UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 8
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990 18" STREET SUITE 300 DENVER, CO 80202-2466
REc~!~~D QX 1 8
Ref: 8EPR-EP Jobn D.Chase, Aceing Director Water Quality Control Division Colorado Department of Public Health and Envfionn 43 00 Cherry Creek Drive South Denver, Colorado 80246-1530
Re: T
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~ Approvals L
Animm River, Demer Lake to Muggie Gul,
nirnas River, Cement Creek to Mneral Cr. nimas River, Mineral Cr. to Elk Creek nimas River, Elk Creek to Junction 0. ement Creek, s o m e to Animus River Creek, source to South MneraI Cr. Creek, South Mineral to Anirnas R
ued Mr. Chase:
We Yeve completed our review of the total +um daily load (TMDL) as submitted by y o y office for the Upper h a s River Basin. The V L s are included in the document
entided "Total Marimurn Daily Load Assessment, A Tatershed Based Approachfor the Upper Animas River Basin"; Colorado Depstrtment of Public Health and Environment (June 2002). This document was transmitted to us for review and ppmvd in wmspondence dated June 24, 2002 and signed by yon In accordance with the Clean Water Act (33 U.S.C. 1251 et. seq.), we apptove all aspects of the TMDL as developed for water quality limited waterbody as described in Section 303(d)(l). Enclosure 1 to this iher provides a summary of the elements of the TMDL and Enclosm 2 provides details of our iew of the TMDL.
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thk
Based on our review, we feel the separate elements Listed in Enclosure 2 adequately address the pollutants of concern, taking into consideration seasonal variation and a mar$n of safety. In approving this TMDL, EPA affirms that the TMDL has been established at a level necessary to attain and maintainthe applicablk water quality standards and has the
Thank you for your submittal. Ifyou have an pestions concerning this approval, feel ,-, ,;.".. -free to contact Kathryn Hernandez of my staff at 3g3 .2-6101.
odson Assista Regional Administrator Office t Ecosystems Protection and Remediation
Page
Total Maximum Daily Load Assessment A Watershed Based Approach for the Upper Animas River Basin Colorado Department of Public Health and Environment Water Quality Control Division December 2002
Upper Animas River Basin Total Maximum Daily Load Assessment
Table of Contents Executive Summary ....................................................................................................................................2 1. Introduction .............................................................................................................................................4 2. Water Quality Standards........................................................................................................................6 3. Problem Identification ..........................................................................................................................18 5. Water Quality Goals and Targets........................................................................................................25 6. Technical Analysis.................................................................................................................................29 7. Implementation......................................................................................................................................43 8. Public Involvement................................................................................................................................45 9. Responsive Statements..........................................................................................................................46 10. Appendix ..............................................................................................................................................48
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Upper Animas River Basin Total Maximum Daily Load Assessment
Executive Summary The Animas River and tributaries originate at high elevations in the San Juan Mountains near Silverton, Colorado. Historic mining, mineral milling, prospecting activities, and natural geologic conditions in the Upper Animas River Basin have resulted in significant impact and degradation to water quality and aquatic life in the watershed. The Colorado Water Quality Control Division of the Colorado Department of Public Health and Environment is required under section 303(d) of the federal Clean Water Act to identify water bodies in the state that are water quality impaired, which is referred to as the 303(d) List. States are required under the federal Clean Water Act to produce Total Maximum Daily Load assessments for water bodies that are identified to be water quality impaired on the 303(d) List. A Total Maximum Daily Load quantifies the amount of a specific pollutant that a water quality impaired water body can assimilate without violating the applicable water quality standard. This document defines the Total Maximum Daily Loads for eight parameters (pH, Al, Cd, Cu, Fe, Mn, Pb, and Zn) in seven segments in the Upper Animas River Basin identified as water quality impaired on the 1998 303(d) List. The water quality goal of this Total Maximum Daily Load assessment is the attainment of the Aquatic Life Use Classifications for the segments where the Colorado Water Quality Control Commission has adopted that classification. Water quality targets are the measurable and quantifiable aspect of the water quality goal. The water quality targets for this Total Maximum Daily Load assessment is the attainment of the numeric water quality standards as adopted by the Colorado Water Quality Control Commission. This Total Maximum Daily Load assessment was produced from the information and mine site remediation plans outlined in the Animas River Use Attainability Analysis developed by the Animas River Stakeholder’s Group in 2001. The Animas River Stakeholders Group was formed in 1994 in order to investigate the water quality conditions of the Upper Animas River Basin, and to make recommendations upon how to improve water quality. The Animas River Stakeholders Group is composed of local watershed interests, mining interests, environmental interests, and government agencies. The Animas River Stakeholder’s Group mine site remediation plans, if completed, should achieve the water quality goals and targets of this Total Maximum Daily Load assessment within twenty years.
