conditions presently found in Segment 13, the Commission concludes that it would not be economically reasonable to retain a classification of aquatic life, Cold Water Class 1 for Segment 13. Hence, the Commission adopts aquatic life, Cold Water 2 to apply to Segment 13 of Ten Mile Creek. The Commission does not find that classifying this Segment with a goal of aquatic life is appropriate. The Segment does contain aquatic life and any upgrading from Class 2 to Class 1 could proceed during periodic review to reflect any possible improvements.
Segmentation The evidence in these proceedings on Ten Mile Creek have shown that Ten Mile Creek for all intents and purposes begins at Climax property boundary at a place designated as the “Parshall Flume”. It is at this point that the natural flows that are intercepted by Climax in the Ten Mile Creek Basin are channelled together and form the source of Ten Mile Creek. Hence, the Commission believes Parshall Flume to be the source of the mainstem of Ten Mile Creek. Also, included in this segment are all tributaries to Ten Mile Creek including those natural tributaries intercepted by Climax. Water Quality Standards The evidence of Climax and the Division in this proceeding has shown that water quality standards in Ten Mile Creek vary considerably during certain periods of the year. The principal cause of this variation is the hydrological condition, mainly the spring run-off (snowmelt bypass). During this period it becomes economically unreasonable, if not impossible, to provide treatment for the large flow of runoff water that comes into contact with the Tailings Ponds located in the Ten Mile Creek Basin. Hence, the Commission has adopted seasonal water quality standards for both Segments 13 and 14 of Ten Mile Creek. Segment 13 The Commission has been presented with Climax data and calculations of such data for various pollutants during the period November, 1979 thru April, 1982. No STORET exists for Segment 13, hence only the Climax data was used. All Climax data was analyzed according to the total method. The water quality standards for the non-runoff period are based on data including all ambient data obtained during the time the Climax Wastewater Treatment facility was operating with the exception of the bypass periods associated with the runoff in the months of January and February during which Climax will not discharge in the future. The Commission recognizes that this period varies from year to year and that it will be determined annually by the Division and Climax. This period shall generally commence not earlier than May 1 and extend approximately 60 days as more specifically defined by the Climax water balance computer model. Historically a bypass has not been necessary every year and may not always be necessary in the future.
The Commission has also been presented with Climax data covering the snowmelt bypass periods of 1980 and 1982. In view of a seasonal variability of the ambient water quality, the Commission adopts x̄+ s of the snowmelt bypass data as water quality standards to apply during this period. In adopting the above water quality standard for Segment 13, the Commission is mindful of its goals to protect the use classifications in Segment 14. The Commission finds that the water quality standards it has adopted for Segment 13 are based on historical data gathered during a period when there was general improvement in stream quality. Hence, the water quality standards based on such data should be sufficient to protect and maintain the uses assigned to both Segments 13 and 14, including water supplies in Segment 14.
Segment 14 The Commission has been presented with STORET and Climax data and calculations for various pollutants during the period November, 1979, through April, 1982. As with Segment 13 data, these have been split according to the snowmelt bypass and non-runoff periods. Climax data was analyzed by the total method. The State data was analyzed according to the State methodology. For the snowmelt bypass period the Commission adopts the x̄+ s of the combined non-runoff data. Evidence indicates the standards as adopted do not require additional technology, and are economically reasonable.
FISCAL IMPACT STATEMENT Revision of Aquatic Life Classification and Certain Numeric Standards Segments 13 and 14 of Ten Mile Creek The principle fiscal impact of the adoption of the aquatic life class 2 classification and revised water quality standards is a significant potential cost savings to be realized by Climax Molybdenum Company. Evidence submitted by Climax Molybdenum Company suggests that without these modifications, Climax would be faced with a strong probability of additional treatment to cost from $8.2 million to $14.6 million in capital expenses and from $3.8 million to $6.6 million in annual operating and maintenance costs. Because evidence suggests that the beneficial uses that are identified and in place will be adequately protected and possibly enhanced with these changes, and because potential beneficial use improvements to be realized by additional treatment do not bear a reasonable relationship to the costs to attain them at this time, the Commission concludes that it is economically reasonable to support the change of the aquatic life classification and revision of certain numeric standards on these segments.
33.12 STATEMENT OF BASIS AND PURPOSE
The proposed phosphorus (P) standard for Dillon Reservoir, Segment 3 of the Blue River in Summit County was 0.010 mg/l in the top five meters, as an annual average. Based on the record, the Commission found that the summer beneficial uses were those that should be protected by the phosphorus standard. Therefore, the adopted standard of 0.0074 mg/l total phosphorus as P measured in the top 15 meters of water is for the months July through October. The standard as proposed in the notice of rulemaking and that which was adopted are based on the same set of phosphorus sampling, but the adopted standard is based only on the July to October data. In adopting the alternate proposal of 0.0074 mg/l P, the Commission reduced the four inorganic numeric special standards for phosphorus assigned only for the Dillon Reservoir portion of Segment 3 of the Blue River. The Commission took this action to maintain the chlorophyll a in the Dillon Reservoir at a level which will protect presently classified beneficial uses. The Commission found there were no significant differences in the phosphorus levels among the areas encompassed by the Reservoir. Maintaining the 0.0074 mg/l of phosphorus should limit chlorophyll a to the 1982 level.
The Commission found that the assignment of a single phosphorus standard to the Dillon Reservoir was economically reasonable.
FISCAL IMPACT STATEMENT Regulations for Control of Water Quality in Dillon Reservoir The fiscal impacts of these control regulations are an extension of the fiscal impacts associated with the phosphorus standards set by the Commission for the Dillon Reservoir. As the phosphorus standards drive the control regulations, the essential economic analysis is more properly attributed to the standards regulation. The Fiscal Impact Statement for the phosphorus standard regulations is attached and linked to this Statement by reference. The Commission is aware of and takes active notice of these impacts in passing these control regulations. Thus, the benefits associated with this regulation are the benefits that surround the phosphorus limits set by the Commission. Likewise, the majority of the costs are linked to the standard.
A unique fiscal impact that is solely a result of these regulations is that which falls on Summit County local government to manage and enforce the phosphorus limits in regard to point/non-point source trade-offs. There was no specific testimony or evidence that put firm figures into the record for the Commission's consideration regarding these costs but the Commission recognizes several important ideas in passing these regulations. As the regional 208 authority is at the planning and management region level, the Northwest Colorado Council of Governments (NWCCOG), the Commission is aware that much of the administrative costs will fall upon this entity. Because the NWCCOG recommended and supported the adopted standards in full awareness of the likely impacts, the Commission concludes that the associated costs are deemed to be reasonable by the NWCCOG. Secondly, the NWCCOG testified that they did not expect these costs to be out of line with the expected benefits of the regulations. Therefore, even in the absence of final estimates of the costs to local government, the Commission must conclude that the costs are reasonable because those that would bear the costs are in support of the regulations that would impose them.
The Commission actively sought and evaluated economic reasonableness testimony regarding the phosphorus standard and found the final adopted standard to be reasonable on economic grounds. Because these control regulations are inextricably linked to the phosphorus standards and because the unique costs that these regulations impose upon local governments are considered reasonable by those that would bear them, the Commission concludes that it has acted in an economically reasonable and responsible manner in passing these regulations.
33.13 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE FOR
TENMILE CREEK The Water Quality Control Commission supports the request to set seasonal standards of 2.1 mg/l for total iron and 1.6 mg/l for total manganese for Segment 13 of Tenmile Creek. Segment 13 is defined as the mainstem of Tenmile Creek from the Climax Parshall Flume to a point immediately above the confluence of West Tenmile Creek and all tributaries, lakes and reservoirs from the source of Tenmile Creek to a point immediately above the confluence with West Tenmile Creek except for specific listing in Segment 15.
The current water quality standards for iron and manganese during the snowmelt bypass period in Segment 13 of Tenmile Creek are based on “Table Value” water quality standards of 1.0 mg/l whereas the actual ambient water quality of iron and manganese during the snowmelt bypass is 2.1 mg/l and 1 6 mg/l. respectively based on a calculation of x̄+ s. Hence, assuming zero low flow, as was done by the Division in the discharge permit under which AMAX is operating, the effluent limitations for iron and manganese cannot be met during the snowmelt bypass period. The snowmelt bypass period is defined as any contiguous period of time not to exceed 60 days commencing not earlier than May 1 and terminating not later than July 31.
Seasonal standards for cyanide, cadmium, copper, lead, and zinc were set for Segment 13 in December, 1982. Those standards were proposed after lengthy discussions between Climax Molybdenum, Colorado Division of Wildlife and Water Quality Control Division. At that time the attention was focused on those parameters that are specified in the BAT requirements for the ore mining and dressing industry, the reasoning being that a minimum of BAT limits would be required for any snowmelt bypass. Iron and manganese, which are not included in BAT requirements and are also in exceedence of the stream standards during snowmelt bypass periods (attachment), were inadvertently neglected in the proposal for seasonal standards.
Discussions between the Water Quality Control Division and the Colorado Division of Wildlife concluded that the proposed seasonal standards for iron and manganese which are only applicable during the snowmelt bypass period would have no significant impact on the aquatic life use classification of Segment 13. Also, the Commission is convinced that downstream water supplies will not be impacted by this action. The snowmelt bypass period is defined as any continuous period of time not to exceed 60 days commencing not earlier than May 1 and terminating not later than July 31. These standards are consistent with the Commission's practice of adopting water quality standards based on instream quality where the data indicates that Table Values are exceeded, but existing uses are nevertheless adequately protected.
During this period (snowmelt bypass) it becomes economically unreasonable, if not impossible, to provide treatment for the large flow of runoff water that comes into contact with the Tailings Ponds located in the Tenmile Basin. Evidence indicates the standards adopted do not require additional technology and are economically reasonable.
The discharge permit issued by the Division includes effluent limitations for iron and manganese during the snowmelt bypass period that cannot be met. As recognized in the Statement of Basis and Purpose, it is economically unreasonable, if not impossible, to provide treatment to achieve the iron and manganese limits during this time.
The specific statutory authority for these amendments is C.R.S. Section 25-8-204. FISCAL IMPACT STATEMENT As in the 1982 rulemaking proceedings, the principal fiscal impact of the adoption of the revised water quality standards is a significant potential cost savings to be realized by AMAX. Evidence submitted by AMAX in the 1982 proceedings suggests that without the proposed modifications, AMAX would be faced with additional treatment costs from $8.2 million to $14.6 million in capital expenses and from $3.8 million to $6.6 million in annual operating and maintenance costs. Because the evidence in this proceeding, as well as that of the 1982 proceeding, suggests that the beneficial uses that are identified and in place will be adequately protected with these changes, and because potential beneficial use improvements to be realized by the additional treatment do not bear a reasonable relationship to the costs to attain them, the Commission concludes that it is economically reasonable to support the revision of the iron and manganese standards for the snowmelt bypass period on Segment 13.
33.14 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE - OAK
CREEK The provisions of 25-8-202(1)(b) and (2), and 25-8-204, C.R.S., provide the specific statutory authority for this amendment.
After hearings held in late 1979, the Commission classified Oak Creek, from the point of discharge of the Oak Creek wastewater treatment plant to the confluence with the Yampa River, as Aquatic Life Class 1 - Cold. At that time, the Commission also adopted an array of numeric standards to protect aquatic life. No ammonia standard was designated for the segment because available evidence indicated that not only was there a limited variety of aquatic life below the Oak Creek drain, but the short distance between the treatment plant and drain in relation to the total segment made it inappropriate to establish an ammonia standard at that time.
In reviewing Colorado's water quality standards, the U.S. Environmental Protection Agency (EPA) noted the lack of an ammonia standard on this segment of Oak Creek and withheld approval of the segment until the Commission either reviewed this segment to determine an appropriate ammonia standard of more fully documented the justification for no standard. The purpose of this hearing is to satisfy EPA's concerns and gain approval of the classifications and standards for the segment. Fisheries data which was not available at the 1979 hearing indicate that the fishery in Oak Creek is more extensive than originally thought. The data indicates numerous sculpin, dace, and suckers present in the stream. Rainbow trout have been stocked at times in the past by the Colorado Division of Wildlife. The evidence indicates that this stocking is not likely to occur in the future. In order to protect the resident fish, i.e. sculpin, dace, and suckers, an unionized ammonia standard of .05 mg/l is proposed. This level is based on a site-specific calculation of the 30-day average criterion which should protect the resident species. This calculation is provided in the Site-Specific Criteria Guidelines, U.S. Environmental Protection Agency 1982b. The 30-day criterion was calculated seasonally by a Region VIII EPA computer program using seasonal mean temperature and pH, the reproducing species present in the Creek, and the national acute to chronic ratio of 16. For comparative purposes, the 30-day seasonal criteria calculated for Oak Creek, Segment 7 using combinations of species is given below: Season Oak Creek with Oak Creek with Oak Creek without Oak Creek without Rainbow Trout Acute Salmonids Acute Rainbow Trout Acute Rainbow Trout Acute = 16 Chronic = 16 Chronic = 16 Chronic = 25*Chronic Nov.-Feb .020 .027 .046 .028 Mar.-Jun. .034 .046 .075 .048 Jul.-Oct. .034 .046 .075 .048 * 25 is acute/chronic for White Sucker which is higher than national value of 16. It should be noted that the species of suckers present in Oak Creek is the Bluehead for which there is no ammonia toxicity data available and, for that reason, the Division believes that using the national acute- chronic ratio of 16 is probably most appropriate to Oak Creek. However, it is felt that a .05 mg/l unionized ammonia standard should be applied year-round to insure protection of all the reproducing species present in the Creek. This would provide protection to the Bluehead sucker during the critical season (low-flow, temperature, pH) of July-October should the acute-chronic ratio for that species be nearer 25 than 16.
FISCAL IMPACT STATEMENT, OAK CREEK The beneficiaries of this regulation will be those persons who enjoy the recreation and aesthetic values of Oak Creek and the upper reaches of the Yampa River that these ammonia limits are designed to preserve. While a monetary value has not been estimated for these beneficial uses, past experience has demonstrated them to be quite substantial.
The proposed ammonia limitations are not likely to result in higher costs to the users of the Oak Creek wastewater system, because it is anticipated that good secondary treatment processes should be sufficient to achieve these limits as translated into the Town's permit. Though it is therefore highly unlikely that system users would have to bear the significant costs associated with installing ammonia removal equipment, the Town may have to utilize a higher technology, short of ammonia removal, with the associated initial capital costs. If any, these costs would be manifest as increased user fees, but it is possible that a portion of such expenditures would be offset by a federal construction grant.
33.15 BASIS AND PURPOSE SEGMENT 13, YAMPA RIVER:
The proponent stated that its discharge permit requires that sampling be on a total metals basis whereas compliance is based on a total recoverable standard. The proponent believed that such a situation creates a “double standard” that poses an unnecessary and unreasonable burden. The proponent requested the standards for manganese and copper be changed to reflect ambient water quality in segment 13. The data supporting this request were collected from undisturbed sites adjacent to the proponents mine area. On sites that have been disturbed by mining subsequent to site installation, only data collected in the natural state were used. Since the tributaries of Fish Creek, Foidel Creek, and Middle Creek drain the proponents mine properties, preference was given to data from these tributaries in the calculation of a revised standard.
The proponent contended in its petition for (207) review that:
1. New evidence indicates that concentrations of copper and dissolved manganese in the ambient streamflow exceed the current stream standards in Segment 13;
2. Ambient stream water quality should provide the basis for the standards in Segment 13. In that Segment, the classified uses presently exist despite the fact that ambient conditions reflect lower water quality than the standards or the “tables” appended to the basic regulations. Further, metals present in the water samples may be tied up in suspended solids when water is present in the stream. In this form, they are not “available” to fish and may not be detrimental to aquatic life. See CDOH, Water Quality Standards and Stream Classification, 5 CCR-1002-8, Section 3.3.7(5)(f) and (g);
3. There exists a clear and present potential for inequity or unreasonable economic impact because ambient water quality exceeds the current standards.
4. The existing standards materially affect the proponents present decision making, regarding treatment alternatives and requirements;
5. There exist evident errors in the standards which the Commission should rectify before its three- year periodic review; and 6. Segment 13 may require more attention than it likely would receive during the triennial review of the entire basin.
FISCAL IMPACT STATEMENT:
Introduction This assessment of economic impacts addresses the concerns associated with modification of the present stream standards to more practically reflect the ambient standards of the receiving stream. Colorado Yampa Coal Company (CYCC) believes that the present effluent limitations, based on stream standards, should be modified in accordance with the ambient conditions of the receiving stream. CYCC has initiated monitoring programs to determine ambient conditions of the receiving stream. Data from the monitoring program will be utilized to evaluate and perform alternative treatability studies, if such studies are necessary to meet the ambient effluents limitation standards. Costs No costs are anticipated to be necessary since the petition only requests that the present stream standard limitations be modified to reflect ambient conditions of the receiving stream. If alternative treatment and disposal methods are ultimately required to comply with ambient stream standards, costs associated with the development, operation, and maintenance of the alternative treatment and disposal methods would be born by the consumer as pass-through costs. Where pass- through costs are not appropriate, it is assumed that the company would carry the financial burden as operations and/or in maintenance costs.
SEGMENT 13, YAMPA RIVER Benefits Approval of the petition would benefit the State of Colorado, the electrical consumer, the citizens of Routt County, and Colorado Yampa Coal Company (CYCC). The State of Colorado would benefit by relieving the Department of Health, Water Quality Control Division (DOH, WQCD) of enforcement responsibilities of certain stream standards which presently may exceed ambient conditions of the receiving stream, while ensuring that the receiving stream quality is not negatively impacted by the mining operation. The electrical consumer would benefit due to the most practical production of coal to generate electricity in an environmentally sound manner. The citizens of Routt County would benefit by the approval of this petition by maintaining direct and indirect employment opportunities for the local population associated with CYCC, attributable to the CYCC operations. CYCC will benefit from the approval of this petition by being able to mitigate potential environmental degradation, due to its mining operations, in the most practicable manner.
Conclusions Considering the cost/benefit analysis above, it is evident that the benefit derived from the approval of this petition are vast and far-reaching in both number of people and areas of the country. It is also evident that this petition, when approved, would not, in any way, reduce the ambient receiving stream quality and as such would have no potential for environmental degradation.
33.16 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE (JUNE, 1987
REVISIONS)
The provisions of 25-8-202(1)(a,(b) and (2); 25-8-203; and 25-8-204 C.R.S., provide the specific statutory authority for adoption of the attached regulatory amendments. The Commission also adopted, in compliance with 24-4-103(4) C.R.S., the following statements of basis and purpose and fiscal impact. BASIS AND PURPOSE:
The changes considered and adopted in this hearing result from recommendations made by the Water Quality Control Division at a September, 1986 triennial review informational hearing. After review of the available data, the Division recommended that no change be made for three segments included in the hearing notice (Page 6, Segment 5; Page 7, Segment 9; and Page 9, Segment 9). The Commission agreed with this recommendation. The hearing notice also addressed additional changes recommended by AMAX Inc. However, AMAX's petition and proposal were withdrawn prior to the hearing. The action taken and the rationale therefor for each applicable segment are described below. Page 1, Segment 2:
The “goal” qualifier for the Recreation Class 1 classification and the temporary modification for fecal coliform are removed. The Recreational Class 1 classification is therefore in effect, with an accompanying 200/100 ml fecal coliform standard.
During the 1979 hearing, data was presented that showed some exceedances of the 200 mpn/100 ml criterion for Recreation Class 1 in some of the lakes. This was determined to probably be due to failing septic systems. Since that hearing two new treatment plants which serve the problem areas have gone on line and the Grand Lake wastewater treatment plant has been phased out. Both plants discharge outside of the lakes' drainage basin. Swimming is a documented use of these lakes and the 200 mpn/100 ml standard is necessary to protect this use. The limited data for Lake Granby shows fecal coliform levels significantly below the 200 mpn/100 ml standard.
Page 2, Segment 9:
The description for this segment is revised to read:
All tributaries to the Colorado and Fraser Rivers, including all lakes and reservoirs, within the Never Summer and Indian Peaks Wilderness Areas.
The Never Summer Wilderness Area was designated subsequent to prior hearings on the Upper Colorado Basin. The change classified waters in the Wilderness Area as High Quality-Class 2 which is consistent with Commission policy and past actions.
Page 3, Segment 2:
The temporary modification for the unionized ammonia standard is removed. The adopted standard of
0.02 mg/l therefore is in effect.
A temporary modification of 0.05 mg/l unionized ammonia was placed on this segment of the Blue River into which Breckenridge discharges because of the possibility of the 0.02 mg/l standard not being met with future growth. Since then, the Breckenridge discharge point has been moved and the effluent goes to a canal that bypasses the River and discharges directly to Lake Dillon. The temporary modification is no longer needed by Breckenridge and there are no other dischargers that will be affected by a 0.02 mg/l standard. The Blue River is a high quality trout stream that also is used as a source for a majority of the Brown trout spawn used in Division of Wildlife hatcheries. The 0.02 mg/l standard for unionized ammonia is needed if the use is to be protected.
Page 4, Segment 7:
The following revised standards and temporary modifications (all in mg/l) are adopted: Standard Temporary Modification Cadmium (Cd) 0.0085 Copper (Cu) 0.016 0.165 Lead (Pb) 0.016 0.021 Zinc (Zn) 0.29 1.6 Manganese (Mn,Tot) 1.2 The changes adopted for the underlying standards and/or temporary modifications are based on the use of recently available 1986 data contained in a Mined Land Reclamation Division report entitled “Documentation and Analysis of the Effects of Diverted Mine Water on a Wetland Ecosystem.” The data from this report and the data from 1978, which is in the 1979 hearing record and was used to calculate the original set of standards, was combined to arrive at the revised standards and temporary modifications. The MLRD report relates to an experimental treatment system intended to remove the influence of the Pennsylvania Mine drainage on the metals levels in Peru Creek (i.e., clean up Peru Creek to levels equal to or better than those upstream). The data from Station PC-6 which is upstream of the Pennsylvania Mine drainage was used to derive the above standards (or underlying goals). For the temporary modifications, the data from the stations downstream of the Pennsylvania Mine were used (PC-5, PC-4, PC-3, PC-1). These stations reflect the existing quality of Peru Creek with the influence of the Pennsylvania Mine drainage. Both the standards and temporary modifications were derived using the x̄ + s methodology, with outliers screened by Chauvenet's criterion. Page 8 Segment 4:
The temporary modification for the unionized ammonia standard is removed. The adopted standard of
0.02 mg/l therefore is in effect.
At the time of the 1979 hearing, Snowmass Water and Sanitation District had been funded for but had not begun construction of a tertiary treatment plant to remove ammonia. It was also felt that tertiary treatment plant to remove ammonia. It was also felt that the treatment technology was untested for the climatic conditions that would be encountered. Therefore, a temporary modification for unionized ammonia was adopted. The plant has been built and is operating efficiently and removing ammonia to levels that indicate operating efficiently and removing ammonia to levels that indicate the 0.02 mg/l standard can be met. The Snowmass discharge permit rationale also recognizes that the temporary modification is no longer needed.
At the following the hearing, Snowmass Water and Sanitation District submitted comments, and related information, requesting that the temporary modification be retained due to uncertainty whether the 0.02 mg/l standard can be met consistently. The Commission did not fee that this information demonstrated that the standard could not be met, and the temporary modification was therefore removed. Page 10, Segment 2:
The following sentence is added to the description of this segment: All tributaries to the North Platte River, including all lakes and reservoirs within the Never Summer Wilderness Area.
The Never Summer Wilderness Area was designated subsequent to prior hearings on the North Platte Basin. The change classifies waters in this Wilderness Area as High Quality-Class 2 which is consistent with Commission policy and past actions.
Page 13, Segments 15, 16, 17:
The notation for these three segments is revised to read: Classified under segments 9 through 13(b), Lower Yampa/Green River, Lower Colorado Basin, 3.7.0. Because these waters overlapped Routt and Moffat Counties and the majority of the activity and data was in Moffat County, the Commission deferred hearing these segments until the Lower Colorado hearings. This change clarifies where the classifications and standards for these waters may be found. Segments 13 and 14, Ten Mile Creek:
The following Statement of Basis and Purpose for segments 13 and 14, Ten Mile Creek of the Blue River, which was originally adopted December 6, 1982, effective January 30, 1983, is readopted so that it will appear in the published version of the regulations:
Use Classification The evidence in this proceeding as well as prior proceedings have established that the Climax discharge, Segment 13, does not have sufficient flow to sustain a classification of aquatic life, Cold Water Class 1 on a year round basis. It is contemplated that Climax will not discharge during the period December 25 through February 28. These months are generally low flow months of the year. Hence, the flow conditions are not present to support an aquatic life, Cold Water Class 1 designation on a year round basis on Segment 13.
The Commission has received testimony and exhibits in this and previous hearings concerning Ten Mile Creek which establish that the number and kind of aquatic species in Segment 13 is limited and that few, if any, sensitive species are found in Segment 13. The Commission believes that the Water Quality standards for Segment 13 that it is adopting today will protect existing species and encourage the establishment of more sensitive species which are compatible with the flow and streambed characteristics of Segment 13.
Testimony has also been presented in a previous hearing on Ten Mile Creek as to the cost of achieving a Class 1 Classification for Segment 13. In weighing these costs together with the cost already expended to improve the water quality of Ten Mile Creek against the low flow and limited aquatic life conditions presently found in Segment 13, the Commission concludes that it would not be economically reasonable to retain a classification of aquatic life, Cold Water Class 1 for Segment 13. Hence, the Commission adopts aquatic life, Cold Water Class 2 to apply to Segment 13 of Ten Mile Creek. The Commission does not find that classifying this Segment with a goal of aquatic life is appropriate. The Segment does contain aquatic life and any upgrading from Class 2 to Class 1 could proceed during periodic review to reflect any possible improvements.
Segmentation:
The evidence in these proceedings on Ten Mile Creek have shown that Ten Mile Creek for all intents and purposes begins at Climax property boundary at a place designated as the “Parshall Flume”. It is at this point that the natural flows that are intercepted by Climax in the Ten Mile Creek Basin are channelled together and form the source of Ten Mile Creek. Hence, the Commission believes Parshall Flume to be the source of the mainstem of Ten Mile Creek. Also, included in this segment are all tributaries to Ten Mile Creek including those natural tributaries intercepted by Climax. Water Quality Standards The evidence of Climax and the Division in this proceeding has shown that water quality standards in Ten Mile Creek vary considerably during certain periods of the year. The principal cause of this variation is the hydrological condition, mainly the spring run-off (snowmelt bypass). During this period it becomes economically unreasonable, if not impossible, to provide treatment for the large flow of runoff water that comes into contact with the Tailings Ponds located in the Ten Mile Creek Basin. Hence, the Commission has adopted seasonal water quality standards for both Segments 13 and 14 of Ten Mile Creek. Page 4, Segment 13 The Commission has been presented with Climax data and calculations of such data for various pollutants during the period November, 1979 thru April, 1982. No STORET exists for Segment 13, hence only the Climax data was used. All Climax data was analyzed according to the total method. The water quality standards for the non-runoff period are based on data including all ambient data obtained during the time the Climax Wastewater Treatment facility was operating with the exception of the bypass periods associated with the runoff and in the months of January and February during which Climax will not discharge in the future. The Commission adopts the x̄ + s of these values as water quality standards to apply during the snowmelt bypass period. The Commission recognizes that this period varies from year to year and that it will be determined annually by the Division and Climax. This period shall generally commence not earlier than May 1 and extend approximately 60 days as more specifically defined by the Climax water balance computer model. Historically a bypass has not been necessary every year and may not always be necessary in the future. The Commission has also been presented with Climax data covering the snowmelt bypass periods of 1980 and 1982. In view of a seasonal variability of the ambient water quality, the Commission adopts x̄ + s of the snowmelt bypass data as water quality standards to apply during this period. In adopting the above water quality standard for Segment 13, the Commission is mindful of its goals to protect the use classifications in Segment 14. The Commission finds that the water quality standards it has adopted for Segment 13 are based on historical data gathered during a period when there was general improvement in stream quality. Hence, the water quality standards based on such data should be sufficient to protect and maintain the uses assigned to both Segments 13 and 14, including water supplies in Segment 14.
Page 5, Segment 14 The Commission has been presented with STORET and Climax data and calculations for various pollutants during the period November, 1979, through April, 1982. As with Segment 13 data, these have been split according to the snowmelt bypass and non-runoff periods. Climax data was analyzed by the total methodology. The State data was analyzed according to the State methodology. For the snowmelt bypass period the Commission adopts the x̄ + s of the combined snowmelt bypass data as the snowmelt bypass water quality standards with the exception of sulphate which is a table number. For the non-runoff period the Commission adopts the x̄+ s of the combined non-runoff data. Evidence indicates the standards as adopted do not require additional technology, and are economically reasonable.
FISCAL IMPACT STATEMENT:
Removal of the temporary modification for unionized ammonia assigned to the mainstem of Brush Creek, segment 4, table page 8, may require the Snowmass Water and Sanitation District to provide additional treatment for ammonia at some future date, if future operation indicates that the ammonia standard cannot be met consistently with existing treatment and if the standard remains unchanged. However, the data currently available indicates that the standard is being met at this time and will probably be met until plant flows exceed the design capacity of the plant.
The remaining changes adopted in this hearing are not expected to result in substantial costs for any existing dischargers. The additional water quality protection provided by these changes benefits the public at large.
The following Fiscal Impact Statement for segments 13 and 14, Ten Mile Creek of the Blue River, which was originally adopted December 6, 1982, effective January 30, 1983, is readopted so that it will appear in the published version of the regulations:
The principle fiscal impact of the adoption of the aquatic life class 2 classification and revised water quality standards is a significant potential cost savings to be realized by Climax Molybdenum Company. Evidence submitted by Climax Molybdenum Company suggests that without these modifications, Climax would be faced with a strong probability of additional treatment to cost from $8.2 million to $14.6 million in capital expenses from $3.8 million to $6.6 million in annual operating and maintenance costs. Because evidence suggests that the beneficial uses that are identified and in place will be adequately protected and possibly enhanced with these changes, and because potential beneficial use improvements to be realized by additional treatment do not bear a reasonable relationship to the costs to attain them at this time, the Commission concludes that it is economically reasonable to support the change of the aquatic life classification and revision of certain numeric standards on these segments. Dated this 2nd day of June, 1987, at Denver, Colorado.
33.17 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE: July 6, 1988 Hearing on Little White Snake Creek The provisions of 25-8-202(1)(a),(b) and (2); 25-8-203; 25-8-204; and 25-8-207 C.R.S. provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted, in compliance with 24-4-103(4), and 24-1-1-3(8)(d), C.R.S., the following statement of basis and purpose and fiscal impact.
BASIS AND PURPOSE:
The Division had no water quality or flow data for the Little White Snake Creek, and made no field inspections prior to the establishment of existing classifications. The Aquatic Life Class 1 and Recreation Class 1 designations are based upon incorrect assumptions made by Division personnel. The purpose for the rulemaking is to correct the designated classifications and standards to reflect actual natural conditions and to preclude the community of Phippsburg from unnecessarily expending funds for dechlorination and ammonia nitrogen removal.
The basis for the rulemaking follows:
Aquatic Life - The existing Class 1 (cold) classification is not now being attained, nor can it be reasonably attained in the near future due to existing natural conditions such as annual low flow of zero, a silt bottom, lack of spawning beds, and lack of benthic organisms.
The Colorado Division of Wildlife has made a site inspection of the stream segment and has concluded that the stream is not a fishery.
It is obvious that this stream segment is more accurately described by the Aquatic Life Class 2 (cold) definition because “the potential variety of life forms is presently limited primarily by flow and stream bed characteristics”. The conditions which presently limit aquatic life forms are natural and are believed “uncorrectable” within a twenty year period.
Recreation - This intermittent stream segment is also unsuitable for Class 1 Recreational activities due to its extremely low flows and drainage ditch character. It is obvious that prolonged intimate contact with the body typical of Class 1 Recreational activities is unlikely. This rationale is supported in the Colorado Water Quality Control Commission Document entitled “Classifications and Numeric Standards Upper Colorado River Basin and North Platte River (Planning Region 12).” Specifically on page 23 where a discussion of the Recreation Class 1 and Class 2 classifications takes place. “The Commission has decided to classify as Recreation Class 2 those stream segments where primary human contact recreation does not exist and cannot be reasonably expected to exist in the future, and where municipal discharges are present which may be unnecessarily affected by the Recreation Class 1 classification.”
This segment from the Phippsburg Sewage Treatment Plant to the Yampa River is better suited for Class 2 Recreation uses.
The Northwest Colorado Council of Governments has voted to change the regional 208 plan to reflect the above conditions and to recommend the Class 2 designations for both Recreation and Aquatic Life classifications.
FISCAL IMPACT:
No costs are anticipated since the petition only requests that the present stream standard classification be modified to reflect ambient conditions of the receiving stream. If the petition had been acted upon unfavorably additional unnecessary expenses would have placed upon the community of Phippsburg under requirements of its discharge permit which is based upon Class 1 standards for recreation and aquatic life.
Routt County 33.18 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE: July 6, 1988 Hearing on Segment 13 of the Yampa River The provisions of 25-8-202(1)(a),(b) and (2); 25-8-203; 25-8-204; and 25-8-207 C.R.S. provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted, in compliance with 24-4-103(4), and 24-4-103(8)(d), C.R.S., the following statement of basis and purpose and fiscal impact.
BASIS AND PURPOSE:
The purpose of this rule is to remove the water supply classification from portions of Segment 13 in which there are no domestic users, and in which the classification is not necessary to protect downstream domestic uses. This result is accomplished by separating these portions of Segment 13 into a separate new segment and removing the water supply classification from the new segment. The basis for the rulemaking follows:
A. There is no domestic water use on Fish, Foidel and Middle Creeks.
B. Domestic use is unlikely to occur in the foreseeable future on Fish, Foidel and Middle Creeks because virtually all adjoining property is owned or controlled either by the Forest Service or by Colorado Yampa Coal Company (CYCC), and is used for coal mining purposes. Additionally, the intermittent nature of the natural streamflow makes use of water in these creeks for domestic purposes impractical.
C. Removing the water supply use classification from resegmented Fish, Foidel and Middle Creeks will not degrade water quality, cause exceedances of applicable water quality standards to protect aquatic life (if any) in the new segment or in Trout Creek or impair existing water supply uses in Trout Creek downstream. In fact, the reclassification and resegmentation would recognize the existing situation and the reality that downstream domestic users are not being impaired at current treatment levels. Extensive and sound data was submitted establishing that no unacceptable degradation will occur. Downstream domestic water users will not be adversely impacted by the change.
D. The petitioner asserted that an additional basis for the rule is that the previous classification would have resulted in areawide adverse social and economic impacts. Studies indicate that it would cost CYCC $1,670,000.00 to construct a treatment plant to remove dissolved manganese from its discharges to levels previously mandated by the water quality standards and classifications. In addition, the treatment plant would cost approximately $596,000.00 annually to operate and maintain. The costs do not include the cost of disposal of 7,900 cubic years per year of sludge which would result from the treatment. The cost of this disposal is not estimated here because the sludge cannot be characterized conclusively in advance, and correspondingly it cannot be said with certainty what regulatory requirements might apply to its disposal. These unreasonable costs are wholly out of proportion to any benefit provided by the current stringency of the standards. These costs, if CYCC were required to incur them, raise the question whether the mine can continue to operate. The impact on the area, socially and economically, of mine closure, including loss of jobs, salaries, tax revenues, and other economic benefits, would be severe, and is not justified by the negligible benefit (if any) to water quality effected by the current standard and use classification.
FISCAL IMPACT:
The regulation will have no adverse fiscal impacts on the public sector. The proposed changes actually represent existing water usage patterns. There is no danger to aquatic life populations in the new segment or downstream. Additionally, the rule will not fiscally adversely affect downstream water users. However, the negative impact on CYCC would be great, including $1,670,000 of capital investment and approximately $596,000 a year in operation and maintenance cost. The rule will have a fiscally positive impact both on CYCC and the area in which it operates. CYCC may continue to operate and need not expend prohibitive sums on treatment. In turn the area will continue to benefit from the economic effects on the community of continued operation, including jobs, salaries, disposable income for the local economy and tax revenues. Parties to the hearing:
Colorado Yampa Coal Company
33.19 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER,
1990 HEARING ON SEVERAL SEGMENTS:
The provisions of 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402 C.R.S. 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:
First, the Commission has adopted new introductory language for the tables in section 3.3.6. The purpose of this language is to explain the new references to “table value standards” (TVS) that are contained in the Tables. These provisions also include the adoption of new hardness equations for acute and chronic zinc standards throughout the basin. Based on information developed since the “Basic Standards” were revised, these new equations have been determined to represent more appropriate zinc criteria. New information contained in a 1987 EPA zinc criteria document indicates Colorado's zinc criteria is overly restrictive, especially at hardness in the range of 50 to 200 mg/l. Adoption of the Colorado zinc criteria as site-specific TVS standards may potentially cause undue treatment costs to dischargers who would be regulated by those standards until they could be adjusted through a section 207 hearing or during the next round of basin hearings.
The existing criteria for zinc contained in the “Basic Standards” was developed by the Commission's Water Quality Standards and Methodologies Committee. At the time of development, the EPA zinc criteria document was not available. Because of some limited data indicating a consistent chronic toxicity level at water hardnesses of 200 mg/l or less, the Commission adopted a chronic criteria of 45 ug/l for hardness of 0 to 200 mg/l. This is much more stringent than EPA criteria which, as an example, specifies chronic zinc levels of 59 ug/l and 190 ug/l at hardness of 50 mg/l and 200 mg/l, respectively. The Commission also has adopted additional organic chemicals standards for certain aquatic life segments. The standards added in section 3.3.5(2)(e) are based on water and fish ingestion criteria contained in the U.S. Environmental Protection Agency's Quality Criteria for Water, 1986 and updates to this document through 1989, which is commonly referred to as the “Gold Book”. The standards are being applied to all Class 1 aquatic life segments. The standards are based on a 10-6 risk factor. The application of these standards to waters where actual or potential human ingestion of fish is likely is important in assuring that Colorado achieves full compliance with the toxics requirement of section 303(c)(2)(B) of the federal Clean Water Act. It is reasonable to assume that most Class 1 aquatic life segments, because of their variety of fish species and/or suitable habitat, have the potential for fishing and the resultant human consumption of the fish or other aquatic life. One other general issue should be addressed at the outset. Several parties to this proceeding submitted documents expressing concern regarding the adoption of high quality 2 designations because of potential impact on water rights held by these entities. The Commission transmitted these document to the State Engineer and the Colorado Water Conservation Board to solicit any comments that they might have. In its transmittal letter, the Commission stated its preliminary assessment that the proposed adoption of high quality 2 designations did not present the potential to cause material injury to water rights. The high quality designation merely indicates that an antidegradation review will be required for certain activities. In its regulations, the Commission has specifically provided that in an antidegradation review “any alternatives that would be inconsistent with section 25-8-104 of the Water Quality Control Act shall not be considered available alternatives.” If an issue should arise as to whether the antidegradation review criteria prohibiting material injury are being applied correctly to a specific proposed activity, that issue would be considered during that specific review process, including going through consultation with the State Engineer and the Water Conservation Board.
The Commission received a letter back from the State Engineer, stating his agreement with the Commission's preliminary assessment. No letter was received from the Water Conservation Board, although the Board had previously indicated its agreement with a similar conclusion when this issue was raised in an earlier rulemaking hearing. Upon consideration of all of the available information, the Commission has determined that the adoption of high quality 2 designations in this proceeding does not cause material injury to water rights.
The other changes considered and adopted are addressed below by segment.
A. Overview of Segment-Specific Changes Two principal issues were in controversy for several of the segments addressed in this hearing. The most controversial was whether to apply a high quality 2 designation to certain waters. In several instances, designations proposed by the Water Quality Control Division were opposed on the basis that there was inadequate information to support such a designation. The three most common challenges to the adequacy of the information were: (1) detection limits for some data were too high to determine whether ambient quality was better than “table values;” (2) for some segments there was not adequate data for some or all of the twelve parameters referenced in section 3.1.8(2)(b)(i)(C); (3) for some segments the sample location(s) of available data were too limited to generalize the results to the whole segment. The Commission explicitly considered establishing minimum data requirements when it adopted the current antidegradation regulation, and consciously rejected that option. Rather, the Commission recognized that it would be necessary to rely on best professional judgment to determine what constitutes representative data in a specific situation. These issues are not new, or unique to high quality designations. The Commission has for years been required to make water quality classification and standards decisions in the absence of perfect information. Requiring substantial, recently acquired data for all parameters from multiple locations in each segment before establishing high quality designations would assure that very few waters in Colorado would receive this protection for many years to come. As a policy matter, the Commission has determined that high quality designations may appropriately be established based on a lower threshold of available data than that suggested by several parties to this proceeding.
The second recurring issue addressed for multiple segments in this hearing was whether to establish a recreation class 1 classification wherever a high quality 2 designation is established. The Division proposed this classification change for applicable segments, since the high quality 2 designation indicates that such segments have adequate water quality to support the recreation class 1 use. However, the Commission generally has declined to change the recreation classification from class 2 to class 2 uses in such circumstances, unless there was also evidence submitted that class 1 uses were present or likely for the waters in question. Unless the use is present or likely, application of use-protection-based water quality standards does not appear appropriate. At the same time, the Commission notes that this approach does not diminish application of antidegradation protection requirements for high quality waters. Where the existing quality is adequate, a high quality 2 designation has been established, requiring antidegradation requirements to be met before any degradation is allowed, even though the recreation classification is class 2.
A related issue is the determination of which uses warrant the class 1 recreation classification. The recreation classification definition in section 3.1.13 (1)(a)(i) of the Basic Standards and Methodologies for Surface Water refers to “activities when the ingestion of small quantities of water is likely to occur,” and states that “such waters include but are not limited to those used for swimming.” In the past the Commission often has applied the class 1 classification only when swimming occurs, and not where other recreational uses that may result in ingestion of small quantities of water occur. The Commission now believes it is appropriate for the class 1 classification also to be applied for uses such as rafting, kayaking, and water skiing. The appropriateness of recreation class 1 versus class 2 classifications was debated for several segments in the Upper Colorado Basin. The Commission has received information regarding actual recreational uses. It has also received substantial input regarding the propriety (or lack thereof) of broadening the application of the class 1 recreation classification, based upon an evolving interpretation of the Basic Standards language. After lengthy discussion, the commission has decided that it is appropriate as a matter of policy in this proceeding to apply the recreation class 1 classification for all uses that involve a significant likelihood of ingesting water, including but not necessarily limited to rafting, kayaking, and water skiing. In particular, the uses at issue for segments in this basin were kayaking and rafting. The Commission has received substantial testimony that kayaking often results in water ingestion. In addition, the testimony presented in this and prior proceedings, as well as the personal experience of individual Commissioners, indicates that rafting--white water or otherwise--also presents a significant potential for water ingestion.
Section 3.1.6(1)(d) of the Basic Standards and Methodologies for Surface Water requires the Commission to establish classifications to protect all actual uses. Therefore, for waterbodies where rafting and kayaking is an actual use, the recreation class 1 use classification should be applied, since ingestion of water is likely to occur. The Commission sees no reason to distinguish between ingestion that may result from swimming and ingestion that may result from rafting or kayaking. In fact, there has been some testimony indicating that ingestion is more likely to result from the latter activities.
The Commission wishes to emphasize that the action that it is now taking is consistent with the existing definition of class 1 recreation uses. Some of the comments submitted stated or suggested that the action now being taken by the Commission would constitute a “definitional change” that should be addressed only in a review of the Basic Standards and Methodologies for Surface Water. No change in the regulatory definitions of the classifications is being considered or adopted at this time. Rather, the Commission is applying what it believes to be the proper interpretation of the existing definition.
The Commission believes that as a matter of policy it is not necessary or appropriate to wait until the July, 1991 rulemaking hearing regarding the Basic Standards and Methodologies for Surface Water to implement its current interpretation of the class 1 recreation classification. Over the last decade, there have been many instances when arguments and facts presented in basin-specific rulemaking hearings have resulted in an evolving interpretation of the provisions of the Basic Standards and Methodologies for Surface Water. This Commission is not bound by interpretations made by its predecessors in other basin-specific hearings. To the degree that the class 1 recreation classification in the past has not been applied for some existing activities that involve a likelihood of ingesting water, the Commission now believes that such decisions were in error.
