5 CCR 1002-34
DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT REGULATION NO. 34 - CLASSIFICATIONS AND NUMERIC STANDARDS FOR SAN JUAN RIVER AND DOLORES RIVER BASINS 5 CCR 1002-34 [Editor's Notes follow the text of the rules at the end of this CCR Document.] _________________________________________________________________________
34.1 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.
34.2 PURPOSE
These regulations establish classifications and numeric standards for the San Juan and the Dolores River Basins, including all tributaries and standing bodies of water south of the northern Dolores County lines, as indicated in section 34.6. 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.
34.3 INTRODUCTION
These regulations and tables present the classifications and numeric standards assigned to stream segments listed in the attached tables (See Appendix 34-1). 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 34-1. 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 regulations”.
34.4 DEFINITIONS
See the Colorado Water Quality Control Act and the codified water quality regulations for definitions.
34.5 BASIC STANDARDS
(1) Temperature All waters of the San Juan/Dolores River Basin 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) Indian Reservations Some of the waterbodies in the San Juan/Dolores River Basin cross boundaries of Indian Reservations of the Southern Ute and Ute Mountain Ute Tribes. The Commission has included water quality classifications and standards on lands within the boundaries of these reservations in order to avoid a gap in the classifications and standards adopted for the river basins in question. EPA has granted the Southern Ute and Ute Mountain Ute Indian tribes’ applications for treatment as a state with respect to adoption of water quality standards. The Commission intends that the classifications and standards that it is adopting apply to the lands in question only to the extent that the state has jurisdiction and is not attempting to resolve that jurisdictional issue here. Segments within Reservation boundaries are noted in the segment description and Appendix 34- 1 tables.
(5) 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.
COSJLP07a Vista Verde Village LLC Vista Verde Village CO0037702 COSJLP08 Elegant Hills Park and Estates LLC Lakeside WWTF COG589098 COSJLP09 Lee Mobile Home Park Lee Mobile Home Park COG589070 COSJLP10 Dove Creek Town of Dove Creek WWTF COG589079 COSJDO04a Fort Beyhan LLC Dolores River RV Park and Cabins COG588071 COSJDO04a Dolores Town of Dolores WWTF CO0040509 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 34.5(5). • 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)).
34.6 TABLES
(1) Introduction The numeric standards for various parameters in this regulation and in the tables in Appendix 34 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 34-1, 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 34-1, 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)
Aluminum(T) Acute = e(1.3695*ln(hardness)+1.8308)
Chromium III(7) Acute = e(0.819*ln(hardness)+2.5736)
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 Silver Acute = 0.5*e(1.72*ln(hardness)-6.52)
Temperature TEMPERATURE STANDARD (°C)
Chronic = e(1.1021*ln(hardness)+2.2382)
Zinc Acute = 0.978*e(0.9094*ln(hardness)+0.9095)
TABLE VALUE STANDARDS - FOOTNOTES (1) Metals are stated as dissolved unless otherwise specified. Nitrogen and phosphorus standards are based upon the concentration of total nitrogen and total phosphorus.
(4) Discharger-specific Variances
Includes a Pollutant Minimization Program (see 34.58(B)). Expiration Date: 12/31/2029.
Discharger-specific Variance, Vista Verde Village, LLC (CO0037702), Adopted 12/14/2020.
Ammonia (acute/chronic): AEL=14 mg/L (5/1-10/31);
Ammonia (acute/chronic): AEL=24 mg/L (11/1-4/30).
Expiration date: 6/30/2031. Effluent concentrations shall not exceed the current condition.
Discharger-specific Variance, Town of Dove Creek (COG589079), Adopted 6/11/2024. Ammonia (acute/chronic): 11/1 – 4/30 Initial AEL=35 mg/L, Final AEL=15 mg/L;
Ammonia (acute/chronic): 5/1 – 10/31 Initial AEL=20 mg/L, Final AEL=10 mg/L.
Includes a Pollutant Minimization Program (see 34.58(B)). Expiration date: 6/30/2029.
(5) Stream Classifications and Water Quality Standards Tables The stream classifications and water quality standards tables in Appendix 34-1 are incorporated herein by reference.
(6) Site-specific Standards, Assessment Locations, and Assessment Criteria The following criteria and/or locations shall be used when assessing whether a specified waterbody is in attainment of the specified standard.
34.7 – 34.14 RESERVED
34.15 STATEMENT OF BASIS AND PURPOSE
I. Introduction These stream classifications and water quality standards for State Waters of the San Juan River Basin including all tributaries and standing bodies of water and the Dolores River Basin including all tributaries and standing bodies of water south of the northern Dolores County line in all or parts of Archuleta, Conejos, Dolores, Hinsdale, La Plata, Mineral, Montezuma, Rio Grande and San Juan Counties implement requirements of the Colorado Water Quality Control Act C.R.S. 1973, 25-8-101 et seq. (Cum. Supp. 1981). They also represent the implementation 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 Regulations) 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, the statement of basis and purpose (Section 3.1.16) of those regulations must be referred to for a complete understanding of the basis and purpose of the regulations adopted herein. Therefore, Section 3.1.16 of the Basic Regulations is incorporated by reference. The focus of this statement of basis and purpose is on the scientific and technological rationale for the specific classifications and standards in the San Juan River Basin. Public participation was a significant factor in the development of these regulations. A lengthy record was built through public hearings held on May 14, 1981. A total of 10 entities requested and were granted party status by the Commission in accordance with C.R.S. 1973, 24-4-101 et seq. (Cum. Supp. 1980). A supplementary public rulemaking hearing was held September 15, 1981, restricted to those issues raised by the changes in the Act contained in Senate Bill 10 (1981). Such issues included but were not limited to: “The economic reasonableness” evaluation required by 25-8-102(5), the effect on water rights as required by 25-8-104; and the new considerations for the adoption of water quality standards required by 25-8-204 C.R.S. 1973, as amended. The record established in these hearings forms the basis for the classifications and standards adopted.
II. General Considerations 1. These regulations are not adopted as control regulations. Stream classifications and water quality standards are specifically distinguished from control regulations in the Water Quality Control Act, and they need not be adopted as control regulations pursuant to the statutory scheme.
2. The Commission has been requested in public hearings to rule on the applicability of these and other regulations to the operation of water diversion facilities, dams, transport systems, and the consequent withdrawal, impoundment, non-release and release of water for the exercise of water rights. The Commission has determined that any such broad ruling is inappropriate in the context of the present regulations. The request does not raise specific questions as to proposed classifications and standards. However, the Commission has taken into account the fact that some issues are unresolved in adopting classifications and standards. On January 5, 1981, the Commission adopted a policy statement on quality/quantity issues that addresses a number of these concerns. Finally, the Commission has adopted these regulations in compliance with the requirements of the Water Quality Control Act that have bearing on these issues (See e.g.) sections 102, 104, and 503(5).
III. Definition of Stream Segments 1. For purposes of adopting classifications and water quality standards, the streams and water bodies are identified according to river basin and specific water segments.
2. Within each river basin, specific water segments are defined, for which use classifications and numeric water quality standards, if appropriate, are adopted. These segments may constitute a specific stretch of a river mainstem, a specific tributary, a specific lake or reservoir, or a generally defined grouping of waters within the basin (e.g., a specific mainstem segment and all tributaries flowing into that mainstem segment).
3. Segments are generally defined according to the points at which the use, water quality, or other stream characteristics change significantly enough to require a change in use classifications and/or water quality standards. In many cases, such transition points can be specifically identified from available data. In other cases the delineation of segments is based upon best judgments of the points where instream changes in uses, water quality, or other stream characteristics occur.
IV. Use Classifications — Generally 1. Initially, recommendations for stream segmentation and use classifications are a result of input from 208 plans, water quality data and reports, the Division of Wildlife, and personal knowledge. After a basic outline of stream segments and use classifications was prepared, water quality data from a variety of sources was compared against the “table value” for the proposed use. “Table value” refers to the four tables attached to the “Basic Regulations”. In general, if the mean plus one standard deviation (x̄ + s) of the available data for the segment indicated that a particular parameter did not exceed the “table value” for that recommended use, the “table value” was listed as the recommended standards for the parameter. If the x̄ + s value was recommended as that standard for that parameter.
2. The use classifications have been established in accordance with the provisions of Section 203 of the Water Quality Control Act and Section 3.1.6 and 3.1.13 of the Basic Regulations.
3. In all cases the basic regulation has been followed, in that an upstream use cannot threaten or degrade a downstream use. Accordingly, upstream segments of a stream are generally the same as, or higher in classification than, downstream segments. In a few cases, tributaries are classified at lower classifications than mainstems, where flow from tributaries does not threaten the quality of mainstem waters and where the evidence indicates that lower classification for the tributaries is appropriate.
4. There have been no “High Quality Class 1”designations assigned in this basin.
5. The Commission has determined that it has the authority to assign the classification “High Quality Waters - Class 1”and “High Quality Waters - Class 2”where the evidence indicates that the requirements of Sections 3.1.13(1)(e) of the basic regulations are met. The appropriateness of this classification has been determined on a case-by-case basis. Streams have in some cases been classified “High Quality - Class 2”for one or more of the following reasons:
6. In accordance with 25-8-104, C.R.S. 1973, the Commission intends that no provision of this regulation shall be interpreted so as to supercede, abrogate, or impair rights to divert water and apply water to beneficial uses.
7. Qualifiers — Seasonal and Intermittent These qualifiers have been used to more fully describe characteristics of certain stream segments.
8. Recreation — Class 1 and Class 2 In addition to the significant distinction between Recreation - Class 1 and Recreation - Class 2 as defined in Section 3.1.13(1) of the Basic Regulations, the difference between the two classifications in terms of water quality standards is the fecal coliform parameter. Recreation - Class 1 generally has a standard of 200 fecal coliform per 100 ml; Recreation - Class 2 generally has a standard of 2000 fecal coliform per 100 ml.
9. Water Supply Classification The Commission finds that Colorado is a water short state and that it is experiencing considerable growth which places additional burdens on already scare water supplies. These considerations mitigate in favor of a conservation approach to protecting future water supplies. Where existing water quality is adequate to protect this use, and in the absence of dischargers to these segments or testimony in opposition to such classification, the water supply use has been assigned because it is reasonable to expect that it may exist in the future in such cases. For stream segments that flow through, or in the vicinity of, municipalities, this conclusion is further justified, since there is a reasonable probability that the use exists or will exist. Where the water supply classification has been opposed, the Commission has evaluated the evidence on a site specific basis, and in many cases the classification has been removed.
V. Water Quality Standards — Generally 1. The water quality standards for classified stream segments are defined as numeric values for specific water quality parameters. These numeric standards are adopted as the limits for chemical constituents and other parameters necessary to protect adequately the classified uses in all stream segments.
2. Not all of the parameters listed in the “Tables”appended to the Basic Regulations are assigned as water quality standards. This complies with Section 3.1.7(c) of the Basic Regulations. Numeric standards have been assigned for the full range of parameters to a number of segments where little or not data existed specific to the segment. In these cases, there was reason to believe that the classified uses were in place or could be reasonably expected, and that the ambient water quality was as good as or better than the numeric standards assigned.
3. A numeric standard for the temperature parameter has been adopted as a basic standard applicable to all waters of the region in the same manner as the basic standards in Section 3.1.11 of the Basic Regulations.
4. Numeric standards for seventeen organic parameters have been adopted as basic standards applicable to all waters of the region in the same manner as the basic standards in Section 3.1.11 of the Basic Regulations. These standards are essential to a program designed to protect the waters of the State regardless of specific use classifications because they describe the fundamental conditions that all waters must meet to be suitable for any use. It is the decision of the Commission to adopt these standards as basic standards because the presence of the organic parameters is not generally suspected. Also, the values assigned for these standards are not detectable using routine methodology and there is some concern regarding the potential for monitoring requirements if the standards are placed on specific streams. This concern should be alleviated by Section 3.1.14(5) of the Basic Regulations but there is uncertainty regarding the interpretation of those numbers by other entities. Regardless of these concerns, because these constituents are highly toxic, there is a need for regulating their presence in State waters. Because the Commission has determined that they have uniform applicability here, their inclusion as basic standards for the region accomplishes this purpose.
5. In many cases, the numeric water quality standards are taken from the “Tables”appended to the Basic Regulations. These table values are used where actual ambient water quality data in a segment indicates that the existing quality is substantially equivalent to, or better than, the corresponding table values. This has been done because the table values are adequate to protect the classified uses.
6. In many cases, instream ambient water quality provides the basis for the water quality standards (See 7 below). In those cases where the classified uses presently exist or have a reasonable potential to exist despite the fact that instream data reflects ambient conditions of lower water quality than the table values, instream values have been used. In these cases, the evidence indicates that instream values are adequate to protect the uses. In those cases where temporary modifications are appropriate, instream values are generally reflected in the temporary modification and table values are reflected in the corresponding water quality standard. (Goals are established for the appropriate classification affected by the parameter). Cases in which water quality standards reflect these instream values usually involve the metal parameters. On many stream segments elevated levels of metals are present due to natural or unknown causes, as well as mine seepage from inactive or abandoned mines. These sources are difficult to identify and impractical or impossible to control. The classified aquatic life uses may be impacted and/or may have adjusted to the conditions. In either case, the water quality standards are deemed sufficient to protect the uses that are present.
7. The Commission rejected the proposal to assign only “temporary” standards pending additional data collection to verify or modify values assigned. Concerned parties concurred that triennial review will lead to updating of standards as necessary. Furthermore, limited financial resources will be focused upon streams with permitted discharges.
8. In those cases where there was no data for a particular segment, or where the data consists of only a few samples for a limited range of parameters, “table values” were generally recommended. Data at the nearest downstream point was used to support this conclusion. In some cases, where the limited data indicated a problem existed, additional data was collected to expand the data base. Additionally, where there may not be existing data on present stream quality, the Commission anticipates that if necessary, additional data will be collected prior to a hearing required by C.R.S. 1973, 25-8-204(3), as amended.
9. In most cases in establishing standards based on instream ambient water quality, a calculation is made based upon the mean (average) plus one standard deviation (x̄ + s) for all sampling points on a particular stream segment. Since a standard deviation is not added to the water quality standard for purposes of determining the compliance with the standard, this is a fair method as applied to discharges.
10. No water quality standards are set below detectable limits for any parameter, although certain parameters may not be detectable at the limit of the standards using routine methodology. However, it must be noted that stream monitoring, as opposed to effluent monitoring, is generally not the responsibility of the dischargers but of the State. Furthermore, the purpose of the standards is to protect the classified uses and some inconvenience and expense as to monitoring is therefore justifiable.
11. The dissolved oxygen standard is intended to apply to the epilimnion and metalimnion strata of lakes and reservoirs. Respiration by aerobic micro-organisms as organic matter is consumed is the primary cause of a natural decrease in dissolved oxygen and anaerobic conditions in the hypolimnion. Therefore, this stratum is exempt from the dissolved oxygen standard.
12. Where numeric standards are established based on historic instream water quality data at the level of x̄ + s, it is recognized by the Commission that measured instream parameter levels might exceed the standard approximately 15 percent of the time.
13. It is the Commission's intention that the Division implement and enforce all water quality standards consistent with the manner in which they have been established.
14. Hardness/Alkalinity Where hardness and alkalinity numbers differed, the Commission elected to use alkalinity as the controlling parameter, in order to be consistent with other river basins and because testimony from the Division staff indicated that in most cases alkalinity has a greater effort on toxic form of metals than does hardness.
VI. Water Quality Standards for Unionized Ammonia On some Class 2 Warm Water Aquatic Life streams containing similar aquatic life communities to those found in the plains streams of the South Platte & Arkansas Basins, .1 mg/l ammonia was selected as being appropriate to protect such aquatic life.
These streams generally contain both lesser numbers and types of species than those inhabiting class 1 streams due to physical habitat characteristics, flow or irreversible water quality characteristics. The Commission felt that the incremental expense to meet a 0.06 mg/l unionized ammonia standard for present or potential dischargers along these streams cannot be justified. Low flow, in these segments is often intermittent or highly impacted by diversions.
Specifically, the Commission has relaxed unionized ammonia standards to .1 mg/l or greater on such streams for the following reasons:
1. limited nature of the aquatic life present;
2. limited recreational value of species present;
3. habitat limitations, primarily flow and streambed characteristics, that impose significant limitations on the nature of aquatic life, even if ammonia reductions were attained;
4. rapid dissipation of ammonia in streams, reducing the impact of such discharges downstream; and 5. economic costs of ammonia removal, especially where such costs would fall primarily on publicly- owned treatment works, and while the availability of construction grant funds is questionable.
6. Biosurveys with support from a bioassay conducted on fathead minnows performed in the Cache la Poudre River, show that a .1 mg/l standard is appropriate to protect existing biota in the stream. The results of these studies may be reasonably extrapolated to similar plains streams; i.e., those streams that demonstrate similar chemical, physical, and biological characteristics. Not all warmwater streams are comparable in terms of flow habitat, and types and numbers of species of aquatic life. Therefore, some variations in an appropriate ammonia standard must be tolerated, with the objective of protecting existing aquatic life. The Commission found this approach preferable to totally removing the aquatic life classification from impacted or marginal aquatic life streams.
VII. Water Quality Standards for Uranium Given the threat that radioactivity from uranium may pose to human health, it is advisable to limit uranium concentrations in streams to the maximum extent practicable. The Commission has adopted a standard of 40 pCi/l or natural background where higher, for the following reasons:
1. 40 pCi/l generally reflects background concentrations of uranium that may be found in streams in Colorado and therefore this amount approximates routine human exposure.
2. The statistical risk of human health hazards is small at 40 pCi/l.
3. 40 pCi/l is an interim level, established now pending the outcome of further studies currently underway.
VIII. Water Quality Standards for Cyanide The Commission acknowledges that total cyanide is to be used in State Discharge permits until a method is authorized by EPA for measuring free cyanide, even though free cyanide is the parameter of concern. While cyanide has received special treatment in cases discussed in the segment - by - segment section which follows, a free cyanide standard based on Table Values has been established for most segments.
IX. Linkage of classifications and Standards The Commission holds that the classifications which it adopts and the standards it assigns to them are linked. Disapproval by EPA of the standards may require reexamination by the Commission of the appropriateness of its original classification.
The reason for the linkage is that the Commission recognizes that there is a wide variability in the types of aquatic life in Colorado streams which require different levels of protection. Therefore, the numbers were chosen in some cases on a site specific basis to protect the species existing in that segment. If any reclassification is deemed a downgrading, then it will be based upon the grounds that the original classification was in error.
X. Economic Reasonableness The Commission finds that these use classifications and water quality standards are economically reasonable. The Commission solicited and considered evidence of the economic impacts of these regulations. This evaluation necessarily involved a case-by-case consideration of such impacts, and reference is made to the fiscal impact statement for this analysis. Generally, a judgment was made as to whether the benefits in terms of improving water quality justified the costs of increased treatment. In the absence of evidence on economic impacts for a specific segment, the Commission concluded that the regulations impose no unreasonable economic burden.
XI. Classifications and Standards - Special Cases 1. Page 1, Segment 2 - San Juan River in Archuleta County (proposed as page 1, segment 2) At issue was the recommendation contained in the Regional Water Quality Management “208”Plan that flow deficiencies and silt attributable to the San Juan - Chama diversion limited use of the segment to agriculture. Although both warm and cold water species, including trout, were observed in the segment, the Commission found from the evidence that there was perennial flow sufficient to support the aquatic life use proposed. In view of controversy in the testimony concerning flow, the Commission considered the recommendation in the “208 Plan, yet classified the aquatic life use as class 1, cold water because other testimony indicated that recorded stream flows were ample to support aquatic life.
2. Page 2, Segment 8 This segment was incorporated into segment 5 of page 1.
3. Page 2, Segment 10 The “208”Plan was relied on by the Commission and no other evidence on this segment was presented.
4. Page 3, Segment 3 - Piedra River The Commission retained the cold water aquatic life class 1 classification after finding that although one small portion of the segment may be intermittent, due to diversion, it quickly remakes itself and the intermittent portion is very small compared with the total length of the segment. The Commission also notes that it's decision will have no impact on any discharger.
5. Page 4, Segment 2(a) and 2(b) Los Pinos River (proposed as page 4, segment 2) The resegmentation recommended by the Division is consistent with segmentation described in the Regional (208) Plan.
6. Page 6, Segment 2 - Animas and Florida Rivers This is a large segment, exhibiting many water quality variables throughout its length. Although there is some evidence of insect life at points in the segment, the evidence regarding the presence of aquatic life is contradictory, and there is no evidence of fish life being present. In the absence of sufficient data to support the classification of any portion of this segment for aquatic life, the current status is being retained and no aquatic life, the current status is being retained and no aquatic life use is assigned. The Commission expects further information to be developed through studies sponsored by the Standard Metals Corporation and the Division. The Commission declined to assign an agricultural classification to the segment due to the absence in the record of any evidence of an agricultural use in the segment.
7. Page 6, Segment 6 Since Cement Creek and its tributaries are degraded by abandoned mine drainage and past discharges, the Commission did not assign aquatic and agricultural classifications to the segment as had been proposed. The segment does not currently have an aquatic life classifications, and thus the status quo is maintained. The Commission placed recreation in the class 2 category as the basic use and found no agricultural use to be in place.
8. Page 7, Segment 7 The Woodling Study indicates that Mineral Creek from its source to its confluence with South Mineral Creek is highly toxic due to mineralization and there is not a likelihood that the sources of that toxicity will be corrected in 20 years. However the Commission concluded that there was likely to be aquatic life in that portion of Mineral Creek from below South Fork to Silverton. By changing the stream segment description such that it covers the mainstem of Mineral Creek including all tributaries from the source to a point immediately above the confluence with South Mineral Creek, the Commission was enabled to preserve the aquatic life classification on South Mineral Creek and the remaining portion of Mineral Creek into Silverton.
9. Page 8, Segment 12(a) and 12(b) (proposed as page 6, segment 12) Lemon Reservoir was resegmented as 12(a) for the purposes of classifying it Recreation Class 1 in recognition of known use appropriate to that classification.
10. Page 8, Segment 13(a) and 13(b)
11. Page 8, Segment 15 Testimony was received by the Commission from the Purgatory Water and Sanitation District that the water supply classification was not applicable below the reservoir. The Commission concurred and determined that there should be no more than a class 2 aquatic life classification for this segment because of its intermittent flow and poor habitat characteristics. It was recommended that recreation class 2, agriculture and water supply be designated for the protection of the reach above the reservoir. Despite opposition to the water supply classification by Purgatory Water and Sanitation District based upon the absence of such use below Duncan Reservoir, the Commission finds that the presence of this use at other locations justifies the classification. This should not impact the District because the numeric standards for protection of the use are less stringent than those for protection of aquatic life and should be met by the discharger without additional treatment facilities.
12. Page 11, Segment 3 - Dolores River in Dolores County Even though the regional “208” Plan recommended that the segment be classified for a water supply use, the Commission received no testimony that there was such use in the segment. Because of high levels of manganese and the lack of evidence of in place water supply use, the Commission did not so classify the segment. Anaconda Corporation proposed numeric standards for silver and mercury. The Division recommended to the Commission that it not utilize the Anaconda proposals for those constituents because they were based on limited data, unusually high values, and questionable analytical techniques. It had not been documented that the levels of those constituents proposed by Anaconda had been routinely found in the stream. Due to this lack of certainty with respect to these metals values, the Commission did not choose to use the Anaconda data on mercury an silver.
34.16 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE:
The provisions of 25—8-202(1)(a)(b) and (2); and 25-8-204 C.R.S. provide the specific statutory authority for the numeric standards that were adopted.
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 - SAN JUAN AND DOLORES RIVER BASINS The basis and purpose for the changes by segment is as follows: Segment 6, Piedra River -This segment contains the lakes listed for inclusion in the proposed Segment 7. In order to separate these lakes from this segment, the description must be changed. Segment 7, Piedra River -The lakes listed are all fisheries and a majority of them are used for sport fishing. Their present inclusion in Segment 6 does not represent their actual use, i.e., Class 1 Aquatic Life, or provide standards to protect this use. The Commission has classified all reservoirs in Segment 7 as Warm Water Class 1 instead of Cold Water Class 1 on the basis that: 1) all reservoirs are already heavily managed, including aeration; 2) trout have been introduced into the reservoirs and do not occur naturally; and 3) at least temperature excursions above that require for cold water classification occur. The Commission notes that the data base supporting this change in classification to warm water Class 1 is not extensive and further water quality monitoring is encouraged. Segment 15, Animas River - Studies conducted by the Water Quality Control Division indicate that both Goulding Creek and Nary Draw are intermittent streams more appropriately classified under Segment 15 than under Segment 12a. The change in the description of Segment 15 will accomplish this and provide adequate protection of the uses.
Segment 8, La Plata River, Mancos- River, McElmo Creek, and San Juan River -The change in description to include Dolores County will include those streams which are unclassified under the existing description.
Change in basin description at top of pages 9 and 10 of the Tables -Change is needed to accurately reflect the streams included in this section with the change in description of Segment 8.
34.17 BASIS AND PURPOSE:
At the triennial review of the San Juan and Dolores River Basins in May, 1985, the Water Quality Control Division pointed out that the Division had recently (April, 1985) granted a variance to the limitation for cadmium in Anaconda Company's Rizo Mine discharge permit. The underlying stream concentration which was used to support the variance was 0.002 mg/l, and was based upon an x̄+ s calculation of fifteen cadmium data points above the St. Louis ponds discharge collected in 1981. The rationale for the variance anticipated the establishment of a revised cadmium standard through the established standards setting procedure of the Water Quality Control Commission, and noted that subsequent to that procedure, an amended discharge elimination in Anaconda's discharge permit would be written. This amendment initiates the standards setting process envisioned when the cadmium variance was granted to Anaconda with the expectation that the variance will expire upon adoption of a new standard. The revision of the cadmium standard from 0.0004 mg/l to 0.0012 mg/l is based upon a review of data supplied by Anaconda at stations D2 and D3 above the discharge point on the Dolores River. Consideration was also given to the existing table value for cadmium at the ambient hardness levels in the river, and the draft position on cadmium is being considered by the Basic Standards Task Force.
34.18 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE; AUGUST,
1989 HEARING ON MULTIPLE SEGMENTS The provisions of 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; 25-8-207 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 3.4.6(2). The purpose of this language is to explain the new references to “table value standards”(TVS) that are contained in the Tables. The other changes considered and adopted are addressed below.
A. Jurisdiction on Tribal Lands On the issue of classifying and setting standards on tribal lands, the Commission was advised to classify and set standards as they would for waters on non-tribal lands with the understanding that the Commission is not attempting to assert jurisdiction or to usurp the authority of the tribe to classify and set standards for waters within the boundaries of the reservation.
B. Table Value Standards for Metals San Juan, Segment 7;
C. New High Quality 2 Designations San Juan, Segments 1, 5, and 9;
Dolores, Segments 4 and 10.