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Upper Animas River Basin Total Maximum Daily Load Assessment
Acronyms ARSG - Animas River Stakeholders Group BLM - U.S. Bureau of Land Management CDPHE – Colorado Department of Public Health and Environment EPA – U.S. Environmental Protection Agency LA – Load Allocation TMDL – Total Maximum Daily Load TVS – Table Value Standards UAA – Use Attainability Analysis USBM - U.S. Bureau of Mines USBR - U.S. Bureau of Reclamation USFS - U.S. Forest Service USGS - U.S. Geological Survey WLA – Waste Load Allocation WQCC - Water Quality Control Commission WQCD - Water Quality Control Division
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Upper Animas River Basin Total Maximum Daily Load Assessment
1. Introduction Upper Animas River Basin The Animas River originates northeast of Silverton, Colorado and flows south to where it joins the San Juan River near Farmington, New Mexico. The location of the Animas River Basin in Colorado is shown in Figure 1. The Upper Animas River Basin (“Upper Basin”) is defined, for this Total Maximum Daily Load (“TMDL”) assessment, as the Animas River and its tributaries above Bakers Bridge, which is near Hermosa, Colorado. The main tributaries of the Animas River in the Upper Basin are Cement Creek and Mineral Creek, which join the Animas River near the Town of Silverton. About a mile below Silverton, the Animas River enters a narrow gorge, where access is limited for twenty-seven miles to foot, boat, or summer tourist rail. Historic mining, mineral milling, prospecting activities, and natural geologic conditions in the Upper Basin have resulted in significant impact and degradation to water quality and aquatic life in the watershed. In the Upper Basin, aquatic life in streams is limited by low pH and high concentrations of dissolved metals. A detailed description of the Upper Basin, including hydrology, geology, and biology, is available in the Animas River Use Attainability Analysis (“Animas River UAA”). 303(d) List and the Total Maximum Daily Load Program Under Section 303(d) of the federal Clean Water Act, States are required to periodically submit to the U.S. Environmental Protection Agency (“EPA”) a list of water bodies that are water quality impaired. This list of water quality impaired water bodies is referred to as the “303(d) List”. In Colorado, the agency responsible for developing the 303(d) List is the Water Quality Control Division (“WQCD”) of the Colorado Department of Public Health and Environment (“CDPHE”). The most recent 303(d) List was submitted to the EPA in March 1998 and was thereafter approved. A large group of stakeholders assisted the WQCD in developing the listing criteria, prioritizing criteria, and preparing the 1998 303(d) List. The State of Colorado is required under the Clean Water Act (“CWA”) to produce TMDL assessments for water bodies that are identified to be water quality impaired on the 303(d) List. A TMDL assessment quantifies the amount of a specific pollutant that a water quality impaired water body can assimilate without violating the applicable water quality
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Upper Animas River Basin Total Maximum Daily Load Assessment
standard. A TMDL apportions that pollutant quantity among its sources, and quantifies the necessary pollutant reduction from each source in order for the water body to attain the applicable water quality standard. A TMDL must also account for seasonal variations and include a margin of safety. A TMDL can be produced with the intent that pollutant control measures will be implemented in the future, and that these pollutant control measures will improve water quality to the level of attaining the adopted water quality standards or better. The 1998 303(d) List identified seven segments in the Upper Basin that are water quality impaired for seven different parameters of concern. Additionally, monitoring data indicate that several segments in the Upper Basin do not attain the adopted manganese standards, which were not detailed in the 1998 303(d) List. Not all the parameters of concern are exceeding water quality standards in each segment. For this TMDL assessment, the pollutants of concern are: pH, total aluminum (Al), dissolved cadmium (Cd), dissolved copper (Cu), total iron (Fe), dissolved manganese (Mn), dissolved lead (Pb), and dissolved zinc (Zn). The seven Upper Animas segments included on the 1998 303(d) List requires development of 29 pollutant specific TMDLs. The State is required to complete TMDLs in accordance with a settlement agreement arising from a lawsuit filed against EPA by the Colorado Environmental Coalition and the Biodiversity Foundation. Under a consent agreement with the litigants, the State is committed to the completion of 50 TMDLs within the two-year period between July 2000 and June 2002. The settlement agreement specifically requires completion of the 29 Upper Animas River Basin TMDLs within this timeframe. Animas River Stakeholders The Animas River Stakeholders Group (“ARSG”), which consists of local watershed interests, mining interests, environmental interests, and government agencies, conducted an extensive pollutant source survey from 1994 to 1999. Water quality, condition of aquatic life, and mine remediation scenarios in the Upper Basin were studied by the ARSG. The ARSG presented their findings and recommendations to the Water Quality Control Commission (“WQCC”) in the Animas River UAA in 2001. A Use Attainability Analysis is defined by federal regulation (CFR 40 §131.3(g)). It is a structured scientific assessment of the factors affecting the attainment of the use, which may include physical, chemical, biological, and
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Upper Animas River Basin Total Maximum Daily Load Assessment
economic factors. The WQCC adopted water quality standards for the Upper Basin based upon the work contained in the Animas River UAA. The ARSG identified 33 draining mine adits (out of 173 characterized) and 32 mine waste sites (out of 157 characterized) that if remediated would significantly improve water quality in the Upper Animas River Basin to the point of attaining the currently adopted water quality standards. Approximately 90% of the metal load from draining adits is accounted for in the 33 ARSG targeted adits, and approximately 90% of the metal load from mine waste sites is accounted for in the 32 ARSG targeted mine waste sites. The water quality improvement that is expected from the ARSG’s remediation goals forms the basis of this TMDL assessment. The information contained in the Animas River UAA was utilized by the WQCD to produce the TMDL assessments for the Upper Basin, which are presented in this document.
2. Water Quality Standards Background The water quality standards for the Upper Basin are set forth in WQCC Regulation No. 34, which has been adopted under authority of the Colorado Water Quality Control Act. Water quality standards for the Upper Basin were first proposed in 1981, and adopted in mid-1982. Subsequent Rulemaking Hearings in 1994 and 2001 have amended the standards. The Upper Basin, due to its degraded water quality from historic mining operations and natural geologic conditions, is one of the most intensively investigated watersheds in the State. As long ago as 1981, the Statement of Basis and Purpose of Regulation No. 34 recognized that the long lasting effects of historic mining operations in the Upper Basin were of such a magnitude that Cement Creek and Upper Mineral Creek could not support aquatic communities and had no prospects for attaining an aquatic life designated use. However, the WQCC at that time documented its hope for returning aquatic life to Mineral Creek below South Mineral Creek. In 1989 and 1990, the Upper Basin was recognized in both the Colorado Nonpoint Assessment Report and the Colorado Nonpoint Management Program report as a severe nonpoint source pollution problem area. In 1991, the WQCD, in conjunction with federal agencies and private mining companies, began an intensive data collection effort that resulted in
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Upper Animas River Basin Total Maximum Daily Load Assessment
sampling and analysis of approximately 360 sites in the Upper Basin. The objectives of the study were to characterize the current chemical, biological, and physical conditions of the Upper Basin; to quantify the areas of highest metal loadings and determine the potential for water quality improvement sufficient to support naturally reproducing trout populations; and to prioritize sites for remedial projects based on relative loading contribution, environmental impact, feasibility, cost, and benefits. Over the next three years, the WQCD, along with the EPA, U.S. Bureau of Land Management (“BLM”), U.S. Forest Service (“USFS”), Colorado Division of Minerals and Geology (“CDMG”), U.S. Geological Survey (“USGS”), U.S. Bureau of Mines (“USBM”), U.S. Bureau of Reclamation (“USBR”), and local stakeholders worked together to form a “stakeholder model for decision making”, which was financed initially through a Clean Water Act Section 319 grant and other EPA grants. The initial public meeting of the stakeholders group, which later became known as the ARSG, was held in Silverton in February 1994. A major grant to support the study and stakeholder effort was received from EPA in June 1994 In 1994, a water quality classification and standards rulemaking hearing for Regulation No. 34 was held in Silverton. At that time, the WQCD proposed temporary modifications to the water quality standards with underlying table value standards for several segments in the Upper Basin. Temporary modifications are a unique solution to severe water quality problems in Colorado. The following is the explanation of temporary modifications from Regulation No. 31, The Basic Standards and Methodologies for Surface Water. Where a numeric standard is not being met at the present time, or there is significant uncertainty regarding the appropriate long-term underlying standard, a temporary modification to the numeric standard may be granted by the Commission. The presence of a modification will be indicated by adding the words "temporarily modified" to the underlying numeric standard. A temporary modification may be granted to an entire stream or water body or to any portion thereof. It may be granted at the time a numeric standard is assigned or at any later time. When the temporary modification expires or is removed by the Commission, the underlying numeric standard will be in full effect. In every case, the modification to the numeric standard shall be temporary. All temporary modifications must be re-examined not less than once every three (3) years. In general, requests for a temporary modification are preferred over a more permanent downgrading of a present classification where it appears that the conditions causing the lower water quality might be temporary within a twenty (20) year time frame. Retaining a classification higher than the present usage will
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Upper Animas River Basin Total Maximum Daily Load Assessment
serve as a reminder that the conditions are correctable and may increase the priority for funding to attain the classified use.