This action does not improperly exclude input from entities interested in other river basins. First, the Commission specifically reopened an earlier hearing on the Gunnison Basin and received input from entities not specifically concerned with that basin. This issue has now received extensive consideration in three separate basins. Moreover, the Commission can further modify its policy if in other basin-specific reviews, or in the upcoming review of the Basic Standards and methodologies, parties that did not participate in this proceeding bring forth new considerations that the Commission believes warrant a modification in the approach to recreation classifications that is now being adopted. The Commission also does not believe that there was any problem with the notice provided for the specific segments at issue in this hearing. Each of the segments for which the recreation classification is being changed from class 2 to class 2 in the original hearing notice. Although the basis for this proposal evolved during the hearing, any parties potentially concerned with a recreation class 1 classification were on notice that this change would be considered in this hearing.
In applying the interpretation of the existing recreation class 1 definition that has been described, the Commission is also influenced by the fact the importance of recreational uses of surface waters in Colorado has increased over the last decade. Testimony in this and prior proceedings indicated that uses such as rafting and kayaking have expanded substantially, and it is therefore even more important that adequate water quality protection now be provided. Some of the testimony submitted addressed the appropriateness of the current fecal coliform standards that are applied in association with recreation classifications. The Commission believes that the appropriateness of the existing standards can and should be addressed, when and if there is new evidence available indicating that the current standards are not appropriate. However, changes in such standards were not at issue in this hearing. The Commission believes that questions regarding the appropriate numerical standards should not interfere with its obligation to establish appropriate classifications to protect existing uses. If members of the public have information indicating that a different indicator parameter should be used, or that different fecal coliform levels are appropriate for the respective recreation classifications, that issue can and should be considered in the upcoming review of the Basic Standards and Methodologies for Surface Water.
Comment also has been submitted to the Commission expressing concern regarding the potential effect of downgrading restrictions, should the Commission now adopt class 1 recreation classifications for certain waters and later change its views regarding the appropriate approach to recreation classifications. The Commission does not believe that this presents a substantial problem. Downgrading is appropriate only when a use is not in place. So long as the class 1 recreation classification is defined as including activities that involve ingestion, applying that classification to waters where uses involving ingestion are present should not present a downgrading issue in the future. If the Commission at some later date should completely revise its approach to, and definition of, recreation classifications, application of the new system would involve a set of “de novo” determinations, and not questions regarding upgrading or downgrading. The Commission recognizes that the approach now being adopted may result in increased economic impacts for some dischargers, to meet the class 1 classifications. The evidence that has been submitted to the Commission indicates that in many instances this will not be the case, because state-wide effluent limitations for fecal coliform and chlorine standards to protect aquatic life will often drive the level of disinfection and dechlorination that are required. Moreover, in some circumstances it may be possible for the Division to consider an expanded use of seasonal effluent limitations that take low flow or high flow circumstances into account. However, irrespective of these considerations, a potential increase in treatment requirements for some dischargers cannot eliminate the Commission's obligation to classify state waters to protect actual uses.
Finally, concern was expressed that the approach now taken by the Commission will result in inconsistency regarding recreation classifications for different waters throughout the state. Anytime a policy interpretation changes or evolves in any significant way, the first time the change is applied to specific state waters there will be come inconsistency among individual water bodies, since site-specific classifications and standards are addressed on a basin-by-basin basis. However, it is the Commission's intention to apply its policy interpretations consistently as individual basins are addressed. This is now the third basin in which this approach has been applied.
B. Aquatic Life Class 1 with Table Values; New High Quality 2 Designations Upper Colorado River segments 3, 4, 5, 7a, 8 Blue River segments 1, 3, 8, 10, 15, 17, 18 Eagle River segments 2, 3, 4, 6, 8, 12 Roaring Fork River segments 2, 3, 5, 6, 7, 8, 10 North Platte River segment 3 Yampa River segments 2a, 3, 9, 10, 11, 18 Numerical standards for metals for these segments have in most instances been based on table values contained in Table III of the previous Basic Standards and Methodologies for Surface Water. Table III has been substantially revised, effective September 30, 1988. From the information available, it appears that the existing quality of these segments meets or exceeds the quality specified by the revised criteria in Table III, and new acute and chronic table value standards based thereon have therefore been adopted. There are also some of these segments whose previous standards were based in part on ambient quality, since their quality did not met old table values based on alkalinity ranges. However, these segments generally have much higher hardness than alkalinity, and the new table values (based on hardness-dependent equations) are now appropriate as standards.
C. Existing High Quality 2 Segments; New Classifications and Standards Upper Colorado River segment 9 Blue River segment 16 Eagle River segment 1 North Platte River segment 2 Yampa River segments 8, 19 These segments were already described as High Quality class 2, and available information indicates that the parallel new High Quality 2 designation continues to be appropriate for each. All are within wilderness areas. In addition, the following use classifications, and associated table value standards, have been adopted for these segments:
D. Existing High Quality 1 Segments; New Designations Upper Colorado River segment 1 Roaring Fork River segment 1 North Platte River segment 1 Yampa River segment 1 These segments were already described as High Quality Class 1, and available information indicates that the parallel new High Quality 1 designation continues to be appropriate for each. All are within wilderness areas.
E. New Use-Protected Designations; No Change in Numeric Standards Blue River segment 20 Eagle River segment 11 North Platte River segment 7 Yampa River segments 4b, 12 These segments all qualify for a use-protected designation based on their present classifications. All are aquatic class 2 streams. Existing standards are recommended because these segments, except Yampa segment 4b, have only a minimal number of standards, with no metal or nutrient standards. For Yampa segment 4b there is no water quality data to support changing to the new dissolved standards.
F. New Use-Protected Designations; Revised Numeric Standards Upper Colorado River segments 6b, 6c Blue River segments 5, 6, 7, 11, 12 Eagle River segment 5 Roaring Fork River segment 4 North Platte River segments 4, 5 All of these segments (except Eagle river segment 5, which is addressed separately below) are aquatic life class 2 streams with numeric standards to protect the existing aquatic life. Except as specified below, numerical standards for metals have been based on table values contained in Table III of the previous Basic Standards and Methodologies for Surface Water. Table III has been substantially revised, effective September 30, 1988. From the information available, it appears that the existing quality of these segments meets or exceeds the quality specified by the revised criteria in Table III, and new acute and chronic table value standards based thereon have been adopted. There are also some of these segments whose previous standards were based in part on ambient quality, since their quality did not meet old table values based on alkalinity ranges. However, these segments generally have much higher hardness than alkalinity, and the new table values (based on hardness-dependent equations) are now appropriate as standards. Ambient quality-based standards:
For Eagle River segment 5 the Commission has retained the existing standard, except that zinc has been changed to a dissolved standard of 400 ug/l.
Finally, expiration dates have been added for the temporary modification for Blue River segment 7 and Eagle River segment 5. The existing standards for Blue River segment 7 (Peru Creek) have been left unchanged, pending new data reflecting the results of an inactive mine drainage treatment project that is now in place.
G. No Change in Classification; No Designations; Revised Numeric Standards Upper Colorado segments 2, 6a, 7b, 10 Blue River segments 2, 13, 14 Eagle River segment 10 Roaring Fork segment 9 North Platte segment 6 Yampa River segments 2b, 4a, 5, 6, 7, 13a, 13b, 14, 15?, 16?, 17? Upper Colorado segment 2 Segment 2 of the Upper Colorado includes Grand Lake, Shadow Mountain Lake and Lake Granby. These lakes and reservoirs form part of the Colorado-Big Thompson Project. Lake Granby and Shadow Mountain Lake are located within the Arapahoe National Recreation Area, which is adjacent to Rocky Mountain National Park and the Indian Peaks Wilderness Area. Grand Lake is adjacent to the National Park and the Recreation Area, and receives natural tributary flows from Rocky Mountain National Park. Because of the locations of these reservoirs, the Commission preliminarily determined that exceptional reasons existed to designate Segment 2 as High Quality 2. The Northern Colorado Water Conservation District and Municipal Subdistrict (the “District”) thereafter moved the Commission to reconsider this designation, in part because of the perceived potential interference with the District's water rights. The District also argued that the data for this segment indicated that the water quality is worse than table values for lead, cadmium, and silver, and therefore the segment should be designated use-protected. The Commission agreed to reconsider its preliminary designation, and reopened the record to allow interested parties to submit written comments, and to comment orally at the Commission's April meeting. As a result of this reconsideration, the Commission changed its preliminary decision, and has decided to leave Segment 2 undesignated. Taking into account all of the available information, including (1) the authorized uses of the waters in this segment, (2) the available data for this segment, and (3) the potential for interference with water rights if other agencies apply the high quality designation in a manner inconsistent with section 25-8-104, the Commission has determined that the provisions of section 3.1.8(2) do not warrant a High Quality 2 designation for this segment at this time. In addition, the Commission recognized that the antidegradation review is already presumptively applicable to this segment because of its current classification as cold water aquatic life 1. Because Segment 2 is presumptively subject to an antidegradation review without the High Quality 2 designation the Commission does not believe designating segment 2 High Quality 2 provides any significant additional protection. By finding that segment 2 should not be designated High Quality 2, the Commission is not determining that the location of a segment within a National Recreational Area, or within or adjacent to a National Park or Forest could not be an exceptional reason for designation as High Quality 2. The Commission is only stating that in this particular case the Commission has determined that the facts do not support a designation as High Quality 2 at this time. The Commission encourages the collection of additional data so that the appropriate designation of this segment can be reassessed with more complete information in the future. Other Segments These are water bodies whose classifications are appropriate for HQ2 designation (CW1 or WW1 and Rec 1) but had quality not suitable for a water supply classification or 85th percentile values of one or more parameters exceeding the criteria for class 1 aquatic life. Table value standards have generally been adopted for these segments, except as indicated below. Due to uncertainties about the aquatic life class 1 classification in Willow Creek below the Bunte Ditch Diversion, segment 6a, the existing classification was retained but the segment was left undesignated. It is anticipated that a use attainability study will be completed on this reach by the next triennial review.
H. Changes in Classification; No Designations; Revised Numeric Standards Eagle River segment 9 Review of available data and existing uses indicates that this segment is appropriate to be upgraded to Recreation class 1 with a corresponding fecal coliform standard of 200 MPN/100 ml. Table value standards are adopted for this segment, except that the dissolved manganese temporary modification has been left in place for six years.
I. No Changes in Classifications or Standards; No Designations Blue River segment 9 Eagle River segment 7 No data are available on Blue River segment 9 to warrant revising the standards at this time. Variable data during Eagle Mine cleanup efforts make any change in standards for Eagle River segment 7 premature, although the description of this segment has been revised to exclude certain waters that are now included in Eagle River segment 1. Parties to the December, 1990 Hearing 1. Summit County Government through its Snake River Sewer Fund 2. Copper Mountain Inc.
3. Copper Mountain Water & Sanitation District 4. Breckenridge Ski Corporation 5. Breckenridge Sanitation District 6. AMAX Inc.
7. The Winter Park Water & Sanitation District 8. The Granby Sanitation District 9. The Fraser Sanitation District 10. The Grand County Water & Sanitation District 11. Division of Wildlife 12. Pitkin County Board of County Commissioners 13. Upper Colorado River Lake Production Association 14. Colorado River Water Conservation District 15. Eagle Sanitation District 16. Three Lakes Water & Sanitation District 17. Upper Eagle Regional Water Authority 18. Upper Eagle Valley Consolidated Sanitation District.
19. Vail Valley Consolidated Water District 20. The Town of Gypsum 21. City & County of Denver acting by and through its Board of Water Commissioners 22. The City of Colorado Springs Water Department 23. Mid-Continent Resources, Inc.
24. Winter Park Recreational Association 25. Keystone Resorts Management, Inc.
26. The Northern Colorado Water Conservancy District 27. Morrison Creek Metropolitan Water & Sanitation District 28. The City of Steamboat Springs 29. Routt County 30. Aspen Consolidated Sanitation District 31. The Town of Frisco 32. Summit County 33. Grand County 34. The Town of Montezuma 35. The Town of Grand Lake 36. Eagle County 37. The Town of Vail 38. Summit Water Quality Committee 39. East Dillon Water District 40. Upper Yampa Water Conservancy District 41. Lake Catamount No. 1 Metro District 42. Paramount Communications Inc.
43. Silverthorne/Dillon Joint Sewer Authority
33.20 FINDINGS REGARDING BASIS FOR EMERGENCY RULE SEPTEMBER 9, 1991:
The Commission held this emergency rulemaking hearing to readopt the numerical standards for one segment of the Upper Colorado River Basin to correct clerical errors in the original filing. The affected regulation was amended on May 8, 1991, and was filed within the required timeframes with the Secretary of State's Office and the Office of Legislative Legal Services. The Commission learned recently that there were errors in the published version of the numerical standards for segment 5 of the Eagle River, page 8 of the tables.
The Commission finds that the immediate adoption of the revised regulation is imperatively necessary for the preservation of public health, safety, or welfare and that compliance with normal notice requirements would be contrary to the public interest. Emergency adoption is necessary to assure that the published regulation is consistent with the regulation that the Commission adopted, to avoid confusion for the public and to assure than an anticipated request for permit revisions for a discharge by Paramount Communications Inc. to this segment is processed in a manner consistent with the Water Quality Control Commission's water quality standards decisions.
33.21 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JANUARY,
1992 HEARING:
The provisions of 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402 C.R.S. 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:
On May 8, 1991, following a rulemaking hearing on December 3, 1990, the Commission took final action to adopt numerous revisions to water quality classifications and standards throughout the Upper Colorado River Basin. On September 9, 1991 the Commission held an emergency rulemaking hearing to correct certain clerical errors in the revisions as filed following May 8 action, specifically relating to segment 5 of the Eagle River. To reflect the proper classifications and standards for this segment, the correction of these clerical errors has now been made permanent.
In addition, clerical errors for segment 7 of the Eagle River have also been corrected in this hearing. PARTIES TO THE JANUARY 6, 1992 HEARING 1. Paramount Communications, Inc.
33.22 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; MARCH 1,
1993 HEARING:
The provisions of 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402 C.R.S. 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:
The changes to the designation column eliminating the old High Quality 1 and 2 (HQ1, HQ2) designations, and replacing HQ1 with Outstanding Waters (OW) designation were made to reflect the new mandates of section 25-8-209 of the Colorado Water Quality Act which was amended by HB 92- 1200. The Commission believes that the immediate adoption of these changes and the proposals contained in the hearing notice is preferable to the alternative of waiting to adopt them in the individual basin hearings over the next three years. Adoption now should remove any potential for misinterpretation of the classifications and standards in the interim.
In addition, the Commission made the following minor revisions to all basin segments to conform them to the most recent regulatory changes:
1. The glossary of abbreviations and symbols were out of date and have been replaced by an updated version in section 3.3.6(2).
2. The organic standards in the Basic Standards were amended in October, 1991, which was subsequent to the basin hearings. The existing table was based on pre-1991 organic standards and are out of date and no longer relevant. Deleting the existing table and referencing the Basic Standards will eliminate any confusion as to which standards are applicable.
3. The table value for ammonia and zinc in the Basic Standards was revised in October, 1991. The change to the latest table value will bring a consistency between the tables in the basin standards and Basic Standards.
4. The addition of acute un-ionized ammonia is meant to bring a consistency with all other standards that have both the acute and chronic values listed. The change in the chlorine standard is based on the adoption of new acute and chronic chlorine criteria in the Basic Standards in October, 1991.
Finally, the Commission confirms that in no case will any of the minor update changes described above change or override any segment-specific water quality standards.
33.23 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE: AUGUST 2,
1993 RULEMAKING HEARING:
The provisions of Sections 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402 C.R.S., 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:
The temporary modification for the un-named tributary near Willow Creek, Segment 6c, would have expired before either the ongoing studies were completed, or the next rulemaking hearing was held. The short-term extension granted here will allow for a 207 hearing to proceed with the benefit of a complete data set late in 1994.
The Eagle River temporary modifications were established to accommodate a Superfund cleanup schedule. It was not possible to simple reaffirm the originally scheduled expiration data because that would have resulted in a greater than three year duration, a practice contrary to Commission policy. The expiration date selected will not extend beyond three years, and will allow the temporary modification to be reconsidered factoring in recent data at the basin rulemaking anticipated mid to late 1995.
33.24 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE, SEPTEMBER
7, 1993:
The provisions of 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402 C.R.S., 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:
On November 30, 1991, revisions to “The Basic Standards and Methodologies For Surface Water”,. 3.1.0 (5 CCR 1002-8), became effective. As part of the revisions, the averaging period for the selenium criterion to be applied as a standard to a drinking water supply classification was changed from 1-day to 30-day duration. The site-specific standards for selenium on drinking water supply segments were to be changed at the time of rulemaking for the particular basin. Only one river basin, the South Platte, has gone through basin-wide rulemaking since these revisions to the “Basic Standards”. Through an oversight, the selenium standards was not addressed in the rulemaking for this basin and has since become an issue in a wasteload allocation being developed for segments 15 and 16 of the South Platte. Agreement on the wasteloads for selenium is dependent upon a 30-day averaging period for selenium limits in the effected parties permits. Therefore, the parties requested that a rulemaking hearing be held for the South Platte Basin to address changing the designation of the 1- ug/l selenium standard on all water supply segments from a 1-day to a 30-day standard. The Water Quality Control Division, foreseeing the possibility of a selenium issue arising elsewhere in the state, made a counter proposal to have one hearing to change the designation for the selenium standard on all water supply segments statewide. The Commission and the parties concerned with South Platte segments 15 and 16 agreed that this would be the most judicious way to address the issue.
The change in the averaging period may cause a slight increase in selenium loads to those segments which have a CPDS permits regulating selenium on the basis of a water supply standard. However, these segments are only five in number and the use will still be fully protected on the basis that the selenium criterion is based on 1975 national interim primary drinking water regulations which assumed selenium to be a potential carcinogen. It has since been categorized as a non-carcinogen and new national primary drinking water regulations were promulgated in 1991 that raised the standard to 50 ug/l. The Commission also corrected a type error in the TVS for Silver by changing the sign on the exponent for the chronic standard for Trout from + 10.51 to - 10.51
33.25 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE:
The provisions of Sections 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402 C.R.S., 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:
The Commission has extended the temporary modification for un-ionized ammonia on stream segment 6c in the Upper Colorado River Basin until March 1, 1996. This extension is to allow the Three Lakes Water and Sanitation District to continue sampling and collecting data on stream segment 6c through the fall, winter, and spring seasons, 1994-1995. This data will be analyzed and, if deemed necessary by the District, presented in a formal petition for revisions to the use classifications and/or water quality standards, to be considered in a November, 1995 rulemaking hearing.
33.26 PROPOSED STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE
(1995 Silver hearing)
The provisions of C.R.S. 25-8-202(1)(b), (2) and 25-8-204; 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 The changes described below are being adopted simultaneously for surface water in all Colorado river basins.
This action implements revisions to the Basic Standards and Methodologies for Surface Water adopted by the Commission in January, 1995. As part of a July, 1994 rulemaking hearing, the Commission considered the proposal of various parties to delete the chronic and chronic (trout) table values for silver in Table III of the Basic Standards. As a result of that hearing, the Commission found that the evidence demonstrated that ionic silver causes chronic toxicity to fish at levels below that established by the acute table values. It was undisputed that silver is present in Colorado streams and in the effluent of municipal and industrial dischargers in Colorado. The evidence also demonstrated that the removal of silver from wastewater can be costly. However, there was strongly conflicting scientific evidence regarding the degree to which silver does, or could in the absence of chronic standards, result in actual toxicity to aquatic life in Colorado surface waters. In particular, there was conflicting evidence regarding the degree to which the toxic effects of free silver are mitigated by reaction with soluble ligands to form less toxic compounds and by adsorption to particulates and sediments. The Commission concluded that there is a need for additional analysis of the potential chronic toxicity of silver in streams in Colorado. The Commission encouraged the participants in that hearing, and any other interested parties, to work together to develop additional information that will help resolve the differences in scientific opinions that were presented in the hearing. The Commission believes that it should be possible to develop such information within the next three years. In the meantime, the Commission decided as a matter of policy to take two actions. First, the chronic and chronic (trout) table values for silver have been repealed for the next three years. The Commission is now implementing this action by also repealing for the next three years, in this separate rulemaking hearing, all current chronic table value standards for silver previously established on surface waters in Colorado. Any acute silver standards and any site-specific silver standards not based on the chronic table values will remain in effect. The Commission intends that any discharge permits issued or renewed during this period will not include effluent limitations based on chronic table value standards, since such standards will not currently be in effect. In addition, at the request of any discharger, any such effluent limitations currently in permits should be deleted.
The second action taken by the Commission was the readoption of the chronic and chronic (trout) table values for silver, with a delayed effective date of three years from the effective date of final action. The Commission also is implementing this action by readopting chronic silver standards with a corresponding delayed effective date at the same time that such standards are deleted from the individual basins. The Commission has determined that this is an appropriate policy choice to encourage efforts to reduce or eliminate the current scientific uncertainty regarding in-stream silver toxicity, and to assure that Colorado aquatic life are protected from chronic silver toxicity if additional scientific information is not developed. If the current scientific uncertainty persists after three years, the Commission believes that it should be resolved by assuring protection of aquatic life.
In summary, in balancing the policy considerations resulting from the facts presented in the July 1994 rulemaking hearing and in this hearing, the Commission has chosen to provide relief for dischargers from the potential cost of treatment to meet chronic silver standards during the next three years, while also providing that such standards will again become effective after three years if additional scientific information does not shed further light on the need, or lack of need, for such standards. Finally, the Division notes that arsenic is listed as a TVS standard in all cases where the Water Supply classification is not present. This is misleading since Table III in the Basic Standards lists an acute aquatic life criterion of 360 ug/l and a chronic criterion of 150 ug/l for arsenic, but a more restrictive agriculture criterion of 100 ug/l. It would be clearer to the reader of the basin standards if, for each instance where the standard “As(ac/ch)=TVS” appears, the standard “As=100(Trec)” is being inserted as a replacement. This change should make it clear that the agriculture protection standard would prevail in those instances where the more restrictive water supply use protective standard (50 ug/l) was not appropriate because that classification was absent.
The chemical symbol for antimony (Sb) was inadvertently left out of the “Tables” section which precedes the list of segments in each set of basin standards. The correction of this oversight will aid the reader in understanding the content of the segment standards. Also preceding the list of segment standards in each basin is a table showing the Table Value Standards for aquatic life protection which are then referred to as “TVS” in the segment listings. For cadmium, two equations for an acute table value standard should be shown, one for all aquatic life, and one where trout are present. A third equation for chronic table value should also be listed. The order of these three equations should be revised to first list the acute equation, next the acute (trout) equation, followed by the chronic equation. This change will also aid the reader in understanding the intent of the Table Value Standards. PARTIES TO THE PUBLIC RULEMAKING HEARING JUNE 12, 1995 1. Coors Brewing Company 2. The Silver Coalition 3. Cyprus Climax Metals Company 4. The City of Fort Collins 5. The City of Colorado Springs
33.27 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE (SEGMENT
6c, UPPER COLORADO RIVER BASIN)
The provisions of 25-8-202(1)(b) and (2); and 25-8-204 and 25-8-402, C.R.S. 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. Summary In this rulemaking proceeding, the Commission (1) reaffirmed the existing acute and chronic un- ionized ammonia standards for Segment 6c of the Upper Colorado River Basin and (2) extended the temporary modification for un-ionized ammonia for that segment. With respect to the temporary modification, the Commission understands that existing quality is based on instream monitoring data collected by the District from 1992 through 1995, at the upper boundary of Segment 6c and reflects the District's existing monthly average discharge levels up to 15 mg/l total ammonia.
B. Background In December, 1990, former Upper Colorado River Basin Segment 6 was resegmented into Segments 6a, 6b and 6c, due to differing water quality conditions in the three new segments. A temporary modification for un-ionized ammonia, set at ambient to reflect existing conditions of discharge and agricultural activities, was established for Segment 6c to allow Three Lakes Water and Sanitation District (“Three Lakes”) time to conduct water quality monitoring and aquatic biological surveys of the segment, for the purpose of consideration of site-specific standards. In 1993 and 1994, the temporary modification was extended to allow Three Lakes to continue sampling and collecting data on Segment 6c. When the temporary modification was extended in 1994, the Commission also scheduled a rulemaking hearing for November, 1995, to consider revisions to the use classifications and/or water quality standards for Segment 6c based on the data collected by Three Lakes.
C. Commission Decision The results of Three Lakes water chemistry monitoring and aquatic biological surveys of Segment 6c indicate that its habitat substantially limits any resident population or natural reproduction of fish species; most of the fish found in the segment are transient from water diversion structures. The Division and EPA remain concerned about the potential impact of un-ionized ammonia contained in the Three Lakes's effluent on aquatic life in the segment. Three Lakes presented evidence and testimony that the cost of providing capital improvements sufficient to meet the underlying standards for the benefit of the few transient fish found in the segment was estimated at 4 million dollars. Three Lakes District is a rural public entity with a limited tax and revenue base to finance any needed capital improvements.
1. Three Lakes Water and Sanitation district 2. Northern Colorado Water Conservancy District and Municipal Subdistrict 3. Northwest Colorado Council of Governments
33.28 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE (1996
RULEMAKING HEARING)
The provisions of 25-8-202(1)(b) and (2); and 25-8-204 and 25-8-402, C.R.S. 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:
The changes described below were adopted by the Commission as proposed by the Water Quality Control Division during the rulemaking hearing:
Corrected several errors in the tables for segments not classified for water supply use. The action entailed deletion of NO3, Cl, and SO4 and revision of As, Crlll, and Se of certain standards applied to these segments that reflected protection of a water supply use. The segments whose standards were modified are: Upper Colorado segment 6c, Blue River segments 11 and 13, North Platte River Segment 6, and Yampa River segments 5, 7, and 13b.
The chronic ammonia (NH3) standard in the Yampa River Basin segment 7 was raised from 0.02 to 0.05 to correct a typographical error. The Commission had adopted the 0.05 standard for the segment in 1985 and it was subsequently inadvertently dropped from the table. On all segments classified for water supply and aquatic life uses, the total recoverable manganese standard of 1000 ug/l is stricken. On segments classified for aquatic life and not water supply the 1000 ug/l standard is designated as dissolved. The aquatic life manganese criterion was changed in 1991 revisions to the Basic Standards from total recoverable to dissolved and on these segments classified for water supply and aquatic life, a more stringent dissolved manganese water supply standard of 50 ug/l is in place.
Mercury standards designated as total recoverable (Trec) are changed to Total (tot). This change reflects the Basic Standards designation of total mercury as the appropriate form of mercury for final residual value (FRV) standards.
The following Water Quality Control Division and Northwest Colorado Council of Governments (NWCCOG) joint proposals were adopted by the Commission. Upper Colorado segment 7b(Rock Creek) was deleted. Segment 7a was renumbered as segment 7. This segment was no longer requires separate segment designation due to elevated mercury. Extended (reestablished) the temporary modifications for Blue River segments 2 (Blue River below French Gulch) and 7 (Peru Creek) which had expired on April 30, 1996 in anticipation of improved water quality in these segments in the future as existing or proposed project are fully implemented. These temporary modifications were given a new expiration date of December 31, 1998. At the request of Viacom International, Inc. the Commission extended (reestablished) the temporary modifications of the numeric standards for dissolved manganese on segments 5 and 9 of the Eagle River for an additional three-year period, from May 1, 1996 until December 31, 1998. The Commission found that the underlying numeric standard for dissolved manganese is not being met in these segments, largely as a result of the effects of past mining in the area, now mostly inactive. The former Eagle Mine and its associated tailings disposal areas have been, and continue to be the subject of remediation actives being implemented under the terms of two consent decrees by Viacom International Inc., the successor to the mine=s former owner. The remediation is still in progress, and while continued water quality improvement is expected, both the extent and the timing of such improvement are unknown at this time.
The Water Quality Control Division is planning to perform water quality measurements in the Eagle River as part of a basin-wide water quality monitoring effort during 1996 and data collected by Viacom, EPA, and the State of Colorado, and others, will be used in a comprehensive review of the classifications and standards for these segments in a rulemaking now anticipated to occur in 1998, at which time these temporary modifications can be reconsidered. Therefore, the Commission has determined that it is appropriate to retain the temporary modifications for dissolved manganese on the affected segments. In response to the petition of Pittsburg & Midway Coal Mining Company (P&M), the Commission decided to revise the segmentation and classifications of Yampa River 13a, by adding a new segment 13c. P&M had asked the Commission to remove the water supply designation for these waters. P&M argued that there is no water supply use currently in place for this segment, that such use is unlikely in the future, that existing quality does not meet water supply standards, and that water supply standards would result in unreasonable treatment costs for P&M. NWCCOG argued that the legal requirements for downgrading had not been met, and instead recommended that a temporary modification of sulfate standard be adopted.
The Commission decided to retain the water supply classification for this segment for the period June through February annually, while removing this classification and corresponding numerical standards on a seasonal basis, for the period March through May. The evidence presented indicated that P&M should not have a problem meeting the effluent limitations associated with a seasonal sulfate standard, so long as that standard is properly implemented as a 30-day average concentration. Finally, the Commission notes that its decision to remove the water supply classification on a seasonal basis is influenced by the fact that the critical standard at issue--sulfate--is based on a secondary drinking water standard rather than a health-based primary standard. The Commission agreed to consider a proposal by the Water Quality Control Division for a proposed designation of outstanding waters for Upper Colorado segment 9 in the scheduled basin-wide rulemaking in 1998.
Climax Molybdenum Company withdrew their proposal to bifurcate Upper Colorado River segment 8. The concerns with manganese and iron standards will be addressed in a request for a rulemaking hearing on this segment next year.
1. Northwest Colorado Council of Governments 2. Pittsburg & Midway Coal Mining Company 3. Viacom International, Inc.
4. State of Colorado, Division of Wildlife, Department of Natural Resources 5. City of Colorado Springs, Water Resources Department 6. Climax Molybdenum 7. Northern Colorado Water Conservancy District
33.29 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JULY, 1997
RULEMAKING The provisions of sections 25-8-202 and 25-8-401, C.R.S., provide the specific statutory authority for adoption of the attached regulatory amendments. The Commission also adopted, in compliance with section 24-4-103(4) C.R.S., the following statement of basis and purpose. BASIS AND PURPOSE The Commission has adopted a revised numbering system for this regulation, as a part of an overall renumbering of all Water Quality Control Commission rules and regulations. The goals of the renumbering are: (1) to achieve a more logical organization and numbering of the regulations, with a system that provides flexibility for future modifications, and (2) to make the Commissions internal numbering system and that of the Colorado Code of Regulations (CCR) consistent. The CCR references for the regulations will also be revised as a result of this hearing.
33.30 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; OCTOBER,
1997 RULEMAKING The provisions of sections 25-8-202, 25-8-204 and 25-8-401, C.R.S., provide the specific statutory authority for adoption of the attached regulatory amendments. The Commission also adopted, in compliance with section 24-4-103(4) C.R.S., the following statement of basis and purpose. BASIS AND PURPOSE A stipulation was presented by the parties to the Commission at the hearing whereby Climax Molybdenum Company withdrew its proposal to adopt seasonal iron and manganese standards for the Williams Fork River. The parties agreed to the adoption of temporary modifications for iron and manganese with an expiration of December 31, 1999. During the term of the temporary modifications, the parties will identify a well as a potential point of compliance and Climax will monitor the iron and manganese levels in the well to obtain baseline water quality data. Assuming that the iron and manganese levels are below the water supply standards, it is expected that the well will be proposed at a subsequent hearing as a point of compliance and that the temporary modifications will be deleted. Any discharge of iron or manganese from the Climax facility during the term of the temporary modification will be regulated based on the 1000 ug/l aquatic life standards. Parties to the Hearing 1. Climax Molybdenum Company 2. Northwest Colorado Council of Governments 3. Grand County Board of County Commissioners 4. U.S. EPA Region VIII
33.31 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; NOVEMBER,
1998 RULEMAKING The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 The Commission has recently approved a new schedule for triennial reviews of water quality classifications and standards for all river basins in Colorado. In this hearing the Commission has extended the expiration dates of temporary modifications [and, for the Animas Basin, the effective dates of underlying standards] without substantive review, so that the next substantive review of the temporary modifications can occur as part of the overall triennial review of water quality standards for the particular watershed. This will avoid the need for multiple individual hearings that would take staff resources away from implementation of the new triennial review schedule.
33.32 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; AUGUST,
1999 RULEMAKING The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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. Resegmentation Some renumbering and/or creation of new segments was made in the basin due to information which showed that: a) the original reasons for segmentation no longer applied; b) new water quality data showed that streams should be resegmented based on changes in their water quality; and/or c) certain segments could be grouped together in one segment because they had similar quality and uses. The following changes were made Upper Colorado segments 3 and 5 - combined into one segment 3. Past data showed water quality differences, more recent data shows there is no significant difference in water quality. Upper Colorado segment 5 - now consists of Wolford Mountain Reservoir which was bifurcated from Upper Colorado segment 6a due to its supporting a Recreation Class 1 use. Yampa River segments 8, 9, 10 and 11 - combined into one segment 8. With the change to recreation class 1 on segment 8, all four segments had identical classifications and standards.
B. Wetlands In March 1993, the Commission amended the Basic Standards and Methodologies for Surface Water, Regulation #31 (5 CCR 1002-31) to include wetlands in the stream classification and standards’ system for the state. Due to that action, it became necessary to revise the segment description for all segments of the “all tributary” type to clarify that wetlands are also part of the tributary system for a given mainstem segment. All tributary wetlands now clearly carry the same classifications and standards as the stream to which they are tributary as provided for in 3.1.13(1)(e)(iv).
C. Manganese The aquatic life manganese criterion was changed in 1997 revisions to the Basic Standards (5 CCR 1002-31) from a single chronic dissolved criterion to acute and chronic hardness-based equations, i.e., Acute=e(0.7693[ln (hardness)]+ 4.4995) and Chronic=e(.5434[ln(hardness)]+ 4.7850). These manganese equations were added as table value standards in 33.6(3). As a result of the adoption of these new TVS, all segments classified for aquatic life use that had a chronic dissolved manganese standard of 1,000 ug/l had the 1,000 standard stricken and replaced with Mn(ac/ch)=TVS.
D. Selenium The regulation in 33.6 (3) listed the table value standards for selenium as Acute=135 ug/L and Chronic=17ug/L. This was updated to reflect the existing acute and chronic criteria for selenium listed in the Basic Standards as Acute=20 ug/L and Chronic=5 ug/L which was adopted in 1995 by the Commission. This change means that all segments with standards for selenium given as TVS now have these lower acute and chronic standards. Because of this change, on all segments classified for a water supply use, the chronic total recoverable selenium of 10 ug/L was stricken and replaced with Se(ac/ch)=TVS.
E. Outstanding Waters Designations Several segments or waterbodies were designated outstanding waters (OW) due to their meeting certain criterion pursuant to section 31.8(2)(a). Other segments that already had the OW designation but whose classifications and/or standards were inconsistent with the those prescribed by the Commission for OW waters in other basins in Colorado were corrected. These changes are discussed below for each segment.
Eagle River segment 1 - All tributaries to the Eagle River system within the Gore Range - Eagles Nest Wilderness Area and Holy Cross Wilderness Area. North Platte River segment 2 - deleted reference to waters in Never Summer W.A. which were moved into North Platte segment 1 With respect to Eagle River segment 1, the Commission is aware of the fact that the Homestake Water Project of the Cities of Aurora and Colorado Springs predated the Holy Cross Wilderness designation and that the Project obtained a Congressional exemption which provided that the wilderness designation would not adversely impact the exercise of the Project’s water rights. Act of December 19, 1980, Public Law No. 96-50, Section 102(a)(5), 94 Stat. 3265, 3266. Having taken into account the Congressional exemption, the location of the Project and its associated water rights, the potential impact of an OW designation on future project activities, the basis for the Commission’s adoption of an OW designation for the segment, and the language of CRS 24-4-104, the Commission has decided to grant a project specific exemption form the OW designation to the Homestake Project as specified in footnote 1 to Eagle River segment 1. For purposes of the Project, the affected stream segment will remain “reviewable water.” This project specific exemption should ensure the future protection of water quality within the segment, while recognizing legitimate pre-existing rights. The project exemption may be revisited once the project has finalized its development plans for the remaining project water rights in the area.
F. Temporary Modifications There were several segments which had temporary modifications that were reviewed and decisions made as to delete them or to extend them, either as is or with modification of the numeric limits.
Blue River segment 7 - Peru Creek.
The temporary modifications were reviewed and revised to reflect data collected from the segment in 1996-98 and they and the underlying standards were adjusted to reflect dissolved metals standards rather than the total recoverable that have been in place since 1980. Eagle River segment 5 - Mainstem of the Eagle River from the compressor house bridge at Belden to the confluence with Gore Creek.
Several ambient standards for metals and a temporary modification for manganese were in place on segment 5 since 1980. The ambient standards and temporary modification were based on limited data and the metal standards were based on the total recoverable form which the Commission had specified for standards prior to 1987. In 1987, Colorado’s Basic Standards prescribed dissolved metals as the standard of choice for all metals standards that are based on toxicity to aquatic life. Also, since the adoption of the standards in 1980, the Eagle Mine and mill area has been declared a Superfund site with remediation begun in 1988. Viacom International, Inc., the responsible party for the remediation, has collected an extensive record of water quality data throughout segment 5 that documents the improvements in quality to date. The purpose of adopting new underlying standards and temporary modifications is to reflect the existing water quality, establish underlying standards (goals) based on ARARs established for the Eagle Superfund site, and make the standards consistent with the dissolve’ criteria established in the 1987 Basic Standards. The underlying numeric standards for cadmium and zinc of 1.1 ug/L and 106 ug/L, respectively, are the ARAR’s established by the U. S. Environmental Protection Agency. The underlying manganese standard of 50 ug/L was the existing standard which was adopted in 1980 to protect the water supply classification. The temporary modifications are adopted for two seasons, May 1 through November 30 and December 1 through April 30, because of the extreme seasonal variation shown by the data. The temporary modifications for chronic cadmium, zinc and manganese are based on the 85th percentile values of the water quality data collected in segment 5 from 1996 through 1998. It is anticipated that at the next triennial rulemaking for the Upper Colorado River Basin the temporary modifications will be reviewed and adjusted, if necessary, to reflect the most recent instream quality of segment 5. At the time of completion of the remediation (estimated to be 10 years) or achievement of an agreed upon acceptable level of recovery of the aquatic biota, should that happen sooner, the water quality data for the segment should be reviewed to ascertain what the levels of instream metals are at that time. Based on those findings, the Commission may determine that ambient standards are appropriate for segment 5 for any metals still exceeding the underlying standards.
The previous use-protected designation for this segment has been removed, since there are now only two parameters (cadmium and zinc) which exceed table values for all or part of the year. Eagle River Segment 7 - Mainstem of Cross Creek from the source to the confluence with the Eagle River.
The lower reach of Cross Creek, like segment 5 of the Eagle River, is part of the Eagle Mine Superfund site. It is still undergoing remediation and at one time the Creek was the receiving stream for the treated wastes from the Eagle Mine. The standards in place were, as in segment 5, based on outdated data, information and criteria in place in the early 80's. As a result of this hearing, temporary modifications to underlying table value standards were adopted for zinc and manganese to reflect the current instream water quality based on samples collected from 1996 through 1998. Because of the seasonality shown by the data, the temporary modifications were adopted for two periods, May 1 through October 31 for manganese (165 ug/L) and November 1 through April 30 for zinc (170 ug/L) and manganese (840 ug/L). Eagle River segment 9 - The existing temporary modification for manganese was reviewed and renewed for three years. Review of the most recent data from this segment indicated that there had not been a significant lowering of the manganese from the existing temporary modification of 85 ug/l. Since the manganese levels in this segment may be related to the remediation underway at the Eagle Mine Superfund site modification it was felt that the temporary modification date should track those established for Eagle River segment 5.
G. Recreation Classifications/Fecal Coliform Standards In a continuation of the Commission’s efforts to comply with the requirements contained in the federal Clean Water Act that all waters of the nation should be suitable for recreation in and on the water (known as the “swimmable” goal), the Commission reviewed all Recreation Class 2 segments. In Colorado, the “swimmable” goal translates into a Recreation Class 1, with the 200/100 ml fecal coliform standard (assigned wherever swimming, rafting, kayaking, etc. are in place or have the potential to occur). In some river basins, the Commission has adopted a Recreation Class 2 classification, with 200/100 ml standard, where only secondary contact recreation is practiced, and the existing quality supports a Class 1 Recreation use and little or no impact to dischargers will result. However, the current Basic Standards and Methodologies for Surface Water do not address this option. To maintain the existing Recreation Class 2, with the 2000/100 ml standard on a segment, it must be shown that there is minimal chance that a Recreation Class 1 activity could exist (e.g. intermittent or small streams that have insufficient depth to support any type of Recreation Class 1 use or very restricted access). Based on the information received that showed Recreation Class 1 uses are in place, the Commission upgraded the following Recreation Class 2 segments to Class 1 with a 200/100 ml standard:
The following segments retained their Recreation Class 2 and 2,000 fecal coliform standard based on the evidence submitted in this rulemaking hearing, including the segment-specific information in the Division’s Rationale and testimony from the parties. No evidence was submitted indicating that these segments have a reasonable potential to support Recreation Class 1 uses. Upper Colorado segments 6a, 6b, 6c and 7c.
Blue River segments 5, 7, 8, 11, 12, 13 and 20.
Eagle River segment 11.
North Platte River segments 2, 5, 6 and 7.
Roaring Fork segments 4, and 10.
Yampa River segments 4, 5, 7, 8, 12, 13d and 19.
The recreation classifications and standards for each of these segments will be reviewed by the Commission in each future triennial review. The Commission encourages all interested persons to submit any available information regarding the potential uses of these segments. In addition, the Commission notes that the system for adopting recreation use classifications and standards will be reviewed in the upcoming triennial review of the Basic Standards and Methodologies for Surface Water.
H. Full Standards Not Applied to Aquatic Life Segments The Commission reviewed information regarding Aquatic Life Class 2 segments where the full set of inorganic aquatic life protection standards have not been applied. EPA is concerned that this be done on those segments that are receiving waters for wastewater treatment plant discharges. Generally, these are dry segments with only rudimentary aquatic life. The Commission=s policy has been that rather than adopt the full set of inorganic standards for these segments, standards for dissolved oxygen, pH and fecal coliform provide sufficient protection. The segments which were reviewed in this hearing and for which sufficient evidence was received for them to retain their present classifications and standards are:
Yampa River segment 4b (Little White Snake River) had, in a 1987 hearing, been determined to not be suitable for an aquatic life class 1 or in need of the protection of aquatic life inorganic standards. The basis and purpose of this decision is detailed in 33.19 of this regulation. In this hearing, the Commission did review the numeric standards for metals on this segment which are based on water supply and agriculture criterion. These standards were revised as appropriate to reflect any amendments to the Basic Standards that occurred since the 1987 hearing. One segment, Blue River segment 5 (Soda Creek), was found to support a sizeable population of brook trout and was given an Aquatic Life Cold 1 classification with a full set of numeric standards. Summit County’s Snake River WWTF discharges at the mouth of this stream where it enters Dillon Reservoir and it is unlikely that they will be affected by the new standards. A site- specific pH standard of 6.0, which was established in 1990, was retained.
I. Ambient Quality-Based Standards There are several segments in the Upper Colorado and North Platte River Basins that contained ambient standards. Ambient standards are adopted where natural or irreversible man-induced conditions result in water quality levels higher than table value standards. EPA had requested the Commission review the information that are the basis for these standards as well as any new information that would indicate whether they are still appropriate, need to be modified or should be dropped. The Division reviewed the reason for the ambient standards and provided testimony that justified ambient standards being retained on the following segments: Blue River segments 11, 12, and 14.