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. Second, in addition to these standards changes, the use classifications have been revised where necessary so that each of these segments has the following classifications: Recreation - Class 1 Cold Water Aquatic Life - Class 1 Water Supply Agriculture
D. Existing High Quality 2 Segments; New Classifications and Standards San Juan, Segment 4;
These segments were already described as High Quality Class 2, as all are wilderness and wild and scenic rivers. Available information indicates that the parallel new High Quality 2 designation continues to be appropriate for each, along with new table value numeric standards and equations for cold water aquatic life classifications, i.e., acute (trout) for cadmium and zinc and chronic (trout) for silver.
The following use classifications, and associated table value standards, have been adopted for these segments:
Recreation - Class 1 Cold Water Aquatic Life - Class 1 Water Supply Agriculture
E. Existing High Quality 2 Segments; New Classifications and Standards San Juan, Segments 3, 10, and 11;
F. New Use-Protected Designation; Table Value Standards Piedra, Segment 7;
G. Revised Recreation Classification San Juan, Segments 2 and 6;
H. Other Revisions 1. Los Pinos, Segments 3 and 5.
2. San Juan, Segment 9 (Four Corners Area)
34.19 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE; FEBRUARY,
1990 EMERGENCY RULEMAKING HEARING The provisions of 25-8-208 and 25-8-402 C.R.S. provide the specific statutory authority for action on these regulatory amendments.
BASIS AND PURPOSE:
The Commission held this emergency rulemaking hearing to readopt the classifications and numeric standards for the San Juan River and Dolores River Basins to correct errors in the original filing. The affected regulation was amended on November 7, 1989 and was filed within the required timeframes with the Secretary of State's Office and the Office of Legislative Legal Services. The Commission learned shortly after the filings that three (3) pages had been inadvertently left out of the regulation, and that a typographical error appeared throughout the classification and standards tables that are part of the regulation. The Commission office was able to correct the errors with a replacement filing with the Secretary of State's Office so that the regulation published in the CCR (Colorado Code of Regulation) correctly reflects the Commission's actions.
The Office of Legislative Legal Services notified the Commission that it could not accept the corrected materials as they had not been submitted within the 20 day timeframe called for in section 24-4-103 (8) (d), C.R.S. of the “State Administrative Procedure Act”. It was suggested that the Commission needed to repromulgate the rules that contained the errors submitted in November, 1989 and resubmit them. The Commission elected to proceed on an emergency rulemaking basis to avoid any confusion that could result due to the fact that the two filings are currently not the same. Therefore, the Commission adopted the corrected version of the regulation at an emergency rulemaking hearing on February 6, 1990. Final action on the readoption is scheduled for June 5, 1990.
34.20 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE; JUNE, 1990
RULEMAKING HEARING The provisions of 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; 25-8-207 and 25-8-402 C.R.S. provide the specific statutory authority for action on these regulatory amendments. BASIS AND PURPOSE:
The Commission held this rulemaking hearing to make permanent the emergency hearing that was held in February, 1990 to readopt the classifications and numeric standards for the San Juan River and Dolores River Basins to correct errors in the original filing. The affected regulation was amended on November 7, 1989 and was filed within the required timeframes with the Secretary of State's Office and the Office of Legislative Legal Services. The Commission learned shortly after the filings that three (3) pages had been inadvertently left out of the regulation, and that a typographical error appeared throughout the classification and standards tables that are part of the regulation. The Commission office was able to correct the errors with a replacement filing with the Secretary of State's Office so that the regulation published in the CCR (Colorado Code of Regulation) correctly reflects the Commission's actions.
The Office of Legislative Legal Services notified the Commission that it could not accept the corrected materials as they had not been submitted within the 20 day timeframe called for in section 24-4-103 (8) (d), C.R.S. of the “State Administrative Procedure Act”. It was suggested that the Commission needed to repromulgate the rules that contained the errors submitted in November, 1989 and resubmit them. The Commission elected to proceed on an emergency rulemaking basis to avoid any confusion that could result due to the fact that the two filings are currently not the same. Therefore, the Commission adopted the corrected version of the regulation at an emergency rulemaking hearing on February 6, 1990.
34.21 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 3.4.6(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.
34.22 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:
On November 30, 1991, revisions to “The Basic Standards and Methodologies for Surface Water”3.10 ( 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 a 1-day to a 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 10 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 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.
34.23 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE;
SEPTEMBER 12, 1994 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 A. BACKGROUND Between 1991 and 1993 the Water Quality Control Division, in cooperation with several federal, state, local and private interests conducted an intensive water quality investigation of the Animas River and its tributaries from Elk Creek to the headwaters. The objectives of the study were to characterize the current chemical, biological, and physical conditions of the Animas River and selected tributaries above Elk Creek and to quantify the areas of highest metal loadings and determine the potential for water quality improvement sufficient to allow naturally reproducing trout populations; and to prioritize sites for remedial projects based on relative loading, environmental impact, feasibility, cost, and benefits.
B. OVERVIEW The starting point for the Commission's analysis is a conclusion that appears to be shared by most, if not all, of the participants in this rulemaking proceeding: current water quality in the Animas River Basin can and should be improved. For example, quoting from the Statement of the Animas River Stakeholders' Group:
In summary, the Commission's action in revising the Animas River Basin water quality classifications and standards should in no way be interpreted as a sanctioning of the status quo. To repeat, current water quality in the Animas River Basin can and should be improved. The purpose of the Commission's action is to establish a clear goal of attaining such improvement, while providing regulatory flexibility intended to encourage cooperative efforts toward such improvement.
C. IMPLICATIONS OF THE HYBRID ACTION Because of the unorthodox nature of the hybrid action being taken, the Commission believes that it may be important to clarify its understanding regarding the implications of this action for various activities or decisions that will need to be undertaken by others during the next three years. For any existing point source discharge permit that may come up for renewal during the next three years, or for any new wastewater discharge permit issued during this period, the Commission intends that the permit would be written based on the ambient quality-based standards then in effect, along with other applicable effluent quality restrictions. The Commission also understands that ambient quality-based standards would require the continuation of current treatment levels for permit renewals, to assure that further degradation of water quality does not occur.
D. DELAYED CLASSIFICATIONS AND STANDARDS This portion of this statement describes the basis for the goal-based standards that are scheduled to go into effect three years after the effective date of this action. The upper Animas water quality study found that the Animas River and several tributaries above Maggie Gulch (segment 2), the Animas River from Cement Creek to Mineral Creek (segment 3b), Cement Creek and its tributaries (segment 7), and Mineral Creek above the confluence with South Mineral Creek (segment 8) do not support diverse forms of aquatic life owing to poor water quality and limited physical habitat. The imposition of effluent limits required under the Federal Act for point sources and cost-effective and reasonable best management practices (BMP's) for nonpoint sources are not likely to lead to the establishment of aquatic life in these segments. Additionally, federal regulation (40 C.F.R. 131.10) allows excluding an aquatic life classification where naturally occurring pollutant concentrations prevent the attainment of the use and/or human caused conditions or sources of pollution prevent the attainment of the use and cannot be remedied or would cause more environmental damage to correct than to leave in place. Therefore, an aquatic life classification is not being adopted for these segments. Downstream use classifications, however, depend on maintaining or improving the water quality in these segments. The Commission has therefore, determined that narrative standards for metals based on the application of BMP's to nonpoint sources and the continuation of current treatment levels for existing point sources for these segments establish an appropriate goal for water quality in these segments. Narrative (and for zinc in segment 3b, numerical) temporary modifications have been adopted based on current ambient quality in these segments, to assure no additional degradation of downstream segments.
E. AMBIENT QUALITY-BASED STANDARDS This portion of this statement describes the basis for the ambient quality-based standards that are adopted for the three-year period starting with the effective date of this action. For segments 2, 3b, 7 and 8, the Commission has adopted a narrative standard based on existing ambient quality for all metals to be applicable for the next three years. For segments 4a, 4b, and 9b, for this same time period the Commission has adopted ambient-quality based numerical standards for specific metals for which ambient quality currently is higher (worse than) table values. These standards are intended to protect the aquatic life that is currently in place in these segments until the goal-based standards go into effect. As discussed above, the primary basis for adopting these numerical and narrative ambient quality-based standards is to provide maximum regulatory flexibility to encourage the cooperative, community-based effort toward clean-up to proceed. This approach provides time in which additional information can be developed regarding the feasibility of specific remedial efforts that will result in water quality improvement.
F. OTHER ISSUES The above discussion, like the evidence submitted at the hearing, focuses principally on appropriate aquatic life classifications and associated water quality standards. In this hearing the Commission also added an agriculture classification to segments 2, 3a, and 7, based on evidence regarding the presence of grazing. In addition, the Commission changed the recreation classification from class 2 to class 1 for segments 4a, 4b, 5a, and 5b, based on evidence regarding the presence of primary contact recreation. Finally, fecal coliform standards for segments 2 and 3a were changed from 2,000 to 200/ml, to provide additional protection that better reflects current ambient conditions. There are no affected point sources on these segments.
34.24 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE: MARCH 14,
1995 HEARING (San Juan and Dolores River Basins revisions) The provisions of 25-8-202(1)(a), (b) and (2): 25-8-204; and 25-8-402 C.R.S. provide the specific statutory authority for the 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 Water Quality Control Division (Division) proposed that the Water Quality Control Commission consider the following changes to the Classifications and Numeric Standards for San Juan River and Dolores River Basins, 3.4.0. The basis and purpose for the changes are organized by topic.
A. Resegmentation Several of the segments contained waters that crossed into or were on the Southern Ute and Ute Mountain Indian Reservations. Both tribes are in the process of developing classifications and standards for waters within their reservations and it was agreeable to both tribes that those segments should be bi-furcated to indicate which portions are on tribal lands and to ease their future removal from the state standards system when the tribes' standards are approved by the
B. Segments Converted to Dissolved Metals Standards There were several segments which still had metals standards based on the old total recoverable criteria. Review of metals data submitted to the hearing allowed the metal standards on the following segments to be appropriately converted from total recoverable to dissolved standards: San Juan River segment 6a Piedra River segment 4a La Plata River segment 2a Mancos River segments 5a and 5b McElmo Creek segment 7 Dolores River segments 2, 3, 5, 6, and 9 C. Revision of Classifications or Standards to Meet the Fishable/Swimmable Goals of Clean Water Act Several segments in the San Juan-Dolores river basins did not have use classifications which met the swimmable goals of the Clean Water Act. Consistent with strategies adopted by the Commission, these segments which are designated recreation class 2 and have no point source dischargers to the segment have had their fecal coliform standard set equal to 200/100 ml. These segments are:
D. Manganese and Mercury Standards On all segments classified for water supply and aquatic life uses, the total recoverable manganese standard of 1,000 ug/l was stricken. The aquatic life manganese criterion was changed in 1991 revisions to the Basic Standards from total recoverable to dissolved and on these segments a more stringent dissolved manganese water supply standard of 50 ug/l is in place.
E. Deletion of Use-Protected Designation One segment classified aquatic class 1, Piedra River segment 7, was found to have a use- protected designation which was based on prior basic standards requirements pertaining to waters classified as warmwater aquatic life class 1, recreation class 2. The designation was removed to conform to the requirements now in effect.
F. Water Supply Classifications and Standards New data on several segments showed the water quality to be suitable for a water supply classification. The water supply classifications and standards were added to the following segments:
1. Pagosa Springs Sanitation District 2. Southwestern Water Conservation District 3. Southern Ute Indian Tribe 4. Pagosa Area Water and Sanitation District 5. Board of County Commissioners of San Juan County 6. U.S. Environmental Protection Agency's Region VIII Office 7. Colorado Division of Wildlife
34.25 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
34.26 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 Commission's 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.
34.27 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; NOVEMBER,
1997 RULEMAKING The provisions of 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 In 1995, the Water Quality Control Commission adopted underlying goal-based numerical and narrative standards with temporary modifications for segments 2, 3b, 4a, 4b, 7, 8 and 9b of the Animas River Basin. The underlying goal-based standards were adopted with a three-year delayed effective date. In the interim, ambient quality-based standards were adopted for the critical segments to protect aquatic life currently in place in these segments. The critical segments did not meet the underlying goal based numeric standards, and it was not clear that the goal-based standards were in fact achievable within a 20- year period. Numeric standards were adopted in other segments of the river where supported by existing water quality. The overall purpose for adopting the underlying goal-based standards with temporary modifications was to encourage continuation of an existing community-based, cooperative watershed improvement initiative designed to improve water quality in the Animas River Basin unencumbered by the potential implications of the goal-based standards being in effect. The Commission charged the Animas Stakeholders Group with the responsibility to determine the feasibility of specific clean-up projects, the quantification of achievable improvements and to identify, prioritize and acquire funding for remediation projects. Based on this work, the Commission expected that recommendations would be made for the permanent adoption of the underlying goal-based numeric standards or for alternative standards that would be achievable within a 20-year period. The Stakeholders have worked successfully toward accomplishment of this end. Significant progress has taken place in the basin in completion of feasibility studies, identification and prioritization of specific clean-up projects, initial funding for projects and on-the-ground remediation work in process. Evidence was submitted in the rulemaking regarding the work accomplished to date, additional work in progress or planned in the near future, and a schedule for the additional work planned during the next three years. Part of the planned work will be completed in conjunction with the U.S. Department of the Interior Abandoned Mined Land Initiative, which is designed to develop practical characterization and remediation methodologies for federal land managers and others to be used in a watershed management approach. The Animas Basin is one of two national pilot projects for this initiative. From this information, it is apparent that additional time is needed to finish studies to adequately characterize pollution sources, quantify feasible remediation levels, and define habitat limitations along with the potential for aquatic life. Completion of this work is necessary to provide a comprehensive recommendation to the Commission for ultimate numeric/narrative standards.
In order to allow the ongoing community-based, cooperative watershed improvements initiative an opportunity to continue the promising effort that is currently underway, the Commission has decided that the delayed effective date of underlying goal-based standards (and associated temporary modifications) should be delayed for another three years, to March 2, 2001. With this extension, the Commission has the following expectations for: (1) preparation by the Stakeholders of a use attainability analysis which proposes aquatic life uses which are potentially attainable, specifies the causes of water quality impairment, determines the sources which may be controlled, and provides an economic evaluation of such a proposal; (2) that the Stakeholders, in conjunction with the Division of Wildlife develop recommendations for an appropriate underlying standard for zinc for segment 4a, as part of the use attainability analysis; and (3) that the delay until March 2, 2001 approved by the Commission for the effective date of underlying standards is adequate for all study to be completed and appropriate standards to be established.
Finally, the Commission notes that the action taken here is a unique approach to the unique situation present in the Animas River Basin, including the presence of a cooperative, community-based effort with unusually broad participation. This action should not be viewed as a precedent for other site-specific hearings.
1. Animas River Stakeholders Group 2. Colorado Division of Wildlife 3. Town of Silverton 4. Sunnyside Gold Corporation 5. The Silver Wing Company, Inc 6. Southwestern Water Conservation District of Colorado 7. Gold King Mines Corporation 8. US EPA Region VIII 9. Southern Ute Indian Tribe
34.28 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.
34.29 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; MAY, 2001
AND JULY, 2001 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 I. Animas and Florida River Segments The primary focus of this portion of the hearing was to revisit the aquatic life classifications and standards for streams in the Animas River Basin that have elevated levels of various metals. The water quality of this area is extensively impacted by heavy metals which are attributed to both natural and anthropogenic sources. Those impacts attributed to past human activities are largely the result of the extensive mining that has occurred in this basin over a period of several decades. It is evident that remediation of these impacts is a complex challenge that will require considerable time and effort. Subsequent to the last major review of these streams, a use attainability analysis (UAA) was prepared by the Animas River Stakeholders Group (ARSG). Over the last several months, this UAA has provided the focal point for extensive discussions involving the Water Quality Control Division, the Colorado Division of Wildlife, U. S. EPA, the U.S. Forest Service, the U. S. Bureau of Land Management, and other participants in the stakeholders group. The Commission wishes to acknowledge and express its appreciation for this extensive collaborative effort. The Commission believes that the revised Animas River Basin classifications and standards adopted as a result of this hearing provide a major step forward in the long-term resolution of water quality issues in this basin. The Commission encourages all of those involved in this effort to continue to work cooperatively in furthering ARSG's mission of improving the water quality in the Animas River and its tributaries.
Upper Animas Segmentation The Commission adopted several changes to the segmentation for streams in the Animas River Basin. The Commission changed descriptions for several segments to correct inaccuracies and to include tributaries previously left out of descriptions. The Commission changed the segment division between segments 4b and 5a to better reflect a natural division between the segments in terms of topography, geomorphology and land use patterns. The Commission also moved the dividing line between segments 4a and 4b upstream to Deer Park Creek, which is the first significant inflow of good quality water below the confluence with Mineral Creek. The streams formerly in segment 9a have been moved to segment 6, and the previous segment 9b renumbered as segment 9. Finally, recognizing the need for a new segment to cover a tributary to the Animas River not previously classified, the Commission created segment 3c to include Arrastra Gulch and applied site-specific standards as described below. Big Horn Creek and all tributaries on the west side of Mineral Creek above its confluence with South Mineral Creek except for a lower portion of Middle Fork of Mineral Creek and the mainstem of Mineral Creek (segment 8), were reclassified as part of segment 6.
Overview of Aquatic Life Classifications and Standards The UAA focused primarily on identifying the achievable remediation and associated water quality for segments 3a, 4a, and 9b (now segment 9) of the Animas. Some of the metals standards previously adopted for these segments were disapproved by EPA in 1998. The UAA identified the water quality that would result from remediation of selected priority sites where metals loadings were determined to be anthropogenic and reversible. Based upon this analysis, and the associated biological evidence submitted, the Commission revised the aquatic life classifications for segment 9b (now segment 9) and for resegmented segment 4a. In addition, the Commission has specified aquatic life indicators in the “goal qualifier” column for these three segments. These indicators identify biological goals for future water quality in these segments.
Numerical standards for these three segments adopted at this time are based on the conclusions of the UAA regarding what remediation is achievable. In some cases, identified remediation goals are expected to attain Table Value Standards. In other cases, site-specific standards are adopted based on the UAA's projections of what water quality will be attained at specific gages in the three key segments as a result of anticipated remediation. Remediation potentials and limitations have been explored in great detail and the resulting site-specific standards are scientifically defensible, recognizing, however, that there is significant uncertainty as discussed below. The standards are reflective of ambitious cleanup goals estimated at a cost of 20 to 30 million dollars. The goals are particularly ambitious given foreseeable funding availability and liability restrictions that may detrimentally affect remediation activity (e.g. there remains a lack of a “Good Samaritan” provision in the federal Clean Water Act). The Commission also notes that additional information appears to be needed to determine attainable/protective water quality conditions in this basin over the long term. There is more than the usual amount of uncertainty associated with the various proposals considered in this hearing. There is uncertainty associated with the remediation targets because there may be additional reversible anthropogenic sources which have not yet been identified or fully characterized. There is uncertainty associated with the biological targets, because for some parameters there is a lack of toxicity data for key species of concern. In view of these uncertainties, the Commission emphasizes the importance of ongoing monitoring efforts and future studies in the Animas Basin to resolve the important issues that have been identified. It is the Commission's expectation that these efforts will proceed and will lead to refinement in the remediation goals in the basin, and in the associated determination of attainable water quality classifications and standards, in the future triennial reviews. Again, the Commission wishes to commend the cooperative efforts and the substantial local initiative that have brought the analysis to this stage. The Commission strongly encourages continued cooperation as these challenges are addressed in the future.
Site-specific Aquatic Life Classifications and Standards When segment 9b (now segment 9) was designated aquatic cold water class 1 in 1995, there was little or no data indicating that dissolved aluminum concentrations and total recoverable iron concentrations reached toxic levels because few or no winter water quality samples had been taken. Winter water quality samples taken since that time indicate dissolved aluminum concentrations almost three times the acute table value standard for aquatic life and total recoverable iron concentrations have been found to be four times the chronic table value standard for aquatic life. The Commission determined that the vast majority of sources of aluminum and iron are not associated with mining sites identified for remediation. In addition, the Commission heard testimony that no fish and few macroinvertebrates are found in segment 9b (now segment 9). Therefore, the Commission changed the use classification of cold water aquatic life class 1 to cold water aquatic life class 2 for segment 9b (now segment 9). Site-specific standards are applied for iron, aluminum, copper, and zinc based upon remediation goals presented by the ARSG. The Commission determined that after remediation of identified priority loading sources, aluminum, iron, and copper concentrations will continue to exceed chronic table value standards for aquatic life during portions of the year in segment 4a. The Commission also determined that after remediation, zinc concentrations will continue to exceed acute and chronic table value standards for aquatic life year round. Based on this information, the Commission removed the use classification goal of cold water aquatic life class 1 from segment 4a and retained the use classification of cold water aquatic life class 2. Site-specific standards are applied for iron, aluminum and zinc based upon remediation goals presented by the ARSG. In addition, the Commission recognized that there are few identified priority sources of cadmium, manganese, and zinc in or upstream of segment 3a. These constituents will continue to exceed aquatic life table value standards either year-round or during part of the year after remediation of the reversible sources. The UAA did not identify the large amount of metal loading entering segment 3a with any specific source. The Commission recognized the many unknowns and uncertainties in the analysis of source loadings in segment 3a. Therefore, the Commission applied site-specific standards based upon remediation goals to segment 3a for these constituents and encouraged the ARSG to continue their characterization efforts to determine the unknown sources of loading. The aluminum standards for segments 3a, 4a and 9 have been specified as “total recoverable”, since that sampling fraction correlates better with the principal aquatic life toxicity studies available than the dissolved fraction. As noted above, the Commission has adopted a new segment 3c for Arrastra Gulch, with a cold water aquatic life class 2 classification.The existing ambient quality for copper and zinc exceed the acute table value standards, therefore, chronic ambient standards could not be adopted. Acute table value standards for copper and zinc were adopted along with temporary modifications set at existing ambient quality. This provides time for the ARSG to investigate Arrastra Gulch and prepare appropriate chronic standards at the next triennial review.
During the hearing, the Commission heard evidence that iron is a major driver in the chemical processes that lower pH. The Commission determined that because most iron sources are not associated with priority remediation sites in the Upper Animas Basin, for some segments and some portions of the year, pH levels are unlikely to reach table value standards for aquatic life with remediation of mine sites. Therefore, the Commission applied seasonal, site-specific pH standards to segments 4a and 9b (now segment 9).
The adopted standards will protect existing aquatic populations and should allow for significant increases in biological diversity, population size, and aquatic health. At this time, there is no assurance that other human-caused conditions or sources of pollution preventing the attainment of Table Value Standards and higher uses can be remedied, given current technologies and regulatory conditions; nor is there assurance that additional remediation will not be feasible in the future. Particularly in view of the uncertainty noted above, as these restrictions to further water quality improvements change it will be necessary to review additional remediation possibilities and to implement standards reflective of these possibilities at future triennial reviews.
Temporary modifications were reviewed and extended to December 31, 2006 for segments 2, 3b, 7, 8 and 9.
Other Classification and Standards Issues The following resegmentation was adopted:
Animas/Florida segment 1 was designated outstanding waters (OW) due to its meeting the criteria in section 31.8(2)(a).
Ambient quality-based standards were removed from the following segments due to new data and/or changes to the Basic Standards which indicated ambient standards were no longer appropriate: segments 2, 3a, 3b, 4a, 4b, 7, 8, 9b.
“Fish Ingestion” and “Water + Fish Ingestion” standards for organic chemicals are discussed in section II.J. of this Statement of Basis and Purpose. For the Animas and Florida Rivers, Fish Ingestion standards were adopted for segment 13a and Water + Fish Ingestion standards were adopted for segments 13b and 13c.
Animas/Florida River, segments 13b, 13c where investigation showed that aquatic life was present were upgraded with the addition of the full suite of inorganic standards to protect aquatic life. Water supply classifications and associated standards were adopted for segments 11b, 13b and 13c. Agriculture classifications are added to segment 4a and to the new segment 3c based on existing or potential grazing uses. In addition, numerical standards are adopted to protect the existing agriculture classifications for segments 2, 7, and 8. In each case, no manganese standard was adopted, because the conditions associated with that criterion are not present. Recreation classifications were changed from class 2 to class 1a for segments 2, 3a, 3b, 6, 7, 8, 9a, 9b, 13a, 13b, 13c, and 15. For several of these segments, the Southwestern Water Conservation District submitted use attainability analyses proposing that a recreation class 2 classification be retained. However, these UAAs were submitted after the deadline for submission of such information for this hearing and generally lacked site-specific analysis of recreation uses on the segments addressed. Existing recreation class 1 classifications were changed to class 1a for segments 1, 4a, 4b, 5a, 5b, 10, 11a, 12a, 12b, and 14. A recreation class 1a classification was also adopted for new segment 11b. The Commission notes that the last paragraph of section 31.6(2)(b) will apply to future changes to the recreation classifications where a proper showing is made through a use attainability analysis that a recreation class 2 classification is appropriate, without application of the other downgrading criteria in this section. Moreover, the Commission is relying in part on previous representations from EPA that completion of a use attainability analysis showing that a lower recreation classification is appropriate satisfies applicable downgrading criteria. Based on these factors, the Commission intends that in a future rulemaking hearing the test for adopting a recreation class 2 classification would be the same as if it had been considered in this hearing.
Based on evidence submitted by the Town of Silverton, the Commission established a seasonal recreation class 1a classification for segment 3b, for the period of May 15 through September 10 and recreation class 2 for the remainder of the year.
II. Other River Segments A. Resegmentation Some segments were renumbered and/or created 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:
La Plata, Segments 8 and 10: Tributaries to McElmo Creek were separated into Segments 8a and 8b to recognize the Ute Mountain Ute Indian Reservation boundaries. La Plata, Segments 8 and 10: All remaining tributaries to the San Juan River in Dolores and Montezuma Counties were moved to Segments 10a and 10b. The portions within the Ute Mountain Ute Indian Reservation are included in Segment 10b. Dolores, Segment 7: The segment description was changed to exclude the upper portion of Coal Creek which is located within the Lizard Head Wilderness Area.
B. Manganese The aquatic life manganese criterion was initially changed in the 1997 revisions to the Basic Standards (5 CCR 1002-31) from a single chronic dissolved criterion to acute and chronic hardness-based equations. The equations were further modified in the 2000 revisions to the Basic Standards. The new manganese acute and chronic equations were added as table value standards in 34.6(3). As a result of the adoption of these new TVS, all segments classified for aquatic life use that had a chronic total recoverable manganese standard of 1,000 µg/L had the 1,000 standard stricken and replaced with Mn(ac/ch)=TVS.
C. Selenium The regulation in 34.6 (3) listed the table value standards for selenium as Acute=135 µg/L and Chronic=17 µg/L. This was updated to reflect the existing acute and chronic criteria for selenium listed in the Basic Standards as Acute=18.4 µg/L and Chronic=4.6 µg/L which was adopted in 2000 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 µg/L was stricken and replaced with Se(ac/ch)=TVS.