In the 1994 hearing, the ARSG preferred an approach that did not include table value standards as a formalized goal. The following excerpts from the Statement of Basis and Purpose for the 1994 hearing illustrate the WQCC’s decision to adopt a hybrid “experimental approach” and its expectations. If substantial progress toward water quality improvement--through the identification, prioritization and implementation of remediation projects--is achieved within the next three years, and if it appears three years from now that the lack of legal effectiveness of the goal-based standards will provide the best stimulus for further progress, further delay in the effective date of the goalbased standards can be considered by the Commission at that time. Of course, such progress could also demonstrate that the identified goals are achievable, or that they should be refined in some manner. If, however, substantial and diligent progress toward water quality improvement is not achieved over the next three years, it is the intent of the Commission that the goal-based standards should and will be allowed to go into effect at that time to stimulate further progress. In a new rulemaking hearing, the burden should be on those that have argued that clean-up will be more successful with a cooperative effort working toward a goal, without that goal being reflected in currently effective water quality standards, to demonstrate the success of this experiment. The Water Quality Control Commission expects that the cooperative effort will be successful and is attempting by this action to send that message to all stakeholders. To those concerned about the potential impacts on property owners of goal-based standards being in effect, the message is that the Commission wants to encourage this locally-driven, cooperative watershed improvement initiative by demonstrating as much flexibility as possible. To federal agencies or others with potential resources to devote to water quality improvement efforts, the message is that working toward such improvement in this basin is an extremely high priority for the State of Colorado. To the Water Quality Control Division and those that supported their proposal in this rulemaking proceeding, the message is that the Commission has been persuaded--based on the unprecedented level of monitoring and analysis that has occurred in this basin--that a sound scientific justification has been provided for the adoption of goal-based water quality standards, and that these standards should be allowed to go into effect unless it is demonstrated that the pending experiment in cooperative watershed management can succeed without this legal impetus. To all of the residents of the Animas River Basin, the message is that the Commission is concerned about water quality in your basin and is willing to work with you to explore whatever options appear most likely to facilitate progress toward water quality improvement in the least disruptive and most expeditious manner.
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Upper Animas River Basin Total Maximum Daily Load Assessment
For a number of stream segments and a number of parameters, the standards were set at ambient levels with temporary modifications of table values to end on March 2, 1998. The next rulemaking hearing was to be held in November 1997. The studies were not finished at that time, and the Stakeholders were not ready to make recommendations. The Statement of Basis and Purpose for that hearing states:
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. …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. 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.
Thus, temporary modifications were extended an additional three years in 1997, resulting in three additional years of intensive study to determine the aquatic life use attainability in the Upper Basin, appropriate numerical standards to protect the potential aquatic life uses, and the sources to be controlled in order to meet those goals. Between 1997 and April 2001, the ARSG continued data collection in the Upper Basin and developed the Animas River UAA. The Animas River UAA was completed in January 2001, and the WQCD received it shortly thereafter. As part of the Animas River UAA, the ARSG proposed site-specific water quality standards based upon the projected water quality condition after remediation of numerous mine sites. The WQCD recognized the significant effort that was involved in producing the Animas River UAA. However, the WQCD had concerns regarding the ARSG’s proposed water quality standards, the methodology in which the standards were developed, and the lack of a biological basis for the proposed site-specific standards. Thus, the ARSG, the WQCD, EPA, Colorado Division of Wildlife (“DOW”), and the federal land management agencies (U.S. Forest Service and U.S. Bureau of Land Management) entered into a series of conversations concerning the 9
Upper Animas River Basin Total Maximum Daily Load Assessment
water quality standards that were proposed by the ARSG in the Animas River UAA in order to address the need for a biological component to the proposed water quality standards. At the time of the May 2001 Rulemaking Hearing, the ARSG’s proposed water quality standards had been modified to reflect the discussion with the WQCD and other agencies. The WQCC adopted the ARSG’s proposal for water quality standards in the Upper Basin, which included Temporary Modifications. The water quality standards adopted by the WQCC in May 2001 become effective on February 20, 2002. The following is the Statement of Basis and Purpose for the May 2001 hearing, which documents the WQCC’s decision to adopt the ARSG’s proposal.
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 258-402; 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.
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Upper Animas River Basin Total Maximum Daily Load Assessment
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
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Upper Animas River Basin Total Maximum Daily Load Assessment
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 yearround 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
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Upper Animas River Basin Total Maximum Daily Load Assessment
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.
Current Water Quality Standards The following tables (Table 1 and 2) are the water quality standards for the Upper Basin that were adopted by the WQCC in May 2001, and became effective on February 20, 2002. A description of water quality standards, including definitions, is available in Regulation No. 31 (The Basic Standards and Methodologies for Surface Water (5 CCR 1002-31)). Water quality standards for dissolved metals are generally shown in the regulations as Table Value Standards (TVS), and these are derived from equations that are dependant upon the stream’s hardness
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Upper Animas River Basin Total Maximum Daily Load Assessment
(dissolved CaCO3). Water quality standards for aluminum and iron are based upon the total recoverable fraction, and, therefore, not based upon hardness. In the Upper Basin, the WQCC adopted monthly specific numeric standards for certain segments for specific metals, which is presented in Table 2.
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Upper Animas River Basin Total Maximum Daily Load Assessment
Table 1: Water quality standards for segments in the Upper Basin. ANIMAS AND FLORIDA RIVER BASIN REGULATION No. 34 Stream Segment Description 1. All tributaries to the Animas River and Florida River, including all wetlands, lakes and reservoirs, which are within the Weminuche Wilderness Area.
Desig
OW
Classifications
Aq Life Cold 1 Recreation 1a Water Supply Agriculture
NUMERIC STANDARDS PHYSICAL and BIOLOGICAL D.O. = 6.0 mg/l D.O. (sp)=7.0 mg/l pH = 6.5-9.0 F.Coli=200/100ml E.Coli=126/100ml
NUMERIC STANDARDS INORGANIC mg/l NH3(ac)=TVS NH3(ch)=0.02 Cl2(ac)=0.019 Cl2(ch)=0.011 CN=0.005
2.