J. Water + Fish Standards One other issue that EPA has requested be addressed in the hearing was the justification for not having the water + fish organic basic standards applied to Aquatic Life Class 2 streams. Prior to the hearing, the Division contacted DOW fisheries personnel and other locals with extensive knowledge of sport fishing in the Upper Colorado and North Platte basins and requested information that would pinpoint any streams or lakes in Aquatic Life Class 2 segments that have fish that are presently being taken for human consumption or have fisheries that would indicate the potential for human consumption. Information received indicated only two additional waterbodies that had the potential for consumption of fish. Blue River segment 5, was reclassified as Aquatic Life Class 1 and thus received the full protection of numeric and water + fish organic basic standards. The “water + fish organics” modifier was added to North Platte segment 7.
K. Other Site-Specific Revisions Eagle River Ammonia Standards Corrections were made to the formatting of the un-ionized ammonia standards for Eagle River segments 1 through 10. These corrections which do not alter the adopted standards on the segments merely correct typographical errors that occurred when routine revisions were made to the Upper Colorado basin standards in 1998.
1. Viacom International 2. Climax Molybdenum Company 3. Spring Valley Sanitation District 4. Spring Valley Development, Inc.
5. Colorado Division of Wildlife 6. Northwest Colorado Council of Governments 7. The Northern Colorado Water Conservancy District 8. The Cities of Aurora and Colorado Springs through the Homestake Project 9. The Three Lakes Water and Sanitation District 10. Colorado River Water Conservation District 11. Trout Unlimited 12. United States Department of the Interior, Fish and Wildlife Service 13. United States Environmental Protection Agency
33.33 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; MAY, 2001
RULEMAKING The provisions of sections 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402, C.R.S., provide the specific statutory authority for adoption of the attached regulatory amendments. The Commission also adopted, in compliance with section 24-4-103(4), C.R.S., the following statement of basis and purpose. BASIS AND PURPOSE As a result of a July, 2000 rulemaking hearing the Commission adopted numerous revisions to the Basic Standards and Methodologies for Surface Water, Regulation #31 (5 CCR 1002-31). These revisions included revisions to the table values in Tables II and III, which are intended to apply to site-specific waters in the various river basins wherever the Commission has adopted “table value standards”. In this current rulemaking, the Commission adopted revisions to section 33.6(3) of this regulation to conform with the revisions to the Basic Standards.
33.34 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE, DECEMBER,
2001 RULEMAKING The provisions of sections 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402, C.R.S., provide the specific statutory authority for adoption of the attached regulatory amendments. The Commission also adopted, in compliance with section 24-4-103(4), C.R.S., the following statement of basis and purpose. BASIS AND PURPOSE In the spring of 2001, the Commission established a new schedule for major rulemaking hearings for each of its water quality classifications and standards regulations, as part of the triennial review process. As part of the transition to this new schedule, in order to facilitate an efficient and coordinated review of all water quality standards issues in this basin, in this hearing the Commission decided to extend the existing temporary modifications of water quality standards previously adopted for segments in this basin, so that such temporary modifications will not expire prior to the next scheduled major rulemaking hearing for this basin.
33.35 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE, MARCH,
2002 RULEMAKING The provisions of sections 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402, C.R.S., provide the specific statutory authority for adoption of the attached regulatory amendments. The Commission also adopted, in compliance with section 24-4-103(4), C.R.S., the following statement of basis and purpose. BASIS AND PURPOSE In this hearing the Commission adopted a proposal by The Pittsburg and Midway Coal Mining Co. to modify the water supply standards for Yampa River segment 13c to conform with the revisions to the Basic Standards and Methodologies for Surface Water (Regulation #31) at 31.11(6) adopted in 2000. P&M requested modification to the water supply standards of iron, sulfate and manganese, for Yampa River segment 13c. P&M has a permit to discharge to this segment and waiting to incorporate these changes until the next basin-wide review would result in a hardship. By this action, Table 33.6(2) Abbreviations is modified to include the “WS(dis)” notation and the explanation from 31.11(6). In addition, the notation for Yampa River segment 13c for iron, sulfate and manganese is changed from numerical values to “WS(dis)”. PARTIES TO THE RULEMAKING HEARING 1. The Pittsburg and Midway Coal Mining Co.
33.36 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JULY, 2003
RULEMAKING The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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. Resegmentation Some renumbering and/or creation of new segments was made in the basin due to information which showed that: a) the original reasons for segmentation no longer applied; b) new water quality data showed that streams should be resegmented based on changes in their water quality; and/or c) certain segments could be grouped together in one segment because they had similar quality and uses. The following changes were made: Upper Colorado River expanded to include all lakes and reservoirs tributary to the Colorado segment 5 River from Rocky Mountain National Park to the Roaring Fork River (previously Wolford Reservoir)
B. Recreation Classifications/Fecal Coliform and E. Coli Standards The biological standards were updated to include the dual standards for E. coli and fecal coliform, which were adopted by the Commission in the 2000 revisions to the Basic Standards. As stated in the statement of basis and purpose for the Basic Standards revisions, the Commission intends that dischargers will have the option of either parameter being used in establishing effluent limitations in discharge permits. In making section 303(d) listing decisions, in the event of a conflict between fecal coliform and E. coli data, the E. coli data will govern. The Commission believes that these provisions will help ease the transition from fecal coliform to E. coli standards. In a continuation of the Commission’s efforts to comply with the requirements contained in the federal Clean Water Act that all waters of the nation should be suitable for recreation in and on the water (known as the “swimmable” goal), the Commission reviewed all Recreation Class 2 segments. In Colorado, the “swimmable” goal translates into Recreation Class 1a, with the 200/100 ml fecal coliform and 126/100 ml E. Coli standard, and Class 1b with the 325/100 ml fecal coliform and 205/100 ml E. coli standard. Class 1a indicates waters where primary contact uses have been documented or are presumed to be present. Class 1b indicates waters where no use attainability analysis has been performed demonstrating that a recreation class 2 classification is appropriate, but where a reasonable level of inquiry has failed to identify any existing class 1 uses. To maintain the existing Recreation Class 2 with the 2000/100 ml fecal coliform and 630/100 ml E. coli standard on a segment, it must be shown that there is not reasonable potential for Recreation Class 1 uses to occur within the next 20-year period (e.g. ephemeral or small streams that have insufficient depth to support any type of Recreation Class 1 use or very restricted access).
C. Aquatic Life Segments without Full Standards The Commission reviewed information regarding Aquatic Life Class 2 segments where the full set of inorganic aquatic life protection standards have not been applied. Generally, these are dry segments with only rudimentary aquatic life. The Commission’s policy has been that rather than adopt the full set of inorganic standards for these segments, standards for dissolved oxygen, pH and fecal coliform provide sufficient protection.
D. Revised Aquatic Life Use Classifications The Commission reviewed information regarding existing aquatic communities. The following segment=s aquatic life classifications were upgraded from aquatic life class 2 to aquatic life class 1 based on information presented that showed diverse aquatic communities in these segments. Blue River segments 13 and 19 E. Ambient Quality-Based Standards There are several segments in the Upper Colorado River Basin that are assigned ambient standards. Ambient standards are adopted where natural or irreversible man-induced conditions result in water quality levels higher than table value standards. EPA had requested that the Commission review the information that is the basis for these standards as well as any new information that would indicate whether they are still appropriate, need to be modified, or should be dropped.
F. Temporary Modifications There were several segments where temporary modifications that reflect current ambient conditions were adopted or retained. Temporary modifications were generally set to expire on 2/28/09 to coincide with the next triennial review except as otherwise noted. The segments and the constituents are:
The Temporary Modification of the Yampa River segment 13d selenium standard is assigned on the basis of uncertainty as per the provisions of 31.7(3)(a)(iii) of the Basic Standards and Methodologies for Surface Waters, Regulation No. 31.
Temporary Modifications were also deleted from several segments, either because the segment is in attainment of new standards adopted by the Commission or because of improvements in water quality. These segments and constituents include: Upper Colorado River segment 6c NH3(ac/ch)
Blue River segment 2 Cd(ch), Zn(ch)
Blue River segment 6 Fe(ch), Mn(ch)
Blue River segment 11 Cd(ch), Pb(ch), Zn(ch)
Eagle River segment 5 Cd(ch)
Eagle River segment 7 Mn(ch)
Eagle River segment 9 Mn(ch)
G. Modification of Water Supply Standards Water supply standards were modified to conform to the changes made by the Commission in the 2000 revisions to the Basic Standards (see Regulation No. 31 at 31.11(6)). The Commission modified the water supply standards for iron, manganese, and sulfate that are based on secondary drinking water standards (based on esthetics as opposed to human-health risks). The numeric values in the tables were changed to Fe(ch) = WS (dis), Mn(ch) = WS (dis), and SO4 =
H. Agriculture Standards Numeric Standards to protect Agricultural Uses were adopted for the following segments: Upper Colorado River segment 6c Eagle River segment 11 Yampa River segment 12 I. Other Site-Specific Revisions The Commission corrected several typographical and spelling errors, and clarified segment descriptions.
“Whenever a State reviews water quality standards pursuant to paragraph (1) of this subsection, or revises or adopts new standards pursuant to this paragraph, such State shall adopt criteria for all toxic pollutants listed pursuant to section 307(a)(1) of this Act for which criteria have been published under section 304(a), the discharge or presence of which in the affected waters could reasonably be expected to interfere with those designated uses adopted by the State, as necessary to support such designated uses. Such criteria shall be specific numeric criteria for such toxic pollutants.” Yampa River segment 13b: The Commission adopted an ambient based iron standard of 1600 ug/L for Foidel and Middle Creeks in Segment 13b of the Yampa River. This ambient standard was adopted pursuant to Regulation 31.7(1)(b)(ii) and evidence presented by Twentymile Coal Company that the high levels of iron in those creeks are due to natural causes. Yampa River segment 13d: The Commission changed the Aquatic Life Classification of Segment 13d from Warm 1 to Warm 2 and the Recreation Classification from Recreation 2 to 1a. It adopted a use protected designation, as well as the full set of water quality standards normally associated with Class 2 streams. The Aquatic Life Warm 2 classification was based on application of Regulation 31.13(1)(c) and evidence provided by Seneca Coal Company and the Division that showed that Dry Creek is not capable of sustaining a wide variety of biota, including sensitive species due to physical habitat and flows. The Commission adopted a temporary modification for selenium of 60 Fg/L based on uncertainty. (Reg. 31.7(3)(a)(iii).) Yampa River segment 13e: The Commission moved Sage Creek from Segment 13d and Grassy Creek from Segment 12 into a new Segment 13e classified as Aquatic Life Warm 2, Recreation Class 2, Agriculture and Water Supply. It adopted a use protected designation as well as the full set of water quality standards normally associated with Class 2 streams. The Aquatic Life Warm 2 classification was based on application of Regulation 31.13(1)(c) and evidence provided by Seneca Coal Company and the Division that showed that Sage Creek and Grassy Creek are not capable of sustaining a wide variety of biota, including sensitive species due to physical habitat and water flows.
PARTIES/MAILING LIST STATUS FOR JULY, 2003 RULEMAKING HEARING
1. Colorado River Water Conservation District 2. Colorado Division of Wildlife 3. Jackson County Water Conservancy District 4. Keystone Resort 5. Northern Colorado Water Conservancy District 6. Northwest Colorado Council of Governments 7. Seneca Coal Company 8. Spring Valley Sanitation District 9. Twenty Mile Coal Company 10. U.S. EPA Region VIII 11. Viacom International, Inc.
12. Xcel Energy 13. Eagle Park Reservoir Company 14. Basalt Sanitation District 15. Climax Molybdenum 16. Eagle River Water and Sanitation District 17. Copper Mountain Resort
33.37 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE (Rulemaking
Hearing 6/13/2005, Effective date of 7/31/2005)
The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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:
Segments 13d and e of the Yampa River are classified Aquatic Life Warm Water 2. Metals standards apply to these segments, including the following standards that apply to trout: Cd (ac) = TVS (tr) and Ag (ch) = TVS (tr). It is not appropriate to apply trout standards to a warm water stream. These errors were apparently made in the 1999 basin rulemaking hearing when Dry Creek and Sage Creek were removed from Segment 12 (an all tributary segment) and included in new Segment 13d, which was classified as Aquatic Life Warm Water 1. Although the hearing notice for the 1999 proposal did not include the erroneous trout standards the final action did. These errors were duplicated in the 2003 basin rulemaking when the new Segment 13e (Sage Creek and Grassy Creek) was added. Accordingly, the Commission deleted reference to trout in the Segment 13d and e standards and adopted the following: Cd (ac/ch) = TVS and Ag (ac/ch) = TVS.
33.38 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
12, 2005 RULEMAKING EFFECTIVE DATE OF MARCH 2, 2006 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 In the process of digitally mapping the segments in the Upper Colorado Basin, the Division discovered errors and inconsistencies between segment descriptions. To resolve these issues the Commission adopted changes in the following segment descriptions:
33.39 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
12, 2005 RULEMAKING EFFECTIVE MARCH 2, 2006 The provisions of sections 25-8-202; 25-8-204; 25-8-402, C.R.S., provide the specific statutory authority for adoption. The Commission also adopted, in compliance with section 24-4-103(4) C.R.S., the following statement of basis and purpose.
BASIS AND PURPOSE The changes described below were adopted by the Commission from a joint proposal by the Hazardous Materials and Waste Management Division (HMWMD) and the U. S. Environmental Protection Agency (EPA). The joint proposal addressed segments 5 (mainstem of the Eagle River from the compressor house bridge at Belden to the confluence with Gore Creek) and segment 7 (Cross Creek).
A. History Segments 5 and 7 are within the sphere of influence of a historic zinc-mining district, including the former Eagle Mine site. From 1980 until 1999, ambient quality-based standards for several metals had been in place on segments 5 and 7. In 1988, remediation of the Eagle Mine site began under Superfund. In the August 1999 rulemaking the Commission adopted new underlying standards (goals) and Temporary Modifications for cadmium and zinc to reflect existing water quality. The standards (goals) were based on ARARs established in the 1993 Eagle Mine Superfund Site Record of Decision (ROD). The ARARs are defined in the ROD as numerical remedial action goals subject to revision, and were based on table values in the Basic Standards. The Commission noted in the 1999 Statement of Basis and Purpose that, upon completion of remedial action or achievement of an agreed-upon acceptable level of recovery of aquatic biota in segments 5 and 7, the water quality data for the segments should be reviewed to ascertain the current levels of in-stream metals. Based on such findings, site-specific standards may be deemed appropriate for segments 5 and 7 for any metals still exceeding the underlying standards/goals.
B. Temporary Modifications The Superfund remedial action requirements were completed in 2001, and have resulted in significant improvement in water quality in segments 5 and 7. Therefore, revision of the Temporary Modifications to reflect these water quality improvements is appropriate. Because water quality data in these segments indicate very strong seasonal trends, seasonal Temporary Modifications have been established for these segments. The 85th percentile of the data for each season was used as the “chronic” value; the 95th percentile was used as the “acute”. The Temporary Modifications are set to expire January 1, 2009, coincident with the effective date of standards set at the June 2008 rulemaking hearing for the next triennial review for this basin. Pending the outcome of additional activities at the Superfund Site, changes to the underlying standards will be proposed during the triennial review process. The revised Temporary Modifications adopted in this rulemaking are based on the water quality measured at an integrator station located near the downstream end of each segment; therefore, mass balance calculations conducted for permitting of discharges within the segments and attainment determinations shall be based on attainment of the standards at the downstream end of the segment. Remaining Uncertainty: Uncertainty still exists as to the appropriate underlying standards to apply to these segments. There is uncertainty regarding what aquatic life use is attainable, based in part on uncertainty regarding the potential for additional remediation and other activity in this watershed. There is also uncertainty regarding what water quality levels are necessary to protect a selected expected aquatic life use. It appears that zinc is the primary environmental variable that negatively influences aquati life. Prior to expiration of these Temporary Modifications, additional studies will be undertaken to address this uncertainty Duration of the Temporary Modification: The Commission has set the Temporary Modification to expire on January 1, 2009. This coincides with the anticipated effective date of changes that will be made in the next basin-wide hearing (June, 2008) The Commission expects that the above mentioned studies as well as the CERCLA process will reduce the uncertainty and provide a basis to move forward with underlying standards in the June 2008 hearing process.
C. Re-segmentation.
D. Antidegradation Because remediation activities have improved water quality in segments 5a, 5b, 5c and 7b, since the September 30, 2000 date established in the Basic Standards as the default baseline, the Commission has included a note in the Designation column in the tables to indicate that the September 30, 2000 default baseline date does not apply to these specific segments. In accordance with the Basic Standards (section 31.8(3)(c)(ii)(B)), the appropriate baseline date and baseline water quality will be determined at the time that a new activity triggers an antidegradation review. It is anticipated that this will be the date upon which the antidegradation review commences. The City of Colorado Springs raised concerns that the antidegradation review process includes calculations of low-flow pollutant concentrations, and that the ultimate development of upstream water rights will decrease instream flows that currently provide dilution flow to these stream segments. The Commission clarifies that nothing in this Regulation is intended to or shall be construed as requiring the maintenance of instream flows for any purpose. PARTIES TO THE RULEMAKING 1. Hazardous Materials and Waste Management Division 2. Viacom International Inc.
3. EPA Superfund Remedial Program 4. Vail Associates, Inc.
5. Eagle Park Reservoir Company 6. Eagle River Water and Sanitation District 7. Colorado Division of Wildlife, 8. City of Colorado Springs 9. Northwest Colorado Council of Governments 10. Eagle River Watershed Council 11. Town of Minturn 12. Kamlet Shepherd & Reichert 13. U.S. Environmental Protection Agency
33.40 STATEMENT OF BASIN SPECIFIC STATUTORY AUTHORITY AND PURPOSE DECEMBER
2006 RULEMAKING REGARDING TEMPORARY MODIFICATIONS, EFFECTIVE MARCH 4, 2007 The provisions of C.R S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 The Commission recently restructured section 31.7(4) and established an annual rulemaking hearing to review temporary modifications (regardless of the basis) that are due to expire in the two years following the rulemaking hearing. In this hearing, the Commission considered evidence as discussed in subsections 31.7(3) (b) and (c) to determine whether the temporary modification should be modified, eliminated or extended.
The Commission deleted the temporary modifications for the following segments thereby allowing the underlying standards to go into effect:
1. Trapper Mining Inc.
2. The City of Grand Junction 3. Corrections Corporation of America 4. Keystone Resort 5. U.S. EPA Region VII 6. The City of Black Hawk and the Black Hawk/Central City Sanitation District 7. The City of Colorado Springs 8. Information Network for Responsible Mining 9. Seneca Coal Company
33.41 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE: January
2007 Rulemaking Hearing; Final Action February 12, 2007; Revisions effective July 1, 2007 The provisions of section 25-8-202(1)(b), 25-8-204; 25-8-402, C.R.S., provide the specific statutory authority for adoption. The Commission also adopted, in compliance with section 24-4-103(4) C.R.S., the following statement of basis and purpose.
BASIS AND PURPOSE:
The Commission revised the basin-wide temperature standards as part of the 2007 rulemaking hearing. These changes clarify the numeric temperature standards that will be in effect until the basin-wide rulemaking hearing in June of 2008. At that time, the Commission intends to consider segment specific temperature standards for all segments with aquatic life uses. The Commission applied 17 °C as an interim chronic standard for small, high elevation streams that are likely to be habitat for brook trout and cutthroat trout. First, second and third order streams are defined at section 31.5 in the Basic Standards.
The Commission also applied 18.2 °C as an interim chronic standard to waters designated by the Colorado Wildlife Commission as “Gold Medal Fisheries”. The Commission agrees that it is important to protect these fisheries that provide important recreational and tourism opportunities in the headwaters of Colorado. This standard is based on a criterion to protect rainbow trout. The Colorado Division of Wildlife presented evidence that rainbow trout thrive in Gold Medal fisheries because they are provided the necessary forage base and thermal conditions to maximize their consumption and growth. Because these thermal conditions also represent the upper temperature tolerance range for this species, it was determined that an interim standard of 20 °C would not be adequate to protect these fisheries. For the remainder of the cold water segments, the Commission left the current 20 °C in place as an interim standard with the clarification that it is a chronic standard. The existing 30 °C criterion for warm water segments was left in place as an interim standard with the clarification that is also to be applied as a chronic standard.
1. The Temperature Group (City of Aurora, City of Boulder, Colorado Springs Utilities, Littleton/Englewood Wastewater Treatment, The Metro Wastewater Reclamation District, Colorado Mining Association, Colorado Rock Products Association, Tri-State Generation & Transmission Assn., Xcel Energy, Denver Water, Northern Colorado Water Conservancy District, Southeastern Colorado Water Conservancy District)
2. City of Grand Junction 3. City of Loveland 4. City of Pueblo 5. Metro Wastewater Reclamation District 6. City of Aurora 7. City of Boulder 8. Colorado River Water Conservation District 9. Colorado Wastewater Utility Council 10. Bear Creek Watershed Association 11. Chatfield Watershed Authority 12. Mountain Coal Company, L.L.C.
13. Northern Colorado Water Conservancy District 14. Colorado Rock Products Association 15. Littleton/Englewood Wastewater Treatment Plant 16. Northwest Colorado Council of Governments 17. Southeastern Colorado Water Conservancy District 18. Colorado Mining Association 19. Colorado Division of Wildlife 20. South Platte Coalition for Urban River Evaluation 21. City and County of Denver 22. City of Colorado Springs and Colorado Springs Utilities 23. City of Westminster 24. Board of Water Works of Pueblo 25. Coors Brewing Company 26. City and County of Broomfield 27. Centennial Water and Sanitation District 28. Plum Creek Wastewater Authority 29. Climax Molybdenum Company 30. Cripple Creek & Victor Gold Mining Company 31. Tri-State Generation and Transmission Association 32. Xcel Energy 33. Sky Ranch Metropolitan District No. 2 34. Parker Water and Sanitation District 35. CAM-Colorado and CAM Mining LLC 36. Aggregate Industries – WCR, Inc.
37. Grand County Water and Sanitation District #1, Winter Park Water and Sanitation District, Winter Park West Water and Sanitation District and Fraser Sanitation District 38. Trout Unlimited and Colorado Trout Unlimited 39. Colorado Contractors Association 40. United States Environmental Protection Agency, Region 8 41. Hot Springs Lodge and Pool 42. Denver Regional Council of Governments
33.42 STATEMENT OF BASIN SPECIFIC STATUTORY AUTHORITY AND PURPOSE MARCH 2007
RULEMAKING REGARDING AMMONIA STANDARDSEFFECTIVE SEPTEMBER 1, 2007 The provisions of C.R S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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:
At the June 2005 Basic Standards rulemaking, the Commission adopted the 1999 Update of Ambient Water Quality Criteria for Ammonia (US EPA, Office of Water, EPA-822-R-99-014, December 1999) as the numeric ammonia criteria for Colorado. These new criteria are in the form of total ammonia rather than un-ionized ammonia. The Commission modified the ammonia equations in 35.6(3) and footnotes to conform to Regulation # 31.
Consistent with the approach outlined in the Basic Standards statement of basis and purpose, the Commission provided flexibility for dischargers faced with the possibility of new, more stringent effluent limits.
Temporary modifications were generally set to expire on 12/31/11. This date is set far enough in the future to allow facilities to consider their specific circumstances and to develop a plan regarding how to proceed, yet soon enough to assure that facilities are making progress in developing facility plans. For those that feel the underlying standards are inappropriate, time is allowed to study the receiving water and develop a proposal for an alternate standard. For those that need time to plan, finance or construct new facilities, time is allowed to develop that facility improvement plan. The intent of the Commission is that in general, the permits for dischargers to warm water segments, that need time to achieve compliance, will contain schedules of compliance in the next renewal. The Commission understands that such a compliance schedule may include time to complete necessary sub- tasks or milestones. For example, this might include time to do facility planning, make financing arrangements, pre-design, design, construction, startup and commissioning. There are several opportunities to revisit the duration of the temporary modifications before they expire on 12/31/2011. For those segments in the Upper and Lower Colorado Basins (Regulations # 33 and 37), persons can come forward at the Issues Formulation hearing in November 2007 with their intent to seek a site-specific adjustment in the June 2008 hearing. For those segments in the South Platte Basin (Regulation # 38), persons can come forward at the Issues Formulation hearing in November 2008 with their intent to seek a site-specific adjustment in the June 2009 hearing. In addition, all of these temporary modifications will be subject to the Annual Temporary Review process which will have hearings in December 2009 and 2010.
The Commission intends that the temporary modifications adopted in this rulemaking are “type i” temporary modifications.
The issues raised in this rulemaking hearing have highlighted the need to clarify the relationship between the temporary modification tool and the compliance schedule tool in Colorado’s water quality management program. The Commission requests that the Division consider this issue further, with input from interested stakeholders, and bring forth any suggested revisions/clarifications for the 2010 Basic Standards rulemaking.
In the meantime, because of the Commission’s previously expressed concerns regarding the unique and widespread challenges associated with compliance with the new ammonia standards, the Commission’s intent with respect to temporary modifications and compliance schedules regarding these new ammonia standards is as follows:
- Where a demonstration has been made that a period of time longer than the end of 2011 will be required for compliance with the new ammonia standards, the Commission has approved an appropriate site-specific temporary modification expiration date. - For segments where the 12/31/11 expiration date applies, and for which discharge permit renewals may be issued prior to that date, it is the Commission’s intent, consistent with section 31.14(15)(a), that the Division have the authority to issue compliance schedules that may not result in full attainment of the ammonia standard prior to expiration of the renewal permit. Such compliance schedules should be issued only where the Division determines that a specific demonstration has been made that additional time is needed to attain the standard. In such cases, the Commission anticipates that permits would include milestones that assure reasonable progress toward attainment of the standard.
1. Boxelder Sanitation District 2. Estes Park Sanitation District 3. City of Pueblo 4. The City of Boulder 5. The Metro Wastewater Reclamation District 6. The Colorado Wastewater Utility Council 7. The Paint Brush Hills Metropolitan District 8. The Grand County Water & Sanitation District #1, the Winter Park West Water & Sanitation District, the Fraser Sanitation District and the Winter Park Water & Sanitation District 9. Mountain Water & Sanitation District 10. The Town of Gypsum 11. The City of Grand Junction 12. City and County of Broomfield 13. Centennial Water & Sanitation District 14. Town of Erie 15. The City of Fort Collins 16. Plum Creek Wastewater Authority 17. The City of Sterling 18. Eastern Adams County Metropolitan District 19. The City of Littleton 20. Two River Metro District 21. H Lazy F Mobile Home Park 22. Rock Gardens Mobile Home 23. Blue Creek Ranch 24. The City of Greeley 25. US EPA
33.43 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE: DECEMBER
10, 2007 RULEMAKING REGARDING TEMPORARY MODIFICATIONS; EFFECTIVE MARCH 1, 2008 The provisions of C.R S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Pursuant to the requirements in the Basic Standards (at 31.7(3)), the Commission reviewed the status of temporary modifications to determine whether the temporary modification should be modified, eliminated or extended.
Language was added to subsection 33.6(2) to explain the terms “type i” and “type iii” temporary modifications.
The following segment’s temporary modification was inadvertently left in the table after last year’s hearing. It was deleted in this hearing.
1. Big Dry Creek Cities (City of Westminster, City of Northglenn, and City and County of Broomfield) 2. Colorado Rock Products Association 3. City of Grand Junction 4. City of Colorado Springs and Colorado Springs Utilities 5. Upper Clear Creek Watershed Association 6. City of Black Hawk and Black Hawk / Central City Sanitation District 7. Department of Energy Office of Legacy Management 8. City of Aurora 9. Shell Frontier Oil & Gas, Inc.
10. City of Boulder 11. Tri-Lakes Wastewater Treatment Facility 12. Security Sanitation District 13. City of Fort Collins 14. Metro Wastewater Reclamation District 15. U.S. EPA
33.44 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JUNE 2008
RULEMAKING; FINAL ACTION AUGUST 11, 2008; EFFECTIVE DATE JANUARY 1, 2009 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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. Waterbody Segmentation The Commission decided to split lakes/reservoirs from segments that contain both streams and lakes/reservoirs so that new temperature standards could be adopted. Lakes and reservoirs were deleted from the following segments that previously encompassed both streams and lakes/reservoirs: Upper Colorado River segments: 1, 2, 9.
The following are newly created lakes/reservoirs segments: Upper Colorado River segments: 11, 12.
Yampa River segment: 1b.
Some renumbering and/or creation of new segments was made due to information which showed that: a) the original reasons for segmentation no longer applied; b) new water quality data showed that streams should be resegmented based on changes in their water quality; and/or c) certain segments could be grouped together in one segment because they had similar quality and uses. In particular, segmentation was changed to facilitate adoption of the new temperature standards into individual segments. The following changes were made:
Upper Colorado River 1: The segment description was amended to exclude lakes and reservoirs. The alteration of this segment, and the resultant creation of Segment 11 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 11.
Upper Colorado River 2: The segment description was amended to exclude lakes and reservoirs. The alteration of this segment, and the resultant creation of Segment 12 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 12.
Upper Colorado River 6a: The segment description was amended to reflect the split of Segment 10 into Segments 10a-c; the additional exclusion of specific listings in Segments 1, 2, 4, 5 and 9; as well as the decision to move the endpoint of the segment from below to above the confluence of Muddy Creek and the Blue River. This alteration eliminated confusion regarding the segment associations pertinent to Muddy Creek and its tributaries. Muddy Creek and its tributaries are intended to be included in portions of segment 7a, 7b, and 7c. The alteration of this segment was necessary to facilitate the adoption of appropriate temperature standards.
Upper Colorado River 7a: The segment description was amended to exclude listings in Segment 7c and clarify the upper boundary of the segment as a point immediately above both the Blue River and Muddy Creek. The alteration of this segment, and the creation of Segment 7c were necessary to facilitate the adoption of appropriate temperature standards (CS-II).
Upper Colorado River 7b: The segment description was amended to include all wetlands within the existing segment.
Upper Colorado River 7c: This new segment was created to group similar streams formerly found within segment 7a. Muddy Creek from the source to a point immediately below the confluence with Eastern Gulch; all tributaries to and wetlands of Muddy Creek from the source to the outlet of Wolford Mountain Reservoir, except for listings in Segment 4. The mainstems of Derby, Blacktail, Cabin and Red Dirt Creeks (all below Wolford Mountain Reservoir), including all tributaries and wetlands, from their sources to their confluence with the Colorado River; except for specific listings in segment 4, were included in the newly created segment. The creation of this segment, and the resultant alteration of Segment 7a were based on geographic location and was necessary to facilitate the adoption of appropriate temperature standards (CS-I).
Upper Colorado River 9: The segment description was amended to exclude lakes and reservoirs and to include streams within the Vasquez Wilderness Area. The alteration of this segment, and the resultant creation of Segment 11 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 11. Upper Colorado River 10a: The segment description was amended to reflect a new endpoint of the mainstem portion of the segment. The mainstem portion of the segment now ends at a point immediately below the Rendezvous Bridge, while all tributaries to the Fraser, including wetlands, from the source to the confluence with the Colorado River are still found within this segment. The split of the mainstem, and the resultant creation of Segments 10b and 10c were necessary to facilitate the adoption of temperature standards. (See Section P)
Upper Colorado River 10b: This new segment was created for the mainstem of the Fraser River from a point immediately below the Rendezvous Bridge to a point immediately below the Hammond Ditch. The creation of this segment, and the alteration of Segment 10a were necessary to facilitate the adoption of temperature standards. This portion of the mainstem was previously part of Segment 10. (See Section P) Upper Colorado River 10c: This new segment was created for the mainstem of the Fraser River from a point immediately below the Hammond Ditch to the confluence with the Colorado River. The creation of this segment, and the alteration of Segment 10a and 10b were necessary to facilitate the adoption of temperature standards. This portion of the mainstem was previously part of Segment 10. (See Section P) Upper Colorado River 11: This new segment was created for lakes located in Rocky Mountain National Park as well as all Wilderness areas within the Upper Colorado River Basin. The creation of this segment, and the alteration of Segments 1 and 9 were necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segments 1 and 9. Upper Colorado River 12: This new segment was created for lakes located in Arapahoe National Recreation Area. The creation of this segment, and the alteration of Segment 2 were necessary to facilitate the adoption of appropriate temperature standards. These lakes, including Grand Lake, Shadow Mountain Lake, and Lake Granby were previously part of Segment 2. Blue River 3: The segment description was amended to include only lakes located in the Blue River Drainage above Dillon Reservoir with the exception of lakes located within Segment 21. The alteration of this segment, and the resultant creation of Segment 4 were necessary to facilitate the adoption of appropriate temperature standards. Stream portions of the segment were moved to Segment 4. Blue River 4a: This new segment was created for tributaries to Dillon Reservoir, including wetlands, except for specific listings in Segments 1, 2a, 2b, 4b, 5, 6, and 10-14. The creation of this segment, and the alteration of Segment 3 were necessary to facilitate the adoption of appropriate temperature standards and antidegradation designations. These streams were previously part of Segment 3. (See Section R)
Blue River 4b: This new segment was created for the North Fork of the Swan River, including all tributaries and wetlands, from the source to the confluence with the Swan River. The creation of this segment, and the alteration of Segment 4a, were necessary to facilitate the adoption of an outstanding waters antidegradation designation. (See Section R)
Blue River 6a: The segment description was amended to reflect the creation of segment 6b. A portion of this segment; Jones gulch, including all tributaries and wetlands; was also moved to Segment 8. The alteration of this segment, the creation of Segment 6b, and the inclusion of Jones Gulch (and tributaries and wetlands) in Segment 8 were necessary to facilitate the adoption of appropriate zinc standards. Blue River 6b: This new segment was created for the mainstem of Camp Creek, including all tributaries and wetlands from the source to confluence with the Snake River. The creation of this segment and the alteration of Segment 6a were necessary to facilitate the adoption of appropriate zinc standards. Blue River 8: The segment description was amended to reflect the inclusion of the mainstem of Jones gulch, including all tributaries and wetlands from the source to the confluence with the Snake River. The addition of these stream reaches, formerly found in segment 6, was necessary to facilitate the adoption of appropriate zinc standards.
Blue River 16: The segment description was amended to exclude lakes and reservoirs. The alteration of this segment, and the resultant creation of Segment 21 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 21.
Blue River 21: This new segment was created for lakes located in Wilderness areas within the Blue River Basin. The creation of this segment, and the alteration of Segments 3 and 16 were necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segment 16. Blue River 22: This new segment was created for lakes located in the Blue River drainage below Dillon Reservoir, except specific listings in Segment 21. The creation of this segment was necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously unassigned to a particular segment.
Eagle River 9a: The segment description was amended to reflect a new endpoint of the segment. The segment now ends at a point immediately below the confluence with Rube Creek. The split of the segment, and the resultant creation of Segment 9b were necessary to facilitate the adoption of appropriate temperature standards.
Eagle River 9b: This new segment was created for the mainstem of the Eagle River below the confluence with Rube Creek. The creation of this segment, and the alteration of Segment 9a were necessary to facilitate the adoption of appropriate temperature standards. This portion of the mainstem was previously part of Segment 9.
Eagle River 10a: The segment description was amended to exclude specific listings in segment 10b. The alteration of this segment and the creation of Segment 10b were necessary to facilitate the adoption of appropriate antidegradation designations. (See Section R) Eagle River 10b: This new segment was created for Abrams Creek, including all tributaries and wetlands, from the source to the eastern boundary of the United States Bureau of Land Management lands. The creation of this segment, and the alteration of Segment 10a, were necessary to facilitate the adoption of an outstanding waters antidegradation designation. (See Section R) Eagle River 13: This new segment was created for lakes located in Wilderness areas within the Eagle River Basin. The creation of this segment was necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously unassigned to a particular segment. Eagle River 14: This new segment was created for lakes located in the Eagle River Basin, except for specific listings in Segment 13. The creation of this segment was necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously unassigned to a particular segment. Roaring Fork River 1: The segment description was amended to exclude lakes and reservoirs. The alteration of this segment, and the resultant creation of Segment 11 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 11.
Roaring Fork River 3a: The segment description was amended to reflect a new endpoint of the mainstem portion of the segment. The mainstem portion of the segment now ends at a point immediately below the confluence with the Fryingpan River. All tributaries to the Roaring Fork, including wetlands, from the source to the confluence with the Colorado River are still found within this segment, except for specific listings in Segment 1 and 3b-10. The split of the mainstem, and the resultant creation of Segment 3c were necessary to facilitate the adoption of appropriate temperature standards. Roaring Fork River 3c: This new segment was created for the mainstem of the Roaring Fork below the confluence with the Fryingpan River to facilitate the adoption of appropriate temperature standards. The mainstem of Three Mile Creek, including all tributaries and wetlands, from the source to the confluence with the Roaring Fork River, is also included in this segment. The creation of this segment, and the alteration of Segment 3a were necessary to facilitate the adoption of appropriate temperature standards. These streams were previously part of Segment 3a.
Roaring Fork River 11: This new segment was created for lakes located in Wilderness areas within the Roaring Fork River Basin. The creation of this segment, and the alteration of Segment 1 were necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segment 1.
Roaring Fork River 12: This new segment was created for lakes located in the Roaring Fork River Basin, except specific listings in Segment 11. The creation of this segment was necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously unassigned to a particular segment.
North Platte River 1: The segment description was amended to also exclude lakes and reservoirs and to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 8.
North Platte River 2: The segment description was amended to exclude lakes and reservoirs. The alteration of this segment, and the resultant creation of Segment 9 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 9.
North Platte River 4a: The segment description was amended to exclude lakes and reservoirs. The segment description was additionally amended to exclude listings in segment 4b. The alterations of this segment, and the resultant creations of Segments 4b and 9 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 9.
North Platte River 4b: This new segment was created to group similar streams formerly found within segment 4a. Included in this segment is the Illinois River and 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. The mainstem of the Canadian River below 12E Road to the confluence with the North Platte River, as well as all tributaries and wetlands which enter the Canadian River from the southwest side of the mainstem, were also included in the new segment. North Platte River 5a: The segment description was amended to reflect a new endpoint of the segment. The segment now ends at a point immediately below the confluence with the North Fork Michigan River. The alteration of this segment, and the resultant change of Segment 5b were necessary to facilitate the adoption of appropriate temperature standards.
North Platte River 5b: The segment description was amended to reflect a new upper boundary of the segment. The segment now starts at a point immediately below the confluence with the North Fork Michigan River. The alteration of this segment, and the change of Segment 5a were necessary to facilitate the adoption of appropriate temperature standards. North Platte River 7a: The segment description was amended to reflect a new endpoint of the segment. The segment now ends at the outlet of Spring Creek (Number 31) Reservoir. The alteration of this segment, and the resultant creation of Segment 7b were necessary to facilitate the adoption of appropriate temperature standards.
North Platte River 7b: The segment description was amended to reflect a new upper boundary of the segment. The segment now starts at the outlet of Spring Creek (Number 31) Reservoir. The creation of this segment, and the alteration of Segment 7a were necessary to facilitate the adoption of appropriate temperature standards.
North Platte River 8: This new segment was created for lakes located in Wilderness areas within the North Platte River Basin. The creation of this segment, and the alteration of Segment 1 were necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segment 1.
North Platte River 9: This new segment was created for lakes located in the North Platte River Basin, except specific listings in Segments 8. The creation of this segment, and the alteration of Segments 2 and 4a were necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segments 2 and 4a.
Yampa River 1a: The segment description was amended to also exclude lakes and reservoirs and to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 1b.
Yampa River 1b: This new segment was created for lakes located in Wilderness areas within the Yampa River Basin. The creation of this segment, and the alteration of Segment 1a were necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segment 1a. Yampa River 2a: The segment description was amended to reflect a new endpoint of the segment. The segment now ends at a point immediately below the confluence with Oak Creek. The alteration of this segment, and the resultant creation of Segment 2c were necessary to facilitate the adoption of appropriate temperature standards.
Yampa River 2b: The segment description was amended to include all lakes and reservoirs tributary to the Little Snake River and to reflect the split of Segment 1 into Segments 1a and 1b. The segment description was additionally amended to reflect the creation of Segment 1b. The alteration of this segment was necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segment 19.
Yampa River 2c: This new segment was created for the mainstem of the Yampa River below the confluence with Oak Creek. The creation of this segment, and the alteration of Segment 2a were necessary to facilitate the adoption of appropriate temperature standards. This portion of the mainstem was previously part of Segment 2a.
Yampa River 3: The segment description was amended to exclude the new Segment 13f. The alteration of this segment, and the creation of Segment 13f were necessary to facilitate the adoption of appropriate temperature standards.
Yampa River 11: This new segment was created for Fish Creek, including all tributaries and wetlands, above Country Road 27, except for specific listings in Segment 20. The creation of this segment, and the alteration of Segment 12 were necessary to facilitate the adoption of appropriate temperature standards. These streams were previously part of Segment 12.
Yampa River 12: The segment description was amended to reflect the creation of Segment 11 which removed the Fish Creek, including all tributaries and wetlands, above County Road 27 from the segment. The alteration of this segment, and the resultant creation of Segment 11 were necessary to facilitate the adoption of appropriate temperature standards.
Yampa River 13a: The segment description was amended to reflect the creation of Segment 13f, which removed the portion of Trout Creek, including all tributaries and wetlands, below the confluence with Fish Creek from the segment. The alteration of this segment, and the resultant creation of Segment 13f were necessary to facilitate the adoption of appropriate temperature standards. Yampa River 13d: The segment description was amended to clarify which Dry Creek is intended to be described for this segment. This segment is meant to describe the Dry Creek that has its confluence with the Colorado River immediately below the town of Hayden, Colorado. Yampa River 13f: This new segment was created for Trout Creek, including all tributaries and wetlands, below the confluence with Fish Creek. The creation of this segment, and the alteration of Segment 13a were necessary to facilitate the adoption of appropriate temperature standards. These streams were previously part of Segment 13a.
Yampa River 14: The segment description was amended to reflect new endpoints of the segment. The segment now ends at points immediately below the confluence with Calf Creek and below 80A Road on the Dry Fork of Elkhead Creek. The alteration of this segment, and the resultant creation of Segment 15 were necessary to facilitate the adoption of appropriate temperature standards. Yampa River 15: This new segment was created for Elkhead Creek, including all tributaries and wetlands, from a point immediately below the confluence with Calf Creek and below 80A Road on the Dry Fork of Elkhead Creek, to the confluence with the Yampa River. The creation of this segment, and the alteration of Segment 14 were necessary to facilitate the adoption of appropriate temperature standards. These streams were previously part of Segment 14.
Yampa River 19: The segment description was amended to exclude lakes and reservoirs. The alteration of this segment was necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 2b. Yampa River 20a: The segment description was amended to reflect new endpoints of the segment. The Elkhead Creek and First Creek portions of the segment now end at the eastern boundary of state lands in California Park. The alteration of this segment, and the resultant creation of Segment 20b were necessary to facilitate the adoption of the appropriate recreation use classification. (See Section X) Yampa River 20b: This new segment was created for portions of First Creek and Elkhead Creek below the eastern boundary of state lands in California Park. The creation of this segment, and the alteration of Segment 20a were necessary to facilitate the adoption of the appropriate recreation use classification. These streams were formerly part of Segment 20. (See Section X) B. Revised Aquatic-Life Use Classifications The Commission reviewed information regarding existing aquatic communities. The following changes to the existing aquatic-life use classifications were made. Yampa River 14 was split and portions were moved to segment 15: a change from Cold 1 to Warm 1.
C. Recreation Classifications and Standards As part of the Basic Standards hearing of 2005, recreation classifications were revised into four new classifications. The Commission reviewed the previous segment classifications (1a, 1b and 2) and determined the appropriate new classification based on classification criteria presented as part of the Basic Standards Hearing, use attainability analyses or other basis. In addition, during the 2005 Basic Standards Hearing, the transition from the use of the fecal coliform standard to E. coli standard was completed. Fecal coliform criteria were deleted from the numeric standards. Based on the information that showed existing primary contact recreation use is in place in at least a portion of the segment, the Commission converted the following segments from Recreation Class 1a to Recreation Class E with a 126/100 ml E. coli standard:
North Platte River segments: 1, 3, 4a, 5a.