D. Outstanding Waters Designations Several segments or waterbodies were designated outstanding waters (OW) due to their meeting certain criteria pursuant to section 31.8(2)(a). Segments which already included wilderness areas in their description were designated OW. The water quality of the following segments met the 12 parameter test and other requirements of 31.8(2)(a):
E. Removal of Use Protected Designation The Division proposed that a number of aquatic life class 2 waterbodies be assigned undesignated status under the state antidegradation regulation due to the presence of Colorado State species of special concern. State regulations governing the “use-protected” designation allow this exception if the Commission determines that the waters are of exceptional ecological significance. The Commission believes that a number of important issues have been raised in this hearing regarding when and how this exception should be applied, and that further examination of these issues should occur. Nevertheless, for purposes of this hearing, the Commission, based upon a concern over the protection of classified uses and the absence of evidence of potential injury to permitted entities, has decided to accept the change to reviewable water status for the following San Juan River, Segment 10 La Plata, Segments 5a, 5b, 6a and 6b.
F. 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 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 for which no existing primary contact uses have been documented following a reasonable level of inquiry. To maintain the existing Recreation Class 2 with the 2000/100 ml standard on a segment, a use attainability analysis must be conducted that shows that it is unlikely that a Recreation Class 1 activity could exist. There was considerable evidence and testimony submitted in this hearing regarding what activities should be considered primary contact recreation. Section 31.13(1)(a) of the Basic Standards provides a non-exclusive list of primary contact activities. In this hearing, much discussion focused on the issue of whether “child's play” in streams that are too shallow to accommodate the primary contact uses listed in the Basic Standards should be considered a primary contact use. The Commission does not believe that a theoretical potential for child's play means that all streams should be classified Recreation Class 1a or 1b. However, the Commission concludes that the evidence submitted demonstrates that there is a potential risk of ingestion of small quantities of water by children playing in relatively shallow streams, based on the hand-to- mouth pathway, which warrants Recreation Class 1 protection in appropriate circumstances as elaborated below. Thus, such ingestion may occur in streams where whole body immersion is not likely.
G. 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.
H. Ambient Quality-Based Standards There are several segments in the San Juan Basin that contain standards based on existing ambient quality. Ambient standards are adopted where natural or irreversible man-induced conditions result in water quality levels higher (i.e. worse) 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. The Division reviewed the reason for the ambient standards and provided testimony that justified ambient standards being retained without adjustment on the following segments:
I. Temporary Modifications There were several segments which had temporary modifications that were reviewed, and decisions were made to delete or to extend them, either as is or with modification of the numeric limits.
J. Organic Chemical Standards The organic chemical standards were updated to include changes adopted by the Commission in the 2000 revisions to the Basic Standards (see section 31.11 in Regulation No. 31). “Water + Fish” organic chemical standards are presumptively applied to all Aquatic Life Class 1 streams which also have a Water Supply classification, and are applied to Aquatic Life Class 2 streams which also have a Water Supply classification, on a case-by-case basis. The “Fish Ingestion” organic chemical standards are presumptively applied to all Aquatic Life Class 1 streams which do not have a Water Supply classification, and are applied to aquatic life class 2 streams which do not have a Water Supply classification, on a case-by-case basis. Existing site-specific applications of additional organics (as noted in the Qualifier column of Table 34.7) were modified to conform to this change.
K. Water Supply Classification These segments had the Water Supply classification added to them or are new segments with a water supply use. The associated water supply standards will now apply to segments: San Juan River, Segments: 6b, 8 Piedra River, Segments: 4b, 6a, 6b Dolores River, Segment 11 L. 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 section 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 aesthetics 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 = WS. These abbreviations mean that for all surface waters with an actual water supply use, the less restrictive of the following two options shall apply as numerical standards, as discussed in the Basic Standards and Methodologies at section 31.11(6): either (i) existing quality as of January 1 2000; or (ii) Iron = 300 µg/L (dissolved); 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 determined as the result of a site-specific rulemaking hearing that such standards are appropriate.
M. Tribally-Owned Lands Many of the waterbodies in the southern parts of these basins are located on tribally-owned lands specifically those of the Southern Ute Indian Tribe and the Ute Mountain Ute Indian Tribe.Waters on tribally-owned lands are not regulated by the WQCC. Both Tribes are in the process of developing water quality standards for waters on their tribally-owned lands. The Commission has segmented the waterbodies which cross reservation boundaries. Water quality standards for waterbodies crossing reservation boundaries were reviewed by the Division in cooperation with Tribal representatives to ensure that the classified uses and numeric standards were consistent. The Commission included water quality classifications and standards on lands within the boundaries of these reservations in agreement with the Southern Ute and Ute Mountain Ute Indian Tribes in order to avoid a gap in the classifications and standards adopted for the river basins in question, since these Tribes have not yet been granted authority by EPA to conduct their own water quality program. Section 34.5 (4) was added to clarify this issue.
N. Agriculture Standards Numeric standards to protect agriculture uses were adopted for the following segments: San Juan, Segment: 3 Los Pinos, Segments: 6a, 6b O. Other Site-Specific Revisions The Commission corrected several typographical and spelling errors, clarified segment descriptions and made the following site-specific revisions: La Plata, Segment 2a: The classification was changed from aquatic life warm 2 to cold 2 because information was presented that indicated the aquatic community includes trout species. La Plata, Segment 7a: The classification was changed from aquatic life warm 2 to warm 1 and removed the Use Protection designation, because information was presented that indicated the aquatic community is diverse and includes DOW species of special concern. PARTIES TO THE RULEMAKING HEARING 1. Animas River Stakeholders Group 2. Colorado Wild, San Juan Citizen's Alliance, Sierra Club-Rocky Mountain Chapter, Colorado Environmental Coalition and The Wilderness Society 3. U.S. Department of the Interior, Bureau of Land Management 4. Sunnyside Gold Corporation 5. The Southwestern Water Conservation District 6. Silver Wing Company, Inc.
7. U.S. Department of Agriculture Forest Service 8. Shenandoah Mining Company Incorporated 9. Town of Silverton 10. Pagosa Area Water and Sanitation District 11. Peter Butler 12. U.S. Department of the Interior National Park Service 13. Climax Molybdenum Company 14. Tri-State Generation and Transmission Association, Inc.
15. Town of Olathe 16. The Board of County Commissioners of the County of Gunnison 17. Gunnison County Stockgrowers Association, Inc.
18. High Country Citizens' Alliance and Western Slope Environmental Resource Council 19. The City of Grand Junction 20. Homestake Mining Company 21. The Board of County Commissioners of the County of San Miguel 22. Mt. Crested Butte Water and Sanitation District 23. Colorado River Water Conservation District 24. Town of Cedaredge 25. The Board of County Commissioners of the County of Mesa 26. The Uncompahgre Valley Water Users Association 27. Umetco Minerals Corporation 28. The Colowyo Coal Company, L.P.
29. The Uncompahgre Valley Association 30. Town of Crested Butte 31. The City of Delta 32. Trapper Mining, Inc.
33. The Colowyo Coal Company, L.P.
34. The City of Grand Junction 35. Colorado River Water Conservation District 36. Yellow Jacket Water Conservation District 37. The Town of Meeker 38. The City of Fruita 39. Exxon Mobil Corporation 40. Shell Frontier Oil & Gas Inc.
41. The Board of County Commissioners of the County of Mesa 42. American Soda, LLP 43. The Rio Blanco Water Conservancy District 44. Colorado Division of Wildlife 45. The Northern Colorado Water Conservancy District and its Municipal Subdistrict 46. Upper Gunnison River Water Conservancy District 47. U.S. EPA Region 48. Ralph E. Clark III 49. U.S. Department of the Interior
34.30 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JULY, 2002
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 As a result of major rulemaking hearings in May and July, 2001, the Commission adopted extensive revisions to the water quality designation, classifications and standards for the waters in this basin. Subsequent to the filing of the final action documents resulting from that rulemaking, minor error were identified in the published revisions. Errors in the water quality designation for San Juan segment 10, manganese standard for Animas River segment 4a, the segment description for Animas River segment 4b, and typographical errors for Animas River segments 9 and 12a were corrected in this rulemaking.
34.31 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
12, 2005 RULEMAKING, EFFECTIVE 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 San Juan and Dolores River Basins, the Division discovered errors and inconsistencies between segment descriptions. To resolve these issues the Commission adopted changes in the following segment descriptions: San Juan segment 8 Dolores segments 6 and 10 The Commission has also adopted the deletion of San Juan Segment 7.
34.32 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JUNE 12,
2006 RULEMAKING; ADOPTED AUGUST 14, 2006; EFFECTIVE JANUARY 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 A. Waterbody Segmentation Some renumbering and/or creation of new segments in the basin 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. The following changes were made: Animas River Basin segment 12c was created for Hermosa Creek and tributaries above Long Hollow, except for the East Fork of Hermosa Creek. The East Fork of Hermosa Creek was excluded from this segment due to uncertainty of future development in this drainage by Durango Mountain Ski Resort.
B. Revised Aquatic Life Use Classifications The Commission reviewed information regarding existing aquatic communities. There were no changes to the Aquatic Life Use Classifications in the San Juan Basin.
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
D. Addition of Water Supply Use Classification and Standards Based on review of information regarding the location of public water supplies, no additional WS classifications and standards were added to Regulation No. 34. E Agriculture Standards Numeric Standards to protect Agricultural Uses were adopted for the following segments: San Juan River Basin segments: 12a and 12b Los Pinos River Basin segments: 7a and 7b La Plata River Basin segments: 10a and 10b F. Changes to Antidegradation Designation Outstanding Waters Designation: Based on evidence that shows the water quality meets the requirements of 31.8(2)a, the OW designation was added to the following segments in Mesa Verde National Park: Segment COSJLP06c was created for waters within Mesa Verde National Park.
G. Ambient Quality-Based Standards There are several segments in the Basins that are assigned standards based on existing ambient water quality. 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 Commission did not adopt any changes to the ambient quality-based standards.
H. Aquatic Life Ammonia Standards 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 34.6(3) and footnotes to conform to Regulation No. 31. In cases where dischargers need time beyond one permit term to assure compliance with new permit limits, temporary modifications have been adopted. These are listed below in the temporary modification section.
I. 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 34.6(3) were modified to conform to Regulation No. 31.
J. 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)
K Uranium Standards Uranium standards were not added for any segments in this basin.
L. 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.
La Plata River Basin segment 5a: NH3 = old TVS, expiration date 12/31/2011; This temporary modification is intended to allow the dischargers such as the Town of Mancos adequate time to assess any potential facility changes that will be required to assure compliance with new ammonia limits. This temporary modification will be reviewed in 2009 and 2010.
La Plata River Basin segment 7a: NH3 = old TVS, expiration date 12/31/2011; This temporary modification is intended to allow the dischargers such as the City of Cortez adequate time to assess any potential facility changes that will be required to assure compliance with new ammonia limits. This temporary modification will be reviewed in 2009 and 2010.
La Plata River Basin segment 8a: NH3 = old TVS, expiration date 12/31/2011; Fe(ch)=1500 ug/l; expiration date 12/31/2011. These temporary modifications are intended to allow the dischargers such as the City of Cortez and Dove Creek adequate time to assess any potential facility changes that will be required to assure compliance with new ammonia limits. This temporary modification will be reviewed in 2009 and 2010. La Plata River Basin segment 8c: NH3 = existing quality, expiration date 12/31/2013; This temporary modification is intended to allow Lee Mobile Home Park adequate time to assess any potential facility changes that will be required to assure compliance with new ammonia limits. This temporary modification will be reviewed in 2009 and 2010. The Upper Animas River Basin is a historic mining region undergoing remedial efforts led by the Animas River Stakeholder Group. There are approved TMDLs for the basin that cover all segments and parameters that are in non-attainment of water quality standards. Due to historic mining there are numerous other point-source discharges to nine segments in the Upper Animas River Basin that are not currently permitted. The Commission decided to retain and update temporary modifications to the historic mining impacted segments to allow flexibility in remedial efforts.
Animas River Basin segment 2: Existing ambient quality for all metals. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 3a: Cd(ch)=3.0, Mn(ch)=3203, Zn(ch)=862. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 3b: Existing ambient quality for all metals. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 3c: Cu(ch)=6.6, Zn(ch)=184, no Cu, Zn acute. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 4a: Al(ch)=2523 (trec), Fe(ch)=4204 (trec), Zn(ch) = 730 ug/L, Cu(ch) = 20 ug/L; Cd(ch) = 2.5 u/L, pH= 5.3; expiration date 12/31/2011. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 4b: Zn(ch)=184. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010. Animas River Basin segment 7: Existing ambient quality for all metals. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 8: Existing ambient quality for all metals. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 9: Al(ch)=3544(Trec), Cu(ch)=22, Fe(ch)=5023(Trec), Zn(ac/ch)=340. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
M. Other changes The hearing of section 34.5(4) has changed to “Indian Reservations”as a more accurate description. In addition, the test of this section was revised to reflect EPA’s approval of the Ute Mountain Utes’ treatment as a state status for the adoption of water quality standards. The Commission corrected several typographical and spelling errors, and clarified segment descriptions.
1. San Juan Citizens Alliance 2. Tri-State Generation and Transmission Association 3. National Park Service 4. Mountain Coal Company 5. West Elk Mine 6. Homestake Mining Company of California 7. Umetco Minerals Corporation 8. Lee Mobile Home Park 9. The Southwest Mesa County Rural Services Public Improvement District 10. Animas River Stakeholders Group 11. Board of County Commissioners of the County of Gunnison, Colorado 12. The Town of Silverton 13. The Town of Cedaredge 14. The Town of Olathe 15. High Country Citizens Alliance 16. Upper Gunnison River Water Conservancy District 17. Colorado Trout Unlimited 18. The City of Grand Junction 19. Gunnison County Stockgrowers Association, Inc.
20. The Southwestern Water Conservation District 21. Vista Verde Village LLC 22. The Colorado Division of Wildlife 23. Nucla Sanitation District 24. Town of Naturita 25. The Pagosa Area Water and Sanitation District 26. The Boxelder Sanitation District 27. City of Ouray 28. Norwood Sanitation District 29. U.S. Environmental Protection Agency 30. Colorado River Water Conservation District
34.33 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 2011. 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
34.34 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 modifications of ammonia standards were reviewed. Deleted: Ammonia temporary modifications were deleted on the following segments because in most cases permits had recently been reissued for dischargers on the segments. Compliance schedules in the permits are adequate to address any necessary treatment plant upgrade issues. In other cases, no permits now discharge to this segment. La Plata, etc segments 5a and 8a Modified: La Plata, etc. segment 7a: The chronic ammonia temporary modification was modified to clarify that the chronic standard’s value is 0.06 mg/l, rather than just “TVS old.” “Type iii” was added to identify that there is significant uncertainty regarding the appropriate underlying standard. The expiration date was extended to 12/31/2012 to allow time for additional study. Other Parameters: Temporary modifications for other parameters were also reviewed. Deleted: Temporary modification were deleted on the following segment because no permitted discharge has been identified that needs a temporary modification. La Plata, etc segment 3a iron Extension of expiration dates: The Commission has decided to delay the basin-wide review of water quality classifications and standards for this basin until June 2012, to accommodate an issue-specific rulemaking for nutrient criteria in June 2011. Consistent with that decision, the expiration dates of the temporary modifications on the following segments that are currently scheduled to expire on 12/31/2011 are extended to 12/31/2012. These will be reviewed again in the December 2010 and December 2011 Temporary Modification hearing. San Juan segment 11a Animas and Florida segments 2, 3a, 3b, 3c, 4a, 4b, 7, 8, and 9 La Plata, etc. segment 8a The Commission would like to emphasize that its intent and expectation is that the issues that necessitated adoption of these temporary modifications should be resolved as soon as possible and in a manner that takes full advantage of the opportunities provided by the December 2010 and December 2011 reviews of temporary modifications. The Commission recognizes that it is important to resolve uncertainty regarding the underlying standards so that temporary modifications can be eliminated and any needed pollution controls can be put in place in a timely manner. 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 15. Colorado Division of Wildlife 16. U.S. Environmental Protection Agency
34.35 STATEMENT OF BASIN SPECIFIC STATUTORY AUTHORITY AND PURPOSE, FEBRUARY
8, 2010 RULEMAKING REGARDING TEMPORARY MODIFICATION FOR RITTER DRAW, 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 The Commission added “Type iii” to the temporary modification of the ammonia standard for an unnamed tributary of Ritter Draw (La Plata River, Mancos River, McElmo Creek and San Juan River in Montezuma and Dolores County, segment 8c) in recognition that there is uncertainty regarding the appropriate underlying standard. A review of the hearing record shows that when this temporary modification was originally adopted (2006) testimony was presented that identified uncertainty regarding the aquatic life use. At that time, the type of temporary modification was not identified for each temporary modification. The Commission’s current action is intended to recognize that time is needed to resolve the uncertainty about the appropriate standard before compliance is required.
34.36 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.
The type iii temporary modification of ammonia standards on La Plata segment 7a was reviewed. It will expire on 12/31/2012. It is anticipated that site-specific standards will be considered as part of the basin- wide review in June 2012.
Temporary modifications of metal standards in the Upper Animas Basin (Animas River segments 2, 3a, 3b, 3c, 4a, 4b, 7, 8 and 9) were reviewed. They will expire on 12/31/2012. It is anticipated that the Animas River Stakeholder Group will present a more comprehensive review as part of the basin-wide review in June 2012.
The temporary modifications of the iron standard on San Juan segment 11a and La Plata segment 8a were reviewed. They will expire on 12/31/2012. When originally adopted, time was allotted to allow dischargers time to assess potential changes to their discharge permits. It is anticipated that these will be addressed as part of the basin-wide review in June 2012. PARTIES TO THE RULEMAKING 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
34.37 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 and a three-month delay of the Regulation #34 basin-wide review. Accordingly, the Commission considered the expiration dates of temporary modifications expiring on or before December 31, 2012 in a written comment rulemaking. The Commission extended the expiration dates of the following temporary modifications to March 31, 2013. They would be reviewed during the September 2012 basin-wide rulemaking hearing. San Juan segment 11a (Fe)
Animas segment 4a (Al, Fe, Zn, Cu, Cd, pH)
Animas segment 4b (Zn)
Animas segment 7 (all metals)
Animas segment 8 (all metals)
Animas segment 9 (Al Cu, Fe, Zn)
La Plata etc, segment 7a (NH3)
La Plata etc, segment 8a (Fe).
34.38 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE;
SEPTEMBER 10, 2012 RULEMAKING; FINAL ACTION NOVEMBER 5, 2012; EFFECTIVE DATE MARCH 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:
A. Waterbody Segmentation The Commission split lakes and reservoirs from segments that also contained streams, so that new temperature standards could be adopted. Lakes and reservoirs were deleted from the following segments that previously encompassed streams and lakes and reservoirs: San Juan River segments: 1a, 3, 4, 5, 6a, 9a, 9b, 11a, 11b, 12a Piedra River segments: 1, 5, 6a, 6b Los Pinos River segments: 1, 4a, 6a, 6b Animas and Florida River segments: 1, 3c, 6, 7, 8, 12a, 13b, 13c La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 1, 3a, 3b, 4a, 6a, 6b, 7a, 8a, 8b, 10a, 10b Upper Dolores River segments: 1, 5a, 11 The following segments were created for lakes and reservoirs: San Juan River segments: 13, 14, 15a, 15b, 16, 17, 18a, 18b, 19 Piedra River segments: 8, 9, 10, 11a, 11b Los Pinos River segments: 8, 9, 10, 11a, 11b Animas and Florida River segments: 16, 17, 18, 19, 20, 21, 22, 23, 24 La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 Upper Dolores River segments: 12, 13, 14, 15 The following segment was deleted when the constituent water bodies were merged with other segments: San Juan River segment: 12b Some existing stream segments were divided into two or more segments at the point where a change in temperature tiers occurred. The following segments were created or revised to facilitate adoption of the new temperature standards into individual segments:
B. Revised Aquatic-Life Use Classifications and Standards The Commission reviewed information regarding the existing aquatic communities. Class 2 segments with exceptionally high MMI scores, or fish data showing the presence of a wide variety of species, were upgraded from Class 2 to Class 1.
The following segments were upgraded from Warm 2 to Warm 1: La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 2b, 5a, 5b San Juan River segment: 11b (revised to include water bodies from the former segment 12b) The following segments were upgraded from Cold 2 to Cold 1: La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 2a Animas and Florida River segments: 12a, 12d Fish Ingestion qualifiers were added to the following segments, based upon review of available data: Piedra River segment 11a La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 14 Fish Ingestion qualifiers were deleted for the following segment that was upgraded from Class 2 to Class 1, since fish ingestion is presumed for all Class 1 waters: La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 2a The following segment was upgraded from Warm 2 to Cold 1 based on biological data showing that the segments have cold-water species, or cold-water species are expected to be present: La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 3c The following segments were designated as Aquatic Life Warm 2 or Cold 2, but lacked standards to fully support the Aquatic Life Use. Available data indicates that the Aquatic Life Use is attainable, and therefore the full suite of standards protective of aquatic life was added to the following segments: San Juan River segments: 3, 12, 19 Los Pinos River segments: 6a, 6b, 11a, 11b La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 10a, 10b Some new lake segments were split from stream segments with no Aquatic Life Use. These new lake segments were designated as Aquatic Life Cold 2, because the Aquatic Life UAAs did not include data from these lakes. The full suite of standards protective of aquatic life was added to the following segments:
C. Recreation Classifications and Standards 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 use classification was inappropriate or that recreation use had changed. The following segments with year-round or seasonal Recreation N standards were upgraded to Recreation E:
D. Water Supply Use Classification and Standards Based on review of information regarding the location of alluvial wells, where the evidence demonstrates a reasonable potential for a hydrological connection between the surface water and the wells, the Water Supply Use classification and standards were added to the following segments: San Juan River segments: 10, 11a Animas and Florida River segments: 9, 13a La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 2a, 2b, 3b, 4c, 5a, 8a Upper Dolores River segment: 3 A Use Attainability Analysis was prepared to remove the Water Supply Use and standards from the following segment:
E. Agriculture Standards A review of the standards associated with the Agriculture Use classification showed that many segments were missing a chronic chromium III standard to protect the use. The chronic chromium III standard to protect the Aquatic Life Use classification may be not be protective of the Agriculture Use in some high hardness situations. A chromium III standard of CrIII(ch)=100(Trec), was added to the following segments classified for Agriculture Use, but not for Water Supply, which has a more restrictive chromium III standard:
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 all segments in Regulation 34 with an Agriculture Use classification; except for La Plata segment 6c, because grazing is not allowed within Mesa Verde National Park. No molybdenum standard was applied to Animas and Florida River segment 3b, because it does not have an Agriculture Use classification.
F. Changes to Antidegradation Designation Outstanding Waters: Based on evidence that shows the water quality meets the requirements of section 31.8(2)(a), and on the presence of conservation populations of native cutthroat trout in all three streams, the Outstanding Waters designation was added to Rio Lado, Little Taylor Creek and Spring Creek (Dolores River segment 5b). The Commission has determined that the evidence demonstrates that the three criteria for an Outstanding Waters designation set forth in section 31.8(2)(a) are met for this proposal. The Commission also 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 there are existing land uses, including grazing permits, in place in the watershed. The evidence demonstrates that these existing land uses are compatible with the Outstanding Waters 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 Outstanding Waters designation 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. Further, acknowledging that the adoption of the Outstanding Waters designation for identified segments is a discretionary undertaking by the Commission, with such designations not being subject to federal approval or disapproval, the Commission may, in the future, remove the Outstanding Waters designation from any such segment in accordance with the state substantive and procedural rules then in effect. The Commission has not adopted the Outstanding Waters designations proposed by WildEarth Guardians for multiple segments. The Commission is not persuaded that the fact of being located within an area identified as a “roadless area” is sufficient to demonstrate that the waters in question constitute an outstanding natural resource. Moreover, the proponents did not provide adequate data to persuasively demonstrate the current quality of the waters in question. Finally, the Commission notes that the proponents did not demonstrate a substantial level of public outreach that might have helped to demonstrate a consensus that the criteria in section 31.8(2)(a) are met. 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. The Commission reviewed available water quality data for all Cold 2 segments that were Use-Protected to determine if that designation was still warranted. The following segment(s) are now Reviewable: Animas and Florida River segments: 17, 19, 20 Decoupling Aquatic Life Warm 2 and UP: As part of the Basic Standards hearing of 2005, the Commission decided that the presence of a Warm Water Class 2 classification would still be a presumptive basis for applying a Use-Protected designation; however, that presumption can be overcome if there is data showing that the water is of high quality. The Commission reviewed available water quality data for all Warm 2 segments to determine if the Use-Protected designation is still warranted. The following segment(s) are now Reviewable:
G. Ambient Quality-Based 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 segments have ambient-based or other site- specific standards:
H. Aquatic Life 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 34.6(3) were modified to conform to Regulation No. 31.
Site-Specific Zinc Standards for Mottled Sculpin: 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. The Commission did not add a sculpin-specific zinc equation to any segment in Regulation 34. The Commission deleted the zinc scuplin standards from the following new and revised lake segments, where mottled sculpin are not expected to be present:
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 34.5(3)(c) to reflect the change to the basin-wide standard. A new section 34.5(3)(c)(i) was added to explain the hyphenated standard. Subsection 34.5(3)(d) was deleted because it was redundant with 34.5(3)(c).
J. Temporary Modifications All existing Temporary Modifications were re-examined to determine if they should be allowed to expire or to extend them. Temporary Modifications were not automatically extended if non-attainment persisted due to revisions made to the Temporary Modification provisions in 2005 and 2010. The following segments had Temporary Modifications that were not extended: San Juan River segment: 11a Animas and Florida River segments: 2, 3a, 3b, 3c, 4a, 4b, 7, 8, 9 La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 8a The following segments have new or extended “Type A”Temporary Modifications for ammonia: Animas and Florida River segment: 13b La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 7a, 8c Temporary Modifications were added or extended for existing discharges to these segments, based upon evidence that the dischargers could not meet water quality based effluent limits for ammonia. The Commission’s intent is to preserve the status quo during the term of the Temporary Modification. Existing discharges to these segments shall continue to be authorized to discharge ammonia at their current permitted concentration and flow levels, including a “report only” value. The Division will work with the existing dischargers to determine whether the table value standard for ammonia is necessary to protect the Aquatic Life Uses of these segments. The uncertainty in the standard for each segment may be resolved through a site-specific standard or a discharger specific variance. The Commission does not intend that Temporary Modifications set at “current condition” will apply to new or expanded facilities. The progress on resolving the uncertainty with the ammonia standards will be reviewed in the annual Temporary Modification hearing in December 2013.
The following segment has a new “Type B” Temporary Modification: Animas and Florida River segment: 3b For Animas River Segment 3b, the Commission adopted a Type B Temporary Modification for copper, cadmium and zinc with a narrative value of “current condition”, and an expiration date of December 31, 2017. The Commission’s intent is to preserve the status quo during the term of the Temporary Modification. Existing discharges to Animas River Segment 3b shall continue to be authorized to discharge copper, cadmium and zinc at their current permitted concentration and flow levels, including a “report only” value. Historic mining impacts upstream from Silverton indicate that elevated levels of copper, cadmium and zinc in the Animas River may be due to irreversible human-induced conditions. Since remediation options are still be evaluated, and some improvement in water quality may be gained, it is not yet feasible to quantify the extent of irreversible impacts. The Commission does not intend that Temporary Modifications set at “current condition” will apply to new or expanded facilities. The progress on resolving the uncertainty with the cadmium, copper and zinc standards will be reviewed in the annual Temporary Modification hearing in December 2015.