3a.
Mainstem of the Animas River, including all tributaries and wetlands, from the outlet of Denver Lake to a point immediately above the confluence with Maggie Gulch, except for specific listings in Segment 6.
Recreation 1a Agriculture UP
Mainstem of the Animas River, including wetlands, from a point immediately below the confluence with Maggie Gulch to immediately above the confluence with Cement Creek.
Aq Life Cold 1 Recreation 1a Agriculture
pH = 5.8-9.0 F.Coli=200/100ml E.Coli=126/100ml
CN(ac)=0.2 NO2(ac)=10
D.O. = 6.0 mg/l D.O. (sp)=7.0 mg/l pH = 6.5-9.0 F.Coli=200/100ml E.Coli=126/100ml
NH3(ac)=TVS NH3(ch)=0.02
S=0.002 B=0.75 NO2=0.05 NO3=10 Cl=250 SO4=WS B(ch)=0.75
NO3(ch)=100
S=0.002 B=0.75
Cl2(ac)=0.019 Cl2(ch)=0.011 CN=0.005
3b.
Mainstem of the Animas River, including wetlands, from a point immediately above the confluence with Cement Creek to a point immediately above the confluence with Mineral Creek.
Sept. 11 to May 14 Recreation 2 UP May 15 to Sept. 10 Recreation 1a
3c.
4a.
Arrastra Gulch including all lakes, tributaries, and wetlands from the source to the confluence with the Animas River.
Mainstem of the Animas River, including wetlands, from a point immediately above the confluence with Mineral Creek to a point immediately above the confluence with Deer Park Creek.
UP
UP
Aq Life Cold 2 Recreation 1a Agriculture
Aq Life Cold 2 Recreation 1a Agriculture
pH = 6.0-9.0 Sept. 11 to May 14 F.Coli=2000/100ml E.Coli=630/100ml May 15 to Sept. 10 F.Coli=200/100ml E.Coli=126/100ml D.O.=6.0 mg/l D.O.(sp)=7.0 mg/l pH = 6.5-9.0 F.Coli=200/100ml E.Coli=126/100ml D.O. = 6.0 mg/l D.O.(sp)=7.0 mg/l F.Coli=200/100ml E.Coli=126/100ml Standards for pH are listed on Table 1.
NUMERIC STANDARDS METALS ug/l As(ac)=50(Trec) Cd(ac)=TVS(tr) Cd(ch)=TVS CrIII(ac)=50(Trec) CrVI(ac/ch)=TVS Cu(ac/ch)=TVS
Fe(ch)=WS(dis) Fe(ch)=1000(Trec) Pb(ac/ch)=TVS Mn(ac/ch)=TVS Mn(ch)=WS(dis) Hg(ch)=0.01(tot)
TEMPORARY MODIFICATIONS AND QUALIFIERS Ni(ac/ch)=TVS Se(ac/ch)=TVS Ag(ac)=TVS Ag(ch)=TVS(tr) Zn(ac/ch)=TVS
As(ch)=100(Trec) CrVI(ch)=100(Trec) Ni(ch)=200(Trec) Be(ch)=100(Trec) Cu(ch)=200(Trec) Se(ch)=20(Trec) Cd(ch)=10(Trec) Pb(ch)=100(Trec) Zn(ch)=2000(Trec) CrIII(ch)=100(Trec) The concentration of dissolved aluminum, cadmium, copper, iron, lead, manganese, and zinc that is directed toward maintaining and achieving water quality standards established for segments 3a, 4a and 4b. Al(ac/ch)=750(Trec) CrVI(ac/ch)=TVS Se(ac/ch)=TVS As(ac)=100(Trec) Fe(ch)=1000(Trec) Ni(ac/ch)=TVS Cd(ac)=TVS(tr) Pb(ac/ch)=TVS Ag(ac)=TVS CrIII(ac/ch)=TVS Hg(ch)=0.01(tot) Ag(ch)=TVS(tr) Cu(ac/ch)=TVS Standards for Cd, Mn and Zn are listed on Table 2.
The concentration of dissolved aluminum, cadmium, copper, iron, lead, manganese, and zinc that is directed toward maintaining and achieving water quality standards established for segments 4a and 4b.
NH3(ac)=TVS NH3(ch)=0.02 Cl2(ac)=0.019
S=0.002 B=0.75 NO2=0.05
As(ch)=50(Trec) Cd(ac)=TVS(tr) Cd(ch)=TVS CrIII(ac/ch)=TVS CrVI(ac/ch)=TVS Cu(ac)=TVS
S=0.002 B=0.75
As(ch)=100(Trec) Cu(ac/ch)=TVS Cd(ac)=TVS(tr) Pb(ac/ch)=TVS Cd(ch)=TVS Hg(ch)=0.01(tot) CrIII(ac/ch)=TVS Ni(ac/ch)=TVS CrVI(ac/ch)=TVS Standards for Al, Fe and Zn are listed on Table 1.
Cl2(ch)=0.011 CN=0.005 NH3(ac)=TVS NH3(ch)=0.02 Cl2(ac)=0.019 Cl2(ch)=0.011 CN=0.005
15
Fe(ch)=1000(Trec) Pb(ac/ch)=TVS Mn(ac/ch)=TVS Hg(ch)=0.01(tot) Ni(ac/ch)=TVS Se(ac/ch)=TVS
Ag(ac)=TVS Ag(ch)=TVS(tr) Zn(ac)=TVS
Se(ac/ch)=TVS Ag(ac)=TVS Ag(ch)=TVS(tr)
Temporary modification: existing ambient quality for all metals. Expiration date of 12/31/06.
Aquatic life indicator goal: Brook Trout. Temporary modifications for: Cd(ch)=3.9 Mn(ch)=2700 Zn(ch)=1290 Cu(ch) for May=12 Expiration date of 12/31/06. Temporary modification: Existing ambient quality for all metals. Expiration date of 12/31/06.
Temporary modifications: Cu(ch)=9.1 Zn(ch)=189 no Cu, Zn acute. Expiration date of 12/31/06. Aquatic life indicator goal: Brook Trout Temporary modifications: Al(ch)=3700(Trec) Fe(ch)=4630(Trec) Zn(ac/ch)=840 Cu(ch)=21 Cd(ch)=2.5 pH=existing quality Expiration date of 12/31/06.
Upper Animas River Basin Total Maximum Daily Load Assessment Table 1 continued: Water quality standards for segments in the Upper Basin. ANIMAS AND FLORIDA RIVER BASIN REGULATION No. 34
Desig
Classifications
Stream Segment Description
4b.