Yampa River segments: 1a, 2a, 2b, 3, 6, 8, 13a-d, 14, 18-20a. The following segments were converted from Recreation Class 1b to Recreation Class P with a 205/100 ml E. coli standard:
Blue River segments: 11-13.
Eagle River segment: 11.
North Platte River segment: 2.
Yampa River segments: 5, 7.
Based on review of existing Use Attainability Analyses showing that primary contact recreation is not attainable, the following segments were converted from Recreation Class 2 to Recreation Class N classification with 630/100 ml E. coli standard:
Yampa River segments: 4, 12, 13e.
D. Addition of Water Supply Use Classification and Standards Based on review of information regarding the location of public water supplies, no additional Water Supply use classifications or standards were added to Regulation No. 33.
E. Agriculture Standards A review of the standards associated with the Agriculture use classification showed that many segments were missing a nitrate standard protective of the use. A nitrate standard, NO3 =100, was added to the following segments with Agriculture use classification: Upper Colorado River segments: 6b, 6c.
F. Changes to Antidegradation Designation Decoupling Cold 2 and UP: As part of the Basic Standards hearing of 2005, the Commission eliminated the direct linkage between cold-water aquatic life class 2 and the use-protected designation. Therefore, all cold-water aquatic life class 2 segments that are use-protected were reviewed to determine if that designation is still warranted. The following segments are now reviewable: Upper Colorado River segments: 6b, 6c.
Yampa River segments: 4, 12.
Decoupling Aquatic Life Warm 2 and UP: There was no decoupling of the segments with an Aquatic Life Warm 2 classification in the Basin.
Outstanding Waters: See Section R.
G. Ambient Quality-Based Standards There is one segment in the Basin that has ambient metals standards. Ambient standards are adopted where natural or irreversible man-induced conditions result in exceedances of table value standards. The Commission reviewed the information that is the basis for these standards as well as any new information that would indicate whether they are still appropriate, need to be modified, or should be dropped. The following ambient based standards have been revised based on a recalculation using existing data: Yampa River segment 13b: Middle Creek: Fe(ch)=1035(Trec). The WAT standard is not attainable in the majority of large lakes (>100 acres in surface area) including many lakes with apparently healthy cold-water fish populations. Summertime temperature for large lakes and reservoirs (collectively referred to as lakes) is very well correlated to the lake's elevation. Since the thermal properties are natural or man-induced irreversible (in the case of reservoirs) the Commission adopted ambient temperature standards for large lakes wherever data were available to characterize a WAT. For lakes, the WAT is assumed to be equivalent to the average temperature of the mixed layer. If there were less than three years of data, the highest observed WAT was selected for the summertime ambient standard. If three to five years of data were available, the second highest observed WAT was used as the ambient standard. Where temperature data from multiple stations in the same reservoir were collected on the same date, the Division used an average of those stations to calculate the WAT. Upper Colorado River segment 5: Wolford Mountain Res: April-December T(WAT)= 19.73°C . . (See Section O.)
H. Aquatic Life Metals Standards New Table Value Standards: 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 33.6(3) were modified to conform to Regulation No. 31.
Site-Specific Zinc Standards for Mottled Sculpin: In low hardness situations (hardness below 113 mg/L) the new zinc chronic equation is not protective of mottled sculpin (Cottus bairdi), a native west-slope fish species. The Commission adopted a mottled sculpin-specific chronic zinc equation as site-specific standards for the following segments that are inhabited by mottled sculpin and also have low hardness: Upper Colorado River segments: 1-3, 7b, 8, 10a-c.
Chromium III Standards: A review of the chromium III standards showed that the chromium standard associated with the Water Supply use classification was not protective of aquatic life where the average hardness was less than 61 mg/l. A chromium standard, CrIII(ch)=TVS was added to following segments with average hardness values less than 61 mg/l.
North Platte River segments: 1, 2, 4b.
Yampa River segments: 1a, 3, 8, 18.
I. Arsenic Standards For arsenic, each use (except recreation) has a different arsenic (“As”) value, including Fish Ingestion (FI) and Water Plus Fish (W+F). In different combinations of uses, different values become the most limiting. In order to eliminate the confusion, the Commission added the operative value to the individual segments. The following matrix displays the most limiting arsenic criteria. Most Limiting Arsenic Criteria Depending on the Possible Combinations of Uses and Qualifiers If the Use Classifications were: These Arsenic Standards were Applied (dissolved unless otherwise noted)
Water supply only As(ch) = 0.02 - 10(Trec)
J. Uranium Standards At the 2005 Basic Standards rulemaking hearing, the Commission changed the drinking water supply table value for uranium from 40 pCi/L to 30 ug/L.
K. Temporary Modifications All temporary modifications were re-examined to determine whether to delete the temporary modification or to extend them, either as existing or with modifications of the numeric standards. Because of the June 2005 changes to Regulation No. 31, temporary modifications were not automatically extended if non- attainment persisted. The following segments had temporary modifications that were not renewed: Blue River segments: 6, 7, 12.
The following segments have temporary modifications for ammonia that were amended to clarify the chronic standard as 0.02, rather than just “TVS old”. As specified in 61.8(2)(c)(iii) (the Permit Rules, Regulation No. 61), where a temporary modification has been adopted, limits in permits are to be set based on the temporary modification and the provision strictly limiting the loading from the facility does not apply. These temporary modifications will be subject to review and rulemaking for the two years before their scheduled expiration in order to track progress towards the full attainment of water body standards and uses.
In some cases the Commission adopted temporary modifications of underlying standards with the notation of “existing quality” rather than a numeric. This was done where it was not possible to derive an appropriate characterization of current instream concentrations or temperature conditions. The Commission's intent of using the notation “existing quality” is to preserve the status quo during the term of the temporary modification. Dischargers to those segments shall maintain the existing water quality or pollutant loading characteristics of their effluent with respect to the parameter that has the temporary modification. The Commission does not intend the temporary modifications to apply to new facilities or in Preliminary Effluent Limitations. The Commission adopted type iii temporary modifications of temperature standards equal to “existing quality,” for the following segments: Eagle River segments: 8 and 9a.
L. Temperature As part of the Basic Standards hearing of 2007, new table values were adopted for temperature. Temperature standards were applied to individual segments based upon the distribution of fish species, as provided by the CDOW, temperature data, and other available evidence. The following segments are cold stream tier one (CS-I): Upper Colorado River segments: 1, 2, 4, 6a, 7b-10a.
Yampa River segments: 1a, 2a, 3, 5, 6, 8, 11, 13a,18-20b. The following segments are cold stream tier two (CS-II): Upper Colorado River segments: 3, 6b-c, 7a, 10b-c.
Eagle River segment: 9b.
Roaring Fork River segments: 3b, 3c.
North Platte River segments: 3, 4b, 5b, 7b.
Yampa River segments: 2c, 4, 7, 12, 13b-c, 13f, 14.
The following segments are cold lakes or cold large lakes (CL,CLL): Upper Colorado River segments: 5, 11, 12.
Yampa River segments: 1b, 2b.
The following segments are warm stream tier two (WS-II): Yampa River segments: 13d, 13e, and 15.
The Commission recognizes that in some cases there is uncertainty about the temperature standards adopted in this hearing. The uncertainty stems from a lack of data about temperature or the aquatic community or where there is a conflict between the lines of evidence. It is the Commission's intent that the Division and interested parties work to resolve the uncertainty for the following segments by the next basin-wide review.
M. Other Site-Specific Revisions Upper Colorado River 6b: The cyanide standard was revised to reflect that CN=0.2 is an acute standard. The standard now reads CN(ac)=0.2.
Upper Colorado River 6a: The recreation use classification was changed from Class 2 (Secondary Contact) to Class P (Potential Primary Contact) to reflect the operation of a guest ranch located on Willow Creek which features fishing and other access to the stream. There are also many other potential opportunities for public access to various stream reaches within this segment. Upper Colorado River 9: The segment description was amended to include the Vasquez Wilderness Area, which had been previously unlisted within the Upper Colorado River Basin. Eagle River 7a: The CrIII standard was revised to reflect that the 50(Trec) standard is acute rather than chronic.
North Platte 5b: The CrIII acute standard was revised to reflect that the acute standard is 50(Trec) rather than TVS.
North Platte River 7a/b: The “Water + Fish organics apply” qualifier was changed to “Fish Ingestion” to reflect an oversight from the 2003 hearing and the lack of a water supply use classifications for these segments.
Yampa River 13a: The temporary modification for NH3 found on this segment was moved to Segment 13d. The Hayden treatment plant discharges to Segment 13d, thus prior assignment of this temporary modification to Segment 13a was incorrect.
N. Other Changes The Commission corrected several typographical and spelling errors, and clarified segment descriptions.
O. Wolford Mountain Reservoir The River District proposed site-specific D.O. and temperature standards for Wolford Mountain Reservoir. After discussions with the Division, EPA and the Division of Wildlife (“DOW”), the River District agreed to withdraw its proposal in order to further study the possible reasons for non-attainment of the D.O. standard in the reservoir. The Division, EPA, and DOW will assist the River District in developing a study to better understand the reasons for the non-attainment and provide assistance in their respective areas of expertise.
The River District and the Division determined that the WAT for Wolford Mountain Reservoir is 19.73°C based on data collected between 2003 and 2007 and measured at the dam (USGS Station #09041395). When determining compliance with the temperature standard for Wolford Mountain Reservoir in the future, the temperature shall be measured at the dam.
P. Fraser River, Upper Colorado Basin—Temperature Standards Grand County Water and Sanitation District #1, the Winter Park West Water and Sanitation District, the Fraser Sanitation District, the Winter Park Sanitation District (Grand County Districts) proposed resegmentation and temperature standards for waters in the Fraser River watershed. The Commission determined that the physical conditions in the Fraser River basin warranted resegmentation based on the instream temperatures, habitat, and fish community composition. Based on instream temperature and fish population monitoring conducted by and for the Grand County Districts and the Grand County Water Information Network (GCWIN), the Commission concluded that a single segment and accompanying temperature standards is not appropriate for the Fraser River. The temperature data indicate a transition from very cold-to cold-to cool in a downstream direction, which is reflected in changes in the fish community with brook trout expected to occur in the upper reaches and a mixed cold water fishery of both game and non-game species in the lower reaches. Based on these findings, the Commission determined that segment 10 would be split into three distinct segments at specific landmarks and hydrologic breaks that represent shifts in floodplain and stream characteristics. Segment 10a ends at the Rendezvous Bridge, located at or near the former confluence of Leland Creek and the Fraser River. It was determined that CS-I TVS for temperature were appropriate for this upper segment for protection of brook trout.
The rest of pre-existing segment 10 was split into two segments (10b and 10c) at the Hammond ditch, a major irrigation ditch located just north of County Road 8. Even though the classifications and standards are the same for both segments, the stream's physical and biological characteristics are substantially different. CS-II TVS for temperature were applied to both segments 10b and 10c reflecting the presence of rainbow and brown trout; however, the existing temperature data demonstrate a small number of exceedances of the CS-II TVS in segment 10b and numerous exceedances of the CS-II TVS in segment 10c, causing uncertainty regarding attainment of the CS-II TVS in these segments. The data also indicate no significant effect of discharges of municipal effluent on stream temperatures. The Commission intends to revisit the temperature standards for segments 10b and 10c in 2013. It is anticipated that the ongoing biological and temperature monitoring will provide information to lessen the uncertainties regarding the appropriate long-term stream classifications and temperature standards. (See Section L)
Q. Grand Lake, Upper Colorado Basin—Clarity Standard The Northwest Colorado Council of Governments, supported by Grand County and the Greater Grand Lake Shoreline Association, proposed a clarity standard for Grand Lake of 4 meter Secchi disk depth, effective July through September.
The Commission determined that it is appropriate to adopt water quality standards for the protection of Grand Lake's clarity because of Grand Lake's uniqueness as Colorado's largest natural lake. Grand Lake adjoins and complements Rocky Mountain National Park in the headwaters of the Colorado River and its social and economic importance is worthy of protection. Senate Document 80 (which recorded the legislative intent of the federal Congress in February 1937) provided in part that the Colorado Big- Thompson Project must be operated in a manner to preserve the scenic attraction of Grand Lake. Concern about the visible loss of transparency of Grand Lake has resulted in local, state and federal initiatives to address the changes in water quality. The earliest measurement of Grand Lake clarity is 9.2 meters (September 6, 1941). The 85th percentile of clarity measurements from 2006 is 2.7 meters. The Commission recognizes that this is the first time that a clarity standard has been adopted in the Colorado. Clarity standards are being adopted pursuant to the Basic Standards at section 31.13(3), which states “In special cases where protection of beneficial uses requires standards not provided by the classification above, special standards may be assigned after full public notice and hearings.” Improvement of clarity within Grand Lake is expected to improve the quality of recreational uses of this unique resource.
The Commission is adopting two clarity standards for Grand Lake. First, the Commission is establishing a narrative clarity standard, to take effect with the other revisions to this regulation. This standard is “the highest level of clarity attainable, consistent with the exercise of established water rights and the protection of aquatic life”. This standard is based on the Commission’s conclusion that improvement in the clarity of Grand Lake is necessary, while noting that efforts to improve clarity need to be undertaken in a manner consistent with established water rights and need to also consider the protection of the aquatic life use. In basing the standard on “attainability”, the Commission intends that attainability is to be judged by whether or not a clarity level can be attained in approximately twenty years by any recognized control techniques that are environmentally, economically, and socially acceptable. An underlying assumption in setting this narrative standard is that clarity in Grand Lake needs to improve. However, the Commission is not determining in this hearing whether the current evidence of reduced clarity warrants inclusion of Grand Lake on Colorado’s Section 303(d) List or the Monitoring and Evaluation List. That issue can be addressed as appropriate in the 2010 hearing on Regulations #93 and #94, based on additional evidence and analysis developed prior to that time. Second, the Commission is establishing a numerical clarity standard of 4 meter Secchi depth for the months of July through September, with an effective date of January 1, 2014. The intention is that for the majority of the summertime days, the water of Grand Lake shall be clearer than 4 meter Secchi depth. Attainment of the 4 meter Secchi depth standard will be assessed by comparing the 85th percentile of available Secchi depth data collected during the months July through September to the 4 meter standard. Fifteen percent of the measurements may have Secchi depth shallower than 4 meters. When two samples are collected in different locations, or by different agencies on the same day, the Secchi depth value is the average of those samples.
The Commission has determined that the adoption of the 4 meter numerical standard with a delayed effective date is an appropriate policy choice to encourage cooperative efforts to improve Grand Lake clarity prior to the time that a specific numerical standard goes into effect, while assuring that a protective numerical standard will go into effect in 2014 if monitoring, assessment and water quality improvement efforts between now and then have not resulted in identification of a more appropriate numerical standard.
All parties agreed that improvement in Grand Lake water clarity is desirable. The Commission strongly encourages all interested stakeholders to work together to further identify the causes of reduced clarity and to explore options for identifying and implementing reasonable and effective measures to improve clarity, consistent with the other factors noted in the narrative standard. The Commission anticipates that these efforts may result in a proposal for a revised site-specific numerical clarity standard for Grand Lake at a later date.
Concerns have been raised regarding the potential impact of the proposed clarity standard on the exercise of water rights. The Commission recognizes that Section 25-8-104, C.R.S. states in part that “Nothing in this article [the Colorado Water Quality Control Act] shall be construed, enforced or applied so as to cause or result in material injury to water rights.” If non-attainment of the numerical clarity standard is determined to be caused by the valid exercise of those water rights and the exceedance cannot be eliminated in a manner consistent with C.R.S. 25-8-104, the Commission would consider adoption of a revised site-specific standard as provided in section 31.7(1)(b)(ii). The Commission is hopeful that options can be identified to improve Grand Lake clarity in a manner consistent with section 25-8-104. The Commission is not determining in this hearing precisely what types of options and alternatives are or are not consistent with section 25-8-104. The Commission believes that that issue is better addressed in the course of a process that more fully examines the causes of current clarity limitations on Grand Lake and the options for mitigating identified impacts.
While stating that it did not oppose a 4 meter clarity standard for Grand Lake, the Colorado Division of Wildlife noted that it is important that efforts to improve clarity in Grand Lake consider potential effects on recreational fisheries. The Commission intends that potential positive or negative impacts on aquatic life in Grand Lake be taken into account in implementing the narrative standard now being adopted, and in any efforts to consider potential refinement of the numerical standard now being adopted with a delayed effective date.
The Commission believes that this is an appropriate first step toward protecting Colorado's high quality water resources in a manner consistent with law and regulation. As with all standards, the clarity standards for Grand Lake are subject to periodic review, and the Commission expects to revisit this issue in future review cycles.
R. Trout Unlimited, Blue and Eagle River Basins—Outstanding Water Designation Based on evidence that shows that water quality meets the requirements of 31.8(2)a and the presence of Colorado River cutthroat trout, the Outstanding Water (OW) designation was added to the new Eagle River segment 10b: Abrams Creek, including all tributaries and wetlands, from the source to the eastern boundary of the United States Bureau of Land Management lands and the new Blue River Segment 4b: North Fork of the Swan River, including all tributaries and wetlands, from the source to the confluence with the Swan River. The Commission understands that existing land uses are in place in these watersheds. The evidence demonstrates that these existing land uses are compatible with the OW designation since the current high level of water quality has been attained with these uses in place. It is the Commission’s intent that this OW designation should not be used to establish additional permit requirements for existing uses within this area.
S. Keystone, Blue River Basin – Metals Standards Keystone Resort (Keystone) proposed resegmentation of waters in the Snake River watershed and site- specific standards for Camp Creek and its tributaries.
Blue River segment 6: The Commission moved Jones Gulch from segment 6 to segment 8 based upon monitoring data collected by Keystone which showed that Jones Gulch meets table value standards for metals. The Commission adopted re-segmentation of segment 6 by renumbering segment 6 as segment 6a and establishing segment 6b based on recognized differences in water quality characteristics between the Snake River and the Camp Creek watershed which is located within the Keystone Ski Area. Segment 6b is now the mainstem of Camp Creek, including all tributaries and wetlands from the source to the confluence with the Snake River.
Site-specific standards for dissolved zinc were adopted for Camp Creek based upon the use of the recalculation procedure. Despite the habitat limitations in Camp Creek, and the fact that it currently does not support a fish population, under a modified recalculation approach the recalculation included species expected to occur in the Blue River Basin, including sensitive fish species such as mottled sculpin. The four most sensitive genera used to calculate the site-specific standards included Cottus, Oncorhynchus, Salmo, and Ranatra. The recalculated hardness-based equations are as follows: zinc (acute) = 0.978*e0.8537(ln Hardness)+1.5227 zinc (chronic) = 0.986*e0.8537(ln Hardness)+1.3519 The recalculated standards for zinc are intended to be fully protective of the aquatic life use in Camp Creek. Keystone will implement drainage and snowmaking system improvements including plumbing modifications and changes in management practices to further reduce the amount of water transferred from the snowmaking system to Camp Creek. Keystone is also working with the NWCCOG and other interested stakeholders on the investigation and potential implementation of measures to reduce acid mine drainage impacts from the Peru Creek tributary of the Snake River which will reduce metals concentrations in the snowmaking water supply. If, after these measures have been implemented, it is determined that the recalculated standards are not attainable or if significant additional water quality improvement has been achieved, the Commission will revisit the appropriate standards for Camp Creek. Blue River segment 8: Monitoring results for water samples collected from 2003 through 2007 show that Jones Gulch meets table value standards. The Commission therefore moved Jones Gulch from Segment 6 to Segment 8.
T. Eagle Mine, Eagle River Basin—Metals Standards The Hazardous Materials and Waste Management Division and USEPA Superfund Program (Superfund Proponents) proposed site-specific zinc, copper and cadmium standards for segments on the Eagle River within the Eagle Mine Superfund Site. Similarly, CBS Operations Inc (CBS) (formerly Viacom International Inc) proposed a different set of site-specific zinc, copper and cadmium standards for segments on the Eagle River within the Eagle Mine Superfund Site.
After review of the evidence submitted, the Commission adopted the Superfund Proponents’ modified proposal for site-specific standards for the Eagle River Segments 5a, 5b, 5c and 7b as described below. These segments are impacted by historical mining activities at the Eagle Mine Superfund Site. Zinc: A recalculation procedure was used for the aquatic species expected to occur in these segments of the Eagle River. After extensive review of available biological data and toxicity information, the recalculation was based on the following four most sensitive species that are expected to occur in these segments of the Eagle River: Cottus bairdi (Mottled Sculpin), Oncorhynchus (Rainbow and Cutthroat Trout), Salmo trutta (Brown Trout) and Ranatra elongata (Water Scorpion). The resulting site-specific recalculated hardness-based equations are:
The biological goal for the Eagle Mine Superfund Site is a healthy brown trout fishery. Concurrent biological and water quality monitoring has shown that to achieve that goal, zinc must be maintained at levels better than those indicated by laboratory-based zinc toxicity studies with brown trout, probably because of combined effects with copper. On-going monitoring suggests that zinc and copper levels currently achieved by the cleanup are too high in March and April to maintain a healthy brown trout population. The equations based on a modified species list (rainbow equations) are incrementally more stringent than the equations based on brown trout and, at this site, offer a way to address this uncertainty and provide an adequate buffer for brown trout. These levels cannot be attained without additional remediation at the Eagle Mine Superfund Site.
The equations which represent the highest attainable water quality were applied by the Commission when and where the attainability analysis indicated they could be met. The rainbow equations were applied by the Commission to Segments 5a year-round and to segments 5b and 7b from January 1 through April 30. The sculpin equations were applied by the Commission to segment 5c year-round and to segments 5b and 7b from May 1 through December 31.
Copper: Similar to zinc, a recalculation procedure was conducted based on the species that are expected to occur at the site. The resulting species list includes the following as the four most sensitive species: Ephoron virgo (Mayfly), Tubifex tubifex (Worm), Plumatella emarginata (Bryozoan), and Oncorhynchus (Rainbow and Cutthroat Trout). The resulting recalculated hardness-based equations are: Acute = 0.96*e0.9801[ln(hardness)]-1.5865 Chronic = 0.96*e0.5897[ln(hardness)]-0.4845 Because these equations rely on Ephoron virgo as the most sensitive species, they are referred to as “Ephoron equations.” These recalculated copper standards are attainable and were applied to Segments 5b, 5c and 7b.
For Segment 5a, an attainability analysis was conducted which showed that it is not feasible to reduce copper loads to a level that would result in attainment of the Ephoron equations. The majority of the copper load originates from upstream sources that cannot be controlled at the site. A modified species list, without Ephoron provided an equation that is based on the following four most sensitive species: Tubifex tubifex (Worm), Plumatella emarginata (Bryzoan), Oncorhynchus (Rainbow and Cutthroat Trout and Lumbriculus variegatus (Worm). The resulting modified hardness-based equations are: Acute=0.96*e0.9801[ln(hardness)] – 1.1073 Chronic=0.96*e0.5897[ln(hardness)] – 0.0053 Because these equations rely on tubifex worms as the most sensitive species, they are referred to as “tubifex equations.” The tubifex equations were applied to Segment 5a. Cadmium: The Commission had previously established an acute cadmium equation “with trout” in Regulation 31. That standard already applies to Segments 5a, 5b, 5c and 7b and continues to be appropriate and attainable. Therefore, no changes were made to the acute cadmium standard. However, using a revised acute/chronic ratio that was previously approved by both EPA and the Colorado Division of Wildlife for the Arkansas River and adopted by the Commission, a revised chronic cadmium equation was derived, as follows:
U. Jackson County, North Platte River Basin—Metals Standards Jackson County Water Conservancy District proposed an ambient quality-based total recoverable iron standard of 1,845 ug/L for North Platte River Basin segments 3, 4 and 5b. This proposal was withdrawn prior to the rulemaking hearing; however, the Commission does recognize that the Coalmont Formation that underlies the North Platte Basin is a source of geologic iron. However, there is a need for additional information to fully characterize current iron levels and establish what anthropogenic factors might be at play. The Commission urges the Jackson County Water Conservancy District to work with the Division to re-examine the segmentation and develop information to support a joint proposal for ambient quality- based total recoverable iron standards where appropriate for the next basin-wide review in 2013.
V. Seneca Coal Company, Yampa River Basin The Commission adopted a CS-II temperature standard for Segment 13b. The Commission adopted WS- II temperature standards for Segments 13d and 13e, while recognizing that uncertainty remains due to limited data about temperature and the aquatic community. It is the Commission's intent that the Division, Seneca and other interested parties work to resolve the uncertainty for these segments by the next basin- wide review. (See Section L)
The Commission also granted type iii temporary modifications for total recoverable iron set at “existing quality” for Segments 13d and 13e (expiration: 5/31/2011). The uncertainty is based on whether the high ambient levels of iron in these segments are caused by natural or irreversible man-induced causes. It is the intention of the parties to preserve the status quo during the term of the temporary modification, i.e., Seneca will not change its operations so as to adversely affect the quality of its discharges for total recoverable iron.
W. USFS, Yampa River Basin—Recreation Use Classification The USFS conducted a reasonable level of inquiry to identify the recreational uses on First and Elkhead Creeks and presented their findings in a Recreation UAA. This information showed that no existing primary recreation uses are occurring on portions of segment 20, nor is there the potential for primary contact recreation uses to occur on these same reaches. Therefore, the Commission established a new segment 20b with a Recreation N classification (E. coli=630/100mL), based on changes in stream access and use characteristics. This new segment consists of the mainstem of First Creek from the eastern boundary of state lands in California Park to the confluence with Elkhead Creek as well as the mainstem of Elkhead Creek from the eastern boundary of state lands in California Park to the National Forest boundary. Consequently, the Commission revised the segment description of 20a, to exclude specific listings in segment 20b. In addition, the Commission revised the Recreation use classification of segment 20a from Class 1a to Recreation Class U (E. coli=126/100mL), due to the lack of a reasonable level of inquiry about existing recreational uses and a lack of a completed use attainability analysis having been completed for this segment.
1. Jackson County Water Conservancy District 2. Medicine Bow-Routt National Forests 3. Seneca Coal Company 4. Northwest Colorado Council of Governments and Grand County 5. 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 6. Keystone Resort 7. Trout Unlimited and Colorado Trout Unlimited 8. Hazardous Materials and Waste Management Division and USEPA Superfund Program 9. CBS Operations Inc.
10. Shell Frontier Oil and Gas, Inc.
11. Tri-State Generation and Transmission 12. Town of Palisade 13. CAM-Colorado LLC and CAM Mining LLC 14. Public Service Company of Colorado, a Colorado corporation 15. Colorado River Water Conservation District 16. Trapper Mining, Inc.
17. Town of Minturn 18. Colorado Division of Wildlife 19. City of Grand Junction 20. Southeastern Colorado Water Conservancy District 21. Twenty Mile Coal Company 22. Eagle River Watershed Council, Inc.
23. ERWC Eagle Mine Ltd. and John Woodling 24. Ginn Entities (Ginn Battle North, LLC, Ginn Battle South, LLC, Ginn-LA Battle One, Ltd., LLLP, and Ginn-LA Battle One A, LLC)
25. Northern Colorado Water Conservancy District 26. Eagle River Water & Sanitation District 27. Upper Eagle Regional Water Authority 28. Eagle Park Reservoir Company 29. Vail Associates, Inc.
30. Black Diamond Minerals, LLC 31. U. S. Environmental Protection Agency (EPA), Region 8 32. United States Department of Agriculture Forest Service, Arapaho-Roosevelt National Forests, Sulphur Ranger District 33. Hot Springs Lodge and Pool 34. White River National Forest 35. U.S. Fish and Wildlife Service 36. City of Aurora
33.45 STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE DECEMBER
2009 RULEMAKING REGARDING TEMPORARY MODIFICATIONS FINAL ACTION FEBRUARY 8, 2010; EFFECTIVE DATE JUNE 30, 2010 The provisions of C.R S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Pursuant to the requirements in the Basic Standards (at 31.7(3)), the Commission reviewed the status of temporary modifications to determine whether the temporary modification should be modified, eliminated or extended.
Ammonia: Temporary modification of the ammonia standard on Yampa River segment 13d was deleted because the Town of Hayden’s permit had recently been reissued. Compliance schedules in recently issued permits are adequate to address any necessary treatment plant upgrade issues. Other Parameters: The temporary modifications of the iron standard for Yampa River segments 13d and 13e were reviewed. The Commission took no action on these temporary modifications which will expire 12/31/2011 and will be reviewed again in the December 2010 Temporary Modification hearing. PARTIES TO THE RULEMAKING 1. City of Grand Junction 2. City of Colorado Springs and Colorado Springs Utilities 3. Tri-Lakes, Upper Monument, Security and Fountain Wastewater Treatment Facilities 4. Paint Brush Hills Metropolitan District 5. Pueblo West Metropolitan District 6. City of La Junta 7. Seneca Coal Company 8. Tri-State Generation and Transmission Association 9. Plum Creek Wastewater Authority 10. Centennial Water and Sanitation District 11. City and County of Broomfield 12. City of Fort Collins 13. Metro Wastewater Reclamation District 14. City of Black Hawk and the Black Hawk/Central City Sanitation District
33.46 STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE JULY 2010
RULEMAKING REGARDING TEMPORARY MODIFICATIONS; EFFECTIVE DATE NOVEMBER 30, The provisions of C.R S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 The Commission has decided to delay the basin-wide review of water quality classifications and standards for this basin until June 2014, to accommodate an issue-specific rulemaking for nutrient criteria in June 2011. Consistent with that decision, the Commission has also decided to extend the effective date for the Grand Lake clarity standard to January 1, 2015. PARTIES TO THE RULEMAKING HEARING 1. Town of Avon 2. City of Black Hawk and Black Hawk/Central City Sanitation District 3. Northern Colorado Water Conservancy District and the Municipal Subdistrict, Northern Colorado Water Conservancy District 4. City of La Junta 5. XTO Energy, Inc.
6. City of Pueblo 7. City of Colorado Springs and Colorado Springs Utilities 8. U.S. Environmental Protection Agency
33.47 STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE DECEMBER
2010 RULEMAKING REGARDING TEMPORARY MODIFICATIONS FINAL ACTION JANUARY 10, 2011; EFFECTIVE DATE JUNE 30, 2011 The provisions of C.R S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Pursuant to the requirements in the Basic Standards (at 31.7(3)), the Commission reviewed the status of temporary modifications to determine whether the temporary modification should be modified, eliminated or extended.
Total Recoverable Iron A. Dry Creek, Yampa River segment 13d Seneca Coal Company proposed revisions to Yampa segment 13d. Based on information on the record that characterized the pre-mining condition, the Commission adopted ambient-based iron standards. The chronic ambient-based standard for Dry Creek was calculated considering pre-mining data collected by Seneca Coal Company from three available sites in the segment (WSH7, WSHF1, and WSD5). The Commission removed the temporary modification for iron for segment 13d and adopted a new seasonal ambient-based chronic standard for iron for segment 13d as follows: Mar - Apr = 3040(Trec);
In order to assure that the same methodology is used when assessing attainment of these standards in the future, Section 33.6(4) was added to the regulation to record the locations that are to be used. Subsection 33.6(4)(a) establishes the locations for Dry Creek. Approximately equal datasets from each of these sites is to be aggregated:
B. Sage and Grassy Creeks, Yampa River segment 13e Given the presence of two individual creeks in segment 13e, with different characteristics, the Commission took separate actions on each creek.
Sage Creek: Seneca Coal Company proposed revisions to Yampa segment 13e. Based on information on the record that characterized the pre-mining condition, the Commission bifurcated Sage Creek and adopted ambient-based iron standards for upper portion, with a dividing line at the west border of Section 18, T5N, R87W. The chronic iron ambient-based standard for upper Sage Creek was calculated to be 1250 ug/L(Trec). The iron standard for the lower portion remains 1000 ug/L (Trec). In order to assure that the same methodology is used when assessing attainment of these standards in the future, Section 33.6(4) was added to the regulation to record the locations that are to be used. Subsection 33.6(4)(b) establishes the assessment location for upper Sage Creek. • Yoast Stream Site 2 on Sage Creek (YSS2): located upstream of the west border of Section 18, T5N, R87W Grassy Creek: Seneca also proposed ambient-based iron standards for Grassy Creek. The upper portion of this area was mined in the 1970's by the Rockcastle Coal Company (Grassy Gap Mine), which obtained bond release and terminated its NPDES permit in 1993. Seneca began its mining operation in the upper portion of the basin in 1998 and the site is currently in the reclamation process. Seneca proposed that the Commission establish ambient-based iron standards based on 1993-1998 water quality data. The Commission determined that Seneca’s evidence was insufficient to characterize natural or irreversible man-induced conditions for Grassy Creek. As a result, the Commission declined to adopt ambient-based iron standards, but extended the temporary modification for iron to 12/31/2012. The Commission will consider Seneca's plan to eliminate the need for a temporary modification at the December 2011 temporary modification hearing.
1. Paint Brush Hills Metropolitan District 2. Tri-State Generation and Transmission Association 3. Seneca Coal Company 4. Mountain Water and Sanitation District 5. City of Grand Junction 6. Colorado Division of Wildlife 7. City of Boulder 8. U. S. Environmental Protection Agency 9. City of Colorado Springs and Colorado Springs Utilities
33.48 STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE JUNE 13,
2011 RULEMAKING REGARDING TEMPORARY MODIFICATIONS; EFFECTIVE DATE JANUARY 1, The provisions of C.R S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 The Commission’s decision to delay consideration of nutrient criteria until March 2012 resulted in cancelation of the December 2011 review of temporary modifications. Accordingly, the Commission considered the expiration dates of all the temporary modifications expiring on or before December 31, 2012 in a written comment rulemaking. The Commission extended the expiration date of the following temporary modification to December 31, 2013. It will be reviewed again in a Temporary Modification hearing in December 2012.
33.49 STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE DECEMBER
10, 2012 RULEMAKING; FINAL ACTION JANUARY 14, 2013 EFFECTIVE DATE JUNE 30, 2013 The provisions of C.R S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Pursuant to the requirements in the Basic Standards (at 31.7(3)), the Commission reviewed the status of temporary modifications scheduled to expire before December 31, 2014, to determine whether the temporary modification should be modified, eliminated or extended. Temporary modifications of 3 standards on 3 segments were reviewed. The Basic Standards Statement of Basis for the 2010 hearing records the Commission’s intent regarding temporary modifications. (see
31.48 at I.A)
The Commission took no action on the temporary modifications on the following segments which are receiving waters for permitted discharges. These temporary modifications will expire 12/31/2013. Eagle River segments 8 and 9a Grassy Creek, Yampa River segment 13e: Seneca Coal Company proposed extending the temporary modification for iron for Grassy Creek. The Commission considered Seneca’s plan to eliminate the need for the temporary modification. Seneca Coal is working to resolve uncertainty and is on schedule to address this segment at the regularly scheduled Basin hearing (June 2014). The Commission extended the expiration date to 12/31/2014, to coincide with the next basin review. PARTIES TO THE RULEMAKING HEARING 1. City of Pueblo 2. Seneca Coal Company 3. Tri-State Generation and Transmission Association 4. Eagle River Water and Sanitation District 5. Board of County Commissioners for the County of Gunnison, Colorado 6. Colorado Parks and Wildlife 7. High Country Citizens’ Alliance 8. Bill Thiebaut, DA for 10th Judicial District and the Office of the DA for the 10th Judicial District 9. City of Colorado Springs 10. Town of Crested Butte 11. Upper Gunnison River Water Conservancy District 12. U.S. Energy Corp.
13. Gunnison County Stockgrowers Association, Inc.
14. Environmental Protection Agency 15. Cherokee Metropolitan District 16. Fountain Sanitation District 17. Lower Fountain Metropolitan Sewage Disposal District 18. Monument Sanitation District 19. Palmer Lake Sanitation District 20. Town of Monument 21. Academy Water and Sanitation District 22. Tri-Lakes Wastewater Treatment Facility 23. Town of Palmer Lake 24. Woodmoor Water and Sanitation District No. 1 25. Upper Monument Creek Regional Wastewater Treatment Facility
33.50 STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE APRIL 8, 2013
RULEMAKING; FINAL ACTION MAY 13, 2013 EFFECTIVE DATE SEPTEMBER 30, 2013 The provisions of C.R S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 In August of 2005, the Commission adopted revisions to the Basic Standards and Methodologies for Surface Waters (Regulation #31) to add a Water + Fish (W+F) table value standard for chronic arsenic of 0.02 micrograms per liter (µg/L). W+F standards are numeric human health-based water quality standards that are calculated protective values that take into account the combined exposure from the pollutant in drinking water and the pollutant accumulated in fish flesh. This criterion automatically went into effect for Aquatic Life Class 1 waters which also have a Domestic Water Supply use, when the changes to the Basic Standards became effective. It was also adopted on a segment by segment basis for Aquatic Life class 2 waters with Domestic Water Supply where the Commission determined there are fish of a catchable size of species that are normally consumed. Because of the complicated nature of the arsenic standards, specific values were added to the basin tables in the basin hearings between 2006 and 2009.
In this hearing, the Commission adopted temporary modifications for W+F chronic arsenic where a permitted discharger with a water quality–based effluent limit compliance problem exists. The adopted temporary modification is listed in the regulation tables as “As(ch)=hybrid”. An explanation of the temporary modification and its expected implementation into control requirements, such as Colorado Discharge Permit System (CDPS) effluent limitations, is described in 33.6(2)(d). The temporary modification was established by the Commission to allow for a temporarily less stringent application of the chronic arsenic standard in control requirements for both existing discharges and new or increased discharges.
For discharges existing on or before 6/1/2013, the temporary modification adopted for W+F chronic arsenic is “current condition”, expiring on 12/31/2021. The Commission intends that, when implementing the temporary modification of “current condition” in a CDPS permit, the Division will assess the current effluent quality, recognizing that it changes over time due to variability in treatment facility removal efficiency and influent loading from natural or anthropogenic sources, and due to changes in the influent flow and concentration over time. Maintaining the current condition will include maintaining permitted total arsenic loading to a treatment facility from arsenic contributors at the levels existing on the effective date of the temporary modification, while expressly allowing for variability in such loading due to changes in effluent quality as described above and due to changes in the influent flow and concentration over time within the permitted design flow of that facility. The Commission understands that the Division's past practice implementing this requirement in permits has been through reporting regarding the arsenic loading to the facility, and not through numeric effluent limitations. The Commission intends that the Division will continue this practice. For facilities that lack enough representative data to quantify arsenic loading, the permittee may satisfy reporting requirements through narrative descriptions of potential sources of arsenic. No permit action shall be approved that allows an increase in permitted total arsenic loading to a treatment facility. The expiration date of the temporary modification was set at 12/31/21 to allow for CDPS permits that are issued prior to the effective date of anticipated changes to the chronic arsenic standard in the 2016 Basic Standards Rulemaking to not have the temporary modification expire within the term of a permit. The Commission adopted this temporary modification to allow time for the Division, dischargers and stakeholders to continue a workgroup process to resolve the uncertainty regarding the appropriateness of the W+F chronic arsenic standard of 0.02 µg/L with respect to a technologically feasible level of treatment.
For new or increased discharges that commence on or after 6/1/2013, the temporary modification adopted is As(ch) = 0.02–3.0 µg/L (Trec), expiring on 12/31/2021. The Commission decided that since the technologically achievable arsenic level is less stringent than the calculated W+F criterion, the temporary modification for new or increased discharges will be a range of 0.02-3.0 µg/L. The first number in the range is the health-based value, based on the Commission’s established methodology for human health- based standards that protect against the combined exposure of drinking water and eating fish. The second number in the range is the Commission’s initial determination of a technologically achievable value for arsenic, set at 3.0 µg/L. Control requirements, such as discharge permits effluent limitations, shall be established using the first number in the range as the ambient water quality target, provided that no effluent limitation shall require an “end of pipe” discharge level more restrictive than the second number in the range during the effective period for this temporary modification. The expiration date of the temporary modification was set at 12/31/21 to allow for CDPS permits that are issued prior to the effective date of anticipated changes to the chronic arsenic standard in the 2016 Basic Standards Rulemaking to not have the temporary modification expire within the term of a permit. The Commission adopted this temporary modification to allow time for the Division, dischargers and stakeholders to continue a workgroup process to resolve the uncertainty regarding the appropriateness of the W+F chronic arsenic standard of 0.02 µg/L with respect to a technologically feasible level of treatment. The technologically feasible level of 3.0 µg/L for arsenic is based upon testimony heard by the Commission at the December 13, 2011 Emergency Revisions to Regulation #38. At the December 13, 2011 hearing, the Commission determined, as a practical manner, that 3.0 µg/L is the lowest level that is technologically achievable for common types of water treatment facilities. At the April 8, 2013 Rulemaking, the Commission heard testimony that concurred with the finding from December 13, 2011 that an initial reasonable lower limit of treatment technology for arsenic is 3.0 µg/L, pending further investigation by the Division, dischargers and stakeholders. The Division intends to address the uncertainty of the W+F chronic arsenic standard with respect to a technologically feasible level of treatment through a continued workgroup process, and propose a revised W+F chronic arsenic standards as part of the 2016 Basic Standards Rulemaking Hearing Temporary modifications were adopted on the following segments. The segments identified have the previously adopted W+F chronic arsenic standard of 0.02 µg/L and an identified CDPS permit or permits that discharge immediately to or directly above the identified segment. Upper Colorado River 3 Upper Colorado River 4 Upper Colorado River 6a Upper Colorado River 7a Upper Colorado River 7b Upper Colorado River 8 Upper Colorado River 10a Upper Colorado River 10b Blue River 1 Blue River 2b Blue River 3 Blue River 4a Blue River 8 Blue River 14 Eagle River 1 Eagle River 3 Eagle River 4 Eagle River 5b Eagle River 6 Eagle River 8 Eagle River 9a Eagle River 9b Eagle River 10a Eagle River 10b Roaring Fork 1 Roaring Fork 2 Roaring Fork 3a Roaring Fork 6 Roaring Fork 8 Roaring Fork 9 Roaring Fork 10 North Platte River 4a North Platte River 4b North Platte River 5a North Platte River 5b Yampa River 1a Yampa River 2c Yampa River 3 Yampa River 6 Yampa River 8 Yampa River 13a Yampa River 13c Yampa River 13f PARTIES TO THE RULEMAKING HEARING 1. Colorado Mining Association 2. Union Gold, Inc.
3. Colorado Department of Transportation 4. City of Colorado Springs and Colorado Springs Utilities 5. Town of Crested Butte 6. Mountain Coal Company 7. Centennial Water and Sanitation District 8. MillerCoors, LLC 9. Plum Creek Wastewater Authority 10. Tri-State Generation & Transmission Association 11. Climax Molybdenum Company 12. Littleton/Englewood Wastewater Treatment Plant 13. Eagle River Water and Sanitation District 14. City of Boulder 15. City and County of Denver 16. Parker Water and Sanitation District 17. U.S. Energy Corp.
18. U.S. Environmental Protection Agency 19. City of Greeley
33.51 STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE DECEMBER
9, 2013 RULEMAKING REGARDING TEMPORARY MODIFICATIONS; FINAL ACTION MARCH 11, 2014 EFFECTIVE DATE JUNE 30, 2014 The provisions of C.R S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Pursuant to the requirements in the Basic Standards (at 31.7(3)), the Commission reviewed the status of temporary modifications scheduled to expire before December 31, 2015, to determine whether the temporary modification should be modified, eliminated or extended. Temporary modifications of 3 standards on 3 segments were reviewed.
Eagle River, segments 8 and 9a: The Commission deleted the temporary modifications of the temperature standards. These temporary modifications expired on 12/31/2013. No Action: The temporary modification to the iron standard on Grassy Creek, Yampa River segment 13e, was reviewed. Seneca Coal Company presented evidence that progress is being made on the plan to resolve uncertainty. Seneca Coal Company is on schedule to address this segment at the regularly scheduled Basin hearing (June 2014).