K. Temperature New table values were adopted for temperature in the 2007 Basic Standards hearing, and revised in the 2010 Basic Standards hearing. Temperature standards were applied to individual segments based upon the fish species expected to be present as provided by Parks and Wildlife, temperature data, and other available evidence.
The following segments have a Cold Stream Tier I temperature standard (CS-I): San Juan River segments: 1a, 4, 5, 7 Piedra River segments: 1, 2a, 3, 5 Los Pinos River segments: 1, 4a, 5 Animas and Florida River segments: 1, 3a, 3c, 4a, 4b, 6, 9, 10a, 12a, 12c, 12d, 13b, 14a, 15 La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 1, 4a Upper Dolores River segments: 1, 2, 3, 5a, 5b, 6, 7, 8, 9, 10, 11 The following segments have a Cold Stream Tier II temperature standard (CS-II): San Juan River segments: 1b, 2, 6a, 6b, 9a, 9b, 10 Piedra River segments: 2b, 4a, 4b Los Pinos River segments: 2a, 2b, 4b, 6a, 6b, 7a, 7b Animas and Florida River segments: 5a, 5b, 10b, 11a, 11b, 13a, 13c, 14b La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 2a, 3c, 4c Upper Dolores River segment: 4a The following segments have a Warm Stream Tier II temperature standard (WS-II): San Juan River segments: 3, 11a, 11b Piedra River segment: 6a La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 2b, 3a, 3b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9 The following segments have a Warm Stream Tier III temperature standard (WS-III): San Juan River segment: 12a Piedra River segment: 6b La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 6c, 8c, 10a, 10b The following segments have a Cold Lakes temperature standard (CL): San Juan River segments: 13, 15a, 15b, 16, 17 Piedra River segments: 9, 10 Los Pinos River segments: 8, 10, 11a, 11b Animas and Florida River segments: 16, 17, 18, 19, 20, 21, 23, 24 La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 12, 15 Upper Dolores River segments: 12, 14, 15 The following segments have a Large Cold Lakes (greater than 100 acres surface area) temperature standard (CLL):
L. Other Site-Specific Revisions La Plata River, Mancos, River, McElmo Creek and San Juan River 2b: The discrepancy between the Recreation Use season and the E. coli standard season was corrected. The fecal coliform standard was also deleted.
Upper Dolores River segment 11: The typographical error in the Agriculture designated use was corrected.
M. Tribally-Owned Lands The Southern Ute Indian Tribe raised an issue with the wording of section 34.5(4). The Commission deleted the phrase “in agreement with the Southern Ute and Ute Mountain Ute Indian Tribes”. This section was added in 2001 and referred to a verbal staff level agreement at that time. PARTIES TO THE RULEMAKING HEARING 1. Trout Unlimited 2. WildEarth Guardians 3. National Park Service, Curecanti National Recreation Area 4. Mountain Coal Company 5. U.S. Energy Corp.
6. Climax Molybdenum Company 7. Gunnison County 8. Gunnison County Stockgrowers Association, Inc.
9. Homestake Mining Company of California 10. Colorado Parks and Wildlife 11. High Country Citizens’ Alliance 12. Town of Crested Butte 13. Upper Gunnison River Water Conservancy District 14. Dolores Water Conservancy District 15. Town of Hotchkiss 16. Town of Olathe 17. Town of Silverton 18. Atlantic Richfield Company 19 City of Delta 20. Environmental Protection Agency 21 R Squared, Inc.
22. Wright Water Engineers, Inc.
23. San Juan Citizens Alliance 24. Colorado Sand and Gravel Association
34.39 FINDINGS IN SUPPORT OF ADOPTION OF EMERGENCY REVISIONS; MAY 13, 2013
The Commission adopted the corrections to the zinc table value equations as an emergency action, making the revisions effective immediately. If the Commission does not adopt revisions as an emergency, the effective date would be delayed and discharge permits with zinc limits may be issued incorrectly, which would result in an unnecessary adverse impact on the public. The Commission finds that these amount to exigent circumstances which warrant emergency adoption of these interim revisions to the relevant water quality standards.The Commission further finds that these emergency revisions are imperatively necessary to preserve public health and welfare and that compliance with the procedural requirements of section 24-4-2103, C.R.S., resulting in further delay would be contrary to the public interest.
The changes to the zinc equation are to be effective immediately upon adoption by the Commission, and continue in effect until the effective date of permanent regulations.
34.40 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; MAY 13,
2013 RULEMAKING; 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:
The Commission adopted revisions to Regulation #34 after a rulemaking hearing in September 2012. Changes to two table value criteria that were made in the 2010 Basic Standards hearing were inadvertently overlooked a the time the proposal for that rulemaking was developed: revisions to the zinc standard equations and temperature values for the Warm Stream tier 2 subclass. In today’s action the Commission adopted the corrections to the table values for these parameters in section 34.6. The changes to the zinc equations were adopted as an emergency temporary action (see 34.39) and as a permanent action. Since this is the initial implementation of the new temperature standards in this basin it is not anticipated that the changes to the temperature table values will result in adverse impacts in any permitting action or to the public.
34.41 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 34.6(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. San Juan River 2 San Juan River 4 San Juan River 5 San Juan River 6a Piedra River 1 Piedra River 2a Piedra River 4b Piedra River 5 Los Pinos River 1 Los Pinos River 2a Los Pinos River 2b Los Pinos River 4a Los Pinos River 4b Animas and Florida River 4b Animas and Florida River 5a Animas and Florida River 5b Animas and Florida River 6 Animas and Florida River 10b Animas and Florida River 11a Animas and Florida River 11b Animas and Florida River 12a Animas and Florida River 13b Animas and Florida River 13c Animas and Florida River 14a Animas and Florida River 14b La Plata River, Mancos River, McElmo Creek, And San Juan River in Montezuma County and Dolores County 1 La Plata River, Mancos River, McElmo Creek, And San Juan River in Montezuma County and Dolores County 4a Dolores River 8 Dolores River 11 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
34.42 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 standards on three segments were reviewed.
Temporary Modifications for ammonia on the following segments were reviewed: Animas and Florida River segment: 13b La Plata River, Mancos River, McElmo Creek, and San Juan River segments: 7a, 8c Temporary Modifications were extended for existing discharges to these segments in 2012, based upon evidence that the dischargers could not meet water quality based effluent limits for ammonia. The uncertainty in the standard for each segment may be resolved through a site-specific standard or a discharger specific variance. The expiration dates were extended to 6/30/2015. The Division intends to have proposals ready to resolve the uncertainty with the ammonia standards for the annual Temporary Modification hearing in December 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
34.43 STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE AUGUST 11,
2014 RULEMAKING HEARING; FINAL ACTION AUGUST 11, 2014; EFFECTIVE DATE MARCH 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 In 2010, the Commission adopted the discharger specific variance provisions at Regulation 31.7(4), which allow a temporary water quality standard to be adopted in cases where water quality based effluent limits 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 water quality based effluent limit (WQBEL) is not feasible.
In reliance upon Durango West Metropolitan District #2’s (DWMD’s) commitment to implement upgrades and a continued maintenance program, the Commission adopted a DSV for Animas and Florida Segment 13b for ammonia that represents the highest degree of protection of the classified use that is feasible for DWMD. For ammonia, the monthly chronic total ammonia effluent limits for DWMD shall not be more restrictive than 15 mg/L prior to 12/31/2024. The Commission expects that DWMD will submit a progress report for the San Juan Basin Issues Formulation Hearing in November 2016 and expects that report to include information regarding whether there are any downstream domestic water supply wells that are impacted by the discharge.
1. Durango West Metropolitan District #2 2. Colorado Parks and Wildlife 3. U.S. Environmental Protection Agency
34.44 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 2 segments were reviewed.
Extension: The Commission extended the expiration date of ammonia temporary modifications on the following segments.
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
34.45 STATEMENT OF BASIS AND PURPOSE REGARDING THE ADOPTION OF NON-
SUBSTANTIVE CHANGES TO THE CLASSIFICATION AND NUMEIRC STANDARDS FOR SAN JUAN RIVER AND DOLORES RIVER BASINS, 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)= …”
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:
• The footnote regarding the variance conditions on Animas and Florida Segment 13b was moved to 34.6(4)(a) because it exceeded 200 characters and could not be shortened without substantively changing the meaning of the text.
34.46 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 3 segments were reviewed.
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
34.47 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 temporary modifications on the following segments since they will be addressed in the basin wide hearing in June 2017. Animas River Segment 3b: temporary modification of the cadmium, copper and zinc standards (expire 12/31/2017).
San Juan River Segment 9a San Juan River Segment 11a Piedra River Segment 7 Los Pinos River Segment 5 Animas Florida River Segment 10a Animas Florida River Segment 13a Animas Florida River Segment 22 La Plata River Segment 2b La Plata River Segment 5a La Plata River Segment 12 Dolores River Segment 1 Dolores River Segment 2 Dolores River Segment 3 Dolores River Segment 4a Dolores River Segment 4b Dolores River Segment 5a Dolores River Segment 5b 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
34.48 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; JUNE 12,
2017 RULEMAKING; FINAL ACTION AUGUST, 2017; EFFECTIVE DATE DECEMBER 31, 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:
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: Animas Florida Segments 2 and 3a: The boundary between Segments 2 and 3a was moved upstream from Maggie Gulch to Minnie Gulch, in order to facilitate a change in use classifications and standards on this portion of the mainstem of the Animas River.
Animas Florida Segments 5b through 5d: Segment 5b was divided into Segments 5b through 5d. The proposed boundaries were developed in consultation with the Southern Ute Indian Tribe, and the resegmentation provides a framework for working toward common water quality standards on waters where there is a jurisdictional dispute.
Animas and Florida Segment 11c: All tributaries to the Florida River formerly in Segment 13c were moved to Segment 11c to improve the organization of waters in this basin. Animas Florida Segment 13c: The unnamed tributary to Coal Gulch was moved to Segment 13c to facilitate a change in the water supply use classification and standards. All water bodies formerly included in Segment 13c were moved to the new Segment 13e, 13f or 11c to improve the organization of waters in this basin.
Animas Florida Segment 13e and 13f: Tributaries to the Animas River were moved to the new Segment 13e (above Basin Creek) and 13f (Basin Creek to New Mexico Border).The proposed boundaries were developed in consultation with the Southern Ute Indian Tribe, and the resegmentation provides a framework for working toward common water quality standards on waters where there is a jurisdictional dispute.
Dolores River Segments 5a: Beaver Creek and Plateau Creek were moved from Segment 5a to a new Segment 11c to facilitate a change in the use classifications and temperature standards. Dolores River Segments 10a and 10b: Segment 10 was split into Segments 10a and 10b to change the temperature standards on the West Dolores River below Fish Creek from CS-I to CS-II. Dolores River Segments 11a, 11b and 11c: Segment 11 was split into Segments 11a, 11b and 11c to facilitate changes to the aquatic life use classifications and temperature standards on tributaries to the Dolores River.
La Plata Segment 2b, 2c and 2d: The mainstem of the La Plata River from the Southern Ute Indian Reservation to the Colorado/New Mexico border was split into Segments 2b, 2c and 2d. The proposed boundaries were developed in consultation with the Southern Ute Indian Tribe, and the resegmentation provides a framework for working toward common water quality standards on waters where there is a jurisdictional dispute.
La Plata Segment 3a and 3e: East Alkali Gulch and Hay Gulch were moved from Segment 3a to Segment 3e to facilitate changes to the water supply and aquatic life use classifications and standards. La Plata Segments 3c and 3d: East Cherry Creek moved from Segment 3c to a new Segment 3d to facilitate changing the temperature standard from CS-II to CS-I. La Plata Segments 5, 6a, 7b, 8, 10 and 17: Segments 5, 6a, 7b, 8, 10 and 17 were revised and/or renumbered to facilitate the exclusion of water bodies inside the Ute Mountain Ute Indian Reservation. Former Segments 5b, 6b, 7b, 8b, 9, 10b, 20, 21 and 22 were deleted entirely, as these contained water bodies entirely within the Ute Mountain Ute Indian Reservation. La Plata Segment 6b: The East Fork of Muddy Creek and East Canyon were moved to a new Segment 6b to facilitate a change in the water supply use classification and standards. La Plata Segment 7b: A portion of the mainstem of McElmo Creek moved to a new Segment 7b to facilitate a change in the water supply use classification and standards. Los Pinos Segments 2b, 2c and 2d and 4b: Segment 2b was split into 2b, 2c, and 2d. All of the water bodies previously included in Segment 4b were moved either to Segment 2c (Beaver Creek) or Segment 2d (Ute Creek and Spring Creek). The proposed boundaries were developed in consultation with the Southern Ute Indian Tribe, and the resegmentation provides a framework for working toward common water quality standards on waters where there is a jurisdictional dispute. Los Pinos Segment 6: Los Pinos Segment 6 was revised to exclude Segment 4b. The Segment number was revised from 6a to 6, since the number for 6b was no longer needed. Los Pinos Segment 7a: Los Pinos Segment 6b was changed to 7a and the segment description was revised to exclude Segments 2b, 2c and 2d.
Los Pinos Segment 7b: The segment description for Segment 7b was revised to include only Trail Canyon and its tributaries. Other tributaries formerly included in Los Pinos Segment 7b were moved to San Juan Segment 11b (direct tributaries to Navajo Reservoir), as it is a more appropriate sub-basin for the geographic location of these tributaries.
Piedra Segment 4a: A portion of Devil Creek was moved from Segment 5 to 4a to facilitate changes to the temperature standards.
Piedra Segment 4b and 4c: Segment 4b was split into Segments 4b and 4c to facilitate changes to the temperature standards.
Piedra Segment 5a and 5b: Segment 5 was split into Segments 5a and 5b to facilitate changing the temperature standard from CS-I to CS-II on some of the tributaries to the Piedra River. Piedra Segment 6c: Stollsteimer Creek was moved from Segment 6b to 6c to facilitate a change in the temperature standards.
Piedra Segment 6d: Steven’s Draw was moved from Segment 6a to a new Segment 6d to facilitate a change in the water supply use classification and standards. San Juan Segments 5 and 6a: The segment description for Segments 5 and 6a was revised in order to facilitate changing the temperature standard on the mainstem of the San Juan River from CS-I to CS-II for the portion between the West Fork and Fourmile Creek.
San Juan Segments 6a through 6f: Segments 6a was divided into two segments, Segments 6a and 6b. The former Segment 6b was renumbered as Segment 6c, and waters from this segment were divided into four Segments 6c through 6f. These changes in segmentation were made to facilitate changes to temperature standards on the mainstem of the San Juan River below Pagosa Springs. San Juan Segment 11c: A new Segment 11c was created to facilitate changes to the aquatic life use classifications and standards for McCabe Creek.
Segment descriptions were also edited to improve clarity, correct typographical errors, and correct spelling errors. These changes are listed in Section Q B. Aquatic Life Use Classifications and Standards The commission reviewed information regarding the existing aquatic communities. For segments lacking an Aquatic Life use classification, a use was added where biological information demonstrated that these waters are capable of sustaining aquatic biota. Additionally, Class 2 segments with high MMI scores or a wide variety of fish species were upgraded from Class 2 to Class 1. The following segments were upgraded from no Aquatic Life use to Aquatic Life Cold 1: Animas Florida segment: 2 (a portion was moved from Segment 3a, resulting in the upgrade) The following segments were upgraded from Cold 2 to Cold 1: Dolores River segment: 9 For segments where the existing aquatic communities are not aligned with the Aquatic Life use, the following segments were upgraded from Warm to Cold:
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, and no changes were adopted at this time. 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.
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:
The commission recognizes that there is scientific uncertainty about the appropriate standards for chloride and/or sulfate to protect the Aquatic Life use, and that appropriate standards may need to recognize that toxicity is affected by site water characteristics (similar to the influence of hardness on the toxicity of dissolved metals). The commission’s intention is that future revisions to the numeric standards assigned to these segments, and also to Regulation No. 31 (i.e., aquatic life-based table values chloride and/or sulfate), can be considered if: (1) EPA issues new or updated CWA § 304(a) Aquatic Life criteria recommendations, (2) another state adopts new or revised Aquatic Life criteria and EPA approves, or (3) protective criteria otherwise become available that incorporate the latest scientific information on the risks to aquatic life posed by these pollutants.
E. Agriculture Use Classification and Standards A review of the segments with an existing Agriculture use classification showed that some segments were missing one or more standards to protect that use. The full suite of Agriculture standards was added to the following segments:
F. Other Standards to Protect Agriculture, Aquatic Life, and Water Supply Uses
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. 34 that have an Agriculture use classification, and where livestock or irrigated forage are present or expected to be present. The following segments do not have an Agriculture or a Water Supply use classification. No molybdenum standard was applied to these segments:
Animas Florida Segment 3b 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: Animas Florida segments: 3a, 3c, 4a, 4b, 6 and 9 Dolores River segment: 9 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. 34 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: San Juan segments: 1a, 1b, 2, 4, 5, 6a, 6b, 6c, 6d, 6e, 6f, 7, 8, 9a, 9b, 10, 11a, 11b, 11c, 13, 15a, 15b, 16, 17 Piedra River segments: 1, 2a, 2b, 3, 4a, 4b, 4c, 5a, 5b, 6a, 6b, 6c, 7, 8, 9, 10, 11a, 11b Los Pinos segments: 1, 2a, 2b, 2c, 2d, 3, 4, 5, 6, 7a, 8, 9, 10 Animas Florida segments: 1, 4b, 5a, 5b, 5c, 5d, 5e, 6, 9, 10a, 10b, 11a, 11b, 11c, 12a, 12b, 12c, 12d, 13a, 13b, 13e, 13f, 14a, 14b, 15, 16, 18, 21, 22, 23, 24 La Plata River segments: 1, 2a, 2b, 2c, 2d, 3b, 3c, 3d, 3e, 4a, 4b, 4c, 5, 6b, 7b, 8, 11, 12, 15 Dolores River segments: 1, 2, 3, 4a, 4b, 5a, 5b, 6, 7, 8, 10a, 10b, 11a, 11b, 11c, 12, 13, 14, 15 4. Aquatic Life Criteria for Selenium and Ammonia: The commission declined to adopt EPA’s revised 304(a) Aquatic Life criteria for selenium and ammonia 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 Warm 2 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 removed from the following segments: Piedra River segment: 6a La Plata River segment: 3b H. Ambient Quality-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. [ The commission reviewed all existing site-specific standards. Based on an evaluation of the available data and information, no 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 or allowed to expire on 12/31/2017 certain temporary modifications on the following segments:
The commission revised or extended Temporary Modification on the following segments: Animas Florida Segments 3b and 4a: Temporary modifications of the copper standards were extended to 12/31/2022 on Segment 3b and adopted on Segment 4a. The Town of Silverton presented evidence that additional time is needed to resolve the uncertainty regarding the underlying copper standards. There is uncertainty regarding the degree to which existing concentrations of copper are irreversible, because the U.S. EPA Superfund Program is evaluating potential remediation projects in the watershed that may reduce loading of copper to the Animas River. There is also uncertainty regarding the degree to which the copper loading from Silverton’s effluent is irreversible, and Silverton will complete an alternatives analysis to resolve this uncertainty and determine how much copper reduction is feasible. Therefore, the commission extended the expiration date of the “current conditions” temporary modifications for copper to 12/31/2022.
J. Discharger Specific Variances There is currently one segment in the San Juan and Dolores River Basins (Animas Florida Segment 13c) that has a discharger specific variance (DSV) for ammonia. The commission reviewed the basis for this DSV and the available information regarding progress toward achieving the highest attainable water quality. The commission determined that this DSV is still appropriate and does not require revision at this time.
K. Temperature Standards for Rivers and Streams 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 2012, the new temperature standards were adopted for all segments with an Aquatic Life use classification in Regulation No. 34. 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.
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-I to CS-II: San Juan River segment: 6a Piedra River segment: 5b Dolores River segment: 10b, 11b The following segments were changed from CS-II to CS-I: La Plata River segment: 3d The following segments were changed from CS-II to WS-II: San Juan River segment 2 Dolores River segment 11c The following segments were changed from WS-II to CS-II: La Plata River segment 3e The following segments were changed from WS-III to WS-II: Piedra River segment: 6c Ambient temperature standards were adopted where a use attainability analysis was conducted demonstrating that elevated ambient temperatures are the result of natural conditions or are not feasible to improve to the level required by the current numeric standard, but are adequate to protect the highest attainable use. Ambient temperature standards were adopted for the following segments:
San Juan River segments: 6b, 6c, 6d, 6e, 6f, 11c Piedra River segments: 4a, 4b, 4c Adequate data or resources were not always available to support a revision of the use classification or a temperature standards change. In these cases, no change was proposed. It is the commission's intent that the division and interested parties work to resolve the uncertainty. There is uncertainty regarding the appropriate use classifications and temperature standards to protect the highest attainable use still exist for the following segments: San Juan River segments: 3, 9a and 9b Los Pinos River segments: 2c, 2d, 4b, 7a and 11b Animas Florida segment: 4a, 5b – 5e, 11a, 11b, 11c, 13b, 13c, 13f, 14b La Plata River segments: 2b, 2c, and 2d 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.
L. Ambient Quality-Based Temperature Standards for Lakes The WAT standard was found to be unattainable for a number of cold large lakes and reservoirs where evidence indicated there are healthy cold water fish populations. Because summertime temperature in the mixed layer for large lakes and reservoirs is very well correlated to the water body’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 or irreversible man-induced conditions. Ambient temperature standards were adopted for the following lakes:
M. Nutrients In March 2012, the commission adopted interim nutrient values in the Basic Standards (Regulation No.
31) and created a new statewide control regulation (Regulation No. 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 considered adoption of 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 2020. 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 No. 85 effluent limits and discharging prior to May 31, 2012. A new section (4) was added at 34.5 describing implementation of the interim nutrient values into the tables at 34.6, and includes a table which lists these facilities and the segment to which they discharge.
For lakes and reservoirs segments, a note was added to total phosphorus and chlorophyll standards adopted for lakes in the tables at 34.6, as these standards only apply to lakes larger than 25 acres. 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 to adopt standards based on this provision in this rulemaking (see section N).
31.17(e)(iii) also allows the commission to adopt numeric nutrient standards for circumstances where the provisions of Regulation No. 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: San Juan River segments: 1a, 1b, 2, 3, 4, 5, 6a, 6b, 7, 8, 9a, 9b, 10, 11a, 11b, 11c, 12, 13, 14, 15a, 15b, 16, 17, 18a, 18b, 19 Piedra River segments: 1, 2a, 2b, 3, 4a, 5a, 5b, 6a, 6b, 6c, 6d, 8, 9, 10, 11a, 11b Los Pinos River segments: 1, 2a, 4, 5, 6, 7a, 7b, 8, 9, 10, 11a, 11b Animas Florida River segment: 1, 2, 3a, 3b, 3c, 6, 7, 8, 9, 10a, 10b, 11c, 12a, 12b, 12c, 12d, 13a, 13b, 13c, 13d, 13e, 13f, 14a, 14b, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 La Plata River segments: 1, 2a, 2b, 2c, 2d, 3a, 3b, 3c, 3d, 3e, 4a, 4b, 4c, 5, 6a, 6b, 6c, 7a, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 Dolores River segments: 1, 2, 3, 4a, 4b, 5a, 5b, 6, 7, 8, 9, 10a, 10b, 11a, 11b, 11c, 12, 13, 14, 15 Total Phosphorus standards were adopted for the following segments: San Juan River segments: 1a, 1b, 2, 3, 4, 5, 6a, 6b, 7, 8, 9a, 9b, 10, 11a, 11b, 11c, 12, 13, 14, 15a, 15b, 16, 17, 18a, 18b, 19 Piedra River segments: 1, 2a, 2b, 3, 4a, 5a, 5b, 6a, 6b, 6c, 6d, 8, 9, 10, 11a, 11b Los Pinos River segments: 1, 2a, 4, 5, 6, 7a, 7b, 8, 9, 10, 11a, 11b Animas Florida River segment: 1, 3a, 3c, 6, 9, 10a, 10b, 11c, 12a, 12b, 12c, 12d, 13a, 13b, 13c, 13e, 13f, 14a, 14b, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 La Plata River segments: 1, 2a, 2b, 2c, 2d, 3a, 3b, 3c, 3d, 3e, 4a, 4b, 4c, 5, 6a, 6b, 6c, 7a, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 Dolores River segments: 1, 2, 3, 4a, 4b, 5a, 5b, 6, 7, 8, 9, 10a, 10b, 11a, 11b, 11c, 12, 13, 14, 15 N. 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” (DUWS), in Regulation No. 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. 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. Piedra River segment: 7 (Hatcher and Stevens Reservoirs) Animas Florida River segment: 23 (City Reservoir #1 and Lake Durango) La Plata River segment: 4b (Jackson Gulch Reservoir)
31.17(e)(ii) also allows the commission to adopt numeric nutrient standards for DUWS lakes and reservoirs. No proposals were made to adopt standards based on this provision in this rulemaking.
O. Other/Site-Specific Revisions The commission revised segment descriptions and/or deleted entire segments to exclude all waters within the Ute Mountain Ute Indian Tribe from Regulation No. 34: La Plata River, Mancos River, McElmo Creek, and San Juan River in Montezuma County and Dolores County: Segments 5, 6a, 7b, 8, 10 and 17 P. Duration of nitrite standard The commission corrected the duration of the nitrite standard from chronic to acute on all segments. When the commission adopted the new format for tables in 2016, all nitrite standards were incorrectly included in the “chronic” standards column.
Q. Typographical and Other Errors The following edits were made to segment descriptions to improve clarity and correct typographical errors:
1. Town of Silverton 2. Animas River Stakeholders Group 3. Homestake Mining Company 4. Mt. Emmons Mining Company 5. Colorado Parks and Wildlife 6. Colorado Waste Water Utility Council 7. Ouray Silver Mines Inc.
8. Trout Unlimited 9. U.S. Environmental Protection Agency, Region 8 Office 10. Towns of Hotchkiss, Lake City, Olathe, Ridgway 11. Southwestern Water Conservation District 12. Dolores Water Conservancy District 13. High Country Conservation Advocates 14. Upper Gunnison River Water Conservancy District 15. Littleton/Englewood Wastewater Treatment Plant 16. Eagle River Water and Sanitation District 17. Town of Crested Butte, Gunnison County, Coal Creek Watershed Coalition 18. Northern Colorado Water Conservancy District 19. Tri-State Generation and Transmission Association, Inc.