5a.
Mainstem of the Animas River, including wetlands, from the confluence with Deer Park Creek to Bakers Bridge.
Mainstem of the Animas River, including wetlands, from Bakers Bridge to the Southern Ute Indian Reservation boundary.
5b. Mainstem of the Animas River, including wetlands, from the Southern Ute Indian Reservation boundary to the Colorado/New Mexico border.
6.
7.
8.
9.
Mainstem of the Animas River from the source to the outlet of Denver Lake. Mainstem, including all tributaries, wetlands, lakes and reservoirs of Cinnamon Creek, Grouse Creek, Picayne Gulch, and Minnie Gulch. All tributaries including the tributaries’ wetlands, lakes and reservoirs to the Animas River from immediately above Maggie Gulch to Elk Park except for those listed under segments 3c, 7, 8 and 9. Mainstem of Cement Creek, including all tributaries, wetlands, lakes, and reservoirs, from the source to the confluence with the Animas River.
Mainstem of Mineral Creek, including wetlands, from the source to a point immediately above the confluence with South Mineral Creek. All tributaries on the east side of this segment of Mineral Creek including wetlands, lakes and reservoirs except for Big Horn Creek. Mainstem of the Middle Fork of Mineral Creek including all tributaries, wetlands, lakes and reservoirs from the source to the confluence with Mineral Creek except for Crystal Lake and its exiting tributary to confluence with Middle Fork of Mineral Creek. Mainstem of Mineral Creek, including wetlands, from immediately above the confluence with South Mineral Creek to the confluence with the Animas River.
Aq Life Cold 1 Recreation 1a Water Supply Agriculture
D.O. = 6.0 mg/l D.O.(sp)=7.0 mg/l pH = 6.5-9.0 F.Coli=200/100ml E.Coli=126/100ml
Aq Life Cold 1 Recreation 1a Water Supply Agriculture
D.O. = 6.0 mg/l D.O. (sp)=7.0 mg/l pH = 6.5-9.0 F.Coli=200/100ml E.Coli=126/100ml
Aq Life Cold 1 Recreation 1a Water Supply Agriculture
D.O. = 6.0 mg/l D.O. (sp)=7.0 mg/l pH = 6.5-9.0 F.Coli=200/100ml E.Coli=126/100ml
Aq Life Cold 1 Recreation 1a Water Supply Agriculture
D.O. = 6.0 mg/l D.O. (sp)=7.0 mg/l pH = 6.5-9.0 F.Coli=200/100ml E.Coli=126/100ml
Recreation 1a Agriculture
D.O. = 3.0 mg/l pH = 3.7-9.0 F.Coli=200/100ml E.Coli=126/100ml
UP
Recreation 1a Agriculture UP
UP
NUMERIC STANDARDS PHYSICAL and BIOLOGICAL
Aq Life Cold 2 Recreation 1a Agriculture
NUMERIC STANDARDS INORGANIC mg/l
NH3(ac)=TVS NH3(ch)=0.02 Cl2(ac)=0.019 Cl2(ch)=0.011 CN=0.005 NH3(ac)=TVS NH3(ch)=0.02 Cl2(ac)=0.019 Cl2(ch)=0.011 CN=0.005 NH3(ac)=TVS NH3(ch)=0.02 Cl2(ac)=0.019 Cl2(ch)=0.011 CN=0.005 NH3(ac)=TVS NH3(ch)=0.02 Cl2(ac)=0.019 Cl2(ch)=0.011 CN=0.005 CN(ac)=0.2 NO2(ac)=10
S=0.002 B=0.75 NO2=0.05 NO3=10 Cl=250 SO4=WS S=0.002 B=0.75 NO2=0.05 NO3=10 Cl=250 SO4=WS S=0.002 B=0.75 NO2=0.05 NO3=10 Cl=250 SO4=WS S=0.002 B=0.75 NO2=0.05 NO3=10 Cl=250 SO4=WS B(ch)=0.75
N03(ac)=100
D.O. = 3.0 mg/l pH = 4.5 - 9.0 F.Coli=200/100ml E.Coli=126/100ml
CN(ac)=0.2 NO2(ac)=10
D.O. = 6.0 mg/l D.O. (sp)=7.0 mg/l F.Coli=200/100ml E.Coli=126/100ml Standards for pH are listed on Table 1.
NH3(ac)=TVS NH3(ch)=0.02
B(ch)=0.75
N03(ac)=100
Cl2(ac)=0.019 Cl2(ch)=0.011 CN=0.005
16
S=0.002 B=0.75 NO2=0.05
NUMERIC STANDARDS METALS ug/l
TEMPORARY MODIFICATIONS AND QUALIFIERS
Al(ac/ch)=TVS As(ch)=50(Trec) Cd(ac)=TVS(tr) Cd(ch)=TVS CrIII(ac/ch)=TVS CrVI(ac/ch)=TVS Cu(ac/ch)=TVS
Fe(ch)=WS(dis) Fe(ch)=1000(Trec) Pb(ac/ch)=TVS Mn(ch)=WS(dis) Mn(ac/ch)=TVS Ni(ac/ch)=TVS
Hg(ch)=0.01(tot) Ni(ac/ch)=TVS Se(ac/ch)=TVS Ag(ac)=TVS Ag(ch)=TVS(tr) Zn(ac/ch)=TVS
Al(ac/ch)=TVS As(ch)=50 Cd(ac)=TVS(tr) Cd(ch)=TVS CrIII(ac)=50(Trec) CrVI(ac/ch)=TVS Cu(ac/ch)=TVS Al(ac/ch)=TVS As(ch)=50 Cd(ac)=TVS(tr) Cd(ch)=TVS CrIII(ac)=50(Trec) CrVI(ac/ch)=TVS Cu(ac/ch)=TVS As(ac)=50(Trec) Cd(ac)=TVS(tr) Cd(ch)=TVS CrIII(ac)=50(Trec) CrVI(ac/ch)=TVS Cu(ac/ch)=TVS
Fe(ch)=WS(dis) Fe(ch)=1000(Trec) Pb(ac/ch)=TVS Mn(ac/ch)=TVS Mn(ch)=WS(dis) Hg(ch)=0.01(tot) Ni(ac/ch)=TVS Fe(ch)=WS(dis) Fe(ch)=1000(Trec) Pb(ac/ch)=TVS Mn(ac/ch)=TVS Mn(ch)=WS(dis) Hg(ch)=0.01(tot) Ni(ac/ch)=TVS Fe(ch)=WS(dis) Fe(ch)=1000(Trec) Pb(ac/ch)=TVS Mn(ac/ch)=TVS Mn(ch)=WS(dis) Hg(ch)=0.01(tot)
Se(ac/ch)=TVS Ag(ac)=TVS Ag(ch)=TVS(tr) Zn(ac/ch)=TVS
As(ch)=100(Trec) Be(ch)=100(Trec) Cd(ch)=10(Trec)
CrVI(ch)=100(Trec) Cu(ch)=200(Trec) Pb(ch)=100(Trec) Zn(ch)=2000(Trec)
Se(ac/ch)=TVS Ag(ac)=TVS Ag(ch)=TVS(tr) Zn(ac/ch)=TVS
Temporary modification: Zn(ch)=256 Expiration date of 12/31/06.