1. Rio Grande Silver, Inc.
2. Black Hawk/Central City Sanitation District and City of Black Hawk 3. Centennial Water & Sanitation District, City of Littleton, City of Englewood 4. Colorado Parks and Wildlife 5. Homestake Mining Company of California 6. Metro Wastewater Reclamation District 7. South Platte Coalition for Urban River Evaluation (SP CURE) 8. City of Boulder 9. Seneca Coal 10. Tri-State Generation and Transmission Association 11. City of Fort Collins 12. MillerCoors, LLC 13. Environmental Protection Agency 14. Barr Lake and Milton Reservoir Watershed Association 15. Plum Creek Water Reclamation Authority
33.52 STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE JUNE 9, 2014
RULEMAKING; FINAL ACTION AUGUST 11, 2014; EFFECTIVE DATE DECEMBER 31, 2014 The provisions of C.R S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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. Waterbody Segmentation The Commission deleted, renumbered, and/or created new segments to facilitate appropriate organization of waterbodies in this regulation. The following changes were made: Upper Colorado River Segment 5: This segment was deleted and the lakes and reservoirs in this segment were moved to a new Segment 13 at the end of the subbasin to be consistent with the organization of lakes and reservoirs segments in other basins. Blue River Segment 1: Based on the information presented by the Upper Blue Sanitation District (UBSD), the mainstem of the Blue River from the confluence with the Swan River to Dillon Reservoir was moved to new Segment 2c to simplify the segmentation of the Upper Blue River and to facilitate the adoption of appropriate nutrient standards.
Blue River Segment 3: This segment was deleted and the lakes and reservoirs in this segment were moved to a new Segment 22 at the end of the subbasin to be consistent with the organization of lakes and reservoirs segments in other basins. The waters previously in Segment 22 were renumbered to Segment 23 as a result.
Eagle River Segments 9a and 9b: The lower portion of Eagle River Segment 9a, the mainstem of the Eagle River from a point immediately below Squaw Creek to a point immediately below Rube Creek, was moved to a new Segment 9b to facilitate the adoption of appropriate temperature standards. Segment 9b was renumbered to 9c to facilitate this change.
Roaring Fork River Segment 3d: The following waters were moved from existing Segment 3a to a new Segment 3d: Cattle Creek, including all tributaries and wetlands, from the source to the most downstream White River National Forest boundary (39.467850, -107.065410). These waters were split into different segments to facilitate the adoption of an Outstanding Waters designation for Segment 3d. Roaring Fork River Segment 10a and 10b: The following waters were moved from existing Segment 10 to a new Segment 10b: Mainstem of North Thompson Creek, including all tributaries and wetlands, from the source to the White River National Forest boundary (39.316522,-107.305749). Mainstem of Middle Thompson Creek, including all tributaries and wetlands, from the source to a point immediately below the confluence with the South Branch of Middle Thompson Creek (39.295749, -107.308788). These waters were split into different segments to facilitate the adoption of an Outstanding Waters designation for Segment 10b.
Yampa River Segment 1b: The lakes and reservoirs in this segment were moved to a new Segment 21 at the end of the subbasin to be consistent with the organization of lakes and reservoirs segments in other basins. Segment 1a was also changed to Segment 1 as a result. Yampa River Segment 2b: The lakes and reservoirs in this segment were moved to a new Segment 22 at the end of the subbasin to be consistent with the organization of lakes and reservoirs segments in other basins. Segment 2c was also changed to Segment 2b as a result. Yampa River Segments 6 and 7: The boundary of these two segments did not change, but the description was altered as it is not the Commission’s practice to use the location of an outfall as a segment boundary. The boundary is now described as “a point 0.25 mile below County Road 27” instead of “the point of discharge of the Oak Creek wastewater treatment plant.” Yampa River Segments 13b, 13d, 13e, 13g, 13h, 13i, 13j: The Commission created new segments for a number of segments in the Yampa River sub-basin. Seneca Coal, Peabody Sage Creek Mining LLC, and Twentymile Coal, LLC collected seasonal water quality and biomonitoring data over two years from multiple drainages within Yampa River segments 13b, 13d, 13e. The upper reaches of segments 13b, 13d, and 13e (i.e., Cow Camp Creek, Bond Creek, Little Grassy Creek, Grassy Creek, Sage Creek, and Dry Creek) only flow seasonally, largely in response to spring snowmelt (March – July); the remainder of the year flow is greatly limited. The lower reaches of these segments have limited flow as well; spring flows are consistent, but summer and fall streamflow is primarily restricted to small sections of flowing water and/or isolated pools, likely freezing over in the winter months. The only exceptions to this flow regime are the mainstems of Fish, Foidel, and Middle Creeks, which normally maintain flow year-round, and select locations within lower Dry and Grassy Creeks which maintain sufficient pools to support hold- over populations of fish. The reaches of the steams with ephemeral flows have been included in segments 13d, 13e, 13g, 13h, 13i. The streams with perennial flows have been included in segments 13b and 13j.
Yampa River Segments 22 and 23: Elkhead Reservoir was moved to a new Segment 23. These waters were split into different segments to facilitate a revision of the Aquatic Life use from Cold 1 to Warm 1. The following segment descriptions were edited to improve clarity, correct typographical errors, and correct spelling errors:
B. Revised Aquatic-Life Use Classifications Yampa River Segment 23: Based on a Use Attainability Analysis (UAA) prepared by Colorado Parks and Wildlife and the Colorado River Water Conservation District, the Commission adopted a change in the Aquatic Life use classification and standard from Cold 1 to Warm 1 and a new Yampa River Segment 23 for Elkhead Reservoir. Available temperature and fish data identify that the original classification of Elkhead Reservoir as a cold water lake was in error and that only warm water species are expected to occur due to natural and man-induced irreversible conditions. Yampa River Segments 13b, 13g: Based on fish species expected to be present, temperature data, and other available evidence in a Use Attainability Analysis submitted by Seneca Coal, Inc., the Commission changed the aquatic life use classification for Yampa River segment 13b from Cold 1 to Warm 1. For Segment 13g the Commission maintained the aquatic life use classification of Warm 1. The Commission found that this was necessary to protect the fish collected in tributaries to Fish Creek in segment 13g, which included a round tail chub, a species that has been designated by Colorado Parks and Wildlife as a species of special concern. It is likely that the chub and other species use the streams in 13g when flow and habitat are present. Segments 13h, 13i, and 13j inherited their aquatic life use classifications as a result of re-segmentation.
C. Recreation Classifications and Standards A review of the segments with an existing Recreation use classification showed that one segment had an incorrect E. coli standard to protect that use. The E. coli standard was corrected for the following segment:
D. Water Supply Use Classification and Standards The Commission added a Water Supply use classification and standards where the evidence demonstrated a reasonable potential for a hydrological connection between surface water and alluvial wells used for drinking water. The Water Supply use classification and standards were added to the following segments:
A molybdenum standard of 210 ug/l was applied to the following segments to protect the Water Supply use classification:
E. Agriculture Standards Molybdenum: In 2010, the Commission adopted a new standard for molybdenum to protect cattle from the effects of molybdenosis. The table value adopted at that time was 300 ug/l, but included an assumption of 48 mg/day of copper supplementation to ameliorate the effects of molybdenosis. State and local experts on cattle nutrition indicated that copper supplementation in the region is common, but is not universal. Therefore, copper supplementation assumption was removed from the equation, which yields a standard of 160 ug/l. The Commission expects that this value may be revised when data on the copper and molybdenum content of local forage becomes available. The Commission also notes that in light of EPA’s disapproval of the 300 ug/l table value in the Basic Standards and Methodologies for Surface Water, the Commission intends to review this value during the next Basic Standards triennial review. The Agriculture table value assumes that the safe copper:molybdenum ratio is 4:1. Food and water intake is based on a 273 kg (600 lb) feeder steer consuming 6.8 kg/day of dry matter and 20% of its body weight in water per day. Total copper and molybdenum intakes are calculated from the following equations: Cu intake mg/day = [([Cu] forage, mg/kg) x (forage intake, kg/day)] + [([Cu] water, mg/l) x (water intake, L/day)] + (Cu supplementation, mg/day)
Mo intake mg/day = [([Mo] forage, mg/kg) x (forage intake, kg/day)] + [([Mo] water, mg/l) x (water intake, L/day)] + (Mo supplementation, mg/day)
The assumed values for these equations are as follows:
[Cu] forage = 7 mg/kg, [Mo] forage = 0.5 mg/kg, forage intake = 6.8 kg/day, [Cu] water = 0.008 mg/L, [Mo] water = 0.375 mg/L, water intake = 54.6 L/day, Cu supplementation = 0 mg/day, Mo supplementation = 0 mg/day.
A molybdenum standard of 160 ug/l was adopted for the following segments in Regulation 33 that have an Agriculture use classification, and where livestock or irrigated forage are present or expected to be present.
0.375 mg/L, Cu supplementation = 0 mg/day, Mo supplementation = 0 mg/day. Water intake = 67.8 L/day (NRC, 2000), based on an ambient temperature of 80°C (ave. daily max. at Kremmling, CO).
F. Changes to Antidegradation Designation Roaring Fork Segment 3d: The Commission adopted an Outstanding Waters (OW) designation for this segment based on evidence presented by WildEarth Guardians showing that water quality meets the requirements of 31.8(2)(a). The presence of designated Critical Cutthroat Trout Habitat by the State of Colorado proves the exceptional recreational or ecological significance of the waters. Outreach conducted by WildEarth Guardians demonstrated support for the change in designation, the outstanding nature of these waters and the need for the additional protection of the outstanding waters designation. The Commission understands that existing land uses, including grazing, are in place in these watersheds. The evidence demonstrates that these existing land uses are compatible with the OW designation since the current high level of water quality has been attained with these uses in place. It is the Commission’s intent that this OW designation should not be used to establish additional permit requirements for existing uses within this area.
Roaring Fork Segment 10b: The Commission adopted an Outstanding Waters (OW) designation for this segment based on evidence presented by Trout Unlimited showing that the criteria of 31.8(2)a has been met for these waters. In addition to meeting the water quality requirements of 31.8(2)a, these waters support Colorado River cutthroat trout, including key conservation populations in North and Middle Thompson Creek. The Colorado River cutthroat trout is listed as a species of concern in Colorado and is subject to a conservation agreement to prevent potential federal Endangered Species Act listing. The Commission notes that the outreach undertaken by Trout Unlimited as proponent of this designation helps to demonstrate broad support for the conclusion that these waters constitute an outstanding natural resource and that the additional protection provided by this designation is appropriate. The Commission understands that existing land uses, including grazing, are in place in these watersheds. The evidence demonstrates that these existing land uses are compatible with the OW designation since the current high level of water quality has been attained with these uses in place. It is the Commission’s intent that this OW designation should not be used to establish additional permit requirements for existing uses within this area.
Yampa River Segments 13d, 13e, 13h, 13i, and 13j: The Commission retained use protected designation for segments 13d and 13e, and segments 13h, 13i, and 13j inherited their use protected designations as a result of re-segmentation.
G. Ambient Standards Ambient standards are adopted where natural or irreversible man-induced conditions result in exceedances of table value standards. The Commission reviewed the information that is the basis for these standards, as well as any new information that would indicate whether they are still appropriate, need to be modified, or should be dropped. In some cases, new ambient standards were adopted. The following segments have ambient-based standards that were revised: Upper Colorado River Segments: 12 (Lake Granby) and 13 (Wolford Mountain) North Platte River Segment: 9 (Lake John)
Yampa River Segment 13b: Foidel Creek is achieving the table value standard for total recoverable iron which is 1000 ug/L with assessment locations specified in 33.6(4)(c), which the Commission adopted due to spatial variability in iron concentrations throughout the stream reach. Accordingly the Commission retained the 1000 ug/L total recoverable iron standard for Foidel Creek. The Commission updated the annual ambient-based standard on Middle Creek to a seasonal ambient-based standard for March-June of 2090 ug/L, based on the most recent five years of data. TVS applies for the remainder of the year for Middle Creek.
Yampa River Segments 13h and 13j: While the Commission did not adopt ambient based selenium standards proposed in this hearing on these segments, parties are encouraged to collect additional data to further evaluate the appropriateness of an ambient based selenium standard in the future.
H. Aquatic Life Ammonia and Metals Standards New Table Value Standards: The zinc, zinc sculpin, and aluminum table values were revised in the 2010 Basic Standards hearing. The acute and chronic zinc, zinc sculpin, and aluminum equations in 33.6(3) were modified to conform to Regulation 31. The footnotes to the table values in 33.6(3) were renumbered to match the appropriate references. Footnote (4 old) was deleted and a new footnote 4 was added. Zinc sculpin standards: In low-hardness situations (hardness below 102 mg/l), the zinc equation is not protective of mottled sculpin (Cottus bairdi), a native west-slope fish species. A review of existing hardness and fishery data showed numerous segments with low average hardness (<102 CaCO3 mg/l) and where the Colorado Division of Parks and Wildlife expects sculpin to be present. A sculpin-specific zinc equation was added to the following segments:
I. Uranium Standards At the 2010 Basic Standards rulemaking hearing, the Commission changed the Water Supply table value for uranium from 30 ug/l to a hyphenated standard of 16.8-30 ug/l. The Commission revised the language in 33.5(3)(c) to reflect the change to the basin-wide standard. A new section 33.5(3)(c)(i) was added to explain the hyphenated standard. Subsection 33.5(3)(d) was deleted because it was redundant with 33.5(3)(c).
J. Temporary Modifications To remain consistent with the Commission’s decisions regarding arsenic at 33.50, all existing temporary modifications for arsenic of “As(ch)=hybrid” (expiration date of 12/31/21) were retained. An arsenic temporary modification was added to the following segments, which had an existing or newly added chronic arsenic standard of 0.02 ug/l and a permitted discharger with a predicted water quality–based effluent limit compliance problem:
Selenium Yampa River Segments 13b, 13d, 13e, 13g, 13i: Seneca Coal, Peabody, and Twentymile originally proposed numeric fish tissue-based site-specific standards for selenium for Yampa River segments 13b, 13d, 13e, 13g and 13i. In support of their proposal they provided data including in-stream selenium concentration and fish-tissue selenium concentrations along with proposed implementation methodologies. However, during the rulemaking process EPA issued new draft selenium criteria. In response to EPA’s May 2014 draft selenium criteria, Seneca Coal, Peabody, and Twentymile withdrew their site-specific standard proposal and revised their proposal to a narrative “current conditions” temporary modification for selenium for these segments. The Commission adopted a current conditions temporary modification for selenium for these segments. Peabody presented information that shows a demonstrated or predicted compliance problem for each of these segments. Additionally, the Commission found there was significant uncertainty regarding the water quality standard necessary to protect current and/or future uses, and that there is substantial uncertainty about the extent to which existing quality is the result of natural or irreversible human-induced conditions. Molybdenum Blue River Segment 14: The Commission adopted a temporary modification of the molybdenum standard for this segment of Mo(ch)=“current conditions” (Exp. 12/31/16). The Commission recognizes that there is new toxicological information that should be included in recalculation of a human health-based criterion. Parties do not agree on the uncertainty factors that need to be included in the calculations. Since this issue is larger than a segment-specific issue, it is more appropriate to address this situation in the review of the Basic Standards and the expiration date was set to accommodate that schedule. There is also uncertainty regarding the extent to which existing quality in Blue River Segment 14 is the result of irreversible human-induced conditions due to forthcoming new treatment facilities at the Climax Mine. Climax also presented information that shows a predicted compliance problem and has submitted an adequate plan for eliminating the need for the temporary modification.
K. Temperature Ambient temperature standards for lakes In the 2008 triennial review, the WAT standard was found to be unattainable for a number of cold large lakes and reservoirs with apparently healthy cold-water fish populations. Because summertime temperature in the mixed layer for large lakes and reservoirs is very well correlated to the waterbody’s elevation, the Commission adopted ambient temperature standards for large lakes wherever data were available to characterize a WAT and the thermal characteristics of the lakes and reservoirs were determined to be the result of natural conditions. As a result of setting ambient temperature standards, the adequate refuge defined in Regulation 31, Table 1, footnote 5(c)(iii) was assessed using the site- specific temperature standard, and many lakes with obvious dissolved oxygen issues were considered to have adequate refuge.
Footnote 5(c)(iii) states:
In this hearing, based on information presented by ERWSD and CPW, the Commission adopted site- specific temperature standards for Eagle River segments 8, 9a, and 9b to protect the aquatic life use (31.7(1)(b)(iii)) and re-segmentation where appropriate (Section A). The spring shoulder season standards were adjusted to protect cutthroat trout spawning and incubation. The fall shoulder season standards were adjusted to protect brook and brown trout migration and spawning. The basis for these temperature standards is specific to the temperature and biological conditions in the Eagle River Segments 8, 9a, and 9b, and accounts for the seasonal temperature requirements for the various life stages of the aquatic species expected to occur in this area while recognizing that these segments include a transitional zone between Cold Stream Tier I and Tier II. This action is not intended to revise the biological goals for the Eagle River established by the Commission in 2008, regarding the Eagle Mine Superfund Site.
The Commission recognizes the high quality fishery that exists in these segments is economically important, yet is currently stressed and in recovery. Local stakeholders are actively working to protect and improve water quality including projects associated with urban runoff, stream and riparian restoration, hydrologic conditions, and the Eagle Mine Superfund Site. Future refinements of temperature standards for these segments may be warranted as more information becomes available regarding their natural and existing thermal regimes, and the temperatures needed to protect the aquatic species expected to occur. Segment 8: The lower portion of this segment is currently designated a Gold Medal Fishery. Cutthroat, brook, brown and rainbow trout are all expected to occur in this segment. The Commission adopted site-specific chronic temperature standards based on a modification of Cold Stream Tier I table values Segment 9a: This segment is impacted by metals contributions from historic mining. Cutthroat, brook, rainbow, and brown trout could occur in this segment. The Commission adopted site- specific chronic temperature standards based on a modification of Cold Stream Tier I table values.
Yampa River Segments 13b, 13d, 13e, 13g, 13h, 13i, and 13j: Based on fish species expected to be present, temperature data, and other available evidence submitted by Peabody, Warm Stream Tier II temperature standards were retained for segments 13d and 13e, and were adopted for segments 13b and 13g. Segments 13h, 13i, and 13j inherited their Warm Stream Tier II temperature standards as a result of re-segmentation.
L. Nutrients In March 2012, the Commission adopted interim nutrient values in the Basic Standards (Regulation 31) and created a new statewide control regulation (Regulation 85) to address nutrients in Colorado. Regulation 31.17 includes interim nutrient values for total phosphorus, total nitrogen, and chlorophyll a for both lakes and reservoirs, and rivers and streams. Due to the phased implementation approach adopted with these criteria (31.17(e)), the Commission adopted only total phosphorus and chlorophyll a standards at this time. Nitrogen standards were not considered as part of this rulemaking hearing, but will be considered in the next triennial review, currently scheduled for June, 2019. Total phosphorus and chlorophyll a standards were adopted for waters upstream of all permitted domestic wastewater treatment facilities discharging prior to May 31, 2012 or with preliminary effluent limits requested prior to May 31, 2012, and any non-domestic facilities subject to Regulation 85 effluent limits and discharging prior to May 31, 2012. A new section (4) was added at 33.5 describing implementation of the interim nutrient values into the tables at 33.6, and includes a table which lists these facilities and the segment to which they discharge.
31.17(e)(ii) also allows the Commission to adopt numeric nutrient standards for Direct Use Water Supply (DUWS) lakes and reservoirs. No proposals were made by the Division to adopt standards based on this provision in this rulemaking.
31.17(e)(iii) also allows the Commission to adopt numeric nutrient standards for circumstances where the provisions of Regulation 85 are not adequate to protect waters from existing or potential nutrient pollution. No proposals were made to adopt standards based on this provision in this rulemaking. Chlorophyll a standards were adopted for the following segments: Upper Colorado River Segments: 1, 2, 3, 4, 6a, 7b, 8, 9, 10a, 11, 12 and 13 Blue River Segments: 1, 2a, 4a, 4b, 5, 6a, 6b, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 21, 22 and 23 Eagle River Segments: 1, 2, 3, 4, 6, 7a, 7b, 8, 10a, 10b, 11, 12, 13 and 14 Roaring Fork River Segments: 1, 2, 3a, 3c, 3d, 4, 5, 6, 7, 8, 9, 10a, 10b, 11 and 12 North Platte River Segments: 1, 2, 3, 4a, 4b, 5a, 8 and 9 Yampa River Segments: 1, 2a, 3, 5, 6, 7, 8, 13a, 13b, 13c, 13d, 13f, 13g, 13h, 14, 15, 18, 19, 20a, 21, 22 and 23 Total Phosphorus standards were adopted for the following segments: Upper Colorado River Segments: 1, 2, 3, 4, 6a, 6b, 7a, 7b, 7c, 8, 9, 10a, 11, 12 and 13 Blue River Segments: 1, 2a, 4a, 4b, 5, 6a, 6b, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 19, 20, 21, 22 and 23 Eagle River Segments: 1, 2, 3, 4, 6, 7a, 7b, 8, 10a, 10b, 11, 12, 13 and 14 Roaring Fork River Segments: 1, 2, 3a, 3b, 3c, 3d, 4, 5, 6, 7, 8, 9, 10a, 10b, 11 and 12 North Platte River Segments: 1, 2, 3, 4a, 4b, 5a, 5b, 6, 7a, 7b, 8 and 9 Yampa River Segments: 1, 2a, 3, 4, 5, 6, 7, 8, 11, 12, 13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h, 13i, 13j, 14, 15, 18, 19, 20a, 20b, 21, 22 and 23 Blue River Segments 1, 2a, 2b and 2c: Nutrient standards were adopted for Blue River Segment 1, as this segment is located entirely above qualified dischargers. Nutrient standards were adopted with a footnote “C” for Segment 2a, as the Upper Blue Sanitation District’s (UBSD) Iowa Hill Water Reclamation Facility is a qualified discharger listed at 33.5(4) and is located within this segment. Nutrient standards were not adopted for Blue River Segment 2b and new Segment 2c, as these segments are located entirely below the Iowa Hill Water Reclamation Facility and nutrient standards do not apply. The UBSD’s South Blue River wastewater treatment facility is located within Blue River Segment 1. However, this facility discharges to groundwater and it is not subject to Regulation 85 nutrient limitations for surface water discharges. It is therefore not a qualified discharger listed at 33.5(4). If the nature of the discharge from UBSD’s South Blue River wastewater treatment facility changes to include a discharge to surface water, this issue will be revisited to reflect such a change.
M. Direct Use Water Supply Sub-classification Also in the March 2012 rulemaking hearing, the Commission adopted a sub-classification of the Domestic Water Supply Use called “Direct Use Water Supply Lakes and Reservoirs Sub-classification” (Regulation 31, at 31.13(1)(d)(i)). This sub-classification is for water supply lakes and reservoirs where there is a plant intake location in the lake or reservoir or a man-made conveyance from the lake or reservoir that is used regularly to provide raw water directly to a water treatment plant that treats and disinfects raw water. In this action today, the Commission has begun to apply this sub-classification and anticipates that it will take several basin reviews to evaluate all the reservoirs in the basin. The Commission adopted the DUWS sub-classification on the following reservoirs and added “DUWS” to the classification column in the standards tables. The public water systems are listed along with the reservoirs and segments. Upper Colorado River Segment 12: Grand Lake (YMCA)
Upper Colorado River Segment 13: Ute Creek Reservoir (Climax – Henderson Mill) Blue River Segment 22: Goose Pasture Tarn (Town of Breckenridge) Roaring Fork River Segment 12: Leonard Thomas Reservoir (City of Aspen) Roaring Fork River Segment 12: Wildcat Reservoir (Wildcat Ranch) Yampa River Segment 22: Steamboat Lake (Steamboat Lake State Park) Yampa River Segment 22: Stagecoach Reservoir (Stagecoach State Park) Yampa River Segment 22: Yampa River Holding Pond (PSCO OF CO - Hayden Station) 31.17(e)(iii) also allows the Commission to adopt numeric nutrient standards for Direct Use Water Supply (“DUWS”) lakes and reservoirs. No standards were adopted based on this provision in this rulemaking.
N. Chromium III Standards A review of the chromium III standards showed that standards to protect the Aquatic Life use classification may not be protective of the Agriculture use in some high-hardness situations. A chromium III standard of CrIII(ch)=100(Trec) was added to segments with Aquatic Life and Agriculture use classifications, but no Water Supply use. The acute chromium III standard associated with the Water Supply use is protective of the Agriculture use, but is not protective of the Aquatic Life use when hardness is less than 61 ug/l. For segments that have both Aquatic Life and Water Supply use classifications, a chronic chromium III standard of CrIII(ch)=TVS was added to all segments that did not previously have that standard. Changes were made to the following segments: Upper Colorado River Segments: 3, 4, 6c, 7a, 7b, 7c, 9, 11, 12 and 13 Blue River Segments: 1, 6a, 6b, 11, 12, 13, 14, 16, 17, 19, 20, 21, 22 and 23 Eagle River Segments: 2, 3, 5a, 5b, 5c, 8, 9a, 9b, 9c, 10a, 10b, 12, 13 and 14 Roaring Fork River Segments: 1, 3a, 3b, 3c, 3d, 4, 6, 7, 8, 9, 10a, 10b, 11 and 12 North Platte River Segments: 3, 6, 7a, 7b, 8 and 9 Yampa River Segments: 2a, 2b, 5, 6, 7, 13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h, 13i, 13j, 14, 15, 19, 20a, 20b, 21, 22 and 23 O. Other Site-Specific Revisions Upper Colorado River Segment 12: The Commission determined in 2008 that the adoption of a 4 meter numerical standard with a delayed effective date was an appropriate policy choice to encourage cooperative efforts to improve Grand Lake clarity. At the same time, the Commission adopted the following narrative “The highest level of clarity attainable, consistent with the exercise of established water rights and the protection of aquatic life” as the effective standard. Efforts since 2008 have focused on data collection and understanding the factors controlling clarity. In today’s action, the Commission adopted a change to the narrative clarity standard that added “protection of water quality throughout the Three Lakes System” as another consideration for attainability in order to recognize the interdependence of water quality in the entire system. The Commission also decided that further delay in the effective date of the numerical standard was justified in view of the progress that has been made cooperatively by the parties and by the obstacles they have yet to overcome.
Sufficient effort has not yet been focused on determining an “attainable” level of clarity that is consistent with the constraints identified in the narrative standard. It is the Commission’s hope that improvement in clarity can be achieved by a balanced approach that does not sacrifice water rights, the recreational fishery, or water quality. The Commission expects and anticipates a cooperative effort that will focus on identifying an attainable and protective Grand Lake clarity standard. The effort should address the following questions that consider the constraints imposed on attainability:
Roaring Fork River Segment 3b: A footnote “A” was added to the chronic arsenic standard to explain the hyphenated standard.
Yampa River Segment 4: A footnote “A” was added to the chronic arsenic standard to explain the hyphenated standard.
Yampa River Segment 13d: A footnote “A” was added to the chronic arsenic standard to explain the hyphenated standard.
1. Grand County, Northwest Colorado Council of Governments and Northern Colorado Water Conservancy District 2. Eagle River Water and Sanitation District 3. Trout Unlimited 4. WildEarth Guardians 5. Tri-State Generation and Transmission Association 6. Seneca Coal Company, Peabody Sage Creek Mining, LLC, and Twentymile Coal Company 7. Western Resource Advocates 8. Colorado River Water Conservation District 9. Climax Molybdenum Company 10. Trapper Mining, Inc.
11. Upper Blue Sanitation District 12. Clinton Ditch & Reservoir Company 13. Vail Resorts, Inc. and Vail Summit Resorts, Inc.
14. Eagle Park Reservoir Company 15. Upper Eagle Regional Water Authority 16. Colorado Parks and Wildlife 17. Denver Water 18. Environmental Protection Agency 19. Powdr-Copper Mountain, LLC 20. Town of Frisco
33.53 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
8, 2014 RULEMAKING; FINAL ACTION JANUARY 12, 2015; EFFECTIVE DATE JUNE 30, 2015 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Pursuant to the requirements in the Basic Standards (at 31.7(3)), the Commission reviewed the status of temporary modifications scheduled to expire before December 31, 2016, to determine whether the temporary modification should be modified, eliminated or extended. Temporary modifications of standards on two segments were reviewed.
No action: The Commission took no action on the temporary modification of the chronic molybdenum standard for Blue River segment 14: Climax Molybdenum has presented evidence of an adequate plan for eliminating the need for the temporary modification and progress is being made on resolving the uncertainty regarding the underlying molybdenum standards on Blue River segment 14. The Commission made no change to the expiration date of 12/31/2016 as the original time allotment was deemed adequate.
Extension: The Commission reviewed the definitive temporary modification implementation plan submitted by Seneca Coal Company and Peabody-Sage Creek Mining, LLC (“Peabody”). Based on the existence of that plan, as modified at the hearing, the Commission extended the temporary modification to the iron standard for Yampa River Segment 13i to December 31, 2017. The Commission expects that Peabody will meet with the Division, CPW and EPA in the spring and fall of 2015 regarding the reference site approach and progress on its plan. Progress on the Plan will be reviewed by the Commission in December 2015.
1. Pioneer Natural Resources USA, Inc. and XTO Energy, Inc.
2. U.S. Energy Corp.
3. Plum Creek Water Reclamation Authority 4, Upper Clear Creek Watershed Association 5. Upper Thompson Sanitation District 6. Colorado Parks and Wildlife 7. U.S. Environmental Protection Agency 8. High Country Conservation Advocates 9. Metro Wastewater Reclamation District 10. Climax Molybdenum Company 11. Rio Grande Silver, Inc.
12. City of Pueblo 13. Tri-State Generation and Transmission, Inc.
14. Centennial Water and Sanitation District 15. Xcel Energy 16. MillerCoors 17. Seneca Coal Company 18. Peabody-Sage Creek Mining, LLC 19. City of Boulder
33.54 STATEMENT OF BASIS AND PURPOSE REGARDING THE ADOPTION OF NON-
SUBSTANTIVE CHANGES TO THE CLASSIFICATION AND NUMEIRC STANDARDS FOR UPPER COLORADO RIVER BASIN AND NORTH PLATTE RIVER (PLANNING REGION 12), JANUARY 11, 2016 RULEMAKING; EFFECTIVE DATE MARCH 1, 2016 The provisions of C.R.S. 25-8-202(1)(i) and 25-8-401(2) 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 The Commission, in a public rulemaking hearing adopted extensive changes to the format of this regulation. The Commission does not intend to change any existing designations, use classifications or standards, or the implementation of any standards as the results of changing the format. This rulemaking was in response to longstanding issues with managing the information contained in the standards tables. The changes made in this hearing reflect a change from storing the information in word processing documents to storing the information in a relational database. This change in platform will provide better consistency, facilitate error checking as well as a more readable format for the standards tables. Storing the information in a database allows it to be used more efficiently by other programs in the Division.
While it was the Commission’s intent not to change the substantive meaning of the regulations in this rulemaking, in cases where there was ambiguity the revised regulation reflects the Commission’s interpretation of the previous format based on Regulation #31 (the Basic Standards and Methodologies for Surface Water) and the experience of the Commission and its staff. Overall format changes: The new format displays parameters by name, rather than by period table element abbreviations. The section formerly titled “Temporary Modifications and Qualifiers” does not appear in the new format. Instead, there is a separate section for qualifiers, and an “Other” section. Temporary modifications, variances and other footnotes are displayed in the “Other” section. Many items that were formerly in the “Temporary Modifications and Qualifiers” column will be displayed in the “Other” column and will have a different appearance or modified wording, although the information is substantively the same. Each footnote in the “Other” section is preceded by a heading that indicates where the footnote applies:
• Footnotes regarding a use classification will begin with the heading “Classification…” • Footnotes regarding the antidegradation designation begin with the heading “Designation…” • Footnotes that relate to a particular standard begin with the name of the parameter, for example “Selenium(chronic)= …”
Also, since there is more room for information within each segment, footnotes “B” and “C” were replaced with the full text in each segment where these footnotes were applied. Footnote “A” was maintained because the text is too long to be displayed in the “Other” section for each segment where it applies. Footnote “D” was changed to footnote “B” and was maintained because the text is too long to be displayed in the “Other” section.
Constraints of the new format: Some adjustments were made to the way that data is displayed in order to be compatible with the functions of the Standards Database. Database organization requires that information which relates to multiple standards must be attached to each individual parameter. For example, a segment with a temporary modification listed for “all parameters” in the old format will have a temporary modification listed for each individual parameter in the new format. There are also spacing constraints in the new format, which require some information to be moved either to the “other” box on the new format, or moved out of the segment entirely and into another location in the regulation. Clarification of changes: The shift to a database organizational structure required consistency in the way each data element is addressed. To insure that data is stored and displayed correctly, the following changes were made • The “type” of temporary modification is no longer displayed in the segment tables, since they have no regulatory effect and have been inconsistently displayed. • In the old format, waters that had a reviewable antidegradation designation were identified by the absence of either “UP” or “OW” in the designation column. These segments now display the word “reviewable” under the designation heading. There needed to be a value in the designation column for every segment.
• Dissolved standards are not specifically noted as dissolved in the new format. All metals standards are dissolved unless noted with a “T” or a “t”. For example, a manganese standard in the old format of “WS(dis”) is displayed as “WS” in the new format. • A new footnote 7 was added to clarify that although E. coli is listed in the “chronic” column, the standard is a two-month geometric mean rather than a 30-day average. The language of footnote 7 was taken from Regulation 31, Table 1, footnote 7.
• A new footnote 8 was added to indicate that all phosphorus standards are based upon the concentration of total phosphorus. In the old format, individual phosphorus standards were noted as “total” in some basins and not others.
• A new footnote 9 was added to clarify that although pH is listed in the “acute” column, the standard is not applied as a 1-day average. The language of footnote 7 was taken from Regulation 31, Table 1, footnote 3.
• Physical and Biological Parameters: Some parameters are not specifically identified in the old format segment tables as acute or chronic. The new format requires that each parameter is placed in either the acute or chronic column. Specifically, these parameters and the basis for being identified as acute or chronic are as follows:
33.55 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
14, 2015 RULEMAKING; FINAL ACTION JANUARY 11, 2016; EFFECTIVE DATE JUNE 30, 2016 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Pursuant to the requirements in the Basic Standards (at 31.7(3)), the Commission reviewed the status of temporary modifications scheduled to expire before December 31, 2017, to determine whether the temporary modification should be modified, eliminated or extended. Temporary modifications of standards on two segments were reviewed.
In addition, the Commission corrected the Regulation #33 numeric tables for Yampa River segment 13i to indicate that the iron temporary modification applies to Grassy Creek, not Little Grassy Creek. This correction is consistent with Regulation #33 and its Statements of Basis and Purpose for the iron temporary modification on Grassy Creek as adopted by the Commission in the Colorado Basin hearings in 2008 and 2014.
1. City of Delta 2. Resurrection Mining Company 3. U.S. Energy Corp.
4. City of Pueblo 5. Peabody Sage Creek Mining and Seneca Coal Company 6. Climax Molybdenum Company 7. Rio Grande Silver 8. City of Colorado Springs and Colorado Springs Utilities 9. Tri-State Generation and Transmission Association, Inc.
10. High Country Conservation Advocates 11. U.S. Environmental Protection Agency 12. Colorado Parks and Wildlife 13. Town of Crested Butte and Coal Creek Watershed Coalition 14. Public Service Company of Colorado
33.56 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; APRIL 11,
2016 RULEMAKING; FINAL ACTION MAY 9, 2016; EFFECTIVE DATE JUNE 30, 2016 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 While United States Senate Document No 80, does not bind the Commission, the portion entitled “Manner of Operation of Project Facilities and Auxiliary Features,” states that the Colorado-Big Thompson Project must be operated in such a manner as to most nearly effect the following primary purposes:
In 2008, the Commission adopted dual numeric and narrative standards for the protection and improvement of water clarity in Grand Lake pursuant to 31.13(3), because of Grand Lake's uniqueness as Colorado's largest natural lake. In doing so, the Commission stated that “Improvement of clarity within Grand Lake is expected to improve the quality of recreational uses of this unique resource.” In 2008, the Commission also adopted a delayed effective date for the numeric standard as an appropriate policy choice to encourage cooperative efforts to improve Grand Lake clarity. These efforts have been difficult and protracted, but they have also yielded important progress in understanding the factors controlling clarity of Grand Lake. In 2014, the effective date was extended for two more years and the parties were directed that “the goal of the effort is to develop and propose by January 2016, an attainable and protective clarity standard for Grand Lake for consideration by the Commission.” The purpose of this hearing was to consider a joint proposal by Grand County, Northwest Colorado Council of Governments, Colorado River Water Conservation District, and Northern Colorado Water Conservancy District (“Proponents”) to modify the numeric clarity standard for Grand Lake. While arguments were raised that the noticed proposal may go beyond the Commission’s authority, the Commission did not make that finding. Rather, the Commission adopted a compromise proposal from the Division, and supported by the Proponents, the Bureau of Reclamation and other parties, that better balances the clarity, the water rights, the recreational fishery, and the water quality in the Three Lakes system. In today’s hearing, the Commission deleted the 4-meter standard (which has not yet become effective) and adopted the proposed numeric values of 3.8-meter Secchi depth average and 2.5-meter Secchi depth daily minimums as Goal Qualifiers to the existing narrative standard. Goal Qualifiers are unique to Colorado’s water quality standards framework and are not subject to EPA section 303(c)(2) review and approval and federal Clean Water Act standards and, in themselves, do not trigger section 303(d) assessment and listing. Goal Qualifiers are defined in Regulation #31 as appending to the use classification, and have been traditionally used in conjunction with a temporary modification. However, a temporary modification is not appropriate for Grand Lake because there are no permitted discharges (now a prerequisite for temporary modifications). The Commission has, in at least two other instances (Lower Yampa Segment 3b, Johnson Gulch; and Animas River Segments 3a, 4a and 9), used Goal Qualifiers to express a future desired water quality condition, rather than a future use classification goal. The existing 4-meter summertime 85th percentile value standard was revised to 3.8-meter average Goal Qualifier as a refinement of the estimate of resulting clarity when there has been no pumping for at least seven days. The season was also refined to end just after the Labor Day weekend. This is the same concept that was the basis for the 2008 action, and achieving this level of clarity would signify protection of Grand Lake's clarity. The Commission also added a 2.5-meter daily minimum Goal Qualifier as a floor on clarity such that averaging clarity measurements over the entire summer will not mask abrupt decreases in clarity.
In this hearing the Commission reaffirmed its commitment to improved water clarity in Grand Lake. The Commission reiterates that improvement in the clarity of Grand Lake is necessary, while noting that a single “attainable” level of clarity may not exist. The current and future cooperative efforts should continue to focus on a feasible, balanced approach that does not sacrifice water rights, the recreational fishery, or water quality in the Three Lakes system. The Commission remains concerned that it may be infeasible or impractical to find a single numeric standard that can be implemented uniformly in all years due to the fundamental requirement for the CB-T system to operate in a manner which varies year-to-year depending on supply of and demand for water. Any future, proposed attainability-based numeric standard must address these implementation issues.
The Goal Qualifiers should be useful to guide the adaptive management process as embodied in the Memorandum of Understanding between the Proponents and the Bureau of Reclamation. Over the next five years, the Commission expects that the Parties to the MOU will engage in adaptive management that will improve clarity, and inform the operational component of the alternatives being considered. The adaptive management process will result in regular communication between the Parties to the MOU, monitoring of the operational adjustments on clarity, and an evaluation of the relative clarity improvements. Exhibit C to the MOU outlines the monitoring protocols. Three monitoring sites are identified (GL-WES, GL-MID, GL-ATW) and a sampling schedule is outlined, which states that samples will be collected once a week starting May 1 (or as soon as ice is off), 3 times per week from July 1 through September 11 (may be increased to daily sampling based on operational planning), and once a week from September 12 through October 30. From July 1 through September 11, measurements must be taken at all three sites, and will be averaged to evaluate whether the Goal Qualifiers are being met. If data for at least one of the three sites are missing on any given day, an average for that day will not be computed.
The narrative standard remains in effect and can serve to inform the purpose and need statement for the Bureau of Reclamation’s assessment of alternatives. Once the Bureau’s assessment is complete and there is a final assessment of the attainability constraints already identified, a proposal for an attainability- based clarity standard can be considered by the Commission. The Division will assess consistency with the adopted narrative standard by monitoring whether the Proponents continue to implement the adaptive management process described in their Memorandum of Understanding and will review clarity measurements. Evaluation of the Goal Qualifiers will be accomplished by reviewing annual reports and summarizing progress at the Basin Issues Scoping Hearing. In addition, as with all standards, the clarity standards (and goals) for Grand Lake are subject to periodic review, and the Commission expects to review and revisit this issue in future review cycles. PARTIES TO RULEMAKING 1. Grand County 2. Northwest Colorado Council of Governments 3. Colorado River Water Conservation District 4. Northern Colorado Water Conservancy District 5. Larimer County 6. Mid-West Electric Consumers Association 7. New Red Top Valley Ditch Company 8. U. S. Bureau of Reclamation 9. Environmental Protection Agency 10. Colorado Parks and Wildlife
33.57 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
12, 2016 RULEMAKING; FINAL ACTION JANUARY 9, 2017; EFFECTIVE DATE JUNE 30, 2017 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Pursuant to the requirements in the Basic Standards (at 31.7(3)), the commission reviewed the status of temporary modifications scheduled to expire before December 31, 2018, to determine whether the temporary modification should be modified, eliminated or extended. No action: The commission took no action on the following temporary modifications: Blue River Segment 14: temporary modification of the molybdenum standard. The commission made no change to the expiration date of 12/31/2017 since this issue will be addressed in mid-2017 in a molybdenum-specific hearing. Yampa River Segments: Seneca-Peabody presented evidence that it is making progress on the plan for eliminating the need for need for the temporary modifications. The commission made no change to the expiration date of the temporary modifications on these segments as the original time allotment was deemed adequate to resolve the uncertainty.
Segment 13i, selenium, (exp 12/31/2018)
Extension Yampa River Segments 13d and 13i: temporary modifications of the iron standards. Seneca-Peabody presented evidence that additional time was necessary to resolve the uncertainty regarding the underlying iron standard. The commission extended the expiration dates of the iron temporary modifications to December 31, 2018. New Temporary Modifications of the Arsenic Standard:
Consistent with the actions taken in 2013, the commission adopted a temporary modification of the arsenic standard on segments on the following list, with an expiration date of 12/31/2021. At the April 8, 2013 rulemaking, the commission heard testimony that concurred with the finding from December 13, 2011 hearing that an initial reasonable lower limit of treatment technology for arsenic is 3.0 μg/L, pending further investigation by the division, dischargers and stakeholders. The temporary modification was established by the commission to allow for a temporarily less stringent application of the chronic arsenic standard in control requirements for both existing discharges and new or increased discharges.
Upper Colorado Segment 1 Blue River Segment 6a Blue River Segment 12 Blue River Segment 17 Blue River Segment 18 Eagle River Segment 2 Eagle River Segment 5c Eagle River Segment 9b Eagle River Segment 12 Roaring Fork Segment 3c Roaring Fork Segment 10b PARTIES TO THE RULEMAKING HEARING
1. Colorado Parks and Wildlife 2. Resurrection Mining Company 3. Public Service Company of Colorado 4. City of Pueblo 5. Peabody Sage Creek Mining Company and Seneca Coal Company 6. Tri-State Generation and Transmission Association, Inc.
7. Climax Molybdenum Company 8. Rio Grande Silver, Inc.
9. Mt. Emmons Mining Company 10. Plum Creek Water Reclamation Authority 11. Environmental Protection Agency 12. Raytheon Company 13. City of Boulder Open Space and Mountain Parks 14. High Country Conservation Advocates 15. City of Colorado Springs and Colorado Springs Utilities 16. City of Black Hawk and Black Hawk/Central City Sanitation District 17. Town of Crested Butte and Coal Creek Watershed Coalition 18. Parker Water and Sanitation District
33.58 STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE AUGUST 7,
2017 RULEMAKING; FINAL ACTION AUGUST 7, 2017; EFFECTIVE DATE SEPTEMBER 30, 2017 The provisions of C.R S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Blue River Segment 14: Temporary Modification of the chronic molybdenum standard. Climax Molybdenum Company presented evidence that progress has been made on its plan to eliminate the need for a temporary modification and to resolve uncertainty associated with the underlying molybdenum standard of 210 ug/L on Segment 14. A third study sponsored by the International Molybdenum Association (IMOA) on the health effects of molybdenum was completed in late 2016. An abstract and a study report were made available to the Division and other interested stakeholders in early 2017. Because of unanticipated delays associated with the IMOA’s finalization of the full study report it was necessary for the Commission to postpone the hearing concerning the molybdenum standards that was scheduled for August 2017. The molybdenum hearing will be held December 12, 2017. The current temporary modification expires December 31, 2017. In view of the above, the Commission extended the temporary modification in Segment 14 to December 31, 2018.