20. Climax Molybdenum Company 21. Northwest Colorado Council of Governments Water Quality/Quantity Committee
34.49 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:
34.50 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
9, 2019 RULEMAKING; FINAL ACTION JANUARY 13, 2020; 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 modifications: La Plata Segment 7a (COSJLP07a): The commission extended the temporary modifications for Ammonia (ac/ch) = current condition on La Plata Segment 7a until 06/30/2021. Vista Verde continues to make progress on resolving the uncertainty regarding the degree to which the ammonia loading from Vista Verde’s effluent discharge is irreversible, and is working with the division to complete an alternatives analysis to resolve this uncertainty and determine how much water quality improvement is feasible. Vista Verde will participate in the small ammonia lagoons discharger specific variance (DSV) rulemaking hearing, which is anticipated to take place by December of 2020.
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 34.6(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.
34.51 STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER
9, 2019 RULEMAKING; FINAL ACTION JANUARY 13, 2020; 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 A. Aquatic Life Standards for Cadmium 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 2017 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: Animas Florida: 3a, 3c, 4a, 4b, 6 and 9 Dolores River: 9 B. Clarifications to Appendix 34-1 To improve the clarity and usability of the tables, an acronym list was added to the front of Appendix 34-1 and the footnote referencing Section 34.6 was also simplified.
34.52 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: Animas River segments 3b and 4a (COSJAF03b and COSJAF04a): temporary modifications of the acute and chronic copper standards (expire 12/31/2022). The Town of Silverton provided an update regarding progress being made in implementing the plan to resolve uncertainty and demonstrating the ongoing justification for the temporary modifications. There continues to be demonstrated instream nonattainment, predicted compliance issues, and remaining uncertainty regarding the appropriate underlying standards to protect the uses and the extent to which instream and effluent conditions are reversible. The update provided by the Town of Silverton included details regarding the scheduled investigations and actions to resolve the uncertainty pertaining to the reversibility of copper concentrations in their effluent by 12/31/2022. This work includes improvements to the collection systems to reduce inflow and infiltration, as well as improvements to the wastewater treatment facility. The operative value of the temporary modifications is the narrative “current conditions.” In future reviews of these temporary modifications, the commission will use the following values to compare to the most recent five years of representative data to determine if effluent and waterbody quality is maintained and ensure that the existing uses are protected. These values are for use by the commission in future reviews of the temporary modification and are not intended to direct implementation of "current condition" temporary modifications in permits:
The commission took no action on the temporary modifications set to expire on or before the effective date of this hearing, allowing the following temporary modifications to expire and be deleted from Appendix 34-1:
34.53 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. La Plata Segment 7a The commission adopted a discharger specific variance (DSV) for La Plata Segment 7a (COSJLP07a) for ammonia that represents the highest degree of protection of the classified use that is economically feasible for Vista Verde Village Mobile Home Park (Vista Verde). The ammonia acute and chronic alternative effluent limits are, 24 mg/L from November through April and 14 mg/L from May through October. The seasonal change in limits is intended to address changes in treatment performance due to temperature. Since aerated lagoons have long detention times (greater than 30 days) and do not provide the opportunity to control for daily variation, the AELs shall apply to both the acute and chronic WQBELs. The DSV requires that Vista Verde’s ammonia 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 6/30/2031. A comprehensive alternatives analysis demonstrated that compliance with the ammonia WQBELs would cause substantial and widespread adverse social and economic impacts in the area where the discharge is located. Alternatives that would achieve compliance, such as replacing the lagoon with a mechanical plant or consolidation with the nearest city, would result in costs that the entity would not be able to pay while still operating a viable business. The commission determined that closing the mobile home park would result in the loss of affordable housing to the typically low-income residents of Vista Verde. The commission adopted a DSV with an alternative effluent limit that is based upon the expected ammonia effluent quality that will be achieved through feasible improvements to the lagoon. There is some uncertainty in the final effluent quality that will be achieved. Vista Verde will collect additional data to characterize the effectiveness of the improvements, which the commission will review upon re- evaluation of the AEL at future hearings. Since the basis for this DSV is economic feasibility, at future re- evaluations of the DSV, the commission will review whether economic conditions have changed in a way that would make additional reductions in ammonia feasible. The commission expects that Vista Verde will submit a progress report including updated facility data and improvements to date for the commission’s review of the DSV and the AEL at the June 2022 and June 2027 rulemaking hearings. The commission will re-evaluate the requirements of the DSV at these rulemaking hearings, and will consider whether the information at that time demonstrates an ability to reliably achieve lower ammonia concentrations than the AEL originally adopted. If warranted, the commission will modify the AEL to reflect the highest attainable condition.
B. La Plata Segment 10 The commission adopted a DSV for La Plata Segment 10 (COSJLP10) for ammonia that represents the highest degree of protection of the classified use that is economically feasible for the Town of Dove Creek. The ammonia AEL is 20 mg/L from November through May and 10 mg/L from June through October. The seasonal change in limits is intended to address changes in treatment performance due to temperature. Since aerated lagoons have long detention times (greater than 30 days) and do not provide the opportunity to control for daily variation, the AELs shall apply to both the acute and chronic WQBELs. The DSV requires that the Town of Dove Creek’s ammonia 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 6/30/2025.
A comprehensive alternatives analysis demonstrated that compliance with the ammonia WQBELs 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 Dove Creek to meet the ammonia WQBELs, 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 1.25% of median household income for the Town of Dove Creek’s residents was economically infeasible at this time, due to the current economic conditions in the Town of Dove 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 AEL that is based upon the expected ammonia effluent quality that will be achieved through feasible improvements to the lagoon. There is some uncertainty in the final effluent quality that will be achieved. Dove Creek will collect additional data to characterize the effectiveness of the improvements, which the commission will review upon re-evaluation of the AEL The commission expects that Dove Creek will submit a progress report for the commission’s review of the DSV and the AEL at the June 2022 rulemaking hearing. 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. If a subsequent variance is warranted, the Town of Dove Creek may propose a new DSV at the December 2024 rulemaking hearing.
34.54 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 34.6(4) (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 34.5(2) 'Table B' was added to the reference to organic standards at 31.11 to align with changes to Regulation No. 31.
• At 34.6(1), text was added to clarify that the tables in Appendix 34-1 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 34.6(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”. • Footnote 4 of the Table Value Standards table was modified to clarify that the “T” in the chronic ammonia equations stands for temperature.
• Information was added at 34.6(5) specifying that the mercury standards apply to the total recoverable fraction of all forms, both organic and inorganic, of mercury in water. This change brings the regulation into alignment with Regulation Nos. 32, 33, 36, 37, and 38; the commission made this change in those regulations during triennial reviews in 2018 through 2020.
• Information was added at 34.6(5) specifying that the ammonia, nitrate, and nitrate standards are to be reported as nitrogen. This is consistent with the description of the standards as they are included in Table II of Regulation No. 31. This change brings the regulation into alignment with Regulation Nos. 33, 37, and 38; the commission made this change in those regulations during triennial reviews in 2019 through 2020. • The formatting of the tables in Appendix 34-1 was modified to include only parameters that have been adopted in a majority of segments. The tables include rows for physical and biological, inorganic, and metals for all parameters which the commission commonly adopts into segments. In segments where there is no numeric standard for a commonly adopted parameter, a blank row for that parameter is included to show the commission's site-specific decision not to adopt a numeric standard for that parameter. The commission removed beryllium and aluminum from all segments where no standard has been adopted because these parameters have only been adopted on a site-specific basis, rather than basin-wide. This change brings the regulation into alignment with Regulation Nos. 32, 33, 36, 37, and 38; the commission made this change in those regulations during triennial reviews in 2018 through 2020. • Other minor edits were made to improve clarity and consistency.
34.55 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. 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: San Juan segments 4 and 5 (COSJSJ04 and COSJSJ05): Portions of Fall Creek (from its source to the irrigation diversion just upstream from the confluence with Wolf Creek), Wolf Creek (from the boundary of the Weminuche Wilderness area to the confluence with Fall Creek), and Quartz Creek (from the boundary of the South San Juan Wilderness area to the boundary of the San Juan National Forest), including their tributaries and wetlands, were moved from Segment 5 to Segment 4. The move facilitated changing the antidegradation designation of these waterbodies from Reviewable to Outstanding Waters. As part of this change, Segment 5 was revised to exclude listings in Segment 4.
B. Temporary Modifications Pursuant to the requirements in the Basic Standards (at 31.7(3)), all existing temporary modifications were examined to determine whether they should be deleted, modified, extended, or left unchanged.
The division submitted a plan to resolve uncertainty in the 2019 Temporary Modifications rulemaking. 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 35.6(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.
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 headwaters (i.e., no dischargers on upstream segments, who may receive WQBELs based on protection of downstream uses). Temporary modifications for arsenic were deleted from the following segments: San Juan River: 4 (COSJSJ04)
Piedra River: 1 (COSJPI01)
Los Pinos River: 1 (COSJPN01)
Dolores River: 1 and 5b (COSJDO01 and COSJDO05b)
C. 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.
D. Discharger-specific Variances The commission reviewed the basis, available information, and progress toward achieving the alternative effluent limits (AELs) and implementing Pollutant Minimization Programs (PMPs) for the three discharger- specific variances (DSVs) in Regulation No. 34.
The commission determined that these dischargers continue to make progress on the plans set forth in their PMPs as part of their DSVs and that the adopted AELs continue to represent the highest attainable water quality that is feasible for these dischargers to achieve. Therefore, the commission determined that the DSVs are still appropriate and do not require revision at this time. The commission expects that the dischargers will submit annual reports to the division describing the progress made on PMP implementation until the end of the DSVs.
The commission added details to Section 34.6(4) for the Durango West DSV, including notation of the interim (25 mg/L [starting 1/1/2017]) and final (15 mg/L [starting 1/1/2019]) ammonia (acute/chronic) AELs, as well as the adoption and expiration dates of the DSV. The commission adopted non-substantive revisions to the format of these DSVs in Section 34.6(4) and the Appendix 34-1 tables to provide clarity and consistency. General DSV implementation information previously noted for the Durango West DSV was removed because it was not unique to that particular DSV and general implementation guidance for DSVs can be found in Regulation No. 31 at 31.7(4). In addition, the acronym “AEL” was defined at 34.6(2)(a).
E. Aquatic Life Use Classifications and Standards Animas Florida Segment 8b (COSJAF08b): Based on evidence provided by the Bonita Peak Community Advisory Group (CAG), an Aquatic Life Cold 1 use classification and standards were added to new Segment 8b (COSJAF08b). Over the last twenty-five years, remediation of historical mine sites in the upper reaches of Mineral Creek has substantially improved water quality in the drainage to such a degree that a portion of Mineral Creek (new Segment 8b) now supports aquatic life, including brook trout and macroinvertebrate communities that are better than the Multi-Metric Index attainment thresholds presented in WQCC Policy 10-1. As such, new Segment 8b is capable of supporting a wide variety of biota, including sensitive species.
Based on water quality and biological data and information presented in this hearing (CAG Prehearing Statement Exhibits D, E, and G1-G4 and Rebuttal Exhibits S, T, U, and V), the commission resegmented Segment 8 into 8a (COSJAF08a) and 8b (COSJAF08b). New Segment 8b contains the portion of Mineral Creek from below Mill Creek to above the Middle Fork of Mineral Creek. The rest of the segment was retained in Segment 8a, for which the use classifications and water quality standards remain unchanged from the parent Segment 8.
For Segment 8b, the commission adopted an Aquatic Life Cold 1 use per 31.13(1)(c), and in accordance with 31.7(1)(b), table value water quality standards to protect the Aquatic Life use. Thallium standards to protect the Fish Ingestion and Aquatic Life uses, which are adopted on a site-specific basis, were also adopted on Segment 8b due to the documented presence of this Clean Water Act Section 307 priority pollutant in the segment. The commission declined to adopt aluminum standards to protect aquatic life on Segment 8b at this time. As discussed at 34.55(G), EPA released updated 304(a) Aquatic Life criteria for aluminum in 2018, but has not released finalized implementation guidance. Studies are currently underway 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. The commission acknowledges that the table value standards for chronic and acute copper, chronic lead, chronic cadmium, and chronic and acute zinc are not currently attained during spring runoff (April-June), and that the chronic and acute zinc table value standards may not be attainable throughout the year. The commission also acknowledges that information suggests that some portion of the concentrations for these parameters may be natural or infeasible to clean up to the level of table value standards. However, at this time, the comprehensive analysis and review required at 31.7(1)(b)(ii) to develop ambient quality- based site-specific standards is not available. Therefore, the commission adopted table value standards to protect the Aquatic Life Cold 1 use classification and the highest attainable use, as per 31.6, 31.7(1)(b), and 31.13(1)(c).
There are no practical implications of the new table value standards for permitted facilities, because no permitted discharges exist within or upstream of Segment 8b. Though the segment would be subject to review for 303d listing, when developing future priorities for development of total maximum daily loads (TMDLs), the division will consider 1) the significant water quality improvement achieved to date and the completed restoration work in this watershed and 2) progress toward the development of site-specific standards, to ensure that division and stakeholder resources are expended appropriately. Finally, this action is not expected to restrict options for future Superfund remedial actions, based on the flexibilities afforded at 31.11(5) and under CERCLA (e.g., CERCLA Section 121(d)(4)) to consider site-specific conditions, as appropriate. It is the commission’s understanding that interested parties and stakeholders, including EPA Superfund staff, the Colorado Hazardous Materials and Waste Management Division, and the CAG, will continue to evaluate the appropriateness and necessity of developing site-specific standards for this segment. If sufficient information becomes available to support feasibility-based ambient standards or site-specific criteria-based standards (per 31.7(1)(b)(ii) or 31.7(1)(b)(iii), respectively), adoption of site-specific standards for this segment may be considered by the commission. It is not the commission’s intention for the table value standards to drive cleanup measures of sources of water for the ecologically-rare Chattanooga iron fens alongside of Segment 8b (CAG Prehearing Statement Exhibit P), without consideration of how cleanup may affect the fens. One of those sources is discharge from an abandoned mine, commonly known as the Ferrocrete Mine (37.86810827, - 107.7266958), that is not a major source of copper, lead, cadmium, and zinc to the segment. This mine has not been designated as part of Bonita Peak Mining District Superfund Site.
F. Standards to Protect the Aquatic Life, Recreation, Water Supply, and Agriculture Uses The commission reviewed the standards applied to each segment to determine if the standards are consistent with the uses. 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 commission adopted the missing standards for the following segments: Piedra River 6a (COSJPI06a): chronic iron and manganese standards to protect the Water Supply Use, which were inadvertently deleted in 2017, were adopted back onto this segment. Los Pinos River 7a (COSJPN07a): chronic arsenic standard of 7.6 µg/L was changed to 0.02-10 µg/L to protect the Water Supply Use adopted on this segment in 2017.
G. Other Standards to Protect Aquatic Life and Recreation Uses 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.
H. Antidegradation Designations: Outstanding Waters The commission designated several segments or waterbodies as Outstanding Waters based on evidence provided by the Southwest Colorado Outstanding Waters Coalition (SCOWC) that satisfied the criteria for Outstanding Waters designation set forth in Section 31.8(2)(a). The SCOWC is a diverse coalition comprising American Rivers, American Whitewater, Conservation Colorado, High Country Conservation Advocates, San Juan Citizens Alliance, The Pew Charitable Trusts, Trout Unlimited/Colorado Trout Unlimited/Dolores River Anglers, and Western Resource Advocates, 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 SCOWC 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 SCOWC, 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:
Additionally, as discussed below, some waterbodies supported some 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. San Juan Segment 4 (COSJSJ04): The SCOWC demonstrated that Fall Creek and Wolf Creek have exceptional ecological value because they support San Juan lineage cutthroat trout and high-scoring benthic macroinvertebrate communities.
The SCOWC demonstrated that Priest, Wildcat, and Slate Creek have exceptional ecological value because they support populations of Green lineage (Colorado River) cutthroat trout. In addition, the Slate Creek headwaters originate in the Lizard Head Wilderness Area. The SCOWC demonstrated that Stoner Creek has exceptional ecological value because it supports a population cutthroat trout like to be Green lineage (Colorado River) cutthroat trout. The SCOWC demonstrated that Coal Creek has exceptional ecological value because it supports a population of Blue lineage (Colorado River) cutthroat trout. In addition, the Coal Creek headwaters originate in the Lizard Head Wilderness Area. For all of these waterbodies, the SCOWC demonstrated that additional protection is needed due 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.
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.
I. Clarifications and Correction of Segmentation, Typographical, and Other Errors The following edits were made to the regulation and Appendix 34-1 to improve clarity and correct typographical errors:
San Juan River: 5, 6b, 10, 11b, 11c Piedra River: 3, 4a, 5a, 5b, 6c, 6d Los Pinos River: 2c, 2d, 4, 5, 7a, 7b Animas and Florida River: 6, 11c, 12a, 12c, 12d, 13a, 13b, 13c, 13d, 13e, 13f, 14a, 14b, 15 La Plata River: 3d, 3e, 4c, 5, 6a, 6b, 6c, 9 Dolores River: 5b, 6, 8, 9, 10a, 10b, 11a, 11c 7. The commission adopted the missing statement of “*Southern Ute Indian Reservation" to the Appendix 34-1 table for COSJPN07a, to indicate that this segment is located within the Southern Ute Indian tribe’s reservation boundaries.
““The aluminum standards for segments 3a, 4a and 9 have been specified as “total recoverable”, since that sampling fraction correlates better with the principal aquatic life toxicity studies available than the dissolved fraction.” 10. The dates for when the Recreation E Use applies to COSJPI07 were corrected to be consistent with the associated E. coli standards in the Appendix 34-1 tables.
34.56 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 34.5(5) 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 34.6(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 34.6(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 34-1, 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.
C. Clarifications and Corrections The following edits were made to the regulation and Appendix 34-1 to improve clarity and correct errors: • The Direct Use Water Supply (DUWS) references in segments in Appendix 34-1 were revised to improve clarity and consistency.
34.57 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 (34.41) and subsequent rulemaking hearings (34.47 and 34.48), 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 (34.50(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 34.6(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:
To remain consistent with the commission’s decisions regarding arsenic in section 34.41, all existing temporary modifications for arsenic of “As(ch)=hybrid” (expiration date of 12/31/24) were retained.
34.58 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.
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 34.6(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 Programs (PMPs) for two discharger- specific variances (DSVs) in Regulation No. 34. These DSVs were reviewed in this rulemaking hearing because they were scheduled to expire soon; specifically, on December 31, 2024 (Durango West Metro Dist. #2) and June 20, 2025 (Town of Dove Creek).
The commission adopted a DSV with initial AELs to protect the ambient water quality in the receiving stream and final AELs that are based upon the expected ammonia effluent quality that will be achieved through feasible improvements to the lagoon system. Because there is uncertainty in the final effluent quality that will be achieved, the Town of Dove Creek will collect additional data to characterize the effectiveness of the improvements, which the commission will review upon reevaluation of the DSV. The commission expects that the Town of Dove Creek will submit annual reports to the division describing the progress made on PMP implementation in November of each year until the end of the DSV. If, at the end of the DSV, it remains infeasible for the Town of Dove Creek to achieve ammonia WQBELs and the Town of Dove Creek substantially complied with all conditions of this variance, a subsequent DSV may be appropriate. COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT 5 CCR 1002-34 REGULATION NO. 34 CLASSIFICATIONS AND NUMERIC STANDARDS FOR SAN JUAN RIVER AND DOLORES RIVER BASINS APPENDIX 34-1 Stream Classifications and Water Quality Standards Tables Effective 12/31/2024 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 San Juan River Basin 1a. Mainstem of the Navajo River including all wetlands and tributaries from the boundary of the South San Juan Wilderness Area to below the confluence with Sheep Creek. Mainstem of the Little Navajo River, including all wetlands and tributaries, from the boundary of the South San Juan Wilderness Area to the San Juan-Chama Diversion. COSJSJ01A Classifications Physical and Biological Metals (ug/L) 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 34.5(3) for details.
COSJSJ01B Classifications Physical and Biological Metals (ug/L) 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 34.5(3) for details.
2. Mainstem of the Navajo River from the Colorado/New Mexico border to the confluence with the San Juan River. COSJSJ02 Classifications Physical and Biological Metals (ug/L) 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) --- 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 Mo dification(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 * * * S U U o r r a a u n n th i i u u e m m rn ( ( c a U h c t u r e o t e n In )
ic d = )
o n f r o d r e d t e a t i a ls i .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS
3. Mainstem of the Little Navajo River from the San Juan-Chama diversion to the confluence with the Navajo River; all tributaries to the Navajo River and the Little Navajo River, including all wetlands, from the San Juan-Chama diversions to the confluence with the San Juan River. COSJSJ03 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 2 Temperature °C WS-II WS-II Arsenic 340 --- Recreation N 11/1 - 4/30 acute chronic Arsenic(T) --- 100 Recreation P 5/1 - 10/31 D.O. (mg/L) --- 5.0 Beryllium(T) --- 100 Qualifiers: pH 6.5 - 9.0 --- Cadmium TVS TVS Other: chlorophyll a (mg/m2) --- TVS Chromium III TVS TVS
4. All tributaries to the San Juan River, Rio Blanco, and Navajo River including all wetlands which are within the Weminuche Wilderness area and South San Juan Wilderness Area. Mainstem of Fall Creek, including tributaries and wetlands, from its source to the irrigation diversion just upstream from the confluence with Wolf Creek. Mainstem of Wolf Creek, including tributaries and wetlands, from the boundary of the Weminuche Wilderness area to the confluence with Fall Creek. Mainstem of Quartz Creek, including tributaries and wetlands, from the boundary of the South San Juan Wilderness area to the boundary of the San Juan National Forest. COSJSJ04 Classifications Physical and Biological Metals (ug/L) 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 34.5(3) for details.
5. The East and West Forks of the San Juan River, including all tributaries and wetlands, from the boundary of the Weminuche Wilderness Area (West Fork) and the source (East Fork) to the confluence of the mainstem of the San Juan River, except for the listings in Segment 4. All tributaries and wetlands to the San Juan River from a point below the confluence with the West Fork to a point below the confluence with Fourmile Creek. COSJSJ05 Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 34.5(5). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 34.5(3) for details.
t = total MWAT = maximum weekly average temperature 128 San Juan River Basin 6a. Mainstem of the San Juan River from a point immediately below the confluence with the West Fork to Highway 160 in Pagosa Springs. COSJSJ06A Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 34.5(5). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 34.5(3) for details.
6b. Mainstem of the San Juan River from Highway 160 in Pagosa Springs to the Southern Ute Indian Reservation Northern boundary. Mainstem of Mill Creek, including wetlands, from the source to the confluence with the San Juan River. COSJSJ06B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C 11/1 - 3/31 CS-II CS-II Arsenic 340 --- Recreation E Temperature °C 4/1 - 10/31 varies* varies* C Arsenic(T) --- 0.02 Water Supply Cadmium TVS TVS Qualifiers: acute chronic Cadmium(T) 5.0 --- Other: D.O. (mg/L) --- 6.0 Chromium III --- TVS D.O. (spawning) --- 7.0 Chromium III(T) 50 --- Temporary Modification(s):
fo .1 r a a s n s d e D ss M m = e n t . 8 lo cations.
Phosphorus --- TVS* Uranium varies* varies* Sulfate --- WS Zinc TVS TVS(sc)
Sulfide --- 0.002 t = total MWAT = maximum weekly average temperature 129 San Juan River Basin 6c. Mainstem of the San Juan River from the Southern Ute Indian Reservation northern boundary to the confluence with Taylor Canyon. COSJSJ06C Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C 11/1 - 3/31 CS-II CS-II Arsenic 340 --- Recreation E Temperature °C 4/1 - 10/31 26.4* 22.1* C Arsenic(T) --- 0.02 Water Supply Cadmium TVS TVS Qualifiers: acute chronic Cadmium(T) 5.0 --- Other: D.O. (mg/L) --- 6.0 Chromium III --- TVS D.O. (spawning) --- 7.0 Chromium III(T) 50 --- *Southern Ute Indian Reservation pH 6.5 - 9.0 --- Chromium VI TVS TVS *Uranium(acute) = See 34.5(3) for details.
chlorophyll a (mg/m2) --- TVS Copper TVS TVS *Uranium(chronic) = See 34.5(3) for details.
Phosphorus --- --- Uranium varies* varies* Sulfate --- WS Zinc TVS TVS Sulfide --- 0.002 6d. Mainstem of the San Juan River from the confluen ce with Taylor Canyon to the confluenc e with t he R io Blanco. COSJSJ06D Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C 11/1 - 3/31 CS-II CS-II Arsenic 340 --- Recreation E Temperature °C 4/1 - 10/31 27.1* 22.5* C Arsenic(T) --- 0.02 Water Supply Cadmium TVS TVS Qualifiers: acute chronic Cadmium(T) 5.0 --- Other: D.O. (mg/L) --- 6.0 Chromium III --- TVS D.O. (spawning) --- 7.0 Chromium III(T) 50 --- *Southern Ute Indian Reservation pH 6.5 - 9.0 --- Chromium VI TVS TVS *Uranium(acute) = See 34.5(3) for details.
chlorophyll a (mg/m2) --- TVS Copper TVS TVS *Uranium(chronic) = See 34.5(3) for details.
Phosphorus --- --- Uranium varies* varies* Sulfate --- WS Zinc TVS TVS Sulfide --- 0.002 t = total MWAT = maximum weekly average temperature 130 San Juan River Basin 6e. Mainstem of the San Juan River from the confluence with the Rio Blanco to the confluence with the Navajo River. COSJSJ06E Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C 11/1 - 3/31 CS-II CS-II Arsenic 340 --- Recreation E Temperature °C 4/1 - 10/31 28.7* 23.5* C Arsenic(T) --- 0.02 Water Supply Cadmium TVS TVS Qualifiers: acute chronic Cadmium(T) 5.0 --- Other: D.O. (mg/L) --- 6.0 Chromium III --- TVS D.O. (spawning) --- 7.0 Chromium III(T) 50 --- *Southern Ute Indian Reservation pH 6.5 - 9.0 --- Chromium VI TVS TVS *Uranium(acute) = See 34.5(3) for details.
chlorophyll a (mg/m2) --- TVS Copper TVS TVS *Uranium(chronic) = See 34.5(3) for details.
Phosphorus --- --- Uranium varies* varies* Sulfate --- WS Zinc TVS TVS Sulfide --- 0.002 6f. Mainstem of the San Juan River from the confluen ce with the Navajo River to Navajo Res ervoir. COSJSJ06F Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C 11/1 - 3/31 CS-II CS-II Arsenic 340 --- Recreation E Temperature °C 4/1 - 10/31 28.8* 24.2* C Arsenic(T) --- 0.02 Water Supply Cadmium TVS TVS Qualifiers: acute chronic Cadmium(T) 5.0 --- Other: D.O. (mg/L) --- 6.0 Chromium III --- TVS D.O. (spawning) --- 7.0 Chromium III(T) 50 --- *Southern Ute Indian Reservation pH 6.5 - 9.0 --- Chromium VI TVS TVS *Uranium(acute) = See 34.5(3) for details.
chlorophyll a (mg/m2) --- TVS Copper TVS TVS *Uranium(chronic) = See 34.5(3) for details.