Southern Ute Indian Reservation.
Ni(ac/ch)=TVS Se(ac/ch)=TVS Ag(ac)=TVS Ag(ch)=TVS(tr) Zn(ac/ch)=TVS
Ni(ch)=200(Trec) Temporary modification: Se(ch)=20(Trec) existing ambient quality for all metals. Expiration date of 12/31/06.
CrIII(ch)=100(Trec) The concentration of dissolved aluminum, cadmium, copper, iron, lead, manganese, and zinc that is directed toward maintaining and achieving water quality standards established for segments 4a and 4b. As(ch)=100(Trec) CrVI(ch)=100(Trec) Ni(ch)=200(Trec) Be(ch)=100(Trec) Cu(ch)=200(Trec) Se(ch)=20(Trec) Cd(ch)=10(Trec) Pb(ch)=100(Trec) Zn(ch)=2000(Trec) CrIII(ch)=100(Trec) The concentration of dissolved aluminum, cadmium, copper, iron, lead, manganese, and zinc that is directed toward maintaining and achieving water quality standards established for segments 4a and 4b.
Temporary modification: existing ambient quality for all metals. Expiration date of 12/31/06.
As(ch)=100(Trec) Cu(ac)=TVS Ni(ac/ch)=TVS Cd(ac/ch)=TVS(tr) Pb(ac/ch)=TVS Se(ac/ch)=TVS CrIII(ac/ch)=TVS Mn(ac/ch)=TVS Ag(ac)=TVS CrVI(ac/ch)=TVS Hg(ch)=0.01(tot) Ag(ch)=TVS(tr) Zn(ac)=TVS Standards for Al, Cu, Fe and Zn are listed on Table 2.
Temporary modifications: Al(ch)=5000(Trec) Cu(ch)=57 Fe(ch)=6270(Trec) Zn(ac/ch)=590 Expiration date of 12/31/06. Aquatic Life indicator goal: Macroinvertebrates; Brook Trout corridor
Upper Animas River Basin Total Maximum Daily Load Assessment
Table 2: Segment specific monthly numeric water quality standards for the Upper Animas River Basin. Segment 3a Acute Standards JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC Zn 720 780 1060 1200 760 410 280 340 380 440 510 590 Chronic Standards JAN FEB MAR Cd TVS TVS TVS Mn TVS TVS 2571 Zn 720 780 1060
APR 3.5 2179 1200
MAY 2.2 TVS 760
JUNE TVS TVS 410
JULY TVS TVS 280
AUG TVS TVS 340
SEPT TVS TVS 380
OCT TVS TVS 440
NOV TVS TVS 510
DEC TVS TVS 590
Segment 4a Acute Standards JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC Al(Trec) 3100 3550 2800 2020 1010 740 700 1360 1490 1610 2280 2570 Zn 460 520 620 570 430 250 170 240 290 340 380 420 Chronic Standards JAN FEB pH 5.9-9.0 5.7-9.0 Al(Trec) 3100 3550 Fe 3473 2961 Zn 460 520
MAR 6.2-9.0 2800 3776 620
APR 6.5-9.0 2020 3404 570
MAY 6.5-9.0 1010 2015 430
JUNE 6.5-9.0 740 1220 250
JULY 6.5-9.0 700 1286 170
AUG 6.5-9.0 1360 1830 240
SEPT 6.5-9.0 1490 1623 290
OCT 6.5-9.0 1610 2258 340
NOV 6.5-9.0 2280 2631 380
DEC 5.9-9.0 2570 3511 420
NOV 6.2-9.0 3450 TVS 3620 TVS
DEC 5.4-9.0 4050 TVS 3490 TVS
Segment 9 Acute Standards JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC Al(Trec) 4680 4950 4560 3800 1390 1350 1290 2040 2570 2680 3450 4050
Chronic Standards JAN FEB pH 4.9-9.0 4.8-9.0 Al(Trec) 4680 4950 Cu TVS TVS Fe 3420 3800 Zn TVS TVS
MAR 4.9-9.0 4560 TVS 4370 TVS
APR 5.9-9.0 3800 18 3370 TVS
MAY 6.5-9.0 1390 20 3150 230
JUNE 6.5-9.0 1350 TVS 2210 TVS
17
JULY 6.5-9.0 1290 TVS 2275 TVS
AUG 6.5-9.0 2040 TVS 2280 TVS
SEPT 6.5-9.0 2570 TVS 3020 TVS
OCT 6.5-9.0 2680 TVS 3580 TVS
Upper Animas River Basin Total Maximum Daily Load Assessment
3. Problem Identification Background Degraded water quality in the Upper Basin from natural conditions and mining operations was recognized as early as the late nineteenth century (see Animas River UAA Chapter 7 Appendixes). The WQCD has actively been involved with water quality studies in the Upper Basin since the early 1980’s. The ARSG was formed in 1994 in order to study the water quality degradation in the Upper Basin, and to conduct watershed restoration projects. 1998 303(d) List The 1998 303(d) List identified seven stream segments in the Upper Basin with impaired water quality. Segment 3a was not identified on the 1998 303(d) List. In the May 2001 Rulemaking Hearing, segment 9B was changed to segment 9 with a segment description change. The water quality parameters that are not attaining water quality standards are shown in Table 3. Stream segmentation is shown in Figure 2. Table 3: Segments and pollutants of concern in the Upper Basin identified on the 1998 303(d) List. Segment (WBID) COSJAF02 COSJAF03B COSJAF04A COSJAF04B COSJAF07 COSJAF08 COSJAF09B