33.59 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
11, 2017 RULEMAKING; FINAL ACTION JANUARY 8, 2018; EFFECTIVE DATE JUNE 30, 2018 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Pursuant to the requirements in the Basic Standards (at 31.7(3)), the commission reviewed the status of temporary modifications scheduled to expire before December 31, 2019 to determine whether the temporary modification should be modified, eliminated, or extended. No action: The commission took no action on the temporary modifications on the following segments:
Upper Colorado Segment 2 Blue River Segment 2a Roaring Fork Segment 12 Yampa River Segment 2a PARTIES TO THE RULEMAKING HEARING
1. Peabody Sage Creek Mining Company, Seneca Coal Company and Twentymile Coal, LLC 2. Tri-State Generation and Transmission Association, Inc.
3. Colorado Parks and Wildlife 4. Environmental Protection Agency 5. City of Black Hawk and Black Hawk/Central City Sanitation District 6. Rio Grande Silver, Inc.
7. MillerCoors LLC 8. Plum Creek Water Reclamation Authority 9. Public Service Company of Colorado 10. City of Pueblo
33.60 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JANUARY 8,
2018 RULEMAKING; FINAL ACTION MARCH 12, 2018 EFFECTIVE DATE JUNE 30, 2018 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Blue River Segment 14: Temporary Modification of the chronic molybdenum standard for water supply. Climax Molybdenum Company presented evidence that progress has been made on its plan to eliminate the need for a temporary modification and to resolve uncertainty associated with the underlying molybdenum standard of 210 µg/L on Segment 14.
Three studies sponsored by the International Molybdenum Association (IMOA) on the health effects of molybdenum were completed and full reports were made available for consideration in a hearing originally scheduled for December 12, 2017. The hearing was to consider revisions to both the water supply and agriculture molybdenum standards in Regulations 31 and 33, as well as to resolve the temporary modification to the molybdenum water supply standard on Blue River Segment 14. At the prehearing conference on November 29, 2017, the Commission hearing chair heard arguments regarding a Climax request to continue the rulemaking hearing. These arguments centered on the Division’s position in rebuttal that the Commission should not consider any revisions to the water supply molybdenum standard until the most recent IMOA study was peer-reviewed and published as a technical journal article, and until the Agency of Toxic Substances and Disease Registry (ATSDR) considers the recent IMOA study results in the updated version of its draft toxicological profile for molybdenum. The Division presented evidence at the prehearing conference that ATSDR planned to revisit the draft profile in spring 2018, and that an updated version could be expected in approximately one year. On December 1, 2017, the Commission issued its Prehearing Order, continuing the consideration of water supply and agriculture molybdenum standards in Regulation 31 and Regulation 33 until November 2019. The Commission also continued the rulemaking until January 8, 2018, for the limited purpose of considering an extension of the temporary modification of the water supply standard in Blue River Segment 14. The Commission established additional filing deadlines for Climax to submit additional information to support the extension of the temporary modification. In this hearing, the Commission considered the additional information presented by Climax in support of the extension of the temporary modification on Segment 14, and found that nonattainment of the underlying standards was demonstrated, there was predicted non-attainment of a water quality based effluent limit, and there was uncertainty regarding the water quality standard necessary to protect current uses. There is also uncertainty regarding the extent to which existing quality in Blue River Segment 14 is the result of irreversible human-induced conditions. The Commission accepted Climax’s revised plan to resolve the uncertainty associated with the underlying standard of 210 µg/L with some additional considerations. Climax’s plan includes publication of the third IMOA study, awaiting publication of the ATSDR revised Toxicological Profile for Molybdenum, continued water quality monitoring of effluent and Tenmile Creek, source identification, potential additional monitoring, and updates to stakeholders. Furthermore, in order to resolve the uncertainty as to whether attainment of the underlying standard is feasible, in addition to what is outlined in Climax’s plan, Climax will conduct investigations for molybdenum including identification of sources, influent control measures, investigation of potential treatment alternatives and treatment optimization, and available blending. Climax will identify treatment options, source control and water management alternatives, the expected effluent quantity and quality that could be achieved with each alternative, and an estimated cost for each alternative. Given the continuation of the Commission’s consideration of revised molybdenum standards until November 2019, which is after the expiration date of December 31, 2018 of the current temporary modification, the Commission extended the “current conditions” temporary modification in Segment 14 to June 30, 2020. “Current conditions” will preserve the status quo. As expressed by the Commission in a previous rulemaking, “current conditions” recognizes that during the term of the temporary modification, variability in a permitted discharger’s effluent quality may occur. See Reg. 31, Section 31.53(V)(B). The Commission also heard evidence that Climax is committed to continuing to resolve outstanding issues associated with the agriculture standard during the pendency of the continued standards rulemaking.
1. Climax Molybdenum Company 2. Clinton Ditch and Reservoir Company 3, Eagle Park Reservoir Company 4. Eagle River Water and Sanitation District 5. Upper Eagle Regional Water Authority 6. U.S. Environmental Protection Agency 7. Denver Water 8. Copper Mountain Consolidated Metropolitan District 9. Powdr-Copper Mountain, LLC 10. Grand County 11. Northwest Colorado Council of Governments 12. Town of Frisco 13. City of Thornton
33.61 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
10, 2018 RULEMAKING; FINAL ACTION JANUARY 14, 2019 EFFECTIVE DATE JUNE 30, 2019 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Pursuant to the requirements in the Basic Standards (at 31.7(3)), the commission reviewed the status of temporary modifications scheduled to expire before December 31, 2020 to determine whether the temporary modification should be modified, eliminated, or extended. For the temporary modifications set to expire after the effective date of this hearing, the commission reviewed progress toward resolving the uncertainty in the underlying standard and/or the extent to which conditions are a result of natural or anthropogenic conditions, and evaluated whether the temporary modifications were still necessary. The commission took no action on the following temporary modifications:
33.62 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JUNE 10,
2019 RULEMAKING; FINAL ACTION AUGUST 12, 2019; EFFECTIVE DATE DECEMBER 31, 2019 The provisions of C.R.S. 25-8-202(1)(a) and (b); 25-8-203; 25-8-204; and 25-8-402 C.R.S., 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. Water Body Segmentation Some segments were renumbered, combined, or new segments were created to facilitate appropriate organization of water bodies in this regulation. Renumbering and/or creation of new segments was made based on information that showed: a) the original reason for segmentation no longer applied; b) significant differences in uses, water quality and/or physical characteristics warrant a change in standards on only a portion of the existing segment; and/or c) certain segments could be merged into one segment because they had similar water quality and uses. The following changes were made: Upper Colorado segments 2, 5, and 6a: The mainstem of Willow Creek from the outlet of Willow Creek Reservoir to the confluence with the Colorado River was moved from segments 2 and 6a to a new Segment 5 to facilitate adoption of appropriate temperature standards. New Segment 5 was assigned CS-II temperature standards. Segments 2 and 6a retained CS-I temperature standards. Segment 2 is classified as Recreation E, and Segment 6a is classified as Recreation
B. Aquatic Life Use Classifications and Standards Some segments assigned an Aquatic Life use classification were missing a standard to protect that use. The commission adopted the missing standards for the following segments: Upper Colorado River: 4 (sculpin qualifier), 6a (sculpin qualifier), 6b (full suite of aquatic life use standards), 7c (sculpin qualifier)
The following segments were upgraded from Cold 2 to Cold 1: Yampa River: 11 The commission reviewed all Class 2 segments that have fish that are “of a catchable size and which are normally consumed and where there is evidence that fishing takes places on a recurring basis.” Water + Fish or Fish Ingestion standards were applied to the following segments: Eagle River: 11 C. Recreation Use Classifications and Standards The commission reviewed information regarding the current Recreation use classifications and evidence pertaining to actual or potential primary contact recreation. In addition, newly created segments were given the same Recreation use classification as the segment from which they were split, unless there was insufficient evidence to support keeping that classification, or evidence to show that the existing use classification was inappropriate.
Based upon evidence that portions of these segments are publicly accessible and located in a developed area where there is easy access for children, it was determined that primary contact recreation is expected to occur. The following segments with a Recreation N use classification and standards were upgraded to Recreation E:
D. Water Supply Use Classification and Standards The commission added a Water Supply use classification and standards where the evidence demonstrated a reasonable potential for a hydrological connection between surface water and alluvial wells used for drinking water. The Water Supply use classification and standards were added to the following segments:
E. Agriculture Use Classification and Standards The commission reviewed the single segment lacking an Agriculture use (COUCBL07). Based on an evaluation of the available data and information, no changes were adopted at this time. Some segments assigned an Agriculture use classification were missing a standard to protect that use. The commission adopted the missing standards for the following segments: Yampa River: 13g, 13h, 13i (total recoverable trivalent chromium) F. Other Standards to Protect Agriculture, Aquatic Life, and Water Supply Uses
Cuforage = 7 mg/kg, Forageintake = 6.7 kg/day, Cuwater = 0.008 mg/L, Waterintake = 56.8 L/day, Cusupplementation = 0 mg/day, Cu:Mo Safe Ratio = 4:1, Moforage = 0.5 mg/kg. In 2010, the commission also adopted a new standard for molybdenum to protect the Water Supply use that was calculated in accordance with Policy 96-2. A molybdenum standard of 150 µg/L was adopted for all segments in Regulation No. 33 that have an Agriculture use classification, and where livestock or irrigated forage are present or expected to be present.
The following segments (or portions of segments) have an Agriculture use classification and a Water Supply use, but livestock watering does not occur. A molybdenum standard of 210 µg/L was retained on these segments to protect the Water Supply use: Blue River: 14, 15 The following segment has an Agriculture use classification, but livestock watering does not occur. A numeric molybdenum standard does not apply to this segment. Instead, a narrative standard applies to protect the Water Supply use in downstream waters. Blue River: 13 The following segment has an Agriculture use classification, but a site-specific molybdenum standard has been previously adopted. The site-specific molybdenum standard of 190 µg/L was retained on this segment to protect the Agriculture use: Upper Colorado River: 8 2. Cadmium for Aquatic Life: The commission adopted updated hardness-based cadmium Aquatic Life standards on a targeted, site-specific basis in cold waters to reflect the most up-to-date science. The new standards, released by the U.S. Environmental Protection Agency (EPA) in March 2016, are protective of sensitive cold water aquatic life (i.e., trout). The cadmium criteria recommended by EPA and adopted by the commission are as follows:
Acute = e(0.9789*ln(hardness) ̶ 3.866)*(1.136672-(ln(hardness)*0.041838)) Chronic = e(0.7977*ln(hardness) ̶ 3.909)*(1.101672-(ln(hardness)*0.041838)) EPA’s updated cadmium criteria are less stringent than Colorado’s current cadmium standards when water hardness is greater than 45 mg/L CaCO3. Although the criteria are less stringent, they were developed using the latest science and are protective of aquatic life, and it is expected that Colorado’s state-wide cadmium standards will likely be updated using the 2016 EPA cadmium criteria at a later date. Therefore, the commission determined it was appropriate to adopt the new criteria for waters known to be impaired for cadmium to ensure forthcoming clean-up goal development and Total Maximum Daily Load (TMDL) evaluations are based on the most relevant water quality standards available. The updated cadmium standards were adopted for the following segments: Blue River: 2c, 4a, 6a, 7, 12 Eagle River: 2, 5a (acute), 5c (acute), 6 3. Cadmium, Nickel, and Lead for Water Supply: A review of the cadmium, nickel, and lead standards showed that uses were not always adequately protected by the standards currently in the tables. Depending on hardness, the Aquatic Life standards for cadmium, lead, and nickel were not protective of the Water Supply use. The division reviewed all segments in Regulation No. 33 to determine if the current standards applied to each segment are fully protective of the assigned uses, and revised or added standards where appropriate.
The cadmium Water Supply standard was added because the acute Aquatic Life standard is not protective when the hardness was greater than 200 mg/L in non-trout streams and 345 mg/L in trout streams; the lead Water Supply standard was added because the acute Aquatic Life standard is not protective when hardness is greater than 79 mg/L; and the nickel Water Supply standard was added because the chronic Aquatic Life standard is not protective when hardness is greater than 216 mg/L. Cadmium, lead, and nickel Water Supply standards were added to the following segments: Upper Colorado River: 1, 2, 3, 4, 5, 6a, 7a, 7b, 7c, 7d, 8, 9, 10a, 10b, 10c, 11, 12, Blue River: 1, 2a, 2b, 2c, 4a, 4b, 6a, 6b, 8, 9, 10, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 Eagle River: 1, 2, 3, 4, 5a, 5b, 5c, 6, 7a, 7b, 8, 9a, 9b, 9c, 10a, 10b, 12, 13, 14 Roaring Fork River: 1, 2, 3a, 3b, 3c, 3d, 4, 5, 6, 7, 8, 9, 10a, 10b, 11, 12 North Platte River: 1, 2, 3, 4a, 4b, 5a, 5b, 6, 8, 9 Yampa River: 1, 2a, 2b, 3, 4, 5, 6, 7, 8, 11, 13a, 13c, 13e, 13f, 14, 15, 18, 19, 20a, 20b, 21, 22, 23 4. Aquatic Life Criteria for Selenium, Ammonia, and Aluminum: The commission declined to adopt EPA’s revised 304(a) Aquatic Life criteria for selenium, ammonia, and aluminum at this time; however, the division is committed to evaluating these new criteria. Studies are currently underway for each parameter to improve understanding of these criteria in the context of water quality conditions in Colorado and how these criteria may be adopted and implemented in Colorado in the future.
G. Antidegradation Designations The commission reviewed all segments designated Use Protected to determine if the Use Protected designation was still warranted. Based upon available water quality data that meet the criteria of 31.8(2)b, the Use Protected designation was not removed from any segments. The commission reviewed all Reviewable segments to determine if this Antidegradation designation was still warranted. Based upon available water quality data that fails to meet the criteria of 31.8(2)b, the Reviewable designation was not removed from any segments.
H. Ambient Quality-Based and Site-Specific Criteria-Based Standards Ambient quality-based standards are adopted where a comprehensive analysis has been conducted demonstrating that elevated existing water quality levels are the result of natural conditions or are infeasible to reverse, but are adequate to protect the highest attainable use. All existing ambient-based standards were reviewed and no revisions were made.
Ambient-based standards were deleted from the following segment: Blue River Segment 11 (COUCBL11):
The commission reviewed all other existing site-specific standards. Based on an evaluation of the available data and information, no additional changes were adopted at this time.
I. Temporary Modifications All existing temporary modifications were examined to determine if they should be allowed to expire or if they should be extended, either unchanged or with changes to the numeric limits. The commission deleted temporary modifications on the following segments: Blue River: 12 Eagle River: 1, 4 Roaring Fork River: 1 Yampa River: 1 To remain consistent with the commission’s decisions regarding arsenic in section 33.50, all existing temporary modifications for arsenic of “As(ch)=hybrid” (expiration date of 12/31/21) were retained. In addition, for the following segments, an arsenic temporary modification was adopted for the 0.02 µg/L Water + Fish numeric standard in recognition of the uncertainty regarding “the water quality standard necessary to protect current and/or future uses” (31.7(3)). For arsenic, a known human carcinogen, the uncertainty is multi-faceted. For example, there are unresolved questions about existing water quality conditions (including spatial and temporal variation), the sources and causes of any numeric standard exceedances, and to what extent existing conditions may be a result of natural or irreversible sources. Likewise, with reference to the equations used to calculate the Water + Fish, Water Supply, and Fish Ingestion table value standards for arsenic (Policy 96-2), there are unresolved questions about the cancer slope, the bioconcentration or bioaccumulation factor, and the percentage of total arsenic in fish tissue that is inorganic. The commission recognizes the need to resolve the uncertainty in the arsenic standards and ensure that human health is adequately protected. Temporary modifications for arsenic were added to the following segments:
The commission adopted temporary modifications on the following segments: Yampa River Segment 2b (COUCYA02b): Temporary modification of the chronic temperature standards. The commission adopted a temporary modification of the chronic temperature standards on Segment 2b during July, August, September and November with an expiration date of December 31, 2024 and a narrative operative value of “current conditions”. Steamboat presented information that shows instream non-attainment and a predicted compliance problem with the chronic water quality based effluent limit (WQBEL) for its WWTF during those months. The commission found that there is uncertainty about the extent to which the existing quality is the result of natural or irreversible human-induced conditions. The adoption of this temporary modification is based on a predicted compliance problem in the next permit renewal, after January 2022. The commission would not typically adopt a temporary modification this far in advance of a predicted compliance problem, but is making an exception in this instance based on the work that Steamboat is already doing to characterize thermal drivers in the Yampa River and implement strategies to reduce stream temperatures. Steamboat’s plan to resolve uncertainty includes an alternatives analysis for wastewater cooling technology at the city’s WWTF, with an update to be presented to the commission at the December 2020 temporary modifications hearing. This information will inform whether a temporary modification continues to be justified or whether another regulatory tool such as a compliance schedule would be appropriate.
The operative value of the temporary modification is the narrative “current conditions.” In future reviews, the commission will consider the need for changes to all elements of the temporary modification, including the operative value. Because the division is now working to develop methods to support derivation of numeric operative values and effluent limits, the commission anticipates that numeric operative values are likely to be adopted in the future as more data are available to characterize spatial and temporal variability in effluent and instream temperature conditions.
J. Temperature Standards The commission revised temperature criteria in Regulation No. 31 in 2007, and again in 2010, based on the development of the Colorado Temperature Database and a lengthy stakeholder process. In 2014, the new temperature standards were adopted for all segments with an Aquatic Life use classification in Regulation No. 33. In June 2016, temperature criteria in Regulation No. 31 were further revised, including changes to the temperature table value standards, revision of warm water winter acute standards, and the addition of footnotes to protect lake trout and mountain whitefish.
Upper Colorado River: 4 (Grizzly Creek and No Name Creek), 7b (Piney River) Eagle River: 9a (Eagle River from Gore Creek to Squaw Creek) Roaring Fork River: 3a (Roaring Fork River from Snowmass Creek to the Fryingpan River Threemile Creek, Fourmile Creek), 6 (Fryingpan River), 8 (Crystal River)
Yampa River: 2a (Yampa River from Stagecoach Reservoir to Oak Creek), 3 (Upper Bear River), 8 (Elk River), 20a (Mad Creek and tributaries to the Elk River)
The commission adopted standards to protect mountain whitefish on a season- and site- specific basis where information provided by CPW biologists indicated that thermally- sensitive early life stages of mountain whitefish are known to occur. CS-II summer temperature standards typically apply from April to October. Because mountain whitefish spawning and early life stages are expected to occur from October to May, the mountain whitefish summer temperature standards were applied for the months of April, May, and October. The CS-II table value standards were retained for the remainder of the summer (i.e., June through September). Standards to protect mountain whitefish were not adopted where a site-specific temperature standard was in place. Temperature standards to protect mountain whitefish were applied to the following CS-II segments for the months of April, May, and October:
Upper Colorado River: 3, 7a Roaring Fork River: 3c Yampa River: 2b, 13b, 13f In this hearing, the commission adopted standards to protect lake trout on a site-specific basis where information provided by CPW indicated that this species occurs and protection from thermal impacts is appropriate. Adoption of lake trout standards are dependent on two factors: the existing temperature tier (cold lake or cold large lake) and whether a site-specific temperature standard was already in place. For cold lakes, only the chronic lake trout standard was adopted, as the acute cold lake temperature standard (21.2°C) is more protective than the acute lake trout standard (22.4°C). The chronic lake trout standard (16.6°C) is more protective than the chronic cold lake temperature standard (17.0°C). For cold large lakes, both acute and chronic lake trout standards were adopted unless there was a site-specific standard in place. Acute and chronic lake trout standards (22.4 and 16.6°C, respectively) are more protective than acute and chronic cold large lake standards (24.2 and 18.3°C, respectively). Lake trout standards were not proposed where an existing site-specific standard is applied. Temperature standards to protect lake trout were applied to the following segments: Upper Colorado River: 11 (Rim Lake MWAT), 12 (Grand Lake DM and MWAT; Lake Granby DM), 13 (Deep Lake MWAT; Williams Fork Reservoir DM) Blue River: 23 (DM and MWAT on Green Mountain Reservoir) Roaring Fork River: 11 (Savage Lake and Ivanhoe Lake MWAT, 12 (Ruedi Reservoir DM)
North Platte River: 8 (Blue Lake, Lower Big Twin Lake, and Katherine Lake MWAT), 9 (Upper Big Creek Lake and Lower Big Creek Lake DM and MWAT; Agua Fria Lake MWAT)
In the 2016 Regulation No. 31 hearing, the commission declined to adopt the division’s proposal for statewide solutions for temperature transition zones and shoulder seasons, in favor of a basin-by-basin consideration of temperature standards on a site-specific basis. The basin-by-basin approach was selected as it allows for consideration of temperature attainability and ambient quality-based site-specific temperature standards issues in the context of multiple lines of evidence and site-specific contravening evidence. The sections below describe the considerations and methods used to develop and support the site-specific temperature standards revisions adopted in this basin hearing.
Temperature standards have been implemented and reviewed in Regulation No. 33 during three triennial reviews - 2008, 2014, 2018. The level of emphasis and effort dedicated to understanding the aquatic community and temperature standards implementation during these reviews has resulted in a great deal of progress and application of appropriate temperature standards across the basin. Accordingly, fewer site-specific temperature standards and/or corresponding Aquatic Life use revisions were necessary compared to previous basin reviews.
Based upon information regarding the species expected to occur, temperature data, physical habitat, land cover/use, groundwater inputs, flow conditions, and all other available information regarding thermal drivers, the commission adopted revisions of temperature standards for the segments listed below where water quality is not feasible to improve or where the thermal regime is the result of natural conditions, but is sufficient to protect the highest attainable use.
The following segments were changed from CS-II to CS-I: Roaring Fork: 3a (Threemile Creek)
The following segments were changed from CS-I to CS-II: Upper Colorado River: 5, 7d, 7e Moving forward with this site-specific approach, the commission encourages the division to consider whether any additional information would be appropriate to be included in the use attainability analyses.
K. Standards Corrections and Clarifications
L. Correction of Typographical and Other Errors and Segmentation Clarification The following edits were made to segment descriptions to improve clarity and correct typographical errors:
Upper Colorado River: 6b, 10a, 10b, 10c Blue River: 2a, 2b, 10, 11, 13 Eagle River: 2, 3, 5a, 5b, 6, 7a, 7b Roaring Fork River: 3b North Platte River: 4b Yampa River: 6, 7, 11, 13g, 14, 15, 20b • Upper Colorado River Segment 1: The segment description was amended for clarity and consistency.
• Upper Colorado River Segment 2: An exception for Segment 5 was added to reflect a new segment.
• Upper Colorado River Segment 4: The exception for Segment 1 was removed for clarity. • Upper Colorado River Segment 6a: The segment description was amended for clarity. • Upper Colorado River Segment 7a: Exceptions for segments 7d and 7e were added to reflect new segments.
• Upper Colorado Segment 10a: An exception for Segment 2 was added to correct a previous omission.
• Upper Colorado segments 10b and 10c: The segment description was amended to match the diversion records in Division of Water Resources.
• Upper Colorado Segment 11: The segment description was amended for clarity. • Upper Colorado Segment 13: The segment description was amended for clarity. • Blue River segments 2a and 2b: The reference to Summit County Road 3 was removed and replaced with Coyne Valley Road to improve clarity. • Blue River Segment 4a: Wetlands were added to the segment description to correct a previous omission. Exceptions for Segments 2c, 6a, and 16 were added, and the exception for Segment 5 was removed.
• Blue River Segment 12: The arsenic standard was corrected from 0.02 µg/l to 0.02-10 µg/l to reflect the existing uses.
• Blue River Segment 21: The segment description was amended for clarity and consistency.
• Eagle River Segment 3: An exception for Segment 4 was added to correct a previous omission.
• Eagle River segments 7a and 7b: Minturn Middle School was replaced with Minturn Water Facility in the segment description to reflect a current landmark. The middle school is no longer in operation. The exception for Segment 1 was removed to correct a previous error.
• Eagle River segments 8, 9a and 9b: Dates for temperature table value standards were added to clarify the temperature standards that are effective outside of seasonal site- specific standards. A note was added to the daily maximum on 9b to clarify seasonal standards are effective.
• Eagle River Segment 12: An exception for Segment 1 was added for clarity. • Eagle River Segment 13: The segment description was amended for clarity. • Roaring Fork River Segment 3a: The exception for Segment 3c was removed to reflect Threemile Creek is now included in Segment 3a, and the exception for Segment 10 was changed to 10b to reflect current segmentation.
• Roaring Fork River Segment 5: An exception for Segment 1 was added to correct a previous omission.
• Roaring Fork River Segment 7: The segment description was amended for clarity. • Roaring Fork River Segment 8: Exceptions for Segments 10a and 10b were added to reflect current segmentation.
• Roaring Fork River Segment 11: The segment description was amended for clarity. • North Platte River Segment 4a: The source of the segment was added for clarity, and exceptions for Segments 5a and 5b were added to correct previous omissions. • North Platte River Segment 7a: The reference to the outlet of Spring Creek Reservoir was removed to reflect current segmentation.
• North Platte River Segment 8: The segment description was amended for clarity. • North Platte River Segment 9: The site-specific MWAT standard for Lake John was corrected to from 1.2 to 21.2 to reflect the standard adopted by the commission in 2014. • Yampa River Segment 2a: The segment description was amended for clarity. The mainstem of the Yampa River begins at the confluence of the Bear River and Phillips Creek.
• Yampa River Segment 3: An exception was added for Segment 1, and exceptions for segments 8, 13a-f and 19 were removed to reflect current segmentation. • Yampa River Segment 4: The nutrient note was added to correct a previous omission. • Yampa River Segment 5: The segment description was amended to improve clarity. Chimney Creek becomes Phillips Creek prior to reaching the Yampa River. • Yampa River Segment 8: The segment description was amended for clarity. The West Fork Elk River originates at the Elk River and confluences with the Yampa River. Previously it was unclear if the West Fork was included with the Elk River in Segment 8. The exception for 20b was removed to reflect current segmentation. • Yampa River Segment 12: An exception was added for Segment 8 and 20a to improve clarity and consistency.
• Yampa River Segment 13a: The segment description was amended to improve clarity and consistency with Segments 13b and 13c. Over time tributaries to Trout Creek have been moved to other segments, and it was unclear which tributaries to Trout Creek were included in 13a.
• Yampa River Segment 13b: The segment description was amended for clarity. Wetlands were added to Fish Creek and Middle Creek to correct a previous omission. The erroneous trout standards were removed. The assessment location and temporary modification language was amended for clarity.
• Yampa River 13c: The segment description was amended for clarity and consistency with 13a and 13b. The boundary for tributaries to Trout Creek was moved from County Road 179 approximately 1500 feet downstream to the confluence with Fish Creek to improve clarity.
• Yampa River Segment 13d: The assessment location language was amended for clarity. • Yampa River Segment 13e: The assessment location language was amended for clarity. • Yampa River Segment 13g: The segment description was amended for clarity. Cow Camp Creek is an informal name not included on maps. The erroneous trout standards were removed.
• Yampa River Segment 13h: The spaces for total cadmium and total silver were removed from the table to correct a formatting error. Acute cadmium and chronic silver were added to replace the missing standards to protect Aquatic Life use. • Yampa River Segment 13i: The temporary modification language was modified for clarity. The assessment location was removed to reflect assessment locations adopted by the commission in 33.6(4).
• Yampa River Segment 13j: The seasonal qualifier for selenium was removed to reflect selenium standards as adopted by the commission.
• Yampa River Segment 14: The segment description was amended for clarity. • Yampa River Segment 15: The segment description was amended for clarity. Dry Fork Elkhead Creek confluences with Elkhead Creek prior to the Yampa River. The erroneous trout standards were removed.
• Yampa River Segment 18: The segment description was amended for clarity. The mainstem of the Little Snake River is also within the Lower Colorado River basin. The new description clarifies that tributaries within Segment 18 are within the Upper Colorado River basin.
• Yampa River Segment 20a: This segment description was amended to clarify the beginning of the segment is upstream of the confluence with the Elk River. Previously, tributaries to the Yampa River from above the confluence with the Elk River on National Forest land were not explicitly included in any segment, and 20a was inconsistently applied to National Forest lands.
• Yampa River Segment 23: The erroneous trout standards were deleted.
33.63 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
9, 2019 RULEMAKING; FINAL ACTION JANUARY 13, 2019 EFFECTIVE DATE JUNE 30, 2020 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Pursuant to the requirements in the Basic Standards (at 31.7(3)), the commission reviewed the status of temporary modifications scheduled to expire before December 31, 2021 to determine whether the temporary modification should be modified, eliminated, or extended. For the temporary modifications set to expire after the effective date of this hearing, the commission reviewed progress toward resolving the uncertainty in the underlying standard and/or the extent to which conditions are a result of natural or anthropogenic conditions, and evaluated whether the temporary modifications were still necessary.
A. Temporary Modifications for Standards Other than Arsenic The commission extended the following temporary modification: Blue River Segment 14 (COUCBL14): temporary modification of the chronic molybdenum standard (expires 6/30/2023). The commission extended this temporary modification from 6/30/2020 to 6/30/2023 to provide time for information to become available to support development of an updated molybdenum standard to protect the Water Supply use. In addition, Climax Molybdenum Company continues to make progress to investigate molybdenum sources/source control, influent control measures, water management alternatives, available blending, potential treatment and treatment optimization options, and the expected effluent quantity and quality that could be achieved with each alternative. An extension of the temporary modification is needed due to the delay in the release of the updated version of the Agency of Toxic Substances and Disease Registry’s (ATSDR) draft toxicological profile for molybdenum, which will inform development of an updated molybdenum table value standard. It is unknown when the ATSDR toxicological profile will be available, which has resulted in the indefinite continuation of the commission’s consideration of a revised molybdenum standard. As a result of this delay, the commission extended the “current condition” temporary modification to June 30, 2023. When the ATSDR toxicological profile becomes available, a hearing to consider a revised molybdenum standard will be scheduled expeditiously. During the 2018 temporary modifications rulemaking hearing (see 33.61), the commission directed the division to develop a numeric operative value(s) to replace the existing narrative operative value of “current condition” if this temporary modification was extended. The intended purpose of this change was to establish a baseline condition which must be preserved in Blue River Segment 14 and facilitate future evaluations of status quo preservation in the waterbody and effluent. However, due to differences in statistical methods and the form of molybdenum used in standards assessment versus permitting, the commission determined that adoption of a numeric operative value may inadvertently cause permit compliance issues, and therefore retained the narrative “current condition” operative value for this temporary modification. Maintenance of status quo will instead be addressed through enforceable discharge permit limits (WQCD Exhibit L) and evaluation of instream and effluent data, with the baseline instream and effluent condition characterized in this and previous (33.61) statement of basis. In addition, the division will evaluate loading and may include permit limits or conditions in permitting as appropriate (per 31.9(4)) to address loading concerns to maintain status quo and protect existing uses.
B. Temporary Modifications for Arsenic The temporary modification of the chronic arsenic standard, which applies to numerous segments with a standard of 0.02 µg/l to protect the Water + Fish use, was extended from 12/31/2021 to 12/31/2024. No changes were made to the temporary modification operative values at 33.6(2)(c). For discharges existing on or before 6/1/2013, the temporary modification remains at As(ch)=current condition and numeric effluent limits will be developed by the division using the division's implementation method (WQCD Exhibit L). For new or increased discharges that commence on or after 6/1/2013, the temporary modification remains at 0.02–3.0 μg/L (total recoverable). The extension provides time to resolve the uncertainty in the underlying standard for arsenic to protect human health. Significant uncertainty remains regarding the appropriate standard to protect the use and the extent to which ambient levels of arsenic are the result of natural or irreversible conditions. In addition, there is widespread instream non-attainment of the underlying standard and predicted or demonstrated compliance problems with permit limits based on the underlying standard, as demonstrated in the division’s Prehearing Statement. It is anticipated that the uncertainty regarding the appropriate underlying standard for arsenic to protect human health will be resolved by June 2024, with the adoption of new statewide arsenic use-based standards. The division presented (WQCD Exhibit E) a detailed plan to resolve the multifaceted uncertainty for arsenic. The plan includes conducting a field study to investigate the proportion of inorganic (versus total) arsenic in the tissue of fish collected from Colorado waters, deriving a bioaccumulation or bioconcentration factor for arsenic, appropriate for use in Colorado, and characterizing ambient levels of arsenic in surface waters and groundwater statewide. As discussed below, the division will also be gathering, through permit requirements, targeted data from facilities benefiting from the arsenic temporary modification (WQCD Exhibit D). These data will help the division to better understand the contribution of arsenic in effluent from permitted facilities to ambient levels of arsenic in Colorado waters and will inform the extent to which ambient levels of arsenic are the result of natural or irreversible conditions.
Effluent arsenic concentration data from facilities throughout the state demonstrate that many facilities will likely have issues meeting effluent limits based on the anticipated revised arsenic water quality standard to protect human health. As a result, there is a widespread need to make progress to understand sources of arsenic and options for source control and treatment. To ensure such progress is made, when implementing the “current condition” temporary modification in permits, the division will include additional permit Terms and Conditions, which may include requirements for additional monitoring, source identification, and characterization of source control and treatment options for reducing arsenic concentrations in effluent (WQCD Exhibit D). Under the duration of the temporary modification, facilities would not be required to implement facility improvements to meet a specified effluent limit; however, facilities may be required to evaluate arsenic source control and treatment options for their facility. For purposes of evaluating options to reduce arsenic concentrations in effluent, the arsenic treatment removal recognized in the 2013 Arsenic Rulemaking (3 µg/L) can be used as a point of reference until the uncertainty in the underlying standard is resolved. Implementation guidance for these requirements was included in WQCD Exhibit D. These requirements are reasonable and would not cause undue economic burden for facilities, but will ensure that progress is being made toward future attainment of the underlying standards and protection of the classified uses. Implementation of these requirements would function to increase the amount of time facilities would have for long-term planning and encourage data collection that would facilitate implementation of the most appropriate source reduction and treatment options and selection of the most appropriate regulatory pathways once the new underlying standard is adopted for arsenic.
C. Implementation of Current Condition Temporary Modifications into Permits Several parties to the hearing raised concerns regarding the implementation of current condition temporary modifications into permits, as described in WQCD Exhibit L. The commission was persuaded that the division has existing legal authority to proceed with implementation of these temporary modifications in the absence of a rule or policy addressing this specifically. However, the commission believes it would be beneficial to develop a policy, and therefore requested that the division work toward developing a division policy about how the division will proceed with implementing current condition temporary modifications into permits. The commission requested that the division report back to the commission next year, potentially as part of the division’s annual update to the commission regarding the 10-Year Water Quality Roadmap, regarding what the division believes is a reasonable timeline and process for developing such a policy. The commission encouraged the division to continue with its current efforts at transparency and implementation of current condition temporary modifications consistent with the evidence presented in the rulemaking, including Exhibit L, into permits prior to the development of a policy.
33.64 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
9, 2019 RULEMAKING; FINAL ACTION JANUARY 13, 2019 EFFECTIVE DATE JUNE 30, 2020 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Cadmium is a naturally-occurring element frequently found alongside other metals, and numerous treatment techniques are available to remove cadmium from wastewater. Cadmium has both acute and chronic effects on aquatic life, and can negatively impact survival, growth, reproduction, immune and endocrine systems, development, and behavior.
The commission revised the hardness-based cadmium table value standards to protect the Aquatic Life use. The updated standards incorporate toxicity data that have become available since the cadmium standards were last updated in the 2005 Regulation No. 31 rulemaking hearing. The updated standards are based on the United States Environmental Protection Agency’s (EPA) “Aquatic Life Ambient Water Quality Criteria – 2016” and toxicity data that have become available since EPA’s recommended criteria were released in 2016.
The updated standards include two acute equations (acute(cold) and acute(warm)) and one chronic equation. The acute(cold) and chronic equations are the same as the acute and chronic criteria recommended by EPA in 2016. The acute(cold) equation, which is lowered to protect trout, is protective of trout and other sensitive cold water species and applies in segments classified as Aquatic Life Cold Class 1 or 2. The acute(warm) equation, which is not lowered to protect trout, is protective of warm water species and applies in segments classified as Aquatic Life Warm Class 1 or 2. The chronic equation is protective of both cold and warm water aquatic life and applies in segments classified as either Aquatic Life Cold Class 1 or 2 or Aquatic Life Warm Class 1 or 2. Compared to the previous cadmium table value standards, the updated standards are generally less stringent. The acute(cold) standard is less stringent than the previous acute(trout) standard when water hardness is greater than 45 mg/L CaCO3. The acute(warm) equation is less stringent than the previous acute standard when water hardness is greater than 101 mg/L CaCO3. The updated chronic equation is less stringent than the previous chronic standard at all water hardness values. In the past, Colorado has had separate acute equations for waters with trout and waters without trout. The updated standards include separate acute equations for cold waters (both with and without trout) and warm waters. This change in approach is due to the addition of toxicity data showing that sculpin, which inhabit cold waters, are also sensitive to cadmium. To ensure protection of sculpin and other sensitive cold water aquatic life in waters where trout are absent, the acute(cold) equation applies to all cold waters. As a result, the acute trout (tr) qualifier for cadmium is no longer needed on select cold water segments and was deleted from all segments where it had applied. During the 2019 basin review, the commission adopted EPA’s 2016 recommended criteria as site-specific standards in select cold water segments. The updated table value standards for cold waters are the same as EPA’s 2016 recommended criteria. Therefore, to reflect the commission’s state-wide adoption of the updated table value standards, the cadmium “SSE” were replaced with “TVS” on the following segments: Blue River: 2c, 4a, 6a, 7, 12 Eagle River: 2, 5a (acute), 5c (acute), 6
33.65 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
14, 2020 RULEMAKING; FINAL ACTION FEBRUARY 8, 2021; EFFECTIVE DATE JUNE 30, 2021 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Pursuant to the requirements in the Basic Standards (at 31.7(3)), the commission reviewed the status of temporary modifications scheduled to expire before December 31, 2022 to determine whether the temporary modification should be modified, eliminated, or extended. For the temporary modifications set to expire after the effective date of this hearing, the commission reviewed progress toward resolving the uncertainty in the underlying standard and/or the extent to which conditions are a result of natural or anthropogenic conditions, and evaluated whether the temporary modifications were still justified.
The commission took no action on the following temporary modifications: Yampa River Segment 2b (COUCYA02b): temporary modification of the chronic temperature standard (expires 12/31/2024). As requested by the commission in 2019 at 33.62(I), the City of Steamboat Springs provided an update on its work to resolve the uncertainty in the chronic temperature standard. Steamboat continues to make progress on resolving the uncertainty and eliminating the need for the temporary modification and determining the extent to which the existing quality is the result of natural or irreversible human-induced conditions. The commission made no change to the expiration date, as the original time allotment was deemed adequate to resolve the uncertainty.
Peabody’s plan to resolve uncertainty includes extensive data collection to develop site-specific selenium standards. In previous hearings, the commission has found there was uncertainty regarding the water quality standards necessary to protect current and/or future uses, and uncertainty about the extent to which existing quality is the result of natural or irreversible human- induced conditions. Therefore, to resolve the uncertainty regarding reversibility, the commission expects that any future proposal by Peabody will adequately characterize the extent to which existing conditions are human-induced and include an evaluation of the feasibility of reversing anthropogenic impacts.
Because Peabody intends to propose site-specific standards at the December 2021 temporary modifications rulemaking hearing, the commission did not adopt numeric operative values to determine if the status quo is being maintained during the temporary modification. The commission does not intend that these temporary modifications will be extended. However, if Peabody’s proposal is delayed, representative numeric values to characterize instream and effluent status quo to facilitate future evaluations of status quo preservation and ensure existing use protection will be adopted at the next temporary modifications hearing. The commission deleted temporary modifications on the following segments: Yampa River segments 13b, 13d, 13h (COUCYA13b, COUCYA13d, COUCYA13h): temporary modifications of the chronic selenium standard (expire 12/31/2022). The commission deleted the temporary modifications on segments 13b and 13d because instream selenium data show that the underlying chronic selenium standard is being attained. The commission also deleted the temporary modification on Segment 13h due to a lack of evidence of a demonstrated or predicted water quality-based effluent limit compliance problem on Segment 13h or upstream in Segment 13d.
33.66 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
14, 2020 RULEMAKING; FINAL ACTION FEBRUARY 8, 2021; EFFECTIVE DATE JUNE 30, 2021 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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. Adoption and Re-examination of Discharger-Specific Variances In 2010, the commission adopted the discharger specific variance (DSV) provisions at Regulation 31.7(4), which allow a temporary water quality standard to be adopted in cases where water quality-based effluent limits (WQBELs) are not feasible to achieve. A DSV is a hybrid standard that maintains the long-term water quality goal of fully protecting all designated uses, while temporarily authorizing an alternative effluent limit (AEL) to be developed for a specific pollutant and specific point source discharge where compliance with the WQBEL is not feasible.
Pursuant to 40 CFR 131.14(b)(1)(v)-(vi), the commission must re-evaluate every DSV with a duration longer than five years and provide EPA notice of the results within 30 days of the completion of the reevaluation process. If the commission does not complete this action, the federal regulation states that the DSV will no longer be the applicable water quality standard for purposes of the Clean Water Act. This reevaluation is consistent with commission Regulation 31.7(4), which requires that the commission reexamine all DSVs not less than once every three years.
B. Yampa River Segment 7 The commission adopted a DSV for Yampa River Segment 7 (COUCYA07) for total inorganic nitrogen (TIN) that represents the highest degree of protection of the classified use that is economically feasible for the Town of Oak Creek. The AEL is an acute (1-day) concentration of 15 mg/L, which is to be achieved by the end of the variance through implementation of the selected alternatives. The DSV requires that the Town of Oak Creek’s TIN effluent concentrations do not exceed the current condition at any time during the variance. To ensure that the requirements of the DSV do not result in any lowering of currently attained ambient water quality, the commission relies on the implementation of numeric initial effluent limits to be developed in a method consistent with the division’s policy for current condition temporary modifications (Clean Water Policy 13). The DSV will expire on 6/30/2026. A comprehensive alternatives analysis demonstrated that compliance with the TIN WQBEL would cause substantial and widespread adverse social and economic impacts in the area where the discharge is located. Treatment that would allow the Town of Oak Creek to meet the TIN WQBEL, such as replacing the lagoon with a mechanical plant, would result in user fees that exceed the community’s ability to pay. The commission determined that any alternative that would result in user fees exceeding 1.5% of median household income for the Town of Oak Creek’s residents was economically infeasible at this time, due to the current economic conditions in the Town of Oak Creek, including a high level of debt-per capita and a local median household income that is significantly lower than the State’s average. The commission adopted a DSV with an alternative effluent limit that is based upon the best feasible alternative identified for the Town of Oak Creek. This alternative includes modification of the operation of the plant to recycle a portion of the treated effluent from the moving bed bioreactor (MBBR) unit back to the anaerobic cell, where conditions favor denitrification. The five year term of this DSV provides time for the Town of Oak Creek to run a pilot test to evaluate the effectiveness of this approach. If recycling the effluent results in reductions in TIN concentrations, the recycle will be continued and optimized through the term of the variance. If no improvement is observed within the first two years, the remaining three years of this DSV will be used to modify the MBBR unit to perform both nitrification and denitrification. Currently, there is significant seasonal variability in influent flows to the wastewater treatment plant that is believed to be due to groundwater inflow and residential sump pump contributions to the Town of Oak Creek’s collection system. During the term of this variance, the Town of Oak Creek will be taking steps to reduce groundwater inflow, which will reduce influent volume. At the re-evaluation of this DSV at the 2024 Upper Colorado Basin rulemaking hearing, the commission will review the Town of Oak Creek’s progress towards achieving the alternative effluent limit, and will determine whether the requirements of the DSV continue to be the highest attainable condition. The requirements of the DSV will be reviewed during the re-evaluation rulemaking hearing, and will either remain as the AEL identified at the time of the adoption of the variance or be modified to reflect the highest attainable condition. Because there is significant uncertainty in the final effluent quality that will be achieved, the Town of Oak Creek will collect additional data to characterize the effectiveness of treatment and may request a hearing before the commission to modify the DSV before it is re-evaluated or expires. If it remains infeasible for the Town of Oak Creek to achieve TIN WQBELs at the end of the variance, a subsequent DSV may be appropriate.