Phosphorus --- --- Uranium varies* varies* Sulfate --- WS Zinc TVS TVS Sulfide --- 0.002 t = total MWAT = maximum weekly average temperature 131 San Juan River Basin
7. Mainstem of the Rio Blanco, including all tributaries and wetlands, from the boundary of the South San Juan Wilderness Area to below the confluence with Leche Creek. COSJSJ07 Classifications Physical and Biological Metals (ug/L) 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 34.5(3) for details.
8. Navajo Reservoir. Echo Canyon Reservoir.
COSJSJ08 Classifications Physical and Biological Metals (ug/L) 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) --- 5.0 Cadmium TVS TVS Qualifiers: pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Other: chlorophyll a (ug/L) --- TVS Chromium III --- TVS
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COSJSJ09A Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
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Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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(sc)
9b. Mainstem of the Rio Blanco, including all tributaries and wetlands, from the boundary of the Southern Ute Indian R eservation to the confluence with the San Juan River. COSJSJ09B Classifications Physical and Biological Metals (ug/L) 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 --- *Southern Ute Indian Reservation
10. Mainstem of the Rito Blanco River, including wetlands, from Echo Ditch to the confluence with the Rio Blanco River. COSJSJ10 Classifications Physical and Biological Metals (ug/L) 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 34.5(3) for details.
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Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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 t = total MWAT = maximum weekly average temperature 134 San Juan River Basin 11b. All tributaries to the San Juan River, including wetlands, from the Southern Ute Indian Reservation boundary to the Colorado/New Mexico border except for the specific listings in Segments 6a, 6b, 9a and 9b. Sambrito Creek, Scaggs Canyon, Sandoval Canyon and other unnamed tributaries and wetlands that flow directly into Navajo Reservoir. COSJSJ11B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 1 Temperature °C WS-II WS-II Arsenic 340 --- Recreation E 5/1 - 10/31 acute chronic Arsenic(T) --- 0.02 Recreation N 11/1 - 4/30 D.O. (mg/L) --- 5.0 Cadmium TVS TVS Water Supply pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Qualifiers: chlorophyll a (mg/m2) --- TVS Chromium III TVS TVS Other: E. Coli (per 100 mL) 5/1 - 10/31 --- 126 Chromium III(T) --- 100 E. Coli (per 100 mL) 11/1 - 4/30 --- 630 Chromium VI TVS TVS *Southern Ute Indian Reservation Copper TVS TVS *Uranium(acute) = See 34.5(3) for details.
Inorganic (mg/L) Iron --- WS *Uranium(chro nic) = See 34.5(3) for details.
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 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS 11c. McCabe Creek, including wetlands, from the sou rce to the confluence with the San Juan River. COSJSJ11C Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C 11/1 - 3/31 CS-II CS-II Arsenic 340 --- Recreation E Temperature °C 4/1 - 10/31 25.1* 21.6* C Arsenic(T) --- 0.02 Water Supply Cadmium TVS TVS Qualifiers: acute chronic Cadmium(T) 5.0 --- Other: D.O. (mg/L) --- 5.0 Chromium III --- TVS Temporary Mo dification(s): pH 6.5 - 9.0 --- Chromium III(T) 50 --- Arsenic(chronic) = hybrid chlorophyll a (mg/m2) --- TVS Chromium VI TVS TVS Expiration Date of 12/31/2029 E. Coli (per 100 mL) --- 126 Copper TVS TVS Inorganic (mg/L ) Iron --- WS * * * U U Te r r a a m n n p i i u u e m m ra ( ( t c a u h c r u r e o t ( e n )
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o f r o d r e d t e a t i a ls i .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S See Section 34.6(6) for assessment locations. Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS t = total MWAT = maximum weekly average temperature 135 San Juan River Basin
12. All tributaries to the San Juan River in Archuleta County, including all wetlands, except for specific listings in Segments 1a, 1b, 2, 3, 4, 5, 6a, 6b, 7, 9a, 9b, 10, 11a, 11b and 12b. This segment includes Coyote Creek from its source to the Colorado/New Mexico border. COSJSJ12 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 2 Temperature °C WS-III WS-III Arsenic 340 --- Recreation N 11/1 - 4/30 acute chronic Arsenic(T) --- 7.6 Recreation P 5/1 - 10/31 D.O. (mg/L) --- 5.0 Beryllium(T) --- 100 Qualifiers: pH 6.5 - 9.0 --- Cadmium TVS TVS Other: chlorophyll a (mg/m2) --- TVS Chromium III --- TVS
13. All lakes and reservoirs that are tributary to the mainstem of the Navajo River and the Little Navajo River, from the boundary of the South San Juan Wilderness Area to the Colorado/New Mexico border, except for specific listings in Segment 14. This segment includes Gardner Lake, Fall View Lake, Hidden Lake, Dolomite Lake, Bull Elk Pond, Price Lakes, and Spence Reservoir.
COSJSJ13 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CL CL 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 34.5(3) for details.
14. All lakes and reservoirs that are tributary to the Navajo River and the Little Navajo River, from the San Juan-Chama diversions to the confluence with the San Juan River. COSJSJ14 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 2 Temperature °C WL WL Arsenic 340 --- Recreation N 11/1 - 4/30 acute chronic Arsenic(T) --- 100 Recreation P 5/1 - 10/31 D.O. (mg/L) --- 5.0 Beryllium(T) --- 100 Qualifiers: pH 6.5 - 9.0 --- Cadmium TVS TVS Other: chlorophyll a (ug/L) --- TVS Chromium III TVS TVS
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 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 t = total MWAT = maximum weekly average temperature 137 San Juan River Basin 15b. All lakes and reservoirs which are tributary to the Rio Blanco, from the boundary of the Southern Ute Indian Reservation to the confluence with the San Juan River. COSJSJ15B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CL CL 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 --- *Southern Ute Indian Reservation E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS *Uranium(acute) = See 34.5(3) for details.
Copper TVS TVS *Uranium(chronic) = See 34.5(3) for details.
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 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
16. All lakes and reservoirs which are tributary to the San Juan River, Rio Blanco, and Navajo River and located within the Weminuche Wilderness Area and South San Juan Wilderness Area. This segment includes Archuleta Lake, Spruce Lakes, Turkey Creek Lake, Fourmile Lake, Upper Fourmile Lake, Crater Lake, Quartz Lake, Fish Lake, and Opal Lake.
COSJSJ16 Classifications Physical and Biological Metals (ug/L) OW Aq Life Cold 1 Temperature °C CL CL 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 34.5(3) for details.
17. All lakes and reservoirs that are tributary to the San Juan River and the East Fork and West Fork of the San Juan River, from the boundary of the Weminuche Wilderness Area (West Fork) and the source (East Fork) to the confluence with Fourmile Creek. This segment includes Born Lake, Hatcher Lakes, T Lazy T Reservoir, and Lost Lake. COSJSJ17 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CL CL 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 34.5(3) for details.
COSJSJ18A Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 1 Temperature °C WL WL Arsenic 340 --- Recreation E 5/1 - 10/31 acute chronic Arsenic(T) --- 7.6 Recreation N 11/1 - 4/30 D.O. (mg/L) --- 5.0 Cadmium TVS TVS Qualifiers: pH 6.5 - 9.0 --- Chromium III TVS TVS Other: chlorophyll a (ug/L) --- TVS Chromium III(T) --- 100
COSJSJ18B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 1 Temperature °C WL WL Arsenic 340 --- Recreation E 5/1 - 10/31 acute chronic Arsenic(T) --- 7.6 Recreation N 11/1 - 4/30 D.O. (mg/L) --- 5.0 Cadmium TVS TVS Qualifiers: pH 6.5 - 9.0 --- Chromium III TVS TVS Other: chlorophyll a (ug/L) --- TVS Chromium III(T) --- 100
19. All lakes and reservoirs in Archuleta County which are tributary to the San Juan River, except for specific listings in Segment 18b. All lakes and reservoirs which are tributary to Coyote Creek from its source to the Colorado/New Mexico border. COSJSJ19 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 2 Temperature °C WL WL Arsenic 340 --- Recreation N 11/1 - 4/30 acute chronic Arsenic(T) --- 7.6 Recreation P 5/1 - 10/31 D.O. (mg/L) --- 5.0 Beryllium(T) --- 100 Qualifiers: pH 6.5 - 9.0 --- Cadmium TVS TVS Fish Ingestion chlorophyll a (ug/L) --- TVS Chromium III --- TVS Other: E. Coli (per 100 mL) 5/1 - 10/31 --- 205 Chromium III(T) 100 ---
1. All tributaries to the Piedra River, including all wetlands, which are within the Weminuche Wilderness Area. COSJPI01 Classifications Physical and Biological Metals (ug/L) 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 34.5(3) for details.
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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(sc)
t = total MWAT = maximum weekly average temperature 141 Piedra River Basin 2b. Mainstem of the Piedra River from the confluence with the East and Middle Forks to the confluence with Indian Creek. COSJPI02B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Arsenic 340 --- Recreation E 4/1 - 10/31 acute chronic Arsenic(T) --- 0.02 Recreation N 11/1 - 3/31 D.O. (mg/L) --- 6.0 Cadmium TVS TVS Water Supply D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Qualifiers: pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 ---
3. Mainstem of the East Fork of the Piedra River, inclu ding wetlands, from the Piedra Falls Ditch to the confluence with Pagosa Creek. COSJPI03 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E 4/1 - 10/31 acute chronic Arsenic(T) --- 0.02 Recreation N 11/1 - 3/31 D.O. (mg/L) --- 6.0 Cadmium TVS TVS Water Supply D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Qualifiers: pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 ---
t = total MWAT = maximum weekly average temperature 142 Piedra River Basin 4a. Mainstem of the Piedra River from a point immediately below the confluence with Indian Creek to the Southern Ute Indian Reservation boundary. Devil Creek, including wetlands, from Dunagan Canyon to the confluence with the Piedra River. COSJPI04A Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C 11/1 - 3/31 CS-II CS-II Arsenic 340 --- Recreation E Temperature °C 4/1 - 10/31 varies* varies* C Arsenic(T) --- 0.02 Water Supply Cadmium TVS TVS Qualifiers: acute chronic Cadmium(T) 5.0 --- Other: D.O. (mg/L) --- 6.0 Chromium III --- TVS D.O. (spawning) --- 7.0 Chromium III(T) 50 --- *Uranium(acute) = See 34.5(3) for details.
fo r . 9 a s a s n e d s s D m M e = n t lo .5 c ations.
Phosphorus --- TVS Uranium varies* varies* Sulfate --- WS Zinc TVS TVS(sc)
Sulfide --- 0.002 4b. Mainstem of the Piedra River from the Southern U te Indian Reservation boundary to a po int abov e the confluence with Stollsteimer Creek. COSJPI04B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C 11/1 - 3/31 CS-II CS-II Arsenic 340 --- Recreation E Temperature °C 4/1 - 10/31 28.8* 22.8* C Arsenic(T) --- 0.02 Water Supply Cadmium TVS TVS Qualifiers: acute chronic Cadmium(T) 5.0 --- Other: D.O. (mg/L) --- 6.0 Chromium III --- TVS Temporary Mo dification(s): D.O. (spawning) --- 7.0 Chromium III(T) 50 --- Arsenic(chronic) = hybrid pH 6.5 - 9.0 --- Chromium VI TVS TVS Expiration Date of 12/31/2029 chlorophyll a (mg/m2) --- TVS Copper TVS TVS E. Coli (per 100 mL) --- 126 Iron --- WS *Southern Ute Indian Reservation Iron(T) --- 1000 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Inorganic (mg/L) Lead TVS TVS *Temperature(4/1 - 10/31) = acute chronic Lead(T) 50 --- See Section 34 .6(6) for assessment locations.
Ammonia TVS TVS Manganese TVS TVS/WS Boron --- 0.75 Mercury(T) --- 0.01 Chloride --- 250 Molybdenum(T) --- 150 Chlorine 0.019 0.011 Nickel TVS TVS Cyanide 0.005 --- Nickel(T) --- 100 Nitrate 10 --- Selenium TVS TVS Nitrite --- 0.05 Silver TVS TVS(tr)
Phosphorus --- --- Uranium varies* varies* Sulfate --- WS Zinc TVS TVS Sulfide --- 0.002 t = total MWAT = maximum weekly average temperature 143 Piedra River Basin 4c. Mainstem of the Piedra River from a point above the confluence with Stollsteimer Creek to Navajo Reservoir. COSJPI04C Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C 11/1 - 3/31 CS-II CS-II Arsenic 340 --- Recreation E Temperature °C 4/1 - 10/31 28.8* 22.8* C Arsenic(T) --- 0.02 Water Supply Cadmium TVS TVS Qualifiers: acute chronic Cadmium(T) 5.0 --- Other: D.O. (mg/L) --- 6.0 Chromium III --- TVS Temporary Mo dification(s): D.O. (spawning) --- 7.0 Chromium III(T) 50 --- Arsenic(chronic) = hybrid pH 6.5 - 9.0 --- Chromium VI TVS TVS Expiration Date of 12/31/2029 chlorophyll a (mg/m2) --- TVS Copper TVS TVS E. Coli (per 100 mL) --- 126 Iron --- WS *Southern Ute Indian Reservation Iron(T) --- 1000 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Inorganic (mg/L) Lead TVS TVS *Temperature(4/1 - 10/31) = acute chronic Lead(T) 50 --- See Section 34 .6(6) for assessment locations.
Ammonia TVS TVS Manganese TVS TVS/WS Boron --- 0.75 Mercury(T) --- 0.01 Chloride --- 250 Molybdenum(T) --- 150 Chlorine 0.019 0.011 Nickel TVS TVS Cyanide 0.005 --- Nickel(T) --- 100 Nitrate 10 --- Selenium TVS TVS Nitrite --- 0.05 Silver TVS TVS(tr)
Phosphorus --- --- Uranium varies* varies* Sulfate --- WS Zinc TVS TVS Sulfide --- 0.002 5a. All tributaries to the Piedra River, including all wetlands, from the boundary of the Weminuche Wilderness Area to a point immediately below the confluence with the First Fork of the Piedra River. Devil Creek, including all tributaries and wetlands, from the source to a point below the confluence with Dunagan Canyon. COSJPI05A Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E 5/1 - 10/31 acute chronic Arsenic(T) --- 0.02 Recreation N 11/1 - 4/30 D.O. (mg/L) --- 6.0 Cadmium TVS TVS Water Supply D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Qualifiers: pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Mo dification(s): E. Coli (per 100 mL) 5/1 - 10/31 --- 126 Chromium VI TVS TVS Arsenic(chronic) = hybrid E. Coli (per 100 mL) 11/1 - 4/30 --- 630 Copper TVS TVS Expiration Date of 12/31/2029 Ino rganic (mg/L ) Iron --- WS * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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(sc)
t = total MWAT = maximum weekly average temperature 144 Piedra River Basin 5b. All tributaries to the Piedra River, including wetlands, from a point immediately below the confluence with the First Fork of the Piedra River to a point immediately below the confluence with Devil Creek, except for the specific listings in Segments 4a and 5a. COSJPI05B Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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(sc)
6a. All tributaries to the Piedra River, including all wetlands, from a point immediately below the confluence with Devil Creek to Southern Ute Indian Reservation boundary, except the specific listing in Segment 6d.
COSJPI06A Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 2 Temperature °C WS-II WS-II Arsenic 340 --- Recreation P acute chronic Arsenic(T) --- 0.02-10 A 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
acute chronic Copper TVS TVS *Uranium(chro nic) = See 34.5(3) for details.
Ammonia TVS TVS Iron --- WS Boron --- 0.25 Iron(T) --- 1000 Chloride --- 250 Lead TVS TVS Chlorine 0.019 0.011 Lead(T) 50 --- Cyanide 0.005 --- Manganese TVS TVS/WS Nitrate 10 --- Mercury(T) --- 0.01 Nitrite --- 0.5 Molybdenum(T) --- 150 Phosphorus --- TVS Nickel TVS TVS Sulfate --- WS Nickel(T) --- 100 Sulfide --- 0.002 Selenium TVS TVS Silver TVS TVS Uranium varies* varies* Zinc TVS TVS 6c. Stollsteimer Creek, including all tributaries and we tlands, from the Southern Ute Indian Reservation boundary to th e confluence with the Piedra Rive r. COSJPI06C Classifications Physical and Biological Metals (ug/L) UP Aq Life Warm 2 Temperature °C WS-II WS-II Arsenic 340 --- Recreation P acute chronic Arsenic(T) --- 0.02-10 A 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 E. Coli (per 100 mL) --- 205 Chromium III(T) 50 --- *Southern Ute Indian Reservation Inorganic (mg/L ) Chromium VI TVS TVS *Uranium(acute) = See 34.5(3) for details.
acute chronic Copper TVS TVS *Uranium(chro nic) = See 34.5(3) for details.
Ammonia TVS TVS Iron --- WS Boron --- 0.25 Iron(T) --- 1000 Chloride --- 250 Lead TVS TVS Chlorine 0.019 0.011 Lead(T) 50 --- Cyanide 0.005 --- Manganese TVS TVS/WS Nitrate 10 --- Mercury(T) --- 0.01 Nitrite --- 0.5 Molybdenum(T) --- 150 Phosphorus --- TVS Nickel TVS TVS Sulfate --- WS Nickel(T) --- 100 Sulfide --- 0.002 Selenium TVS TVS Silver TVS TVS Uranium varies* varies* Zinc TVS TVS t = total MWAT = maximum weekly average temperature 146 Piedra River Basin 6d. Steven’s draw, including wetlands, from the outlet of Lake Forest Reservoir to the confluence with Martinez Creek. COSJPI06D Classifications Physical and Biological Metals (ug/L) UP Aq Life Warm 2 Temperature °C WS-II WS-II Arsenic 340 --- Recreation P 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) --- TVS Chromium VI TVS TVS * 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 .
c )
7. Hatcher Reservoir, Stevens Reservoir, Sullenbuge r Reservoir, Village Lake and Forest La ke. COSJPI07 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 1 Temperature °C WL WL Arsenic 340 --- Recreation E 3/2 - 11/30 acute chronic Arsenic(T) --- 0.02 Recreation N 12/1 - 3/1 D.O. (mg/L) --- 5.0 Cadmium TVS TVS Water Supply pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- DUWS* chlorophyll a (ug/L) --- DUWS Chromium III --- TVS Qualifiers:
8. Williams Creek Reservoir.
COSJPI08 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CLL CLL Arsenic 340 --- Recreation E 5/1 - 10/31 acute chronic Arsenic(T) --- 0.02 Recreation N 11/1 - 4/30 D.O. (mg/L) --- 6.0 Cadmium TVS TVS Water Supply D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Qualifiers: pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (ug/L) --- TVS Chromium III(T) 50 ---
9. All lakes and reservoirs tributary to the Piedra River which are within the Weminuche Wilderness Area. This segment includes Window Lake, Monument Lake, Hossick Lake, and Williams Lakes.
COSJPI09 Classifications Physical and Biological Metals (ug/L) OW Aq Life Cold 1 Temperature °C CL CL 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 34.5(3) for details.
10. All lakes and reservoirs which are tributary to the Piedra River, from the boundary of the Weminuche Wilderness Area to a point immediately below the confluence with Devil Creek, except the specific listing in Segment 8. This segment includes Palisade Lake, Martin Lake, and O’Connell Lake. COSJPI10 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CL CL Arsenic 340 --- Recreation E 5/1 - 10/31 acute chronic Arsenic(T) --- 0.02 Recreation N 11/1 - 4/30 D.O. (mg/L) --- 6.0 Cadmium TVS TVS Water Supply D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Qualifiers: pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (ug/L) --- TVS Chromium III(T) 50 ---
COSJPI11A Classifications Physical and Biological Metals (ug/L) UP Aq Life Warm 2 Temperature °C WL WL 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 --- Water + Fish Standards chlorophyll a (ug/L) --- TVS Chromium III --- TVS Other: E. Coli (per 100 mL) --- 126 Chromium III(T) 50 --- Inorganic (mg/L ) Chromium VI TVS TVS *Uranium(acute) = See 34.5(3) for details.
1. All tributaries to the Los Pinos River, including all wetlands, which are within the Weminuche Wilderness Area. COSJPN01 Classifications Physical and Biological Metals (ug/L) 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):
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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 2a. Mainstem of the Los Pinos River from the boundary of the Weminuche Wilderness Area to the boundary of the Southern Ute Indian Reservation except for the specific listing in Segment 3.
COSJPN02A Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 34.5(5). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 34.5(3) for details.
t = total MWAT = maximum weekly average temperature 151 Los Pinos River Basin 2b. Mainstem of the Los Pinos River from the boundary of the Southern Ute Indian Reservation to the Pine Ditch Diversion (37.1906, -107.58778). COSJPN02B Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 * * * S U U o r r a a u n n th i i u u e m m rn ( ( c a U h c t u r e o t e n In )
ic d = )
o n f r o d r e d t e a t i a ls i .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- --- Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS 2c. Mainstem of the Los Pinos River from the Pine Ditch Diversion (37.1906, -107.58778) to above the confluence with Dry Creek. Mainstem of Beaver Creek, including wetlands, from the boundary of the Southern Ute Indian Reservation to the confluence with the Los Pinos River. COSJPN02C Classifications Physical and Biological Metals (ug/L) 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 --- *Southern Ute Indian Reservation E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS *Uranium(acute) = See 34.5(3) for details.
Copper TVS TVS *Uranium(chron ic) = See 34.5(3) for details.
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 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- --- Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS t = total MWAT = maximum weekly average temperature 152 Los Pinos River Basin 2d. Mainstem of the Los Pinos River from above the confluence with Dry Creek to New Mexico state line. Mainstems of Dry Creek, Ute Creek, Spring Creek and Rock Creek, including wetlands, from the boundary of the Southern Ute Indian Reservation to the confluence with the Los Pinos River. COSJPN02D Classifications Physical and Biological Metals (ug/L) 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 --- *Southern Ute Indian Reservation E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS *Uranium(acute) = See 34.5(3) for details.
Copper TVS TVS *Uranium(chron ic) = See 34.5(3) for details.
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 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- --- Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS
3. Vallecito Reservoir.
COSJPN03 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CLL 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 --- Temporary Modification(s):
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- --- Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS t = total MWAT = maximum weekly average temperature 153 Los Pinos River Basin
4. All tributaries to the Los Pinos River and Vallecito Reservoir, including all wetlands, from the boundary of the Weminuche Wilderness Area to a point immediately below the confluence with Bear Creek, except for the specific listing in Segment 5; mainstems of Beaver Creek, Ute Creek, and Spring Creek, including wetlands, from their sources to the boundary of the Southern Ute Indian Reservation.
COSJPN04 Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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(sc)
5. Mainstem of Vallecito Creek, including wetlands, fro m the boundary of the Weminuche Wilderness Area to Vallecito Reservoir. COSJPN05 Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 34.5(5). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 34.5(3) for details.
6. All tributaries to the Los Pinos River, including all wetlands, from a point immediately below the confluence with Bear Creek to the boundary of the Southern Ute Indian Reservation except for specific listings in Segment 4.
COSJPN06 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 Temperature °C CS-II CS-II Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02 Water Supply D.O. (mg/L) --- 6.0 Beryllium(T) --- 100 Qualifiers: D.O. (spawning) --- 7.0 Cadmium TVS TVS Fish Ingestion pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Other: chlorophyll a (mg/m2) --- TVS Chromium III TVS TVS Temporary Mo dification(s): E. Coli (per 100 mL) --- 126 Chromium III(T) --- 100 Arsenic(chronic) = hybrid Chromium VI TVS TVS Expiration Date of 12/31/2029 Inorganic (mg/L) Copper TVS TVS * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I I r r o o n n (T)
- - - - - - 10 W S Boron --- 0.75 Lead TVS TVS Chloride --- 250 Lead(T) 50 --- Chlorine 0.019 0.011 Manganese TVS TVS/WS Cyanide 0.005 --- Mercury(T) --- 0.01 Nitrate 10 --- Molybdenum(T) --- 150 Nitrite --- --- Nickel TVS TVS Phosphorus --- TVS Nickel(T) --- 100 Sulfate --- WS Selenium TVS TVS Sulfide --- 0.002 Silver TVS TVS Uranium varies* varies* Zinc TVS TVS 7a. All tributaries to the Los Pinos River, including wetlands, from the Southern Ute Indian Reservation boundary to the Colorado/New Mexico border, except for the specific listings in Segments 2c and 2d.
COSJPN07A Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 Temperature °C WS-III WS-III Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02-10 A Water Supply D.O. (mg/L) --- 6.0 Beryllium(T) --- 100 Qualifiers: D.O. (spawning) --- 7.0 Cadmium TVS TVS Other: pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- chlorophyll a (mg/m2) --- TVS Chromium III TVS TVS *Southern Ute Indian Reservation
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 Nitrate 100 --- Uranium varies* varies* Nitrite --- 0.05 Zinc TVS TVS Phosphorus --- TVS Sulfate --- --- Sulfide --- 0.002
8. All lakes and reservoirs tributary to the Los Pinos River which are within the Weminuche Wilderness Area, except for the specific listing in Segment 9. This includes Granite Lake, Divide Lakes, Elk Lake, Flint Lakes, Moon Lake, Rock Lake, Betty Lake, Lost Lake, Hidden Lake, Vallecito Lake, Eldorado Lake, Trinity Lake, Leviathan Lake, Sunlight Lake, Hazel Lake, and Columbine Lake.
COSJPN08 Classifications Physical and Biological Metals (ug/L) OW Aq Life Cold 1 Temperature °C CL CL 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 34.5(3) for details.
9. Emerald Lake.
COSJPN09 Classifications Physical and Biological Metals (ug/L) OW Aq Life Cold 1 Temperature °C CLL 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 --- Temporary Modification(s):
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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
10. All lakes and reservoirs tributary to the Los Pinos River and Vallecito Reservoir from the boundary of the Weminuche Wilderness Area to a point immediately below the confluence with Bear Creek (T35N, R7W), except for the specific listing in Segment 3. This segment includes Lake Simpatico. COSJPN10 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CL CL 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 34.5(3) for details.
COSJPN11A Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 Temperature °C CL CL Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 100 Qualifiers: D.O. (mg/L) --- 6.0 Beryllium(T) --- 100 Other: D.O. (spawning) --- 7.0 Cadmium TVS TVS pH 6.5 - 9.0 --- Chromium III TVS TVS *Uranium(acute) = See 34.5(3) for details. chlorophyll a (ug/L) --- TVS Chromium III(T) --- 100 *Uranium(chronic) = See 34.5(3) for details.
COSJPN11B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 Temperature °C CL CL Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 100 Qualifiers: D.O. (mg/L) --- 6.0 Beryllium(T) --- 100 Other: D.O. (spawning) --- 7.0 Cadmium TVS TVS pH 6.5 - 9.0 --- Chromium III TVS TVS *Southern Ute Indian Reservation chlorophyll a (ug/L) --- TVS Chromium III(T) --- 100 *Uranium(acute) = See 34.5(3) for details.
1. All tributaries to the Animas River and Florida River, including all wetlands, which are within the Weminuche Wilderness Area. Mainstem Grasshopper Creek including tributaries and wetlands from source to confluence with Animas River. Mainstem Lime Creek including tributaries and wetlands from source to confluence with Cascade Creek. COSJAF01 Classifications Physical and Biological Metals (ug/L) 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 34.5(3) for details.