Waterbody Description Animas River & Tributaries from Denver Lake to Maggie Gulch Animas River from Cement Creek to Mineral Creek Animas River from Mineral Creek to Elk Creek Animas River from Elk Creek. to Junction Creek Cement Creek from source to Animas River Mineral Creek from source to South Fork of Mineral Creek Mineral Creek from South Fork Mineral of Creek to Animas River
Portion
Pollutant or Condition
All
Al, Cd, Cu, Fe, Pb
All
Al, Cd, Cu, Fe, Pb
All
pH, Cu, Fe, Zn
All
Zn
All
Al, Cd, Cu, Fe, Pb
All
Al, Cd, Cu, Fe, Pb
All
pH, Cu, Fe, Zn
Current Water Quality Conditions The following tables (Tables 4 through 7) contain the monthly metal concentrations (Al, Cd, Cu, Fe, Mn, and Zn) for the four principle water gages in the Upper Animas River Basin. Dissolved manganese was included because the ARSG identified it as a pollutant of concern in the Animas River UAA. The four gages represent the largest amount of sampling data taken by the ARSG and others. The four gages are A68 (bottom of segment 3a), A72 (near the top of
18
Upper Animas River Basin Total Maximum Daily Load Assessment
segment 4a), CC48 (bottom of segment 7), and MC34 (bottom of segment 9). The four principal gage sites are shown in Figure 3. There is only limited water quality data available for segment 4b due to difficult access. The dissolved metal concentrations and total recoverable aluminum were agreed to be representative of the 85th percentile of current water quality conditions by the ARSG, WQCD, DOW, BLM, USFS, and other parties for the May 2001 water quality standards rulemaking hearing. Total recoverable iron was agreed to be representative of the 50th percentile concentration, which is consistent with WQCD regulations. The following tables (Tables 4-7) also include the 15th percentile flow by months, which illustrate the hydrograph of the Upper Basin. The 15th percentile flow was used to approximate the low flow critical condition. Table 4: Current water quality conditions at A68. Month Flow Hardness (cfs) mg/L Jan 17 209 Feb 18 207 Mar 23 189 Apr 32 144 May 131 86 Jun 326 67 Jul 96 71 Aug 49 95 Sep 46 118 Oct 30 144 Nov 29 177 Dec 22 200
pH Al (tot) Cd (dis) Cu (dis) Fe (tot)* Mn (dis) Zn (dis) (s.u.) (µ µg/L) (µ µg/L) (µ µg/L) (µ µg/L) (µ µg/L) (µ µg/L) 6.6-7.4 185 2.7 3.9 293 2020 810 6.7-7.3 183 2.4 3.9 405 2114 857 7.0-7.6 231 2.9 7.1 446 2693 1128 6.8-7.5 286 3.9 10.6 608 2285 1288 6.8-7.4 346 2.3 11.8 460 931 788 6.6-7.5 322 1.3 8.0 398 543 424 6.6-7.6 74 0.9 4.6 270 696 320 6.5-7.6 50 0.9 3.7 210 913 388 6.9-7.7 155 1.3 3.7 219 1162 411 6.5-7.7 65 1.3 4.6 140 1181 487 6.7-7.6 126 1.5 6.1 181 1505 567 6.6-7.6 119 1.7 4.6 239 1913 656
Table 5: Current water quality conditions at A72 Month Flow Hardness pH Al (tot) Cd (dis) Cu (dis) Fe (tot)* Mn (dis) Zn (dis) (cfs) mg/L (s.u.) (µ µg/L) (µ µg/L) (µ µg/L) (µ µg/L) (µ µg/L) (µ µg/L) Jan 46 277 5.6-7.5 3257 2.0 20.3 4500 1331 683 Feb 47 290 5.4-6.7 3705 1.7 21.3 4004 1484 740 Mar 59 268 5.1-6.7 2923 2.5 19.5 4634 1571 820 Apr 86 196 6.0-7.1 2132 2.5 17.5 3941 1400 834 May 285 91 6.0-7.3 1050 1.9 10.6 2201 832 580 Jun 676 53 6.5-7.6 762 1.5 7.6 1372 286 337 Jul 215 72 6.1-7.6 764 1.0 5.8 1498 308 323 Aug 120 124 6.0-7.5 1446 1.1 5.9 2184 511 384 Sep 114 158 6.3-7.4 1556 1.3 5.0 1995 655 401 Oct 82 182 6.6-7.9 1696 1.5 6.5 2749 867 492 Nov 72 215 6.4-7.3 2183 1.7 10.3 3345 1007 548 Dec 56 248 6.0-7.2 2698 1.5 15.0 4450 1173 609
19
Upper Animas River Basin Total Maximum Daily Load Assessment
Table 6: Current water quality conditions at CC48. Month Flow Hardness (cfs) mg/L
pH (s.u.)
Al (tot) Cd (dis) Cu (dis) Fe (tot)* Mn (dis) Zn (dis) (µ µg/L) (µ µg/L) (µ µg/L) (µ µg/L) (µ µg/L) (µ µg/L)
Jan
12
417 3.5-4.0
6335
1.8
33.3
11078
1497
725
Feb
12
591 3.3-4.0
6465
1.7
29.4
8719
2071
758
Mar
13
720 3.6-4.1
6483
2.1
46.1
8996
2499
836
Apr
13
372 3.7-4.6
5336
3.0
62.8
6662
1912
1032
May
39
153 3.9-4.8
3956
3.4
90.6
6027
1215
978
Jun
90
146 4.4-5.3
2927
3.3
96.6
3959
600
727
Jul
30
215 4.1-5.2
3023
2.9
83.7
4165
1129
747
Aug
17
402 3.5-4.3
4303
2.7
63.8
5524
1617
725
Sep
17
390 3.8-4.6
4702
3.4
66.4
7099
1961
866
Oct
12
465 3.9-4.5
5241
3.0
41.2
7022
2015
883
Nov
14
294 3.9-4.4
5425
2.7
40.2
8278
2259
818
Dec 13 * 50th percentile
526 3.6-4.2
6202
2.1
37.4
10790
1913
749
Table 7: Current water quality conditions at MC34. Month Flow Hardness (cfs) mg/L
pH (s.u.)