33.67 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JUNE 14-15,
2021 RULEMAKING; FINAL ACTION AUGUST 9, 2021; EFFECTIVE DATE DECEMBER 31, 2021 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 I. DISCHARGER-SPECIFIC VARIANCES The commission deleted subsections 33.6(6) (a) and (b), which described the regulatory basis and implementation of discharger-specific variances, because this information was revised and consolidated into 31.7(4).
II. CLEANUP, CORRECTIONS, AND CLARIFICATIONS
• At 33.5(2) 'Table B' was added to the reference to organic standards at 31.11 to align with changes to Regulation No. 31.
• At 33.6(1), text was added to clarify that the tables in Appendix 33-1 only show the most stringent standards, and that additional, less stringent standards may be found in Regulation No. 31.
• The reference to the 'temporary modification and qualifiers' column at 33.6(2)(c)(i) was replaced with 'Other' to align with a previous change to the appendix tables. • References to “Trec” were replaced with “total recoverable” or “T”. • Information was added to clarify the application of the sculpin equation in the Table Value Standards table.
• Footnote 4 of the Table Value Standards table was modified to clarify that the “T” in the chronic ammonia equations stands for temperature.
• Other minor edits were made to improve clarity and consistency.
33.68 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JUNE 13-14,
2022 RULEMAKING; FINAL ACTION AUGUST 8, 2022; EFFECTIVE DATE SEPTEMBER 30, 2022 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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. Temporary Modifications Pursuant to the requirements in the Basic Standards (at 31.7(3)), the commission reviewed the status of all temporary modifications to determine whether the temporary modifications should be modified, eliminated, or extended.
Yampa River Segment 2b (COUCYA02b): temporary modification of the chronic temperature standard (7/1-9/30, 11/1-11/30; expires 12/31/2024). The City of Steamboat Springs continues to make progress to resolve the uncertainty in the feasibility of treatment options for controlling temperature and in the temperature standards. The commission made no change to the expiration date, as the original time allotment was deemed adequate to resolve the uncertainty.
33.69 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; APRIL 10,
2023 RULEMAKING; FINAL ACTION APRIL 12, 2023; EFFECTIVE DATE JUNE 14, 2023 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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. Revision of Total Nitrogen and Total Phosphorus Table Value Standards for Lakes and Reservoirs at 31.17 In March 2012, the commission adopted interim numerical nutrient table value standards for chlorophyll a to protect the Aquatic Life, Recreation, and Direct Use Water Supply (DUWS) uses and table value standards for total nitrogen and total phosphorus to protect the Aquatic Life and Recreation uses (31.50) in lakes, reservoirs, rivers, and streams. In its July 2016 action letter for the March 2012 rulemaking hearing, EPA approved with recommendations the numeric values for total nitrogen and total phosphorus for lakes and reservoirs. For Warm lakes, EPA recommended that the commission should apply the total nitrogen and total phosphorus table value standards only where a site-specific analysis demonstrated that uses would be protected. For Warm and Cold lakes, EPA recommended evaluation of options for developing more protective table value standards, to ensure that numeric standards for total nitrogen and total phosphorus could be assigned to individual segments with confidence that uses would be protected. EPA also suggested a classification analysis for lakes and reservoirs to account for the variability between lakes (e.g., Cold and Warm lakes), evaluating confounding factors in the stressor-response relationship between nutrients and chlorophyll a, and evaluating whether the standards are protective of lakes with a high chlorophyll a yield per unit of nutrient. In this hearing, the commission adopted revised total nitrogen and total phosphorus table value standards for lakes and reservoirs to address EPA’s 2016 recommendations and ensure protective table value standards are available for protection of lakes and reservoirs with Aquatic Life and/or Recreation uses (31.17 Table V). The numeric nutrient standards for total nitrogen and total phosphorus represent growing season (July through September) average concentrations with an allowable exceedance frequency of once in five years, and apply to lakes and reservoirs greater than 25 acres in size and with a residence time of at least 14 days. The commission adopted these standards into Regulation No. 31 and the basin regulations (Regulation Nos. 32-38) in this rulemaking; additional details about the revised total nitrogen and total phosphorus standards for lakes and reservoirs are included in 31.60.
B. Implementation of Nutrients Table Value Standards The commission revised 33.5(4) to reflect the current status of the phased implementation framework for nutrients standards and remove information regarding implementation that concluded December 31, 2022. These revisions included removing language regarding phased implementation of chlorophyll a standards for lakes, reservoirs, rivers, and streams, as these standards now apply to all waterbodies with Aquatic Life, Recreation, and/or DUWS uses in Colorado. The information regarding the specific circumstances where nitrogen and phosphorus standards will apply before December 31, 2027 was clarified and includes additional references to 31.17. Also, to be consistent with past practice and the commission’s intent in 31.55, the word “headwaters” was replaced with “waterbodies upstream of certain domestic and non-domestic wastewater treatment facilities”. Finally, references to new Tables V (nutrients standards for lakes and reservoirs) and VI (nutrients standards for rivers and streams) in 31.17 were also added.
The commission revised the Table Value Standards table in 33.6(3) to include chlorophyll a, total nitrogen, and total phosphorus. Instead of replicating the numerical values for these table value standards, the table references 31.17, as 31.17 contains the numeric standards (in Tables V and VI), implementation information, and additional details regarding the phased implementation framework. As part of this change, the commission revised Footnote 1 to specify that the nitrogen and phosphorus standards are based upon the total concentration; this information was previously contained in 33.6(5)(b), which was deleted. Additionally, the commission adopted a new Footnote 6 that clarifies that, with the exception of the chlorophyll a standard to protect the DUWS sub-classification, the chlorophyll a, total nitrogen, and total phosphorus standards apply only to lakes and reservoirs larger than 25 acres surface area. The chlorophyll a standard to protect DUWS lakes and reservoirs applies to lakes and reservoirs of all sizes. This information was previously included in the segment tables in Appendix 33-1, but was moved to Footnote 6 for clarity.
When determining if a site-specific chlorophyll a standard more or less stringent than the table value standard would be protective of a DUWS, the commission may consider factors such as whether disinfection byproducts (DBPs) have been or are currently being produced, the type of treatment technology in use, expected organic carbon removal efficiency during treatment, if the duration of the use is sufficient to result in chronic exposure or require management of disinfection byproducts, and any other relevant factors.
Proposals for site-specific standards or changes to use classifications will need to be scientifically-defensible and protective of uses and meet all requirements of Regulation No. 31 (31.7(1)(b)(ii) and (iii)). In addition, the supporting information for any potential future site-specific standards proposals will need to describe why a departure from specific elements of the table value standards are appropriate; this includes the commission’s dual control (total nitrogen and total phosphorus) approach to nutrient control, and its adoption of independently applicable criteria for chlorophyll a, total nitrogen, and total phosphorus (31.50).
The commission did not adopt total nitrogen or total phosphorus table value standards for this waterbody in this rulemaking hearing.
C. Clarifications and Corrections The following edits were made to Appendix 33-1 to improve clarity and correct errors: • The qualified discharger table at 33.5(4) was updated to accurately reflect the segment location of the Town of Gypsum WWTF. It is in Eagle River Segment 9c (COUCEA09c), not Segment 9b (COUCEA09b).
33.70 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; OCTOBER
10, 2023 RULEMAKING; FINAL ACTION OCTOBER 10, 2023; EFFECTIVE DATE DECEMBER 31, The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 In April 2013 (33.50) and subsequent rulemaking hearings (33.52, 33.57, 33.59, 33.62, 33.63), the commission has adopted and extended temporary modifications for arsenic of “As(ch)=hybrid” (expiration date of 12/31/24) on many segments with the 0.02 µg/L Water + Fish numeric arsenic standard. The arsenic temporary modification recognizes existing and predicted compliance issues, instream nonattainment, and the uncertainty regarding the water quality standard necessary to protect current and/or future uses and the extent to which ambient concentrations of arsenic are natural or irreversible (31.7(3)). The division submitted a plan to resolve uncertainty in the 2019 Temporary Modifications rulemaking (33.63(B)).
The division plans to propose revised standards for arsenic as soon as possible following updated toxicological information from EPA’s Integrated Risk Information System (IRIS) and completion of ongoing studies to better understand arsenic conditions in Colorado. Furthermore, per the conditions of the revised and extended temporary modification at 33.6(2)(c) (effective 6/30/2020 and expires 12/31/2024), and based on the widespread need to make progress to understand sources of arsenic and set forth processes for lowering arsenic in discharges, additional permit Terms and Conditions (T&Cs) are being implemented for facilities benefitting from the “current condition” temporary modification. These T&Cs may include requirements for additional monitoring, source identification, and characterization of source control and treatment options for reducing arsenic concentrations in effluent. The commission recognizes the need to resolve the uncertainty in the arsenic standards and ensure that human health is adequately protected.
The commission identified segments where an arsenic temporary modification had previously been inadvertently omitted. The commission adopted arsenic temporary modifications on the following segments:
North Platte River: 3 (COUCNP03)
Yampa River: 18 (COUCYA18), 19 (COUCYA19), and 22 (COUCYA22) To remain consistent with the commission’s decisions regarding arsenic in section 33.50, all existing temporary modifications for arsenic of “As(ch)=hybrid” (expiration date of 12/31/24), with the exception of those listed below, were retained.
Where evidence indicated the requirements to qualify for a temporary modification were not met, temporary modifications were deleted. The commission deleted chronic arsenic temporary modifications (expiring 12/31/2024) on several segments due to a lack of evidence of a demonstrated or predicted water quality-based effluent limit compliance problem for these segments. These segments have all been designated as Outstanding Waters, have no CDPS permitted dischargers with WQBELs for arsenic, and are without dischargers on upstream segments who may receive WQBELs based on protection of downstream uses. Temporary modifications for arsenic were deleted from the following segments: Upper Colorado River: 1 (COUCUC01)
33.71 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JUNE 10,
2024 RULEMAKING; FINAL ACTION AUGUST 21, 2024; EFFECTIVE DATE DECEMBER 31, 2024 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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 Blue River Segment 14 (COUCBL14): The commission replaced the 210 μg/L chronic molybdenum standard on Blue River Segment 14 with the revised Regulation No. 31 chronic table value standard (TVS) of 530 µg/L to protect the Water Supply use.
Climax Molybdenum Company (Climax) has been working on molybdenum water quality standards issues with stakeholders for over a decade. Climax operates the Climax Mine, a molybdenum mine in Summit and Lake counties, Colorado, that is permitted to discharge to Tenmile Creek, Blue River Segment 13 (COUCBL13). Blue River Segment 13 does not have a molybdenum standard because it is not classified as Water Supply use, and because livestock or irrigated forage are not expected to be present. Blue River Segment 14 is the next downstream segment from Segment 13 and is classified as Water Supply use. In 2014, the commission adopted a Water Supply use-based standard for molybdenum of 210 μg/L on Segment 14. The Agriculture use-based molybdenum standard does not apply to Segment 14 because livestock or irrigated forage are not expected to be present. See Section 33.52(E). The 50th percentile and average molybdenum concentrations in Climax’s effluent for the April 2013 to February 2024 period of record are 538 and 680 µg/L, respectively. There has been significant uncertainty with the Water Supply use-based standard for molybdenum of 210 μg/L since its adoption in Regulation No. 31 in 2010, and on Blue River Segment 14 in 2014, given questions about the science and new toxicological studies that were being conducted. See Section 33.52(J). In recognition of this uncertainty, the commission in 2014 adopted a “current condition” temporary modification to the molybdenum standard on Segment 14. The temporary modification was extended several times to await consideration of a revised molybdenum standard in Regulation No. 31, which was postponed based on delays in issuance of the Agency for Toxic Substances and Disease Registry (ATSDR) final toxicological profile for molybdenum and based on the commission’s hearing schedule. See Sections 33.60, 33.63(A).
ATSDR issued its final profile in May 2020. In January 2022, Climax petitioned the commission to reschedule the molybdenum standards hearing, which had been postponed since 2017. The hearing was rescheduled for June 2023 and the temporary modification was extended through December 31, 2023. The commission later postponed the hearing to revise the molybdenum standards until June 2024 based on resource constraints.
In this 2024 hearing, the commission adopted revisions to the Regulation No. 31 TVS for molybdenum, adopting a human health-based standard of 530 μg/L consistent with the ATSDR Toxicological Profile for Molybdenum issued in May 2020. The commission also determined that a relative source contribution (RSC) of 0.8 and subchronic to chronic uncertainty factor of 3 were justified based on information presented during this hearing.
The commission simultaneously adopted the revised Regulation No. 31 TVS of 530 μg/L on one segment, Blue River Segment 14. Based on the information presented, the commission determined that the RSC of 0.8 was also justified for Blue River Segment 14, and that a site-specific RSC was not necessary. Climax also provided an update on the Climax Mine molybdenum removal water treatment plant (MRWTP) construction. Climax began construction of the $120 million MRWTP in 2022 and is scheduled to complete construction in the first quarter of 2025.
Finally, the commission removed references to the temporary modification on Blue River Segment 14 due to its expiration on December 31, 2023.
33.72 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JUNE 11,
2024 RULEMAKING; FINAL ACTION AUGUST 21, 2024; EFFECTIVE DATE DECEMBER 31, 2024 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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. Temporary Modifications Pursuant to the requirements in the Basic Standards (at 31.7(3)), the commission conducted its biennial review of the status of all temporary modifications to determine whether the temporary modifications should be modified, eliminated, or extended.
Based on evidence that met the 31.7(3) requirements to support extension of temporary modifications, the commission extended the temporary modification by five years, to expire 12/31/2029. No changes were made to the temporary modification operative values at 33.6(2)(c). Therefore, for discharges existing on or before 6/1/2013, the temporary modification remains at As(ch)=current condition and numeric effluent limits will be implemented by the division using the division's Clean Water Policy 13, Permit Implementation Method for Narrative (Current Condition) Temporary Modifications. For new or increased discharges that commence(d) on or after 6/1/2013, the temporary modification remains at 0.02-3.0 μg/L (total recoverable). To support this extension, the division demonstrated continued instream non-attainment of the underlying standard and demonstrated or predicted WQBEL compliance problems with permit limits based on the underlying standard. The division also demonstrated the need for additional time to resolve the remaining uncertainty regarding the appropriate arsenic standard to protect the use and the extent to which existing quality is the result of natural or irreversible human- induced conditions.
The division provided a revised, multifaceted plan to resolve uncertainty (division Prehearing Statement Exhibit F-5) that included details regarding ongoing investigations and information needed to resolve the uncertainty and derive a revised standard by 12/31/2029. The plan includes: evaluating results from the division’s 2020-2023 field study to investigate the proportion of inorganic (versus total) arsenic in the tissue of fish collected from Colorado waters; deriving a Colorado-relevant bioaccumulation or bioconcentration factor for arsenic; characterizing ambient levels of arsenic statewide; gathering facility data for permittees discharging to temporary modification segments and collection of additional arsenic effluent data to better understand the extent of arsenic compliance issues throughout the state; conducting outreach regarding progress on standards revisions; and awaiting the finalization of EPA’s Integrated Risk Information System (IRIS) toxicological assessment for arsenic.
Consistent with the requirements of 31.7(3), the division will also provide annual updates on progress related to the temporary modification and the commission will review this progress as part of the biennial reviews of the temporary modification and include efforts from other states. Additionally, the division will pursue avenues of outreach to engage relevant stakeholders, including, but not limited to, the division’s Water Quality Roadmap Workgroup quarterly meetings, Feasibility and Implementation subgroup meetings, Technical Advisory Committee meetings, permit webinars, or other relevant stakeholder meetings as needed. In addition, the division will consult with the department’s Toxicology and Environmental Epidemiology Office to ensure consideration of impacts to human health statewide is thoroughly evaluated. Additionally, input from potentially impacted Coloradans is essential, especially when considering the disproportionate impacts in some communities from arsenic along with other environmental stressors.
The division will continue implementing permit requirements to gather targeted data from facilities benefiting from the arsenic temporary modification. Effluent arsenic concentration data from facilities throughout the state demonstrate that many facilities will likely have issues meeting effluent limits based on the anticipated revised arsenic water quality standard to protect human health. As a result, there continues to be a widespread need to make progress in understanding sources of arsenic and options for source control and treatment. To ensure such progress is made, when implementing the “current condition” temporary modification in permits, the division will continue to include additional permit Terms and Conditions (T&Cs; division Consolidated Proposal Exhibit F-6 (FINAL)), which may include requirements for additional monitoring, source identification, characterization of source control and treatment options for reducing arsenic concentrations in effluent, and implementation of reasonably achievable effluent quality improvements to control sources of arsenic or reduce arsenic effluent concentrations. Although not required per 33.6(2)(c), new or expanding dischargers are also encouraged to implement the T&Cs.
In 2013, a value of 3 µg/L was identified by the commission as a “reasonable technologically achievable value for arsenic” that could be used as a point of reference until the uncertainty in the underlying standard is resolved. This value is also used as the temporary modification operative value for new or expanding facilities and as a value to categorize facilities for implementation of permit T&Cs. However, it is important to note that arsenic treatment feasibility can vary from facility to facility and is a topic that requires further investigation by the division, dischargers, and stakeholders. In addition, the future revised arsenic standard is anticipated to be at least as stringent as the current standard of 0.02 µg/L. Therefore, when evaluating arsenic treatment options, facilities are encouraged to investigate options that will reduce arsenic as low as possible and not assume 3 µg/L is the limit of technology in all cases. The commission recognizes that various factors, such as influent concentration, financial capacity, and influent competing ions, affect the effluent quality that is feasible for individual facilities to achieve. The commission recognizes that, while arsenic occurs naturally in soil, sediment, and groundwater, there are also man-made sources of arsenic and anthropogenic activities can increase concentrations in the environment. Additionally, arsenic conditions may vary from watershed to watershed, and the relative contributions of point and nonpoint sources may be an area of further study to determine if conditions can be improved by means other than treatment, including source identification and controls. An additional practical consideration is the challenge related to laboratory analysis of arsenic at very low concentrations; specifically, sufficiently sensitive analytical methods to detect arsenic at very low levels such as 0.02 µg/L are not currently available. Thus, the certainty we have when identifying sources of arsenic is limited by the sensitivity of current analytical methods and arsenic may be not detected in water even though the standard has been exceeded. The division will routinely evaluate whether any advances in analytical capabilities have been made, and will provide updates to the commission as information becomes available.
Since 2020, T&Cs have been implemented in some permits that were reissued or modified. To ensure progress continues, when permits that already have the T&Cs are next reissued or modified, additional T&Cs may be added, such as implementation of reasonably achievable effluent quality improvements to control sources of arsenic or reduce arsenic effluent concentrations. Ultimately, the additional T&Cs will benefit facilities by requiring initial steps towards arsenic reduction during the temporary modification. By beginning preliminary investigations while the temporary modification is in place, facilities will have more time to plan for future permit limits, data to inform selection of source reduction and/or treatment options, evidence to identify appropriate future regulatory pathways, and data to assist the division and facilities in resolving the uncertainty for arsenic per 31.7(3)(a)(iii)(B). The additional T&Cs are consistent with the commission’s rule at 31.9(4)(a)(iii), are reasonable, and will not cause undue economic burden for facilities. These requirements will ensure that progress is being made toward future attainment of the underlying standards and protection of the classified uses. Arsenic is a known human carcinogen (e.g., of the bladder, lung, skin, liver, and colon) that is present at levels of concern in many Colorado waterbodies that are classified as water supplies. Despite the human health risks posed by arsenic, the commission has adopted arsenic temporary modifications since 2011 (38.79) to allow for feasible discharge permit requirements while the uncertainty regarding the standard necessary to protect the Water + Fish use and the extent to which arsenic levels are irreversible is resolved.
However, the commission’s intent is for temporary modifications to be temporary; in 2021, the commission adopted rule changes at 31.7(3) and 31.9 to “better ensure that temporary modifications are adopted only when necessary and eliminated in a timely manner” (31.59(VII)). For example, the changes require a detailed, site-specific approach expected to result in sufficient information to resolve each type of uncertainty within the term of the temporary modification. Accordingly, the commission’s intent is that the division and dischargers prepare for implementation of WQBELs following expiration of the temporary modifications on 12/31/2029. It is important for facilities to determine the degree to which effluent quality can be improved and on what timeline the improvements can be achieved.
The commission is determined that Colorado’s temporary modification program will be a tool that encourages and facilitates progress, and not an impediment to achieving water quality improvements. Successful and timely implementation of all components of the Clean Water program is required by state and federal laws, and is necessary to assure continued EPA approval of Colorado temporary modifications.
B. Discharger-specific Variances (DSVs)
The commission reviewed the basis, available information, and progress toward achieving the alternative effluent limits (AELs) and implementing Pollutant Minimization Program (PMP) for the discharger-specific variance (DSV) in Regulation No. 33.
The commission also adopted non-substantive revisions to the format of this DSV in Section 33.6(6) and the Appendix 33-1 table to provide clarity and consistency. In addition, the acronym “AEL” was defined at 33.6(2)(a).
C. Waterbody Segmentation Some segments were renumbered, combined, or new segments were created to facilitate appropriate organization of water bodies in this regulation. Renumbering and/or creation of new segments was made based on information that showed: a) the original reason for segmentation no longer applied; b) significant differences in uses, water quality and/or physical characteristics warrant a change in standards on only a portion of the existing segment; and/or c) certain segments could be merged into one segment because they had similar water quality and uses. The following changes were made: Eagle River segments 1, 10a, and 12 (COUCEA01, COUCEA10a, and COUCEA12): Portions of East Brush Creek (from the source to 39.498914, -106.671722) and West Brush Creek (from the source to the Sylvan Lake State Park boundary (39.469516, -106.729231)), were moved from Segment 12 to Segment 1. All tributaries to West Brush Creek, including wetlands, which are not within Sylvan Lake State Park were moved from Segment 10a to Segment 1. All tributaries to East Brush Creek, including wetlands, were moved from Segment 10a to Segment 1 excluding the following: tributaries and wetlands within Sylvan Lake State Park, the portion of Hat Creek below 39.511013, -106.688716, the portion of Nolan Creek below 39.525486, -106.686495, and the portion of the unnamed tributary below 39.512799, -106.680681; these excluded portions remain in Segment 10a.These moves facilitated changing the antidegradation designation of these waterbodies from Reviewable to Outstanding Waters. As part of this change, Segment 12 was revised to include segments of East Brush Creek (from 39.498914, -106.671722 to the confluence with West Brush Creek) and West Brush Creek (from the Sylvan Lake State Park boundary (39.469516, -106.729231) to the confluence with East Brush Creek) that are not described in Segment 1.
D. Site-specific Standards Site-specific criteria-based standards are adopted where alternate criteria are shown to be protective of the classified uses. Site-specific ambient-based standards are adopted where natural or irreversible human-induced conditions result in pollutant concentrations that exceed table value standards. Feasibility-based ambient standards are adopted where water quality can be improved, but not to the level required by the current numeric standard. Information is currently being gathered to better understand the basis of all existing site-specific standards and determine what information is needed to review each standard in future basin reviews. The commission made no revisions to any site-specific standards at this time.
While the commission made no revisions to any site-specific standards in this rulemaking hearing, a review of progress related to potential future revisions of the site-specific standards on three specific segments in Regulation No. 33 was conducted.
E. Classified Uses and Standards to Protect the Classified Uses The commission reviewed the Aquatic Life, Recreation, Water Supply, and/or Agriculture use classifications and standards applied to each segment to determine if the appropriate use classification(s) and full suite of standards necessary to protect each use applies. Some segments assigned an Aquatic Life, Recreation, Water Supply, and/or Agriculture use classification were missing one or more standards to protect that use, the incorrect standards to protect the use were in place, and/or some segments were missing a classified use. The commission adopted revisions to standards and/or uses for the following segments:
F. Other Standards to Protect Aquatic Life and Recreation Uses As part of the triennial review process, the commission must decide whether to adopt EPA’s Clean Water Act 304(a) criteria recommendations (division Prehearing Statement Exhibit A). The commission declined to adopt EPA’s revised 304(a) Aquatic Life criteria for selenium, ammonia, and aluminum at this time; however, the division is committed to evaluating these new criteria. Studies are currently underway for each parameter to improve understanding of these criteria in the context of water quality conditions in Colorado and how these criteria may be adopted and implemented in Colorado in the future. EPA has also released updated criteria or guidance for several other parameters, including copper (Aquatic Life), E. coli (Recreation), cyanotoxins (Recreation), and the human health risk exposure assumptions. However, the division does not recommend adopting EPA’s recommendations for these parameters at this time, as these items are not included on the division’s 10-year water quality roadmap.
G. Antidegradation Designations: Outstanding Waters The commission designated several segments or waterbodies as Outstanding Waters based on evidence provided by the Colorado River Basin Outstanding Waters Coalition (CRBOWC) that satisfied the criteria for Outstanding Waters designation set forth in Section 31.8(2)(a). The CRBOWC is a diverse coalition comprising American Rivers, American Whitewater, Audubon Rockies, Colorado Trout Unlimited, Eagle River Watershed Council, Friends of the Yampa, The Pew Charitable Trusts, Roaring Fork Conservancy, Trout Unlimited, Western Resource Advocates, and Wilderness Workshop, which have a common goal of safeguarding clean water in Colorado.
Specifically, evidence demonstrated the following conditions were met: 1. existing water quality for the 12 parameters specified at 31.8(2)(a)(i) is equal to or better than necessary to protect uses; 2. the waterbody is considered an outstanding natural resource (i.e. State Gold Medal Trout Fishery, a National Park, National Monument, National Wildlife Refuge, or a designated Wilderness Area, or is part of a designated wild river under the Federal Wild and Scenic Rivers Act, or has exceptional recreational or ecological significance and has not been substantially impacted by human activities) (31.8(2)(a)(ii)); and, 3. The waterbody needs protection in addition to the protections provided by uses, standards, and a Reviewable designation (31.8(2)(a)(iii)).
To further support the proposal, the CRBOWC and stakeholders also provided information that demonstrates these waterbodies have important short- and long-term recreational and ecological value for the local communities. In addition, through the widespread outreach effort to interested and/or potentially impacted stakeholders conducted by the CRBOWC, the commission determined that stakeholders supported the Outstanding Waters designations or, at a minimum, did not oppose the Outstanding Waters designations.
The Reviewable designation was upgraded to Outstanding Waters on the following segments or waterbodies:
● Soda Creek, including all tributaries and wetlands, from the source to the National Forest boundary at 40.541953, -106.790266.
● North Fork Elk River, including all tributaries and wetlands, from the Mount Zirkel Wilderness boundary to above the confluence with Lost Dog Creek. ● Middle Fork Elk River, including all tributaries and wetlands, from the Mount Zirkel Wilderness boundary to above the confluence with the North Fork Elk River. ● South Fork Elk River, including all tributaries and wetlands, from the Mount Zirkel Wilderness boundary to the confluence with Elk River.
● Middle Fork Little Snake River, including all tributaries and wetlands, which are on National Forest land in Routt County.
● Elkhead Creek, including all tributaries and wetlands, from its source to the eastern boundary of state lands in California Park (40.743796, -107.141684). ● First Creek, including all tributaries and wetlands, from its source to the eastern boundary of state lands in California Park (40.743796, -107.141684). To meet the first requirement at 31.8(2)(a)(i), the CRBOWC provided data demonstrating that water quality in all of these waterbodies is equal to or better than the standards necessary to protect the uses for the 12 parameters specified at 31.8(2)(a)(i).
To meet the second requirement at 31.8(2)(a)(ii), the CRBOWC provided evidence that each of these waterbodies is considered an outstanding natural resource. Where waterbodies were determined to be outstanding natural resources because they have exceptional recreational or ecological significance, per 31.8(2)(a)(ii)(B), the waters were shown to not be substantially impacted by human activities. Several types of evidence were used to demonstrate that a waterbody is an outstanding natural resource because it has exceptional ecological significance, including information about fish populations, aquatic- dependent wildlife, the macroinvertebrate community, and/or the aquatic-dependent plant community. ● Fish: In addition to the evidence provided by the CRBOWC, the commission relied on the expertise of Colorado Parks and Wildlife (CPW) staff for determining which waterbodies had fish populations with exceptional ecological significance. In general, CPW found a fish population to be exceptional if it supported a conservation population of cutthroat trout. Cutthroat trout are the only native trout to Colorado and conservation populations of this species are critical to reestablishing pure cutthroat populations in the state. Conservation populations of cutthroat trout are: 1. genetically unaltered and 2. not likely to be extirpated by collocated populations of brook, rainbow, and/or brown trout. Furthermore, many mixed-fishery segments may be considered for cutthroat trout restoration efforts in the future and protecting these waters is crucial so that the next generation of fishery biologist will have the opportunity to make decisions about native species reclamation. Additionally, waterbodies supporting populations of bluehead sucker, mountain sucker, and other special status fish species and/or their spawning grounds, are ecologically exceptional. The bluehead sucker is designated as a Tier 1 State Species of Greatest Conservation Need. The United States Forest Service and the Bureau of Land Management have listed the bluehead sucker as a sensitive species. Mountain sucker is listed as a United States Forest Service Region 2 Sensitive Species and species of CPW State Special Concern.
Additionally, as discussed below, some waterbodies supported a combination of exceptional fish, macroinvertebrates, and plants and/or exhibited exceptional recreational significance. The evidence used to meet the requirement at 31.8(2)(a)(ii) for each waterbody is summarized below. Eagle River Segment 1 (COUCEA01): This segment was already designated Outstanding Waters, but portions of the mainstem and tributaries of East Brush Creek and West Brush Creek were added to this segment to facilitate changing the antidegradation designation from Reviewable to Outstanding Waters on these waterbodies. The CRBOWC demonstrated East and West Brush have exceptional ecological value because they support high-scoring benthic macroinvertebrate communities and populations of Colorado River cutthroat trout. They also support riparian plant species that are considered to be of “High Biodiversity Significance,” based on the CNHP PCA report for East Brush Creek and Hat Creek. East and West Brush Creeks provide exceptional recreational opportunities for anglers to catch four species of trout desirable to anglers.
The CRBOWC demonstrated the South Fork Elk River has exceptional ecological value because it supports high-scoring benthic macroinvertebrate communities and populations of Colorado River cutthroat trout, mottled sculpin, mountain sucker, and mountain whitefish. The upper reaches of the South Fork Elk River lie within the Mount Zirkel Wilderness and are designated Outstanding Waters.
Yampa River Segment 19b (COUCYA19b): This segment was created to designate a portion of the Middle Fork Little Snake River, and its tributaries and wetlands, Outstanding Waters. The CRBOWC demonstrated the Middle Fork Little Snake River has exceptional ecological value because it supports high-scoring benthic macroinvertebrate communities and populations of Colorado River cutthroat trout, mottled sculpin, and speckled dace. It also supports riparian plant species that are considered to be of “High Biodiversity Significance”, based on the CNHP PCA reports for Independence Creek, Little Red Park, Beeler Gulch, and Crane Park. Yampa River Segment 20c (COUCYA20c): This segment was created to designate a portion of Elkhead Creek and First Creek, and their tributaries and wetlands, Outstanding Waters. The CRBOWC demonstrated Elkhead Creek and First Creek have exceptional ecological value because they support populations of Colorado River cutthroat trout, mottled sculpin, mountain sucker, speckled dace, boreal toad (breeding population), northern leopard frog, and sandhill crane.
For all of these waterbodies, the CRBOWC demonstrated that additional protection is needed to preserve critical aquatic habitat, support downstream resiliency and ecosystem services, and provide recreational value. Potential threats to these waterbodies include climate change, drought, wildfire, and anthropogenic impacts from development and recreation. It is well established that protecting vulnerable headwater streams is critical for watershed resilience (Lane et al. 2023; McCluney et al. 2014; Colvin et al. 2019; MacDonald and Coe 2007).
The commission understands that there are existing land uses, including grazing permits, in place in many of these watersheds. The evidence demonstrates that these existing land uses are compatible with the Outstanding Waters designation because the current high level of water quality has been attained with these uses in place. It is the commission's intent that these Outstanding Waters designations should not be the basis upon which federal, state or local agencies place more onerous or costly conditions upon permits or approvals existing at the time of the designation, or upon any renewals thereof.
H. Clarifications and Correction of Segmentation, Typographical, and Other Errors The following edits were made to the regulation and Appendix 33-1 to improve clarity and correct typographical errors:
o Assessment locations at 33.6(4)(h) were reformatted from degrees/minutes/seconds to display the locations in decimal degrees for ease of use and consistency in the regulation. Corrections to locations were made to Middle Creek site 29 and Foidel Creek Site 8 using maps included in the historical hearing record.
o The latitude and longitude were added to assessment locations at 33.6(4)(j). The location for WSH7 was corrected using a map included in the historical hearing record.
o Assessment locations at 33.6(4)(k) were reformatted from township and range to display the location in decimal degrees for ease of use and consistency in the regulation. Refinement to sample locations were made to Sage Creek YSS2 and Sage Creek WSSF3 using maps included in the historical hearing record. ● The segment descriptions in Appendix 33-1 were reviewed, and minor revisions were made to several segments to correct grammar, punctuation, and typos, improve sentence structure, and add details to increase accuracy of the description. Upper Colorado River: 9 Roaring Fork River: 10b ● Existing site-specific temperature standards were reformatted in the Appendix 33-1 tables to provide clarity and consistency for the following segments: Upper Colorado River: 11 Blue River: 23 Eagle River: 8, 9a, 9b Roaring Fork River: 11, 12 North Platte River: 8
33.73 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JUNE 9,
2025 RULEMAKING; FINAL ACTION AUGUST 11, 2025; EFFECTIVE DATE DECEMBER 31, 2025 The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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. Discharger-specific Variances (DSVs)
B. Site-specific Standards Yampa River Segments 13e and 13g (COUCYA13e, COUCYA13g): The commission adopted site- specific criteria-based standards for selenium on Bond Creek and Cow Camp Creek in Yampa River Segment 13g, based on the 2016 EPA 304(a) criteria for selenium for protection of aquatic life and the 2024 EPA Technical Support Materials (2024 TSMs). The site-specific standards and assessment information are included in Section 33.6(4).
The 2016 criterion document provides two modeling methods for translating EPA’s recommended fish tissue criterion to a site-specific water column criterion: bioaccumulation factors (BAF) and the mechanistic bioaccumulation model (MBM).
The BAF approach uses the ratio of selenium concentrations in fish tissue to selenium concentrations instream to estimate how much selenium concentrates in fish tissue relative to the amount of selenium in the water. This ratio is then used to calculate a water column value that is expected to result in attainment of the fish tissue element (e.g., 8.5 mg/kg whole body). This approach is relatively straightforward and only requires site-specific fish tissue and water column data.
The MBM is more complex and characterizes selenium bioaccumulation through each trophic level of the food web using site-specific selenium concentrations in the water column, particulates (sediment, detritus, periphyton), macroinvertebrates, and fish. Either site-specific data or default values can be used for many of the MBM inputs. The 2016 criterion document provides default values that can be used to estimate the species-specific trophic transfer of selenium from one trophic level to the next. The 2016 criterion document also provides species-specific conversion factors to translate between the egg-ovary tissue element and whole body tissue. At a minimum, water column and particulate selenium data are needed as site-specific inputs. Site-specific protective water column (WCp) values were derived using both approaches: 1) for reaches with a consistent fish population (i.e., Bond Creek), the BAF approach was used, and 2) for reaches where fish are limited due to habitat and flow (i.e., Cow Camp Creek), the MBM was used.
Fish species used in calculations: For both the BAF and MBM calculations, creek chub were used as the fish species on which to base the calculations, as proposed by Peabody. EPA guidance recommends selecting the fish species with the greatest selenium sensitivity and bioaccumulation potential. However, fish tissue data showed that the highest bioaccumulation potential varied by species, waterbody, and year. Ultimately, the agencies did not oppose the use of creek chub, but recognized there is still uncertainty whether this species has the highest bioaccumulation potential in the study area. This decision may be revisited in the future when more data are available.
Water column data usage: Both of the models use a water column value paired with a tissue (BAF) or particulate (MBM) value to calculate a WCp value for each sampling event. The 2016 criterion document recommends using temporally and spatially paired data, when possible, but allows pairing of data collected within a year. Peabody and the agencies discussed various options, ranging from using only samples collected concurrently with tissues/particulates or using water samples collected within a year of tissues/particulates. Following rebuttal, Peabody and the agencies reached agreement that using spring water samples leading up to the tissue/particulate sampling best represented the range of selenium concentrations that potentially bioaccumulates through the aquatic food web for this study area. The commission adopted Peabody’s recommendation to use the average of instream selenium concentrations collected from March through June, excluding those samples collected after tissues/particulate collection. Enrichment Factor (EF): The MBM uses the ratio of the selenium concentration in particulates (algae, sediment, detritus) and the selenium concentration in water to calculate an EF. The EF represents the bioavailability of selenium at the base of the aquatic food web. The 2016 criterion document recommends using a combination of sediment, periphyton, and detritus, when available, to characterize particulate selenium conditions. However, Peabody initially proposed using only sediment to calculate the EF, even though periphyton data were also available. Due to the agencies’ opposition to this approach, Peabody agreed to incorporate existing periphyton data into the EF and to collect periphyton samples for selenium analysis in future sampling events, when available.
Trophic Transfer Factors (TTFs): The MBM models the transfer of selenium through the food web, using either EPA-derived TTFs for fish and invertebrates or TTFs calculated from field- collected data. Because fish are not consistently available for sampling on Cow Camp Creek, EPA’s default TTF of 1.06 for creek chub was used in MBM calculations on this waterbody. For the invertebrate TTF on Cow Camp Creek, a TTF of 1.69 was calculated as the average of EPA’s default invertebrate TTFs, excluding mollusks because mollusks were not observed during sampling. Agreement on this decision point was reached after rebuttal. This TTF may be revised in the future using site-specific data once sufficient data are available. Conversion Factor (CF): The CF used in the MBM quantifies the fish species-specific proportion of selenium in eggs and/or ovaries relative to the average concentration of selenium in the whole body or muscle tissue. EPA’s 2016 egg/ovary criterion of 15.1 mg/kg, combined with EPA’s default CF of 1.99 for creek chub, were used in the MBM calculations. How to use multiple WCp values: On each waterbody, Peabody collected data at upstream and downstream locations. The BAF and MBM approaches result in a single WCp value for each sample date and sample location for which sufficient co-located data are available. There was considerable discussion about how to handle multiple WCp values at a single site and on a single waterbody to ensure the resulting standard(s) is protective of the entire waterbody over a range of spatial and temporal conditions.
Peabody proposed calculating the average of upstream and downstream sites’ WCp values as the standard for Cow Camp Creek, and the average of only the downstream site for Bond Creek. While the agencies recommended use of the 20th percentile of WCp values to be consistent with the EPA 2016 criterion, the commission adopted site-specific standards based on Peabody’s proposed use of the average. The approach for each waterbody was determined based on waterbody-specific factors, discussed below.
Although data were available to calculate site-specific water column standards using the MBM for Sage Creek, and Peabody proposed site-specific standards using the MBM for Sage Creek, there was uncertainty in the results due to the extreme variability in selenium concentrations observed in Sage Creek, and Peabody withdrew its Sage Creek proposal after rebuttal. More data are needed to characterize this waterbody due to dramatic selenium spikes causing uncertainty in model outcomes. Due to Peabody’s and the agencies’ concerns regarding the variability in the site-specific calculations, the commission took no action on Sage Creek and did not adopt site- specific standards.
APPENDIX 33-1 Stream Classifications and Water Quality Standards Tables Effective 12/31/2025 Abbreviations and Acronyms Aq = Aquatic °C = degrees Celsius CL = cold lake temperature tier CLL = cold large lake temperature tier CS-I = cold stream temperature tier one CS-II = cold stream temperature tier two D.O. = dissolved oxygen DM = daily maximum temperature DUWS = direct use water supply E.coli = Escherichia coli EQ = existing quality mg/L = milligrams per liter mg/m2 = milligrams per square meter mL = milliliter MWAT = maximum weekly average temperature OW = outstanding waters sc = sculpin SSE = site-specific equation T = total recoverable t = total tr = trout TVS = table value standard µg/L = micrograms per liter UP = use-protected WS = water supply WS-I = warm stream temperature tier one WS-II = warm stream temperature tier two WS-III = warm stream temperature tier three WL = warm lake temperature tier CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Upper Colorado River Basin
1. Mainstem of the Colorado River, including all tributaries and wetlands, within or flowing into Rocky Mountain National Park. COUCUC01 Classifications Physical and Biological Metals (ug/L) Designation Water Supply DM MWAT acute chronic OW Agriculture Temperature °C CS-I CS-I Arsenic 340 --- Aq Life Cold 1 acute chronic Arsenic(T) --- 0.02 Recreation E D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
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. COUCUC02 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Upper Colorado River Basin 3. Mainstem of the Colorado River from the outlet of Lake Granby to below the confluence with the Roaring Fork River. COUCUC03 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C varies* varies* Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
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. COUCUC04 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Upper Colorado River Basin 5. Mainstem of Willow Creek from the outlet of Willow Creek Reservoir to the confluence with the Colorado River. COUCUC05 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
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. COUCUC06A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation P acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 205 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Upper Colorado River Basin 6b. Mainstem of un-named tributary to Willow Creek from the headwaters to the confluence with Willow Creek (40.131422, -105.920895). COUCUC06B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 2 Temperature °C CS-II CS-II Arsenic 340 --- Recreation N acute chronic Arsenic(T) --- 100 Qualifiers: D.O. (mg/L) --- 6.0 Cadmium TVS TVS Other: D.O. (spawning) --- 7.0 Chromium III TVS TVS pH 6.5 - 9.0 --- Chromium III(T) --- 100 *Phosphorus(chronic) = applies only above the chlorophyll a (mg/m2) --- --- Chromium VI TVS TVS facilities listed at 33.5(4).
*Uranium(acute) = See 33.5(3) for details. E. Coli (per 100 mL) --- 630 Copper TVS TVS *Uranium(chronic) = See 33.5(3) for details. Iron(T) --- 1000 Inorganic (mg/L) Lead TVS TVS acute chronic Manganese TVS TVS Ammonia TVS TVS Manganese(T) --- 200 Boron --- 0.75 Mercury(T) --- 0.01 Chloride --- --- Molybdenum(T) --- 150 Chlorine 0.019 0.011 Nickel TVS TVS Cyanide 0.005 --- Selenium TVS TVS Nitrate 100 --- Silver TVS TVS(tr)
COUCUC07A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C varies* varies* Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
*Temperature = Ammonia TVS TVS Lead TVS TVS See 33.6(4) for temperature standards. Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
COUCUC07B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
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.
COUCUC07C Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation N acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- --- Chromium III(T) 50 --- Temporary Modification(s):
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Upper Colorado River Basin 7d. Mainstem of Muddy Creek from the outlet of Wolford Mountain Reservoir to above the Highway 40 Bridge in Kremmling (40.060574, -106.398739). COUCUC07D Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Modification(s):
7e. Mainstem of Muddy Creek from above the Highway 40 Bridge in Kremmling (40.060574, -106.398739) to the confluence with the Colorado River. COUCUC07E Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 7.6 Qualifiers: D.O. (mg/L) --- 6.0 Cadmium TVS TVS Other: D.O. (spawning) --- 7.0 Chromium III TVS TVS pH 6.5 - 9.0 --- Chromium III(T) --- 100 *Phosphorus(chronic) = applies only above the chlorophyll a (mg/m2) --- TVS Chromium VI TVS TVS facilities listed at 33.5(4).