2. Mainstem of the Animas River, including all tributaries and wetlands, from the outlet of Denver Lake to a point immediately above the confluence with Minnie Gulch, except for specific listings in Segment 6.
COSJAF02 Classifications Physical and Biological Metals (ug/L) UP Recreation E Arsenic(T) --- 100 Qualifiers: acute chronic Beryllium(T) --- 100 Other: D.O. (mg/L) --- 3.0 Cadmium(T) --- 10 pH 5.8-9.0 --- Chromium III(T) --- 100 *The concentration of dissolved aluminum, chlorophyll a (mg/m2) --- TVS Chromium VI(T) --- 100 cadmium, copper, iron, lead, manganese, and zinc that is directed toward maintaining and achieving E. Coli (per 100 mL) --- 126 Copper(T) --- 200 s *U ta r n a d n a iu rd m s ( a e c s u ta te b )
V S u f g r / o L m fr o / m 1 - / / - 5 /31 Copper TVS TVS * s M pe a c n if g ic a n s e ta s n e d (c a h rd ro s n .
n ic) = See section 34.6(6) for site-specific Chloride --- --- Molybdenum(T) --- 150 standards.
COSJAF03B Classifications Physical and Biological Metals (ug/L) Designation Recreation E 5/15 - 9/10 DM MWAT acute chronic UP Recreation N 9/11 - 5/14 Arsenic --- --- Qualifiers: acute chronic Cadmium --- --- Other: D.O. (mg/L) --- 3.0 Chromium III --- --- pH 6.0-9.0 --- Chromium VI --- --- *The concentration of dissolved aluminum, chlorophyll a (mg/m2) --- TVS Copper --- --- cadmium, copper, iron, lead, manganese, and zinc that is directed toward maintaining and achieving E. Coli (per 100 mL) 5/15 - 9/10 --- 126 Iron --- --- w an a d te r b q .
u ality standards established for segments 4a
COSJAF04A Classifications Physical and Biological Metals (ug/L) UP Aq Life Cold 2* Temperature °C CS-I CS-I Aluminum(T) varies* varies* Recreation E acute chronic Arsenic 340 --- Qualifiers: D.O. (mg/L) --- 6.0 Arsenic(T) --- 100 Other: D.O. (spawning) --- 7.0 Cadmium TVS TVS pH varies* --- Chromium III TVS TVS * T C ro la u s t sification: Aquatic life indicator goal: Brook chlorophyll a (mg/m2) --- TVS Chromium III(T) --- 100 *Aluminum(T)(acute) = See section 34.6(6) for site- E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS s *A pe lu c m ifi i c n u s m ta ( n T d )
a (c rd h s ro .
e ) = See section 34.6(6) for site-specific Chloride --- --- Molybdenum(T) --- 150 * s Z ta in n c d ( a c r h d r s o .
n ic) = See section 34.6(6) for site-specific Chlorine 0.019 0.011 Nickel TVS TVS *pH(acute) = See section 34.6(6) for site-specific Cyanide 0.005 --- Selenium TVS TVS standards.
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I I r r o o n n (T)
- - - - - - 10 W S Boron --- 0.75 Lead TVS TVS Chloride --- 250 Lead(T) 50 --- Chlorine 0.019 0.011 Manganese TVS TVS/WS Cyanide 0.005 --- Mercury(T) --- 0.01 Nitrate 10 --- Molybdenum(T) --- 150 Nitrite --- 0.05 Nickel TVS TVS Phosphorus --- --- Nickel(T) --- 100 Sulfate --- WS Selenium TVS TVS Sulfide --- 0.002 Silver TVS TVS(tr)
Uranium varies* varies* Zinc TVS TVS 5a. Mainstem of the Animas River, including wetlands , from Bakers Bridge (37.458620, -107.799194) to the Southern Ute Indian Reservation boundary . COSJAF05A Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Aluminum(T) TVS TVS Recreation E acute chronic Arsenic 340 --- Water Supply D.O. (mg/L) --- 6.0 Arsenic(T) --- 0.02 Qualifiers: D.O. (spawning) --- 7.0 Cadmium TVS TVS Other: pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Temporary Mo dification(s): chlorophyll a (mg/m2) --- TVS Chromium III --- TVS Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium III(T) 50 --- Expiration Date of 12/31/2029 Chromium VI TVS TVS Inorganic (mg/L) Copper TVS TVS * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I I r r o o n n (T)
- - - - - - 10 W S Boron --- 0.75 Lead TVS TVS Chloride --- 250 Lead(T) 50 --- Chlorine 0.019 0.011 Manganese TVS TVS/WS Cyanide 0.005 --- Mercury(T) --- 0.01 Nitrate 10 --- Molybdenum(T) --- 150 Nitrite --- 0.05 Nickel TVS TVS Phosphorus --- --- Nickel(T) --- 100 Sulfate --- WS Selenium TVS TVS Sulfide --- 0.002 Silver TVS TVS(tr)
Uranium varies* varies* Zinc TVS TVS t = total MWAT = maximum weekly average temperature 162 Animas and Florida River Basins 5b. Mainstem of the Animas River, including wetlands, from the Southern Ute Indian Reservation boundary (37.214880 -107.855102) to Basin Creek. COSJAF05B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Aluminum(T) TVS TVS Recreation E acute chronic Arsenic 340 --- Water Supply D.O. (mg/L) --- 6.0 Arsenic(T) --- 0.02 Qualifiers: D.O. (spawning) --- 7.0 Cadmium TVS TVS Other: pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Temporary Mo dification(s): chlorophyll a (mg/m2) --- TVS Chromium III --- TVS Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium III(T) 50 --- Expiration Date of 12/31/2029 Chromium VI TVS TVS Inorganic (mg/L) Copper TVS TVS * * * S U U o r r a a u n n th i i u u e m m rn ( ( c a U h c t u r e o t e n In )
ic d = )
o n f r o d r e d t e a t i a ls i .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I I r r o o n n (T)
- - - - - - 10 W S Boron --- 0.75 Lead TVS TVS Chloride --- 250 Lead(T) 50 --- Chlorine 0.019 0.011 Manganese TVS TVS/WS Cyanide 0.005 --- Mercury(T) --- 0.01 Nitrate 10 --- Molybdenum(T) --- 150 Nitrite --- 0.05 Nickel TVS TVS Phosphorus --- --- Nickel(T) --- 100 Sulfate --- WS Selenium TVS TVS Sulfide --- 0.002 Silver TVS TVS(tr)
Uranium varies* varies* Zinc TVS TVS 5c. Mainstem of the Animas River, including wetlands , from Basin Creek to above the confluence with the Florida Rive r. COSJAF05C Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Aluminum(T) TVS TVS Recreation E acute chronic Arsenic 340 --- Water Supply D.O. (mg/L) --- 6.0 Arsenic(T) --- 0.02 Qualifiers: D.O. (spawning) --- 7.0 Cadmium TVS TVS Other: pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Temporary Mo dification(s): chlorophyll a (mg/m2) --- TVS Chromium III --- TVS Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium III(T) 50 --- Expiration Date of 12/31/2029 Chromium VI TVS TVS Inorganic (mg/L) Copper TVS TVS * * * S U U o r r a a u n n th i i u u e m m rn ( ( c a U h c t u r e o t e n In )
ic d = )
o n f r o d r e d t e a t i a ls i .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I I r r o o n n (T)
- - - - - - 10 W S Boron --- 0.75 Lead TVS TVS Chloride --- 250 Lead(T) 50 --- Chlorine 0.019 0.011 Manganese TVS TVS/WS Cyanide 0.005 --- Mercury(T) --- 0.01 Nitrate 10 --- Molybdenum(T) --- 150 Nitrite --- 0.05 Nickel TVS TVS Phosphorus --- --- Nickel(T) --- 100 Sulfate --- WS Selenium TVS TVS Sulfide --- 0.002 Silver TVS TVS(tr)
Uranium varies* varies* Zinc TVS TVS t = total MWAT = maximum weekly average temperature 163 Animas and Florida River Basins 5d. Mainstem of the Animas River, including wetlands from above the confluence with the Florida River to New Mexico state line. COSJAF05D Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Aluminum(T) TVS TVS Recreation E acute chronic Arsenic 340 --- Water Supply D.O. (mg/L) --- 6.0 Arsenic(T) --- 0.02 Qualifiers: D.O. (spawning) --- 7.0 Cadmium TVS TVS Other: pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Temporary Mo dification(s): chlorophyll a (mg/m2) --- TVS Chromium III --- TVS Arsenic(chronic) = hybrid E. Coli (per 100 mL) --- 126 Chromium III(T) 50 --- Expiration Date of 12/31/2029 Chromium VI TVS TVS Inorganic (mg/L) Copper TVS TVS * * * S U U o r r a a u n n th i i u u e m m rn ( ( c a U h c t u r e o t e n In )
ic d = )
o n f r o d r e d t e a t i a ls i .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I I r r o o n n (T)
- - - - - - 10 W S Boron --- 0.75 Lead TVS TVS Chloride --- 250 Lead(T) 50 --- Chlorine 0.019 0.011 Manganese TVS TVS/WS Cyanide 0.005 --- Mercury(T) --- 0.01 Nitrate 10 --- Molybdenum(T) --- 150 Nitrite --- 0.05 Nickel TVS TVS Phosphorus --- --- Nickel(T) --- 100 Sulfate --- WS Selenium TVS TVS Sulfide --- 0.002 Silver TVS TVS(tr)
Uranium varies* varies* Zinc TVS TVS
6. All tributaries and wetlands to the Animas River from the source to the outlet of Denver Lake. Mainstem, including all tributaries and wetlands of Cinnamon Creek, Grouse Gulch, Picayne Gulch, and Minnie Gulch. All tributaries and wetlands to the Animas River from immediately above Maggie Gulch to a point immediately above Elk Creek, except for those listed under segments 3c, 7, 8a, 8b, 9, and 12c. South Mineral Creek and all other tributaries and wetlands to Mineral Creek, except for those specifically listed in segments 8a, 9, and 12c.
COSJAF06 Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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 t = total MWAT = maximum weekly average temperature 164 Animas and Florida River Basins
7. Mainstem of Cement Creek, including all tributaries, and wetlands, from the source to the confluence with the Animas River. COSJAF07 Classifications Physical and Biological Metals (ug/L) UP Recreation E Arsenic(T) --- 100 Qualifiers: acute chronic Beryllium(T) --- 100 Other: D.O. (mg/L) --- 3.0 Cadmium(T) --- 10 pH 3.7-9.0 --- Chromium III(T) --- 100 *The concentration of dissolved aluminum, chlorophyll a (mg/m2) --- TVS Chromium VI(T) --- 100 cadmium, copper, iron, lead, manganese, and zinc that is directed toward maintaining and achieving E. Coli (per 100 mL) --- 126 Copper(T) --- 200 w an a d te r b q .
u ality standards established for segments 4a Inorganic (mg/L ) Iron --- --- *Uranium(acute) = See 34.5(3) for details. acute chronic Lead(T) --- 100 *Uranium(chronic) = See 34.5(3) for details. Ammonia --- --- Manganese --- --- Boron --- 0.75 Mercury(T) --- --- Chloride --- --- Molybdenum(T) --- 150 Chlorine --- --- Nickel(T) --- 200 Cyanide 0.2 --- Selenium(T) --- 20 Nitrate 100 --- Silver --- --- Nitrite 10 --- Uranium varies* varies* Phosphorus --- --- Zinc(T) --- 2000 Sulfate --- --- Sulfide --- --- 8a. Mainstem of Mineral Creek, including all wetlands and tributaries on the east side (except for Big Horn Creek), from the source to a point immediately above the confluence with South Mineral Creek, except for the listing in segment 8b. Mainstem of the Middle Fork of Mineral Creek, including all tributaries and wetlands, from the source to the confluence with Mineral Creek, except for the unnamed tributary exiting Crystal Lake, from the outlet of Crystal Lake to the confluence with the Middle Fork of Mineral Creek. COSJAF08A Classifications Physical and Biological Metals (ug/L) UP Recreation E Arsenic(T) --- 100 Qualifiers: acute chronic Beryllium(T) --- 100 Other: D.O. (mg/L) --- 3.0 Cadmium(T) --- 10 pH 4.5-9.0 --- Chromium III(T) --- 100 *The concentration of dissolved aluminum, chlorophyll a (mg/m2) --- TVS Chromium VI(T) --- 100 cadmium, copper, iron, lead, manganese, and zinc that is directed toward maintaining and achieving E. Coli (per 100 mL) --- 126 Copper(T) --- 200 w an a d te r b q .
u ality standards established for segments 4a Inorganic (mg/L ) Iron --- --- *Uranium(acute) = See 34.5(3) for details. acute chronic Lead(T) --- 100 *Uranium(chronic) = See 34.5(3) for details. Ammonia --- --- Manganese --- --- Boron --- 0.75 Mercury(T) --- --- Chloride --- --- Molybdenum(T) --- 150 Chlorine --- --- Nickel(T) --- 200 Cyanide 0.2 --- Selenium(T) --- 20 Nitrate 100 --- Silver --- --- Nitrite 10 --- Uranium varies* varies* Phosphorus --- --- Zinc(T) --- 2000 Sulfate --- --- Sulfide --- --- t = total MWAT = maximum weekly average temperature 165 Animas and Florida River Basins 8b. Mainstem of Mineral Creek from a point immediately below the confluence with Mill Creek to a point immediately above the confluence with the Middle Fork of Mineral Creek. COSJAF08B Classifications Physical and Biological Metals (ug/L) 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 Beryllium(T) --- 100 Other: D.O. (spawning) --- 7.0 Cadmium TVS TVS pH 6.5 - 9.0 --- Chromium III TVS TVS *Uranium(acute) = See 34.5(3) for details. chlorophyll a (mg/m2) --- TVS Chromium III(T) --- 100 *Uranium(chronic) = See 34.5(3) for details.
9. Mainstem of Mineral Creek, including wetlands, from immediately above the confluence wi th South Min eral Creek to the confluence with the Animas River. COSJAF09 Classifications Physical and Biological Metals (ug/L) UP Aq Life Cold 2* Temperature °C CS-I CS-I Aluminum(T) --- varies* Recreation E acute chronic Arsenic 340 --- Water Supply D.O. (mg/L) --- 6.0 Arsenic(T) --- 0.02-10 A Qualifiers: D.O. (spawning) --- 7.0 Cadmium TVS TVS Other: pH varies* --- Cadmium(T) 5.0 --- chlorophyll a (mg/m2) --- TVS Chromium III TVS TVS * M C a la c s ro s i i n fi v c e a r t t io e n b :
r a A t q e u s;
d = a r S d e s.
s = .
n ic) = See section 34.6(6) for site-specific Chlorine 0.019 0.011 Manganese TVS TVS/WS * s p ta H n ( d a a c r u d t s e .
) = See section 34.6(6) for site-specific Cyanide 0.005 --- Mercury(T) --- 0.01 Nitrate 10 --- Molybdenum(T) --- 150 Nitrite --- 0.05 Nickel TVS TVS Phosphorus --- TVS Nickel(T) --- 100 Sulfate --- WS Selenium TVS TVS Sulfide --- 0.002 Silver TVS TVS(tr)
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
10b. Mainstem of the Florida River from the outlet of L emon Reservoir to the Florida Farmers Canal Headgate (37.29 5 157, -107.791794). COSJAF10B Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 34.5(5). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 34.5(3) for details.
t = total MWAT = maximum weekly average temperature 167 Animas and Florida River Basins 11a. Mainstem of the Florida River from the Florida Farmers Canal Headgate (37.295157, -107.791794) to the Southern Ute Indian Reservation boundary (37.214724, -107.746734). COSJAF11A Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- --- Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS 11b. Mainstem of the Florida River from the Southern Ute Indian Reservation boundary (37.214724, -107.746734) to t he confluence with the Animas Ri ver. COSJAF11B Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 * * * S U U o r r a a u n n th i i u u e m m rn ( ( c a U h c t u r e o t e n In )
ic d = )
o n f r o d r e d t e a t i a ls i .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- --- Selenium TVS TVS Sulfate --- WS Silver TVS TVS(tr)
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS t = total MWAT = maximum weekly average temperature 168 Animas and Florida River Basins 11c. All tributaries, including wetlands, to the Florida River from the Southern Ute Indian Reservation boundary to the confluence with the Animas River. COSJAF11C Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 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 --- Water + Fish Standards pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Mo dification(s): E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Arsenic(chronic) = hybrid Copper TVS TVS Expiration Date of 12/31/2029 Inorganic (mg/L) Iron --- WS * * S P o h u o t s h p e h r o n r u U s te (c I h n r d o i n a i n c )
R = e a s p e p rv li a e t s io o n n ly above the Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
Chloride --- 250 Manganese TVS TVS/WS *Uranium(chronic) = See 34.5(3) for details.
Chlorine 0.019 0.011 Mercury(T) --- 0.01 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 12a. All tributaries, including wetlands, to the Animas River from a point immediately above the confluence with Elk Creek to a point immediately below the confluence with Hermosa Creek except for specific listings in Segments 1, 12c and 15. All tributaries, including wetlands, to the Florida River from the source to below the confluence with Mud Spring Creek, except the specific listing in Segment 1.
COSJAF12A Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 34.5(5). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 34.5(3) for details.
COSJAF12B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CLL 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 34.5(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 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 t = total MWAT = maximum weekly average temperature 170 Animas and Florida River Basins 12d. Mainstem of Junction Creek, including tributaries and wetlands, from the source to the U.S. Forest Boundary. Mainstem of Falls Creek, including tributaries and wetlands, from the source to the confluence with the Animas River.
COSJAF12D Classifications Physical and Biological Metals (ug/L) 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 34.5(3) for details.
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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 t = total MWAT = maximum weekly average temperature 171 Animas and Florida River Basins 13b. All tributaries, including wetlands, to the Animas River from a point immediately below the confluence with Hermosa Creek to the Southern Ute Indian Reservation boundary except for the specific listings in Segments 12d, 13a, 13c, 14a and 14b; all tributaries, including wetlands, to the Florida River, from a point immediately below the confluence with Mud Creek to the Southern Ute Indian Reservation boundary, except for specific listings in Segment 13d. COSJAF13B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 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 --- Water + Fish Standards pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Mo dification(s): E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Arsenic(chronic) = hybrid Copper TVS TVS Expiration Date of 12/31/2029 Inorganic (mg/L) Iron --- WS * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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 13c. Mainstem of the unnamed tributary to Coal Gulch which crosses Highway 160 at (37.267877, -107.961598), including wetlands, from the source to the confluence with Coal Gulch.
COSJAF13C Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 7.6 Qualifiers: D.O. (mg/L) --- 6.0 Cadmium TVS TVS Fish Ingestion D.O. (spawning) --- 7.0 Chromium III --- TVS Other: pH 6.5 - 9.0 --- Chromium III(T) 50 --- chlorophyll a (mg/m2) --- TVS Chromium VI TVS TVS D Am isc m h o a n rg ia e ( r a S c/ p c e h c )
Nitrate 100 --- Uranium varies* varies* Nitrite --- 0.05 Zinc TVS TVS Phosphorus --- TVS* Sulfate --- --- Sulfide --- 0.002 t = total MWAT = maximum weekly average temperature 172 Animas and Florida River Basins 13d. Brice Draw, including tributaries and wetlands, from its source to the Southern Ute Indian Reservation Boundary. COSJAF13D Classifications Physical and Biological Metals (ug/L) Reviewable Recreation E Arsenic(T) --- 100 Qualifiers: acute chronic Beryllium(T) --- 100 Other: D.O. (mg/L) --- 3.0 Cadmium(T) --- 10 pH 6.5 - 9.0 --- Chromium III(T) --- 100 *Uranium(acute) = See 34.5(3) for details. chlorophyll a (mg/m2) --- TVS Chromium VI(T) --- 100 *Uranium(chronic) = See 34.5(3) for details. E. Coli (per 100 mL) --- 126 Copper(T) --- 200 Inorganic (mg/L ) Iron --- --- acute chronic Lead(T) --- 100 Ammonia --- --- Manganese --- --- Boron --- 0.75 Mercury(T) --- --- Chloride --- --- Molybdenum(T) --- 150 Chlorine --- --- Nickel(T) --- 200 Cyanide 0.2 --- Selenium(T) --- 20 Nitrate 100 --- Silver --- --- Nitrite 10 --- Uranium varies* varies* Phosphorus --- --- Zinc(T) --- 2000 Sulfate --- --- Sulfide --- --- 13e. All tributaries to the Animas River, including wetl a nds, from the Southern Ute Indian Res ervatio n bou ndary t o bel ow the confluence with Basin Creek. COSJAF13E Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 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 --- Water + Fish Standards pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Mo dification(s): E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Arsenic(chronic) = hybrid Copper TVS TVS Expiration Date of 12/31/2029 Inorganic (mg/L) Iron --- WS * * S U o ra u n th iu e m rn ( a U c t u e t e In )
d = i a S n e R e e s e .5 rv ( a t )
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS t = total MWAT = maximum weekly average temperature 173 Animas and Florida River Basins 13f. All tributaries, including wetlands, to the Animas River from below the confluence with Basin Creek to the Colorado/New Mexico border, except for Segments 11b and 11c. COSJAF13F Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 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 --- Water + Fish Standards pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- Temporary Mo dification(s): E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS Arsenic(chronic) = hybrid Copper TVS TVS Expiration Date of 12/31/2029 Inorganic (mg/L) Iron --- WS * * S U o ra u n th iu e m rn ( a U c t u e t e In )
d = i a S n e R e e s e .5 rv ( a t )
Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS 14a. Mainstem of Lightner Creek, including tributaries and wetlands, from the source to below the confluence with De e p Creek. COSJAF14A Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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 t = total MWAT = maximum weekly average temperature 174 Animas and Florida River Basins 14b. Mainstem of Lightner Creek, including wetlands, from below the confluence with Deep Creek to the confluence with the Animas River. COSJAF14B Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 34.5(5). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 34.5(3) for details.
Ammonia TVS TVS Lead TVS TVS *Uranium(chronic) = See 34.5(3) for details.
Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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
15. Mainstem of Purgatory Creek, including wetlands, from the source to Cascade Creek; Goulding Creek, including wetlands, from the source to Elbert Creek; and Nary Draw, including wetlands, from the source to Haviland Lake.
COSJAF15 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 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 34.5(3) for details.
16. All lakes and reservoirs tributary to the Animas River and Florida River which are within the Weminuche Wilderness Area. This segment includes Lillie Lake, Castilleja Lake, City Reservoir, Emerald Lake, Ruby Lake, Balsam Lake, Garfield Lake, Vestal Lake, Eldorado Lake, Highland Mary Lakes, Verde Lakes, Lost Lake, and Crater Lake. COSJAF16 Classifications Physical and Biological Metals (ug/L) OW Aq Life Cold 1 Temperature °C CL CL 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 34.5(3) for details.
17. All lakes tributary to Arrastra Gulch from the sourc e to the confluence with the Animas Riv er. This seg ment include s Silver Lake. COSJAF17 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 Temperature °C CL CL Arsenic 340 --- Recreation E 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 34.5(3) for details. chlorophyll a (ug/L) --- TVS Chromium VI TVS TVS *Uranium(chronic) = See 34.5(3) for details.
18. All lakes and reservoirs tributary to Cinnamon Creek, Grouse Creek, Picayne Gulch, Minnie Gulch and Eureka Gulch. All lakes and reservoirs tributary to the Animas River from immediately above Maggie Gulch to Elk Park except for those listed under Segments 16, 17,19, and 20. This segment includes Molas Lake, Bullion King Lake, Columbine Lake, Clear Lake, Island Lake, Ice Lake, Fuller Lake and Crystal Lake. COSJAF18 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CL CL 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 34.5(3) for details.
19. All lakes and reservoirs tributary to Cement Creek from the source to the confluence with the Ani mas River. COSJAF19 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 Temperature °C CL CL Arsenic 340 --- Recreation E 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 34.5(3) for details. chlorophyll a (ug/L) --- TVS Chromium VI TVS TVS *Uranium(chronic) = See 34.5(3) for details.
20. All lakes and reservoirs on the east side of Mineral Creek from the source to a point immediately above the confluence with South Mineral Creek. All lakes and reservoirs tributary to the Middle Fork of Mineral Creek from the source to the confluence with Mineral Creek except for the specific listings in Segment 18. COSJAF20 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 Temperature °C CL CL Arsenic 340 --- Recreation E 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 34.5(3) for details. chlorophyll a (ug/L) --- TVS Chromium VI TVS TVS *Uranium(chronic) = See 34.5(3) for details.
21. All lakes and reservoirs tributary to the Animas River from a point immediately above the confluence with Elk Creek to a point immediately below the confluence with Hermosa Creek except for the specific listing in Segment 22. All lakes and reservoirs tributary to the Florida River from the source to the outlet of Lemon Reservoir, except the specific listings in Segments 12b and 16. This segment includes Little Molas Lake, Andrews Lake, Potato Lake, Scout Lake, Boyce Lake, Columbine Lake, Haviland Lake, Henderson Lake, Ruby Lake, Pear Lake, Webb Lake, Shalona Lake, Stratton Lake, and Wallace Lake. COSJAF21 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CL CL 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):
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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 t = total MWAT = maximum weekly average temperature 178 Animas and Florida River Basins
22. Electra Lake. Lake Nighthorse.
COSJAF22 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CLL 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 Temporary Mo dification(s): chlorophyll a (ug/L) --- 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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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
23. All lakes and reservoirs tributary to the Animas River from a point immediately below the confluence with Hermosa Creek to the Southern Ute Indian Reservation boundary except for the specific listings in Segments 13a and 14; all lakes and reservoirs tributary to the Florida River, from the outlet of Lemon Reservoir to the Southern Ute Indian Reservation boundary. This segment includes Chapman Lake and City Res No 1. COSJAF23 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 Temperature °C CL CL 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 Water + Fish Standards chlorophyll a (ug/L) --- DUWS Chromium III(T) 50 --- Other: chlorophyll a (ug/L) --- TVS Chromium VI TVS TVS
n D g U o.
24. All lakes and reservoirs tributary to the Animas River, from the Southern Ute Indian Reservation boundary to the Colorado/New Mexico border. This segment includes Pastorius Reservoir.