*Uranium(acute) = See 33.5(3) for details. E. Coli (per 100 mL) --- 126 Copper TVS TVS *Uranium(chronic) = See 33.5(3) for details. Iron(T) --- 1000 Inorganic (mg/L) Lead TVS TVS acute chronic Manganese TVS TVS Ammonia TVS TVS Mercury(T) --- 0.01 Boron --- 0.75 Molybdenum(T) --- 150 Chloride --- 250 Nickel TVS TVS Chlorine 0.019 0.011 Selenium TVS TVS Cyanide 0.005 --- Silver TVS TVS(tr)
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. COUCUC08 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS* *Iron(chronic) = Point of compliance at Aspen Canyon Ranch well. acute chronic Iron(T) --- 1000 * A M sp a e n n g a C n a e n s y e o (c n h R ro a n n ic c )
9. All tributaries to the Colorado River and Fraser River, including all wetlands, within the Never Summer, Indian Peaks, Byers Peak, Vasquez Peak, Eagles Nest and Flat Tops Wilderness Areas.
COUCUC09 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS* Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS/TVS(sc)
10b. Mainstem of the Fraser River from a point immediately below the Rendezvous Bridge (39.933728, -105.789785) to a point immediately below the Hammond No 1 Ditch (39.952113, -105.814481).
COUCUC10B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Upper Colorado River Basin 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. COUCUC10C Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
11. All lakes and reservoirs tributary to the Colorado River within Rocky Mountain National Park, Never Summer, Indian Peaks, Byers Peak, Vasquez Peak, Eagles Nest and Flat Tops Wilderness Areas.
COUCUC11 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C varies* varies* Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (ug/L) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
12. Lakes and reservoirs within Arapahoe National Recreation Area, including Grand Lake, Shadow Mountain Lake and Lake Granby. COUCUC12 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C varies* varies* B Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply clarity --- narrative* Cadmium TVS TVS DUWS* D.O. (mg/L) --- 6.0 Cadmium(T) 5.0 --- Qualifiers: D.O. (spawning) --- 7.0 Chromium III --- TVS Goal Qualifier Grand Lake Clarity pH 6.5 - 9.0 --- Chromium III(T) 50 --- Other: chlorophyll a (ug/L) --- DUWS Chromium VI TVS TVS chlorophyll a (ug/L) --- TVS Copper TVS TVS Temporary Modification(s):
*Classification: DUWS applies to Grand Lake. Chloride --- 250 Mercury(T) --- 0.01 *Nitrogen(chronic) = applies only above the facilities Chlorine 0.019 0.011 Molybdenum(T) --- 150 listed at 33.5(4).
*Phosphorus(chronic) = applies only above the Cyanide 0.005 --- Nickel TVS TVS facilities listed at 33.5(4). Nitrate 10 --- Nickel(T) --- 100 *Uranium(acute) = See 33.5(3) for details.
*clarity(chronic) = For Grand Lake, the highest level Nitrogen --- TVS* Silver TVS TVS(tr) of clarity attainable, consistent with the exercise of Phosphorus --- TVS* Uranium varies* varies* established water rights, the protection of aquatic life, and protection of water quality throughout the Sulfate --- WS Zinc TVS TVS Three Lakes system.
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. COUCUC13 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C varies* varies* B Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS DUWS* D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Qualifiers: pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (ug/L) --- DUWS Chromium III(T) 50 --- chlorophyll a (ug/L) --- TVS Chromium VI TVS TVS Temporary Modification(s):
*Uranium(acute) = See 33.5(3) for details. Cyanide 0.005 --- Molybdenum(T) --- 150 *Uranium(chronic) = See 33.5(3) for details. Nitrate 10 --- Nickel TVS TVS *Temperature = Nitrite --- 0.05 Nickel(T) --- 100 See 33.6(4) for temperature standards.
1. Mainstem of the Blue River from the source to above the confluence with French Gulch. COUCBL01 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
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). COUCBL02A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic UP Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium 4 4 Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
Sulfide --- 0.002 Uranium varies* varies* Zinc SSE* SSE* All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Blue River Basin 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. COUCBL02B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium SSE* SSE* Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Cadmium(acute) = 1/2e^(1.0166(ln(hard)-3.132))
acute chronic Iron(T) --- 1000 *Cadmium(chronic) = 1/2e^(1.0166(ln(hard)-3.132))
Ammonia TVS TVS Lead TVS TVS *Uranium(acute) = See 33.5(3) for details.
*Uranium(chronic) = See 33.5(3) for details. Boron --- 0.75 Lead(T) 50 --- *Zinc(acute) = e^(0.9805(ln(hard)+1.402)) Chloride --- 250 Manganese TVS TVS/WS *Zinc(chronic) = e^(0.9805(ln(hard)+1.402)) Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- --- Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Blue River Basin 3. Deleted.
COUCBL03 Classifications Physical and Biological Metals (ug/L) Designation DM MWAT acute chronic Qualifiers: acute chronic Other:
COUCBL04A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Blue River Basin 4b. North Fork of the Swan River, including all tributaries and wetlands, from the source to the confluence with the Swan River. COUCBL04B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
5. Deleted.
COUCBL05 Classifications Physical and Biological Metals (ug/L) Designation DM MWAT acute chronic Qualifiers: acute chronic Other:
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS 6b. Mainstem of Camp Creek, including all tributaries and wetlands, from the source to the confluence with the Snake River. COUCBL06B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
Copper TVS TVS *Zinc(acute) = 0.978*e^0.8537(ln Hardness)+1.5227 Inorganic (mg/L) Iron --- WS *Zinc(chronic) = 0.986*e^0.8537(ln Hardness)+1.3519 acute chronic Iron(T) --- 1000 Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc --- SSE* Zinc SSE* --- All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Blue River Basin
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. COUCBL07 Classifications Physical and Biological Metals (ug/L) Designation Aq Life Cold 1 DM MWAT acute chronic UP Recreation E Temperature °C CS-I CS-I Arsenic 340 --- Qualifiers: acute chronic Arsenic(T) --- 7.6 Other: D.O. (mg/L) --- 6.0 Cadmium TVS TVS D.O. (spawning) --- 7.0 Chromium III TVS TVS *Uranium(acute) = See 33.5(3) for details. pH 6.5 - 9.0 --- Chromium VI TVS TVS *Uranium(chronic) = See 33.5(3) for details. chlorophyll a (mg/m2) --- TVS Copper TVS TVS
8. Mainstem of Keystone Gulch, including all tributaries and wetlands, from the source to the confluence with the Snake River. Mainstem of Chihuahua Creek, including all tributaries and wetlands, from the source to the confluence with Peru Creek. Mainstem of the North Fork Snake River, including all tributaries and wetlands, from the source to the confluence with the Snake River. Mainstem of Jones Gulch, including all tributaries and wetlands, from the source to the confluence with the Snake River. COUCBL08 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Blue River Basin 9. Mainstem of Deer Creek, including all tributaries and wetlands, from the source to the confluence with the Snake River. COUCBL09 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
10. Mainstem of French Gulch, including all tributaries and wetlands, from the source to a point 1.5 miles below Lincoln (39.484661, -105.995074). COUCBL10 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
11. Mainstem of French Gulch from a point 1.5 miles below Lincoln (39.484661, -105.995074) to the confluence with the Blue River. COUCBL11 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic UP Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 7.6 Qualifiers: D.O. (mg/L) --- 6.0 Cadmium EQ* EQ* Other: D.O. (spawning) --- 7.0 Chromium III TVS TVS pH 6.5 - 9.0 --- Chromium III(T) --- 100 *Cadmium(acute) = existing quality chlorophyll a (mg/m2) --- TVS Chromium VI TVS TVS *Cadmium(chronic) = existing quality
12. Mainstem of Illinois Gulch and Fredonia Gulch from their sources to their confluences with the Blue River. COUCBL12 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 2 Temperature °C CS-I CS-I Arsenic 340 --- Recreation P acute chronic Arsenic(T) --- 0.02-10 A Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
13. Mainstem of Tenmile Creek from the Climax Parshall Flume (39.447556, -106.157003) to a point immediately above the confluence of West Tenmile Creek and all tributaries and wetlands from the source of Tenmile Creek to a point immediately above the confluence with West Tenmile Creek, except for the specific listing in Segment 15. COUCBL13 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation P acute chronic Arsenic(T) --- 7.6 Qualifiers: D.O. (mg/L) --- 6.0 Cadmium TVS TVS Other: D.O. (spawning) --- 7.0 Chromium III TVS TVS pH 6.5 - 9.0 --- Chromium III(T) --- 100 *Any water quality based effluent limit shall not chlorophyll a (mg/m2) --- TVS Chromium VI TVS TVS cause or contribute to exceedances of water quality standards adopted to protect downstream uses. E. Coli (per 100 mL) --- 205 Copper TVS TVS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details. Inorganic (mg/L) Lead TVS TVS *Uranium(chronic) = See 33.5(3) for details. acute chronic Manganese TVS TVS Ammonia TVS TVS Mercury(T) --- 0.01 Boron --- 0.75 Molybdenum(T) --- --- Chloride --- --- Nickel TVS TVS Chlorine 0.019 0.011 Selenium TVS TVS Cyanide 0.005 --- Silver TVS TVS(tr)
14. Mainstem of Tenmile Creek, including all tributaries and wetlands, from a point immediately above the confluence with West Tenmile Creek to Dillon Reservoir, except for the specific listings in Segment 16.
COUCBL14 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the acute chronic Iron(T) --- 1000 facilities listed at 33.5(4).
*Uranium(acute) = See 33.5(3) for details. Ammonia TVS TVS Lead TVS TVS *Uranium(chronic) = See 33.5(3) for details. Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 530 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS* Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Blue River Basin 15. Mainstem of Clinton Creek from the source to the confluence with Tenmile Creek. COUCBL15 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Modification(s):
16. All tributaries to the Blue River, including all wetlands, within the Eagles Nest and Ptarmigan Peak Wilderness Areas. COUCBL16 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
17. Mainstem of the Blue River from the outlet of Dillon Reservoir to the confluence with the Colorado River. COUCBL17 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
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. COUCBL18 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Blue River Basin 19. All tributaries to the Blue River, including all wetlands, from the outlet of Green Mountain Reservoir to the confluence with the Colorado River, except for specific listings in Segment 20.
COUCBL19 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation N acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- --- Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
20. Mainstems of Elliot Creek and Spruce Creek, including all tributaries and wetlands, from their sources to the confluence with the Blue River. COUCBL20 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation N acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- --- Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
21. All lakes and reservoirs tributary to the Blue River within the Eagles Nest and Ptarmigan Peak Wilderness Areas. COUCBL21 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C CL,CLL CL,CLL Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (ug/L) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
22. Dillon Reservoir and all lakes and reservoirs tributary to the Blue River above Dillon Reservoir, except for specific listings in Segment 21. COUCBL22 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CL,CLL CL,CLL Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS DUWS* D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Qualifiers: pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (ug/L) --- DUWS Chromium III(T) 50 --- Temporary Modification(s): chlorophyll a (ug/L) --- TVS Chromium VI TVS TVS Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Copper TVS TVS Expiration Date of 12/31/2029 Inorganic (mg/L) Iron --- WS *Classification: DUWS applies to Goose Pasture acute chronic Iron(T) --- 1000 Tarn. Ammonia TVS TVS Lead TVS TVS *Nitrogen(chronic) = applies only above the facilities listed at 33.5(4). Boron --- 0.75 Lead(T) 50 --- *Phosphorus(chronic) = 0.0074 mg/l for Dillon Chloride --- 250 Manganese TVS TVS/WS Reservoir in the top 15 meters of the water column for the months of July, August, September & Chlorine 0.019 0.011 Mercury(T) --- 0.01 O st c a t n o d b a e r r d .
s A a d d d o it p io t n ed a l f t o o r t a th l i p s h s o e s g p m ho e r n u t s d o o r n C o h t l a a p ply to Cyanide 0.005 --- Molybdenum(T) --- 150 Dillon Reservoir. Nitrate 10 --- Nickel TVS TVS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). Nitrite --- 0.05 Nickel(T) --- 100 *Uranium(acute) = See 33.5(3) for details. Nitrogen --- TVS* Selenium TVS TVS *Uranium(chronic) = See 33.5(3) for details. Phosphorus --- 0.0074* Silver TVS TVS(tr) Phosphorus --- TVS* Uranium varies* varies* Sulfate --- WS Zinc TVS TVS Sulfide --- 0.002 All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Blue River Basin 23. All lakes and reservoirs tributary to the Blue River below Dillon Reservoir, except for specific listings in Segment 21. COUCBL23 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C varies* varies* Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (ug/L) --- TVS Chromium III(T) 50 --- Temporary Modification(s):
1. All tributaries to the Eagle River, including all wetlands, within the Gore Range - Eagles Nest and Holy Cross Wilderness Areas. Mainstem of East Brush Creek from the source to 39.498914, -106.671722. All tributaries to East Brush Creek, including wetlands, excluding the following: tributaries and wetlands within Sylvan Lake State Park, the portion of Hat Creek below 39.511013, -106.688716, the portion of Nolan Creek below 39.525486, -106.686495, and the portion of the unnamed tributary below 39.512799, -106.680681; these excluded portions remain in Segment 10a. Mainstem of West Brush Creek from the source to the Sylvan Lake State Park boundary (39.469516, -106.729231). All tributaries to West Brush Creek, including wetlands, which are not within Sylvan Lake State Park. COUCEA01 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW* Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- * s D ec e t s io ig n n a tio -8 n - :
C o n C s .
2. Mainstem of the Eagle River from the source to above the compressor house bridge at Belden (39.526879, -106.394950). COUCEA02 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Eagle River Basin 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.
COUCEA03 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
4. Mainstem of Homestake Creek from the confluence of the East Fork to the confluence with the Eagle River. COUCEA04 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Modification(s):
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Eagle River Basin 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).
COUCEA05A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable* Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS SSE* Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Modification(s):
*Copper(acute) = 0.96*e^0.9801[ln(hardness)] – Chloride --- 250 Lead(T) 50 ---
1.1073
0.0053 Cyanide 0.005 --- Mercury(T) --- 0.01
*Uranium(acute) = See 33.5(3) for details.
COUCEA05B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable* Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS SSE* Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper --- SSE* Inorganic (mg/L) Copper SSE* --- *Designation: 9/30/00 Baseline does not apply *Cadmium(chronic) = (1.101672- acute chronic Iron --- WS [ln(hardness)*(0.041838)])* e^(0.7998 [ln Ammonia TVS TVS Iron(T) --- 1000 (hardness)]-3.1725)
*Copper(acute) = 0.96*e^0.9801[ln(hardness)]- Boron --- 0.75 Lead TVS TVS
1.5865 Chloride --- 250 Lead(T) 50 ---
*Copper(chronic) = 0.96*e^0.5897[ln(hardness)]-
0.4845 Chlorine 0.019 0.011 Manganese TVS TVS/WS
*Uranium(acute) = See 33.5(3) for details. Cyanide 0.005 --- Mercury(T) --- 0.01 *Uranium(chronic) = See 33.5(3) for details.
.
* * e e ^ ^ .
.
[ [ l l n n ( ( h h a a r r d d n n e e s s s s )
12/31 Uranium varies* varies* Zinc --- SSE* Zinc SSE* --- All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Eagle River Basin 5c. Mainstem of the Eagle River from a point immediately above Martin Creek to a point immediately above the confluence with Gore Creek. COUCEA05C Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable* Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS SSE* Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper --- SSE* Inorganic (mg/L) Copper SSE* --- *Designation: 9/30/00 Baseline does not apply *Cadmium(chronic) = (1.101672- acute chronic Iron --- WS [ln(hardness)*(0.041838)])* e^(0.7998 [ln Ammonia TVS TVS Iron(T) --- 1000 (hardness)]-3.1725)
*Copper(acute) = 0.96*e^0.9801[ln(hardness)]- Boron --- 0.75 Lead TVS TVS
1.5865 Chloride --- 250 Lead(T) 50 ---
*Copper(chronic) = 0.96*e^0.5897[ln(hardness)]-
0.4845 Chlorine 0.019 0.011 Manganese TVS TVS/WS
*Uranium(acute) = See 33.5(3) for details. Cyanide 0.005 --- Mercury(T) --- 0.01 *Uranium(chronic) = See 33.5(3) for details.
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. COUCEA06 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Eagle River Basin 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. COUCEA07A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
7b. Mainstem of Cross Creek from below the Minturn Water Facility (39.565419, -106.417032) to the confluence with the Eagle River. COUCEA07B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable* Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS SSE* Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Designation: 9/30/00 Baseline does not apply
1.5865 acute chronic Iron --- WS
* C .4 o p p er(chronic) = 0.96*e^0.5897[ln(hardness)]- Ammonia TVS TVS Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details. Boron --- 0.75 Lead TVS TVS *Uranium(chronic) = See 33.5(3) for details. Chloride --- 250 Lead(T) 50 --- *Zinc(acute) = Chlorine 0.019 0.011 Manganese TVS TVS/WS 0.978*e^0.8537[ln(hardness)]+2.1302 from 1/1 - 4/30 0.978*e^0.8537[ln(hardness)]+1.4189 from 5/1 - Cyanide 0.005 --- Mercury(T) --- 0.01 *Z i / n c (chronic) = Nitrate 10 --- Molybdenum(T) --- 150 0.986*e^0.8537[ln(hardness)]+1.9593 from 1/1 - 4/30 Nitrite --- 0.05 Nickel TVS TVS 0.986*e^0.8537[ln(hardness)]+1.2481 from 5/1 - 12/31 Phosphorus --- TVS Nickel(T) --- 100 Sulfate --- WS Selenium TVS TVS Sulfide --- 0.002 Silver TVS TVS(tr)
8. Mainstem of Gore Creek from the confluence with Black Gore Creek to the confluence with the Eagle River. COUCEA08 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C varies* varies* Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
9a. Mainstem of the Eagle River from above Gore Creek to a point immediately below the confluence with Squaw Creek. COUCEA09A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C varies* varies* Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
*Temperature = Ammonia TVS TVS Lead TVS TVS DM=CS-I and MWAT=16 from 6/1-6/30 Boron --- 0.75 Lead(T) 50 --- DM=CS-I and MWAT=CS-I from 7/1-9/30 DM=CS-I and MWAT=12 from 10/1-10/15 Chloride --- 250 Manganese TVS TVS/WS DM=CS-I and MWAT=11 from 10/16-10/31 Chlorine 0.019 0.011 Mercury(T) --- 0.01 DM=CS-I and MWAT=CS-I from 11/1-5/31 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- --- Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
*Temperature = Ammonia TVS TVS Lead TVS TVS DM=15 and MWAT=12 from 4/1-5/31 Boron --- 0.75 Lead(T) 50 --- DM and MWAT=CS-II from 6/1-9/30 DM=15 and MWAT=12 from 10/1-10/15 Chloride --- 250 Manganese TVS TVS/WS DM=15 and MWAT=11 from 10/16-10/31 Chlorine 0.019 0.011 Mercury(T) --- 0.01 DM and MWAT=CS-II from 11/1-3/31 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- --- Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
acute chronic Iron(T) --- 1000 *Uranium(chronic) = See 33.5(3) for details.
Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS 10b. Abrams Creek, including all tributaries and wetlands, from the source to the eastern boundary of the United States Bureau of Land Management lands. COUCEA10B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details. E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS *Uranium(chronic) = See 33.5(3) for details.
Copper TVS TVS Inorganic (mg/L) Iron --- WS acute chronic Iron(T) --- 1000 Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Eagle River Basin
11. Mainstem of Alkali Creek (near Wolcott) from the source to the confluence with the Eagle River. Mainstem of Milk Creek from the source to the confluence with the Eagle River. COUCEA11 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 2 Temperature °C CS-I CS-I Arsenic 340 --- Recreation P acute chronic Arsenic(T) --- 7.6 Qualifiers: D.O. (mg/L) --- 6.0 Beryllium(T) --- 100 Fish Ingestion Standards Apply D.O. (spawning) --- 7.0 Cadmium TVS TVS Other: pH 6.5 - 9.0 --- Chromium III TVS TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) --- 100 *Uranium(acute) = See 33.5(3) for details.
12. Mainstem of Brush Creek, from the confluence of West Brush Creek and East Brush Creek to the confluence with the Eagle River. Mainstem of East Brush Creek from 39.498914, -106.671722 to the confluence with West Brush Creek. Mainstem of West Brush Creek from the Sylvan Lake State Park boundary (39.469516, -106.729231) to the confluence with East Brush Creek.
COUCEA12 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
13. All lakes and reservoirs tributary to the Eagle River within the Gore Range - Eagles Nest and Holy Cross Wilderness Areas. COUCEA13 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C CL,CLL CL,CLL Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (ug/L) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
14. All lakes and reservoirs tributary to the Eagle River except for specific listings in Segment 13. COUCEA14 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CL,CLL CL,CLL Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (ug/L) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
1. All tributaries to the Roaring Fork River, including all wetlands, within the Maroon Bells/Snowmass, Holy Cross, Raggeds, Collegiate Peaks and Hunter/Fryingpan Wilderness Areas. Avalanche Creek, including all tributaries and wetlands, from the Maroon Bells/Snowmass Wilderness boundary to the National Forest boundary (39.248331, -107.232393). Woody Creek, including all tributaries and wetlands, from the Hunter/Fryingpan Wilderness boundary to USFS Rd 103/Woody Creek Rd (39.244983, -106.751780). Hunter Creek, including all tributaries and wetlands, from the Hunter/Fryingpan Wilderness boundary to the National Forest boundary (39.205635, -106.798061). COUCRF01 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
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.
COUCRF02 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Roaring Fork River Basin 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.
COUCRF03A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
COUCRF03B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 2 Temperature °C CS-II CS-II Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02-10 A Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
Boron --- 0.75 Lead(T) 50 --- *Temperature = See 33.6(4) for temperature standards. Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS* Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS 3d. Mainstem of Cattle Creek, including all tributaries and wetlands, from the source to the most downstream White River National Forest boundary. COUCRF03D Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
Copper TVS TVS Inorganic (mg/L) Iron --- WS acute chronic Iron(T) --- 1000 Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Roaring Fork River Basin
4. Mainstem of Brush Creek from the source to the confluence with the Roaring Fork River. COUCRF04 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
5. Mainstem of the Fryingpan River from the source to the confluence with the North Fork Fryingpan River, except for the portion included in Segment 1. COUCRF05 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Modification(s):
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Roaring Fork River Basin 6. Mainstem of the Fryingpan River from the confluence with the North Fork Fryingpan River to the confluence with the Roaring Fork River. COUCRF06 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
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. COUCRF07 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Modification(s):
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Roaring Fork River Basin 8. Mainstem of the Crystal River, including all tributaries and wetlands, from the source to the confluence with the Roaring Fork River, except for the specific listings in Segments 1, 9, 10a and 10b.
COUCRF08 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
9. Mainstem of Coal Creek, including all tributaries and wetlands, from the source to the confluence with the Crystal River. COUCRF09 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS/TVS(sc)
10b. Mainstem of North Thompson Creek, including all tributaries and wetlands, from the source to the White River National Forest boundary (39.316522, -107.305749). Mainstem of Middle Thompson Creek, including all tributaries and wetlands, from the source to the confluence with Thompson Creek. COUCRF10B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Roaring Fork River Basin 11. All lakes and reservoirs tributary to the Roaring Fork River within the Maroon Bells/Snowmass, Holy Cross, Raggeds, Collegiate Peaks and Hunter/Fryingpan Wilderness Areas. COUCRF11 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C varies* varies* Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (ug/L) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
12. All lakes and reservoirs tributary to the Roaring Fork River, except for the specific listings in Segment 11. COUCRF12 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C varies* varies* B Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS DUWS* D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Qualifiers: pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (ug/L) --- DUWS Chromium III(T) 50 --- Temporary Modification(s): chlorophyll a (ug/L) --- TVS Chromium VI TVS TVS Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Copper TVS TVS Expiration Date of 12/31/2029 Inorganic (mg/L) Iron --- WS *Classification: DUWS applies to Leonard Thomas acute chronic Iron(T) --- 1000 Reservoir and Wildcat Reservoir. Ammonia TVS TVS Lead TVS TVS *Uranium(acute) = See 33.5(3) for details.
Copper TVS TVS Inorganic (mg/L) Iron --- WS acute chronic Iron(T) --- 1000 Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS
2. Mainstem of the Encampment River, including all tributaries and wetlands, from the source to the Colorado/Wyoming border, except for those tributaries included in Segment 1. COUCNP02 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation P acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
3. Mainstem of the North Platte River from the confluence of Grizzly Creek and Little Grizzly Creek to the Colorado/Wyoming border. COUCNP03 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Modification(s):
COUCNP04A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS 5a. Mainstem of the Michigan River from the source to a point immediately below the confluence with the North Fork Michigan River. COUCNP05A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
acute chronic Iron(T) --- 1000 *Uranium(chronic) = See 33.5(3) for details.
Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS North Platte River Basin 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. COUCNP05B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Arsenic 340 --- Recreation N acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- --- Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 630 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
Ammonia TVS TVS Lead TVS TVS *Uranium(chronic) = See 33.5(3) for details.
Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS* Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS
6. Mainstem of Pinkham Creek from the Routt National Forest boundary to the confluence with the North Platte River. COUCNP06 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation N acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- --- Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
COUCNP07A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 2 Temperature °C CS-I CS-I Arsenic 340 --- Recreation N acute chronic Arsenic(T) --- 7.6 Qualifiers: D.O. (mg/L) --- 6.0 Cadmium TVS TVS Fish Ingestion Standards Apply D.O. (spawning) --- 7.0 Chromium III TVS TVS Other: pH 6.5 - 9.0 --- Chromium III(T) --- 100 chlorophyll a (mg/m2) --- --- Chromium VI TVS TVS *Uranium(acute) = See 33.5(3) for details.
Iron(T) --- 1000 Inorganic (mg/L) Lead TVS TVS acute chronic Manganese TVS TVS Ammonia TVS TVS Mercury(T) --- 0.01 Boron --- 0.75 Molybdenum(T) --- 150 Chloride --- --- Nickel TVS TVS Chlorine 0.019 0.011 Selenium TVS TVS Cyanide 0.005 --- Silver TVS TVS(tr)
Nitrate 100 --- Uranium varies* varies* Nitrite --- 0.05 Zinc TVS TVS Phosphorus --- TVS Sulfate --- --- Sulfide --- 0.002 All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS North Platte River Basin 8.All lakes and reservoirs tributary to the North Platte and Encampment Rivers within the Mount Zirkel, Never Summer, and Platte River Wilderness Areas. COUCNP08 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C varies* varies* Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (ug/L) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
Copper TVS TVS *Temperature = DM and MWAT=CL,CLL from 1/1-3/31 Inorganic (mg/L) Iron --- WS Blue Lake, Lower Big Twin Lake, Katherine Lake acute chronic Iron(T) --- 1000 DM=CL and MWAT=16.6 from 4/1-12/31 Ammonia TVS TVS Lead TVS TVS All others Boron --- 0.75 Lead(T) 50 --- DM and MWAT=CL,CLL from 4/1-12/31 Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Nitrogen --- TVS Selenium TVS TVS Phosphorus --- TVS Silver TVS TVS(tr)
Sulfate --- WS Uranium varies* varies* Sulfide --- 0.002 Zinc TVS TVS 9.All lakes and reservoirs tributary to the North Platte and Encampment Rivers except for specific listings in Segment 8. COUCNP09 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C varies* varies* B Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (ug/L) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
Copper TVS TVS *Temperature = See 33.6(4) for temperature standards. Inorganic (mg/L) Iron --- WS acute chronic Iron(T) --- 1000 Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Nitrogen --- TVS Selenium TVS TVS Phosphorus --- TVS Silver TVS TVS(tr)
Sulfate --- WS Uranium varies* varies* Sulfide --- 0.002 Zinc TVS TVS All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Yampa River Basin
1. All tributaries to the Yampa River, including all wetlands, which are within the Mount Zirkel, Flat Tops and Sarvis Creek Wilderness Areas. Walton Creek, including all tributaries and wetlands, from the source to below the confluence with Beaver Creek. Soda Creek, including all tributaries and wetlands, from the source to the National Forest boundary (40.541953, -106.790266). North Fork Elk River, including all tributaries and wetlands, from the Mount Zirkel Wilderness boundary to above the confluence with Lost Dog Creek. Middle Fork Elk River, including all tributaries and wetlands, from the Mount Zirkel Wilderness boundary to the confluence with the North Fork Elk River. South Fork Elk River, including all tributaries and wetlands, from the Mount Zirkel Wilderness boundary to the confluence with the Elk River. COUCYA01 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
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. COUCYA02A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Yampa River Basin 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. COUCYA02B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C varies* varies* Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS temperature(MWAT) = current Inorganic (mg/L) Iron --- WS conditions* Expiration Date of 12/31/2027 acute chronic Iron(T) --- 1000 Ammonia TVS TVS Lead TVS TVS *Uranium(acute) = See 33.5(3) for details.
te /2 m p e rature = applies from 7/1-9/30.
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. COUCYA03 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Yampa River Basin 4. Mainstem of Little White Snake Creek from the source to the confluence with the Yampa River. COUCYA04 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 2 Temperature °C CS-II CS-II Arsenic 340 --- Recreation N acute chronic Arsenic(T) --- 0.02-10 A Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- --- Chromium III(T) 50 --- * fa P c h il o it s ie p s h o lis ru te s d (c a h t r o n i .
5. Mainstem of Chimney Creek and Phillips Creek, including all tributaries and wetlands, which are not on National Forest lands, from their sources to the confluence with the Yampa River.
COUCYA05 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Water Supply acute chronic Arsenic(T) --- 0.02 Recreation P D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 205 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
6. Mainstem of Oak Creek, including all tributaries and wetlands, from the source to a point 0.25 mile below County Road 27 (40.279241, -106.965405). COUCYA06 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
7. Mainstem of Oak Creek, including all tributaries and wetlands, from a point 0.25 mile below County Road 27 (40.279241, -106.965405) to the confluence with the Yampa River. COUCYA07 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Arsenic 340 --- Recreation P acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 205 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Discharger Specific Variance(s): Inorganic (mg/L) Iron --- WS Nitrate(acute) = See Section 33.6(6) acute chronic Iron(T) --- 1000 f o o f r O d a e k ta C ils re o e n k .
the variance for the Town Ammonia TVS TVS Lead TVS TVS Expiration Date of 6/30/2026 Boron --- 0.75 Lead(T) 50 --- *Phosphorus(chronic) = applies only above the Chloride --- 250 Manganese TVS TVS/WS facilities listed at 33.5(4).
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. COUCYA08 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Phosphorus(chronic) = applies only above the facilities listed at 33.5(4). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details.
9. Deleted.
COUCYA09 Classifications Physical and Biological Metals (ug/L) Designation DM MWAT acute chronic Qualifiers: acute chronic Other:
10. Deleted.
COUCYA10 Classifications Physical and Biological Metals (ug/L) Designation DM MWAT acute chronic Qualifiers: acute chronic Other:
11. Fish Creek, including all tributaries and wetlands, from the source to County Road 27 (40.355559, -107.105131), except for specific listings in Segment 20a. COUCYA11 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Water Supply acute chronic Arsenic(T) --- 0.02 Recreation N D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- --- Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 630 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Yampa River Basin 12. All tributaries to the Yampa River, including all wetlands, from above the confluence with the Elk River to above the confluence with Elkhead Creek, except for specific listings in Segments 8, 11, 13a-13j and 20a.
COUCYA12 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 2 Temperature °C CS-II CS-II Arsenic 340 --- Recreation N acute chronic Arsenic(T) --- 100 Qualifiers: D.O. (mg/L) --- 6.0 Cadmium TVS TVS Other: D.O. (spawning) --- 7.0 Chromium III TVS TVS pH 6.5 - 9.0 --- Chromium III(T) --- 100 *Uranium(acute) = See 33.5(3) for details. chlorophyll a (mg/m2) --- --- Chromium VI TVS TVS *Uranium(chronic) = See 33.5(3) for details.
COUCYA13A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Yampa River Basin 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. COUCYA13B Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Warm 1 Temperature °C varies* varies* Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 7.6 Qualifiers: D.O. (mg/L) --- 6.0 Cadmium TVS TVS Other: D.O. (spawning) --- 7.0 Chromium III TVS TVS pH 6.5 - 9.0 --- Chromium III(T) --- 100 *Iron(T)(chronic) = See section 33.6(4) for standards chlorophyll a (mg/m2) --- TVS Chromium VI TVS TVS and assessment locations for Foidel Creek and Middle Creek. E. Coli (per 100 mL) --- 126 Copper TVS TVS *Uranium(acute) = See 33.5(3) for details.
COUCYA13C Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS Temporary Modification(s): chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Expiration Date of 12/31/2029 Copper TVS TVS Inorganic (mg/L) Iron --- WS *Uranium(acute) = See 33.5(3) for details.
*Uranium(acute) = See 33.5(3) for details. Inorganic (mg/L) Copper TVS TVS *Uranium(chronic) = See 33.5(3) for details. acute chronic Iron(T) --- varies* Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Manganese TVS TVS Chloride --- --- Mercury(T) --- 0.01 Chlorine 0.019 0.011 Molybdenum(T) --- 150 Cyanide 0.005 --- Nickel TVS TVS Nitrate 100 --- Selenium TVS TVS Nitrite --- 0.05 Silver TVS TVS Phosphorus --- TVS Uranium varies* varies* Sulfate --- --- Zinc TVS TVS Sulfide --- 0.002 13e. Mainstem of Sage Creek, including all tributaries and wetlands, from the source to the confluence with the Yampa River. COUCYA13E Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic UP Aq Life Warm 2 Temperature °C WS-II WS-II Arsenic 340 --- Water Supply acute chronic Arsenic(T) --- 0.02-10 A Recreation N D.O. (mg/L) --- 5.0 Cadmium TVS TVS Qualifiers: pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Other: chlorophyll a (mg/m2) --- --- Chromium III --- TVS
*Temperature = Ammonia TVS TVS Lead TVS TVS See 33.6(4) for temperature standards. Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Inorganic (mg/L) Copper TVS TVS acute chronic Iron(T) --- 1000 Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Manganese TVS TVS Chloride --- --- Mercury(T) --- 0.01 Chlorine 0.019 0.011 Molybdenum(T) --- 150 Cyanide 0.005 --- Nickel TVS TVS Nitrate 100 --- Selenium TVS TVS Nitrite --- 0.05 Silver TVS TVS Phosphorus --- TVS Uranium varies* varies* Sulfate --- --- Zinc TVS TVS Sulfide --- 0.002 13i. Mainstem of Grassy Creek, including all tributaries and wetlands, from the source to immediately above the confluence with Scotchmans Gulch. COUCYA13I Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic UP Aq Life Warm 2 Temperature °C WS-II WS-II Arsenic 340 --- Recreation N acute chronic Arsenic(T) --- 100 Qualifiers: D.O. (mg/L) --- 5.0 Cadmium TVS TVS Other: pH 6.5 - 9.0 --- Chromium III TVS TVS chlorophyll a (mg/m2) --- --- Chromium III(T) --- 100 Temporary Modification(s):
Selenium(chronic) = current E. Coli (per 100 mL) --- 630 Chromium VI TVS TVS conditions* Inorganic (mg/L) Copper TVS TVS Expiration Date of 12/31/2023 acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details. Ammonia TVS TVS Lead TVS TVS *Uranium(chronic) = See 33.5(3) for details. Boron --- 0.75 Manganese TVS TVS *TempMod: Selenium = Adopted 6/9/2014 Chloride --- --- Mercury(T) --- 0.01 Chlorine 0.019 0.011 Molybdenum(T) --- 150 Cyanide 0.005 --- Nickel TVS TVS Nitrate 100 --- Selenium TVS TVS Nitrite --- 0.05 Silver TVS TVS Phosphorus --- TVS Uranium varies* varies* Sulfate --- --- Zinc TVS TVS Sulfide --- 0.002 All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Yampa River Basin 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. COUCYA13J Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic UP Aq Life Warm 2 Temperature °C WS-II WS-II Arsenic 340 --- Recreation N acute chronic Arsenic(T) --- 100 Qualifiers: D.O. (mg/L) --- 5.0 Cadmium TVS TVS Other: pH 6.5 - 9.0 --- Chromium III TVS TVS chlorophyll a (mg/m2) --- --- Chromium III(T) --- 100 Temporary Modification(s):
Selenium(chronic) = current E. Coli (per 100 mL) --- 630 Chromium VI TVS TVS conditions* Inorganic (mg/L) Copper TVS TVS Expiration Date of 12/31/2023 acute chronic Iron(T) --- 1000 *Uranium(acute) = See 33.5(3) for details. Ammonia TVS TVS Lead TVS TVS *Uranium(chronic) = See 33.5(3) for details. Boron --- 0.75 Manganese TVS TVS *TempMod: Selenium = Adopted 12/11/2017 Chloride --- --- Mercury(T) --- 0.01 Chlorine 0.019 0.011 Molybdenum(T) --- 150 Cyanide 0.005 --- Nickel TVS TVS Nitrate 100 --- Selenium TVS TVS Nitrite --- 0.05 Silver TVS TVS Phosphorus --- TVS Uranium varies* varies* Sulfate --- --- Zinc TVS TVS Sulfide --- 0.002 14. Mainstem of Elkhead Creek, including all tributaries and wetlands, from the boundary of the National Forest lands, to a point immediately below the confluence with Calf Creek. Dry Fork Elkhead Creek, including all tributaries and wetlands, from the source to a point immediately below 80A Road (40.612676, -107.228533), which are not on National Forest lands.
COUCYA14 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
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. COUCYA15 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Warm 1 Temperature °C WS-II WS-II Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 5.0 Cadmium TVS TVS Qualifiers: pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Other: chlorophyll a (mg/m2) --- TVS Chromium III --- TVS
16. Deleted.
COUCYA16 Classifications Physical and Biological Metals (ug/L) Designation DM MWAT acute chronic Qualifiers: acute chronic Other:
17. Deleted.
COUCYA17 Classifications Physical and Biological Metals (ug/L) Designation DM MWAT acute chronic Qualifiers: acute chronic Other:
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. COUCYA18 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Modification(s):
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Yampa River Basin 19a. All tributaries to the South Fork Little Snake River, including all wetlands, which are on National Forest lands in Routt County. COUCYA19A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Modification(s):
19b. Middle Fork Little Snake River, including all tributaries and wetlands, which are on National Forest lands in Routt County. COUCYA19b Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Modification(s):
*Uranium(chronic) = See 33.5(3) for details. Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Yampa River Basin 20a. All tributaries to the Yampa River, including all wetlands, from above the confluence with the Elk River to below the confluence with Elkhead Creek, which are on National Forest lands, except for specific listings in Segment 20b and 20c. COUCYA20A Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
Copper TVS TVS Inorganic (mg/L) Iron --- WS acute chronic Iron(T) --- 1000 Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS 20c. First Creek, including all tributaries and wetlands, from the source to the eastern boundary of state lands in California Park (40.731309, -107.141684). Elkhead Creek, including all tributaries and wetlands, from the source to the eastern boundary of state lands in California Park (40.743796, -107.141684). COUCYA20C Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (ug/L) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
Copper TVS TVS Inorganic (mg/L) Iron --- WS acute chronic Iron(T) --- 1000 Ammonia TVS TVS Lead TVS TVS Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Cyanide 0.005 --- Molybdenum(T) --- 150 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS/TVS(sc)
All metals are dissolved unless otherwise noted. D.O. = dissolved oxygen T = total recoverable DM = daily maximum t = total MWAT = maximum weekly average temperature tr = trout See 33.6 for further details on applied standards. sc = sculpin CODE OF COLORADO REGULATIONS 5 CCR 1002-33 REGULATION #33 STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS Yampa River Basin 21. All lakes and reservoirs tributary to the Yampa River within the Mount Zirkel, Flat Tops and Sarvis Creek Wilderness Areas, except for those lakes and reservoirs included in Lower Yampa River Segment 28.
COUCYA21 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic OW Aq Life Cold 1 Temperature °C CL,CLL CL,CLL Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (ug/L) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
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.
COUCYA22 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Cold 1 Temperature °C varies* varies* B Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS DUWS* D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Qualifiers: pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (ug/L) --- DUWS Chromium III(T) 50 --- chlorophyll a (ug/L) --- TVS Chromium VI TVS TVS Temporary Modification(s):
*Nitrogen(chronic) = applies only above the facilities Chloride --- 250 Manganese TVS TVS/WS listed at 33.5(4).
23. Elkhead Reservoir COUCYA23 Classifications Physical and Biological Metals (ug/L) Designation Agriculture DM MWAT acute chronic Reviewable Aq Life Warm 1 Temperature °C WL WL Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Other: pH 6.5 - 9.0 --- Chromium III --- TVS chlorophyll a (ug/L) --- TVS Chromium III(T) 50 --- *Uranium(acute) = See 33.5(3) for details.
(A) Whenever a range of standards is listed and referenced to this footnote, the first number in the range is a strictly health-based value, based on the Commission’s established methodology for human health-based standards. The second number in the range is a maximum contaminant level, established under the federal Safe Drinking Water Act that has been determined to be an acceptable level of this chemical in public water supplies, taking treatability and laboratory detection limits into account. Control requirements, such as discharge permit effluent limitations, shall be established using the first number in the range as the ambient water quality target, provided that no effluent limitation shall require an “end-of-pipe” discharge level more restrictive than the second number in the range. Water bodies will be considered in attainment of this standard, and not included on the Section 303(d) List, so long as the existing ambient quality does not exceed the second number in the range.
(B) Assessment of adequate refuge shall rely on the Cold Large Lake table value temperature criterion and applicable dissolved oxygen standard rather than the site-specific temperature standard.
________________________________________________________________________ Editor’s Notes History Entire rule eff. 07/01/2007.
Rules 33.6, 33.42 eff. 09/01/2007.
Rules 33.6, 33.43 eff. 03/01/2008.
Rules 33.3, 33.5, 33.6, 33.44 eff. 01/01/2009.
Rules 33.6 (Tables 1-18), 33.45 eff. 06/30/2010.
Rules 33.6 (Tables 1-18), 33.46 eff. 11/30/2010.
Entire rule eff. 06/30/2011.
Rules 33.6 (Table pg. 17), 33.48 eff. 01/01/2012.
Rules 33.6 (Table pg. 17), 33.49 eff. 06/30/2013.
Rules 33.6(2)(d), 33.6 (Tables pgs. 1-2, 4-6, 8-13, 15-17), 33.50 eff. 09/30/2013. Rules 33.6 Basin Eagle River segments 8-9a, 33.51 eff. 06/30/2014. Rules 33.5-33.6, 33.52 eff. 12/31/2014.
Rules 33.6 Basin Yampa River segment 13i, 33.53 eff. 06/30/2015. Rules 33.5, 33.6, 33.54, Appendix 33-1 eff. 03/01/2016. Rules 33.55, 33.56, Appendix 33-1 eff. 06/30/2016.
Rules 33.57, Appendix 33-1 eff. 06/30/2017.
Rules 33.58, Appendix 33-1 eff. 09/30/2017.
Rules 33.6(4), Appendix 33-1, 33.59, 33.60 eff. 06/30/2018. Rules 33.61, Appendix 33-1 eff. 06/30/2019.
Rules 33.2, 33.3, 33.5, 33.6, 33.62, Appendix 33-1 eff. 12/31/2019. Rules 33.6, 33.63, 33.64, Appendix 33-1 eff. 06/30/2020. Rules 33.6(6), 33.65, 33.66, Appendix 33-1 eff. 06/30/2021. Rules 33.5-33.6, 33.67, Appendix 33-1 eff. 12/31/2021.
Rules 33.68, Appendix 33-1 eff. 09/30/2022.
Rules 33.5(4), 33.6(3), 33.6(5), 33.69, Appendix 33-1 eff. 06/14/2023. Rules 33.70, Appendix 33-1 eff. 12/31/2023.
Rules 33.5(2),(4), 33.6(2)(a)(c), 33.6(4),(6), 33.71, 33.72, Appendix 33-1 eff. 12/31/2024. Rules 33.6(4)(l)-(n), 33.6(6)(a), 33.73, Appendix 33-1 eff. 12/31/2025.