COSJAF24 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 Temperature °C CL CL 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 --- Water + Fish Standards pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (ug/L) --- TVS Chromium III(T) 50 ---
1. Mainstem of the La Plata River, including all wetlands and tributaries from the source to the Hay Gulch diversion south of Hesperus. COSJLP01 Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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(sc)
2a. Mainstem of the La Plata River from the Hay Gulc h diversion south of Hesperus to the boundary of Southern Ute I n dian Reservation. COSJLP02A Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CS-II CS-II Arsenic 340 --- Recreation E 5/1 - 10/31 acute chronic Arsenic(T) --- 0.02 Recreation N 11/1 - 4/30 D.O. (mg/L) --- 6.0 Cadmium TVS TVS Water Supply D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Qualifiers: pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 ---
t = total MWAT = maximum weekly average temperature 181 La Plata River, Mancos River, McElmo Creek and San Juan River in Montezuma County and Dolores County 2b. Mainstem of the La Plata River from the boundary of the Southern Ute Indian Reservation to above the confluence with Cherry Creek. COSJLP02B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 1 Temperature °C WS-II WS-II Arsenic 340 --- Recreation E 5/1 - 10/31 acute chronic Arsenic(T) --- 0.02 Recreation P 11/1 - 4/30 D.O. (mg/L) --- 5.0 Cadmium TVS TVS Water Supply pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Qualifiers: chlorophyll a (mg/m2) --- TVS Chromium III --- TVS Other: E. Coli (per 100 mL) 5/1 - 10/31 --- 126 Chromium III(T) 50 --- Temporary Mo dification(s): E. Coli (per 100 mL) 11/1 - 4/30 --- 205 Chromium VI TVS TVS Arsenic(chronic) = hybrid Copper TVS TVS Expiration Date of 12/31/2029 Inorganic (mg/L) Iron --- WS * * S U o ra u n th iu e m rn ( a U c t u e t e In )
ic d = )
o n f r o d r e d t e a t i a ls i .
ls .
B C o h r lo o r n id e - - - - - - .
5 I L r e o a n d (T )
TV -- S - 1 T V S Chlorine 0.019 0.011 Lead(T) 50 --- Cyanide 0.005 --- Manganese TVS TVS/WS Nitrate 10 --- Mercury(T) --- 0.01 Nitrite --- 0.05 Molybdenum(T) --- 150 Phosphorus --- TVS Nickel TVS TVS Sulfate --- WS Nickel(T) --- 100 Sulfide --- 0.002 Selenium TVS TVS Silver TVS TVS Uranium varies* varies* Zinc TVS TVS t = total MWAT = maximum weekly average temperature 182 La Plata River, Mancos River, McElmo Creek and San Juan River in Montezuma County and Dolores County 2d. Mainstem of the La Plata River from Long Hollow to the Colorado/New Mexico border. COSJLP02D Classifications Physical and Biological Metals (ug/L) 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 Temporary Mo dification(s): E. Coli (per 100 mL) --- 126 Chromium III(T) 50 --- Arsenic(chronic) = hybrid Inorganic (mg/L ) Chromium VI TVS TVS Expiration Date of 12/31/2029 acute chronic Copper TVS TVS Ammonia TVS TVS Iron --- WS * * * S U U o r r a a u n n th i i u u e m m rn ( ( c a U h c t u r e o t e n In )
ic d = )
o n f r o d r e d t e a t i a ls i .
ls .
B C o h r lo o r n id e - - - - - - .
5 I L r e o a n d (T )
TV -- S - 1 T V S Chlorine 0.019 0.011 Lead(T) 50 --- Cyanide 0.005 --- Manganese TVS TVS/WS Nitrate 10 --- Mercury(T) --- 0.01 Nitrite --- 0.05 Molybdenum(T) --- 150 Phosphorus --- TVS Nickel TVS TVS Sulfate --- WS Nickel(T) --- 100 Sulfide --- 0.002 Selenium TVS TVS Silver TVS TVS Uranium varies* varies* Zinc TVS TVS 3a. All tributaries to the La Plata River, including all wetlands, from the Hay Gulch diversions south of Hesperus to the Southern Ute Indian Reservation boundary, except for specific listing in Segment 3c, 3d and 3e.
COSJLP03A Classifications Physical and Biological Metals (ug/L) 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 *Uranium(acute) = See 34.5(3) for details. E. Coli (per 100 mL) --- 630 Chromium VI TVS TVS *Uranium(chro nic) = See 34.5(3) for details.
o d = f i a S n e / R e e / s e .5 r v ( a t )
TV -- S - 1 T V S *Uranium(chronic) = See 34.5(3) for details. Chlorine 0.019 0.011 Lead(T) 50 --- Cyanide 0.005 --- Manganese TVS TVS/WS Nitrate 10 --- Mercury(T) --- 0.01 Nitrite --- 0.05 Molybdenum(T) --- 150 Phosphorus --- TVS Nickel TVS TVS Sulfate --- WS Nickel(T) --- 100 Sulfide --- 0.002 Selenium TVS TVS Silver TVS TVS Uranium varies* varies* Zinc TVS TVS 3c. Cherry Creek, including all tributaries and wetland s, from the source to the boundary of the Southern Ute Indian R e servation boundary. COSJLP03C Classifications Physical and Biological Metals (ug/L) 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 34.5(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 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(sc)
t = total MWAT = maximum weekly average temperature 184 La Plata River, Mancos River, McElmo Creek and San Juan River in Montezuma County and Dolores County 3d. East Cherry Creek, including wetlands, from the source to the confluence with Cherry Creek. COSJLP03D Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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(sc)
3e. East Alkali Gulch, including wetlands, from the source to the Southern Ute Indian Boundary. Hay Gulch, including tributaries and wetlands, from the source to the Southern Ute Indian Boundary.
COSJLP03E Classifications Physical and Biological Metals (ug/L) UP 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) --- 5.0 Cadmium TVS TVS Qualifiers: pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Other: chlorophyll a (mg/m2) --- --- Chromium III TVS TVS
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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 4b. Mancos Reservoir (Jackson Gulch Reservoir).
COSJLP04B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CLL 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 --- chlorophyll a (ug/L) --- TVS Chromium VI TVS TVS *Uranium(acute) = See 34.5(3) for details.
i o c = f )
o f r o d r e d t e a t i a ls i .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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
5. Mainstem of the Mancos River from Hwy 160 to the boundary of the Ute Mountain Indian Reservation and mainstem of Weber Canyon, including wetlands, from source to boundary of the Ute Mountain Ute Indian Reservation.
COSJLP05 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 1 Temperature °C WS-II WS-II Arsenic 340 --- Recreation E 5/1 - 10/31 acute chronic Arsenic(T) --- 0.02 Recreation N 11/1 - 4/30 D.O. (mg/L) --- 5.0 Cadmium TVS TVS Water Supply pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Qualifiers: chlorophyll a (mg/m2) --- TVS Chromium III --- TVS Other: E. Coli (per 100 mL) 5/1 - 10/31 --- 126 Chromium III(T) 50 --- Temporary Mo dification(s): E. Coli (per 100 mL) 11/1 - 4/30 --- 630 Chromium VI TVS TVS Arsenic(chronic) = hybrid Copper TVS TVS Expiration Date of 12/31/2029 Inorganic (mg/L) Iron --- WS *Phosphorus(c hronic) = applies only above the acute chronic Iron(T) --- 1000 facilities listed at 34.5(5). Ammonia TVS TVS Lead TVS TVS *Uranium(acute) = See 34.5(3) for details.
COSJLP06B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 2 Temperature °C WS-II WS-II Arsenic 340 --- Recreation N 11/1 - 4/30 acute chronic Arsenic(T) --- 0.02-10 A Recreation P 5/1 - 10/31 D.O. (mg/L) --- 5.0 Cadmium TVS TVS Water Supply pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Qualifiers: chlorophyll a (mg/m2) --- TVS Chromium III TVS TVS Other: E. Coli (per 100 mL) 5/1 - 10/31 --- 205 Chromium III(T) --- 100
COSJLP07A Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 1 Temperature °C WS-II WS-II Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 7.6 Qualifiers: D.O. (mg/L) --- 5.0 Cadmium TVS TVS Other: pH 6.5 - 9.0 --- Chromium III TVS TVS chlorophyll a (mg/m2) --- TVS Chromium III(T) --- 100 D Am isc m h o a n rg ia e ( r a S c/ p c e h c )
Chloride --- --- Mercury(T) --- 0.01 *Uranium(chronic) = See 34.5(3) for details.
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 t = total MWAT = maximum weekly average temperature 189 La Plata River, Mancos River, McElmo Creek and San Juan River in Montezuma County and Dolores County 7b. Mainstem of McElmo Creek from the confluence with Alkali Canyon to the Colorado/Utah border, except portion within the Ute Mountain Indian Reservation. COSJLP07B Classifications Physical and Biological Metals (ug/L) 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 TVS E. Coli (per 100 mL) --- 126 Chromium III(T) --- 100 Temporary Modification(s):
Inorganic (mg/L ) Chromium VI TVS TVS Arsenic(chronic) = hybrid acute chronic Copper TVS TVS Expiration Date of 12/31/2029 Ammonia TVS TVS Iron --- WS * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
B C o h r lo o r n id e - - - - - - .
5 I L r e o a n d (T )
TV -- S - 2 T V S Chlorine 0.019 0.011 Lead(T) 50 --- Cyanide 0.005 --- Manganese TVS TVS/WS Nitrate 10 --- Mercury(T) --- 0.01 Nitrite --- 0.05 Molybdenum(T) --- 150 Phosphorus --- --- Nickel TVS TVS Sulfate --- WS Nickel(T) --- 100 Sulfide --- 0.002 Selenium TVS TVS Silver TVS TVS Uranium varies* varies* Zinc TVS TVS
8. All tributaries to McElmo Creek, including wetlands, from the source to the Colorado/Utah border, except for the portions within the Ute Mountain Indian Reservation and except for specific listings in Segments 7a and 9.
COSJLP08 Classifications Physical and Biological Metals (ug/L) UP Aq Life Warm 2 Temperature °C WS-II WS-II Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 0.02-10 A 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 TVS
9. Unnamed tributary to Ritter Draw (confluence at 37.4059, -108.5325), including wetlands. COSJLP09 Classifications Physical and Biological Metals (ug/L) UP Aq Life Warm 2 Temperature °C WS-III WS-III Arsenic 340 --- Recreation E 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) --- TVS Chromium III(T) --- 100 * 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 .
10. All tributaries to the San Juan River in Montezuma Dolores and San Miguel Counties, inc luding a ll we tlands, except for the specific listings in Segments 2 through 9. COSJLP10 Classifications Physical and Biological Metals (ug/L) UP Aq Life Warm 2 Temperature °C WS-III WS-III Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 7.6 Qualifiers: D.O. (mg/L) --- 5.0 Beryllium(T) --- 100 Other: pH 6.5 - 9.0 --- Cadmium TVS TVS chlorophyll a (mg/m2) --- TVS Chromium III TVS TVS D Am isc m h o a n rg ia e ( r a S c/ p c e h c )
of 6/30/2029 acute chronic Copper TVS TVS Ammonia TVS TVS Iron(T) --- 1000 *Phosphorus(chronic) = applies only above the facilities listed at 34.5(5). Boron --- 0.75 Lead TVS TVS *Uranium(acute) = See 34.5(3) for details.
11. Narraguinnep, Puett and Totten Reservoirs.
COSJLP11 Classifications Physical and Biological Metals (ug/L) 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) --- 5.0 Cadmium TVS TVS Qualifiers: pH 6.5 - 9.0 --- Cadmium(T) 5.0 --- Other: chlorophyll a (ug/L) --- TVS Chromium III --- TVS
12. All lakes and reservoirs tributary to the La Plata River from the source to the Hay Gulch diversion south of Hesper u s. COSJLP12 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CL CL 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 Mo dification(s): chlorophyll a (ug/L) --- 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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia Ino rganic (mg/L )
a T c V u S t e c T h V ro S n ic I I L r r e o o a n n d (T )
TV - - - - S - - 1 T W V S S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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 t = total MWAT = maximum weekly average temperature 192 La Plata River, Mancos River, McElmo Creek and San Juan River in Montezuma County and Dolores County
13. All lakes and reservoirs tributary to the La Plata River from the Hay Gulch diversions south of Hesperus to the Southern Ute Indian Reservation boundary. COSJLP13 Classifications Physical and Biological Metals (ug/L) UP Aq Life Warm 2 Temperature °C WL WL Arsenic 340 --- Recreation P 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 (ug/L) --- TVS Chromium III(T) --- 100 *Uranium(acute) = See 34.5(3) for details. E. Coli (per 100 mL) --- 205 Chromium VI TVS TVS *Uranium(chronic) = See 34.5(3) for details.
14. All lakes and reservoirs tributary to the La Plata River from the boundary of the Southern Ute Indian Reservation to the Colorado/New Mexico border. The segment includes Mormon Reservoir (a.k.a. Red Mesa Ward Reservoir) and Long Hollow Reservoir (a.k.a. Bobby K. Taylor Reservoir). COSJLP14 Classifications Physical and Biological Metals (ug/L) UP Aq Life Warm 2 Temperature °C WL WL Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 7.6 Qualifiers: D.O. (mg/L) --- 5.0 Cadmium TVS TVS Fish Ingestion pH 6.5 - 9.0 --- Chromium III TVS TVS Other: chlorophyll a (ug/L) --- TVS Chromium III(T) --- 100
15. All lakes and reservoirs tributary to the Mancos River from the source of the East, West and Middle Forks to Hwy 160, except for the specific listing in Segment 4b. This segment includes Weber Reservoir, Bauer Lake, Little Bauer Reservoir, Hackley Reservoir, Joe Moore Reservoir, and Coppinger Reservoir. COSJLP15 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CL CL Arsenic 340 --- Recreation E 5/1 - 10/31 acute chronic Arsenic(T) --- 0.02 Recreation N 11/1 - 4/30 D.O. (mg/L) --- 6.0 Cadmium TVS TVS Water Supply D.O. (spawning) --- 7.0 Cadmium(T) 5.0 --- Qualifiers: pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (ug/L) --- TVS Chromium III(T) 50 ---
16. All lakes and reservoirs tributary to the Mancos Ri v er, from Hwy 160 to the boundary of th e Ute M oun tain Indian R e servation. COSJLP16 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 2 Temperature °C WL WL Arsenic 340 --- Recreation N 11/1 - 4/30 acute chronic Arsenic(T) --- 100 Recreation P 5/1 - 10/31 D.O. (mg/L) --- 5.0 Cadmium TVS TVS Qualifiers: pH 6.5 - 9.0 --- Chromium III TVS TVS Other: chlorophyll a (ug/L) --- TVS Chromium III(T) --- 100
17. All lakes and reservoirs tributary to the San Juan River in Montezuma Dolores and San Miguel Counties except for the specific listings in Segments 4b, 11 through 16, 18 and 19. COSJLP17 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 2 Temperature °C WL WL Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 7.6 Qualifiers: D.O. (mg/L) --- 5.0 Beryllium(T) --- 100 Other: pH 6.5 - 9.0 --- Cadmium TVS TVS chlorophyll a (ug/L) --- TVS Chromium III TVS TVS *Nitrogen(chronic) = applies only above the facilities
*Phosphorus(chronic) = applies only above the Inorganic (mg/L ) Chromium VI TVS TVS f * a U c r i a lit n ie iu s m li ( s a t c e u d t e a )
t 3 = S .5 e ( e 5 )
18. All lakes and reservoirs tributary to Yellow Jacket C reek, from the source to the confluenc e with M cElm o Creek. COSJLP18 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Warm 1 Temperature °C WL WL Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 7.6 Qualifiers: D.O. (mg/L) --- 5.0 Cadmium TVS TVS Other: pH 6.5 - 9.0 --- Chromium III TVS TVS chlorophyll a (ug/L) --- TVS Chromium III(T) --- 100 *Uranium(acute) = See 34.5(3) for details. E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS *Uranium(chronic) = See 34.5(3) for details.
19. All lakes and reservoirs tributary to McElmo Creek from the source to the Colorado/Utah border, except for those within the Ute Mountain Indian Reservation and except for the specific listings in Segment 11. This segment includes Denny Lake. COSJLP19 Classifications Physical and Biological Metals (ug/L) UP Aq Life Warm 2 Temperature °C WL WL Arsenic 340 --- Recreation E acute chronic Arsenic(T) --- 7.6 Qualifiers: D.O. (mg/L) --- 5.0 Cadmium TVS TVS Fish Ingestion pH 6.5 - 9.0 --- Chromium III TVS TVS Other: chlorophyll a (ug/L) --- TVS Chromium III(T) --- 100
1. All tributaries and wetlands to the Dolores River and West Dolores River, which are within the Lizard Head Wilderness area. Mainstems of Coal Creek and Slate Creek, including tributaries and wetlands, from the boundary of the Lizard Head Wilderness Area to their confluences with the Dolores River. COSJDO01 Classifications Physical and Biological Metals (ug/L) 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 34.5(3) for details.
2. Mainstem of the Dolores River from a point immedi ately below the confluence with Snow Spur Creek to a point imm ediately above the confluence wi th Horse Creek . COSJDO02 Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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(sc)
t = total MWAT = maximum weekly average temperature 197 Dolores River Basin 3. Mainstem of the Dolores River from a point immediately above the confluence with Horse Creek to a point immediately above the confluence with Bear Creek. COSJDO03 Classifications Physical and Biological Metals (ug/L) 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 TVS Temporary Mo dification(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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/255 Chlorine 0.019 0.011 Mercury(T) --- 0.01 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS 4a. Mainstem of the Dolores River from a point immediately above the confluence with Bear Creek to the bridge at Bradfield Ranch (Forest Route 505, near Montezuma/Dolores County Line).
COSJDO04A Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 34.5(5). acute chronic Iron(T) --- 1000 *Uranium(acute) = See 34.5(3) for details.
COSJDO04B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C 1/1 - 3/31 CLL CLL Arsenic 340 --- Recreation E Temperature °C 4/1 - 12/31 CLL* varies* B Arsenic(T) --- 0.02 Water Supply Cadmium TVS TVS DUWS* acute chronic Cadmium(T) 5.0 --- Qualifiers: D.O. (mg/L) --- 6.0 Chromium III --- TVS Other: D.O. (spawning) --- 7.0 Chromium III(T) 50 --- Temporary Mo dification(s): pH 6.5 - 9.0 --- Chromium VI TVS TVS Arsenic(chronic) = hybrid chlorophyll a (ug/L) --- DUWS Copper TVS TVS Expiration Date of 12/31/2029 chlorophyll a (ug/L) --- TVS Iron --- WS
h r ( o n ).
i c) = applies only above the facilities acute chronic Lead(T) 50 --- * f * a P U c h r i a l o it n s ie i p u s h m o li ( s r a u t c e s u d (c t e a h )
t r o = n S i .
s f o o r n l d y e a ta b i o ls v .
e the A Bo m r m on o nia TV -- S - T 0.
V S M M a e n rc g u a r n y( e T s )
e TV -- S - TVS /W .0 S *Uranium(chronic) = See 34.5(3) for details. Chloride --- 250 Molybdenum(T) --- 150 *Temperature(4/1 - 12/31) = Chlorine 0.019 0.011 Nickel TVS TVS S M u c m Ph m e it e R R e e s s e e r r v v o o ir ir M M W W A A T T = = .
.
1 Cyanide 0.005 --- Nickel(T) --- 100 Nitrate 10 --- Selenium TVS TVS Nitrite --- 0.05 Silver TVS TVS(tr)
Nitrogen --- TVS* Uranium varies* varies* Phosphorus --- TVS* Zinc TVS TVS Sulfate --- WS Sulfide --- 0.002 5a. All tributaries to the Dolores River and West Dolores River, including all wetlands, from the source to a point immediately below the confluence with the West Dolores River except for specific listings in Segments 1 and 5b through 10. COSJDO05A Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 * * * U U Zi r r n a a c n n ( i i c u u h m m ro ( (c a n h c ic u r )
o t e = n )
i c C = )
u o l f r p o d i r n e d s t e a ta t i a ls n i .
l d s a .
rd Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
COSJDO05B Classifications Physical and Biological Metals (ug/L) 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 34.5(3) for details.
6. Mainstem of Coke Oven Creek, including wetlands, from the Lizard Head Wilderness Area boundary to its confluen c es with the Dolores River. COSJDO06 Classifications Physical and Biological Metals (ug/L) 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 34.5(3) for details.
7. Deleted.
COSJDO07 Classifications Physical and Biological Metals (ug/L) Designation DM MWAT acute chronic Qualifiers: acute chronic Other:
8. Mainstem of Horse Creek, including wetlands, from the source to the confluence with the Dolores River. COSJDO08 Classifications Physical and Biological Metals (ug/L) 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 Mo dification(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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 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 t = total MWAT = maximum weekly average temperature 201 Dolores River Basin
9. Mainstem of Silver Creek, including wetlands, from a point immediately below the Town of Rico's water supply diversion to the confluence with the Dolores River. COSJDO09 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CS-I CS-I Arsenic 340 --- Recreation E 5/1 - 10/31 acute chronic Arsenic(T) --- 7.6 Recreation N 11/1 - 4/30 D.O. (mg/L) --- 6.0 Cadmium TVS TVS Qualifiers: D.O. (spawning) --- 7.0 Chromium III TVS TVS Fish Ingestion pH 6.5 - 9.0 --- Chromium III(T) --- 100 Other: chlorophyll a (mg/m2) --- TVS Chromium VI TVS TVS
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 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 t = total MWAT = maximum weekly average temperature 202 Dolores River Basin 10b. Mainstem of the West Dolores River, including wetlands, from above the confluence with Fish Creek to the confluence with the Dolores River. COSJDO10B Classifications Physical and Biological Metals (ug/L) 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 34.5(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 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 11a. Lost Canyon, including tributaries and wetlands, from the source to the Forest Service Boundary. COSJDO11A Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 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 --- Water + Fish Standards pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 --- E. Coli (per 100 mL) --- 126 Chromium VI TVS TVS *Uranium(acute) = See 34.5(3) for details.
Copper TVS TVS *Uranium(chron ic) = See 34.5(3) for details.
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 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS(sc)
t = total MWAT = maximum weekly average temperature 203 Dolores River Basin 11b. All tributaries to the Dolores River, including all wetlands, from a point immediately below the confluence of the West Dolores River to the inlet of McPhee Reservoir, except for the specific listing in Segments 4a and 11a.
COSJDO11B Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 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 --- Water + Fish Standards pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (mg/m2) --- TVS Chromium III(T) 50 ---
i o c = f )
o f r o d r e d t e a t il a s i .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS(sc)
11c. All tributaries to McPhee Reservoir, including wetlands, except for the specific listings in Segments 4a and 11b. All tributaries to the Dolores River, including wetlands, from the outlet of McPhee Reservoir to the bridge at Bradfield Ranch (Forest Route 505, near Montezuma/Dolores County Line). Beaver Creek and Plateau Creek, including tributaries and wetlands, from their sources to their confluences with the Dolores River. COSJDO11C Classifications Physical and Biological Metals (ug/L) 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) --- 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 Mo dification(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 * * U U r r a a n n i i u u m m ( (c a h cu ro te n )
ic = ) = S e S e e e 3 4 .
ls .
Ammonia a T c V u S t e c T h V ro S n ic I L r e o a n d (T )
TV -- S - 1 T V S Boron --- 0.75 Lead(T) 50 --- Chloride --- 250 Manganese TVS TVS/WS Chlorine 0.019 0.011 Mercury(T) --- 0.01 Nitrate 10 --- Nickel TVS TVS Nitrite --- 0.05 Nickel(T) --- 100 Phosphorus --- TVS Selenium TVS TVS Sulfate --- WS Silver TVS TVS Sulfide --- 0.002 Uranium varies* varies* Zinc TVS TVS t = total MWAT = maximum weekly average temperature 204 Dolores River Basin
12. All lakes, and reservoirs tributary to the Dolores River and West Dolores River, which are within the Lizard Head Wilderness area. This segment includes Navajo Lake. COSJDO12 Classifications Physical and Biological Metals (ug/L) OW Aq Life Cold 1 Temperature °C CL CL 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 34.5(3) for details.
13. Groundhog Reservoir.
COSJDO13 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CLL 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 34.5(3) for details.
14. All lakes and reservoirs tributary to the Dolores River and West Dolores River, from the source to a point immediately below the confluence with the West Dolores River except for specific listings in Segments 12 and 13.
COSJDO14 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 1 Temperature °C CL CL 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 34.5(3) for details.
15. All lakes and reservoirs which are tributary to the Dolores River from a point immediately below the confluence of the West Dolores River, to the bridge at Bradfield Ranch (Forest Route 505, near Montezuma/Dolores County Line), except for the specific listing in Segment 4b. This segment includes Campbell Reservoir, Summers Reservoir, Red Lake, and Long Draw Reservoir.
COSJDO15 Classifications Physical and Biological Metals (ug/L) Reviewable Aq Life Cold 2 Temperature °C CL CL 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 --- Water + Fish Standards pH 6.5 - 9.0 --- Chromium III --- TVS Other: chlorophyll a (ug/L) --- TVS Chromium III(T) 50 ---
(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.
(C) For certain site-specific temperature standards, the temperature excursions listed in Table I - Footnote 5(c) of 31.16 do not apply. Assessment of ambient-based temperature standards should be conducted in a way that represents similar conditions to those under which the criteria were developed (i.e., air, low flow, and warming event excursions should not apply). Similarly, where site-specific adjustments to the winter shoulder season have been adopted, the winter shoulder season excursion does not apply.
_________________________________________________________________________ Editor’s Notes History Rules 34.5, 34.32 eff. 07/01/2007.
Rules 34.6 (Tables 1-18), 34.33, 34.34 eff. 06/30/2010. Rules 34.6 (Tables 1-18), 34.35 eff. 06/30/2011.
Rules 34.6 (Table pp. 2, 7, 8, 12), 34.36 eff. 01/01/2012. Rules 34.5(1), 34.5(3)-34.5(4), 34.6(2)-34.6(3), 34.38 eff. 03/30/2013. Rules 34.6(3), 34.39 emer. rules eff. 05/13/2013.
Rules 34.6(2)(d), 34.6(3), (Tables pgs. 1, 5, 7, 9-12, 15, 21), 34.40-34.41 eff. 09/30/2013. Rules 34.6 Animas and Florida River segment 13b, La Plata River, McElmo Creek, and San Juan River segments 7a, 8c, 34.42 eff. 06/30/2014.
Rules 34.6 Animas and Florida River segment 13b, 34.43 eff. 03/01/2015. Rules 34.6 La Plata River, Mancos River, McElmo Creek, and San Juan River segments 7a, 8c, 34.44 eff. 06/30/2015.
Rules 34.6, Appendix 34-1, 34.45 eff. 03/01/2016.
Rule 34.46, Appendix 34-1 eff. 06/30/2016.
Rule 34.47, Appendix 34-1 eff. 06/30/2017.
Rules 34.2-34.6, 34.48, Appendix 34-1 eff. 12/31/2017.
Rule 34.49, Appendix 34-1 eff. 06/30/2019.
Rules 34.6, 34.50, 34.51, Appendix 34-1 eff. 06/30/2020. Rules 34.6(4), 34.52, 34.53, Appendix 34-1 eff. 06/30/2021. Rules 34.5-34.6, 34.54, Appendix 34-1 eff. 12/31/2021.
Rules 34.5(4)(5), 34.6(2)(a),(4),(6), Appendix 34-1 eff. 09/30/2022. Rules 34.5(5), 34.6(3), 34.56, Appendix 34-1 eff. 06/14/2023. Rules 34.57, Appendix 34-1 eff. 12/31/2023.
Rules 34.6(2)(c)(ii),(iii), 34.6(4)(a),(c), 34.58, Appendix 34-1 eff. 12/31/2024.