Al (tot) Cd (dis) Cu (dis) Fe (tot)* Mn (dis) Zn (dis) (µ µg/L) (µ µg/L) (µ µg/L) (µ µg/L) (µ µg/L) (µ µg/L)
Jan
16
255 4.6-5.5
5039
1.1
48.6
5748
575
482
Feb
16
241 4.5-5.4
5299
1.3
49.3
6163
589
508
Mar
21
226 4.8-5.2
4830
1.6
57.3
6274
584
588
Apr
31
170 5.2-6.6
3993
1.6
47.5
4378
687
530
May
109
86 6.1-7.3
1458
1.3
28.1
3445
276
362
Jun
264
60 6.5-7.5
1385
0.6
7.0
2431
158
139
Jul
82
76 6.6-7.5
1388
0.7
5.0
2589
265
127
Aug
44
126 6.2-7.4
2184
0.8
8.2
3497
321
254
Sep
42
151 6.6-7.1
2711
1.0
8.4
3762
324
257
Oct
30
192 6.4-6.9
2867
1.3
13.5
4569
405
348
Nov
26
217 5.5-6.5
3666
1.4
34.1
5187
448
430
253 5.2-6.0
4335
1.1
42.7
5600
513
460
Dec 19 * 50th percentile
pH The 1998 303(d) List identified pH as exceeding the water quality standard in segments 4a and 9 (former segment 9b). For this TMDL assessment of the Upper Basin, total iron values will be used as surrogate pH TMDLs for segments 4a and 9. This method for pH TMDLs has been utilized in other legacy mining districts with water quality impairments, for example in the
20
Upper Animas River Basin Total Maximum Daily Load Assessment
Water Quality Restoration Plan for the Cooke City TMDL Planning Area prepared by the Montana Department of Environmental Quality. The ARSG did not address the expected pH improvements in the Animas River UAA in a specific, quantifiable manner. In the Upper Basin, pH changes on a seasonal and diurnal basis. This, along with the physical nature of pH, makes it very difficult to quantify into a total maximum daily load. Therefore, the surrogate approach is necessary for this TMDL assessment. Acid drainage, which leads to low pH values and elevated metal concentrations in surface and ground water, is the result of the oxidation of metallic sulfide minerals. Because of the link between pH and the oxidation of metallic sulfide minerals, it is assumed that the remediation plans developed by the ARSG to address metal loading in the basin will also address the conditions that lead to low pH values at the 65 remediation sites. Since pyrite (FeS2) is the most common mineral that produces acidic drainage, iron is considered the most appropriate surrogate for pH. This approach will be evaluated during the next periodic review of water quality standards in 2005.
Lead Lead was identified on the 1998 303(d) List as a pollutant exceeding water quality standards in segments 2, 3b, 7, and 8 of the Upper Basin. Because a preponderance of the monitoring data showed dissolved lead concentrations at the principle gage sites to be below the analytical detection limit, the ARSG found that lead met the WQCC criteria for TVS at three of the four principal gage sites. The WQCD’s method of assessing data where samples are below the analytical detection limit is to change those values to zero and then assess the dissolved data as the 85th percentile. Table 8 shows the number of dissolved lead samples taken during 1992-1999 at the four principle gage sites, the number of dissolved lead detections below the analytical detection limit, the 85th percentile of the dissolved lead samples using the standard WQCD method, the maximum lead detection of the samples taken, and the water quality standard (chronic TVS) at low flow condition (maximum hardness). Using the standard WQCD method, the four principal gage sites are attaining the dissolved lead standard.
21
Upper Animas River Basin Total Maximum Daily Load Assessment
Table 8: Dissolved lead samples taken at the four principle gage stations in the Upper Basin. 85th Number of Number of Total Maximum Water Quality Standard Pb (dis) Number of Pb (dis) Percentile of Pb (dis) (chronic TVS) for Pb (dis) Samples Samples Pb (dis) Pb (dis) Sample at Low Flow Condition Above Below Samples Detection Detection Taken Limit Limit (19921999) A68 210 175 35 1.0 µg/l 51.7 µg/l 5.6 µg/l A72 193 175 18 0.0 µg/l 40.0 µg/l 7.5 µg/l CC48 215 183 32 17.0 µg/l 50.2 µg/l 11.4 µg/l (dis)*, 100 (trec) MC34 154 44 110 0.0 µg/l 61.7 µg/l 6.9 µg/l *Cement Creek does not have a current dissolved Pb standard. It is included to be consistent with the watershed based approach of this TMDL assessment. Gage Station
Because of the occasional or periodic non-attainment of the lead standard (chronic and acute standards) at A68, A72, and MC34, the EPA in their February 15, 2002 comments regarding the first draft version of the TMDL assessment believes that TMDLs must be developed for lead for the 303(d) listed segments for lead (segments 02, 03B, 7, and 8). Therefore, TMDLs for lead at the four principal gage stations were developed based upon the current promulgated numeric water quality standards.
Manganese Manganese was not identified on the 1998 303(d) List as a pollutant causing impairment of the aquatic life use in segments of the Upper Basin. However, the ARSG identified that dissolved manganese is a pollutant of concern in the Upper Basin, and determined it should be addressed. In several of the segments in the Upper Basin, the current dissolved manganese concentration is above the Table Value Standard for manganese, but should be reduced through the remediation effort. The WQCC adopted a monthly site specific water quality standard for manganese in segment 3a. Although TMDLs are not currently required in the Upper Basin for dissolved manganese, as manganese was not identified on the 1998 303(d) List, they have been developed for this document. The WQCD considers them viable TMDLs under Section 303(d)(4)(A) of the CWA.
22
Upper Animas River Basin Total Maximum Daily Load Assessment
4. Analysis of Pollutant Sources Background The Animas River Stakeholder’s Group conducted an extensive analysis of pollutant sources in the Upper Basin beginning in 1992 that continues to the present. The WQCD, EPA, DOW, USFS, BLM, local mining interests, and other local interests have supported this large effort. The results of the pollutant source inventory are detailed in Chapter 8 of the Animas River UAA. There are over 1,500 sites related to mining and milling operations in the Upper Basin. These mining sites include: mine adits that have a continuous discharge of water; adits that have seasonal or periodic discharge of water; adits that are dry and have no discharge of water; mine waste sites that contain mine waste rock; mine waste sites that contain mine waste rock and milled tailings; mine waste sites that contain only milled tailings; and other mining features such as prospect pits, smelter sites, and mill sites. ARSG Pollutant Source Sampling and Ranking The WQCD (1992-1995) and the ARSG (1995-present) conducted an extensive pollutant source sampling effort. The results of the pollutant source sampling done between 1992 and 1999 are contained in the Animas River UAA. The sampling effort included water quality sampling, flow measurements, and site information. After completing the pollutant source sampling effort, the ARSG ranked the mining sites in terms of their current loading and potential for remediation. The ARSG focused upon draining adits and mine waste sites. The ARSG ranked the draining adits and mine waste sites based upon a methodology developed and outlined in the Animas River UAA. The result of the ARSG ranking methodology identifies a total of 65 remediation projects (33 draining adits and 32 mine waste sites) as the most significant sources of pollutants to the basin. The ARSG determined that the 65 identified remediation projects (33 draining adits and 32 mine waste sites) account for approximately ninety percent of the known mining related metal loading to the Upper Basin. Some of the remediation project sites are shown in Figure 4.
ARSG Potential Load Reductions Methodology
23
Upper Animas River Basin Total Maximum Daily Load Assessment
The expected load reductions from the 65 remediation projects were estimated by the ARSG based upon the best professional judgment and the experience of the members of the group. The ARSG also relied upon four feasibility reports produced by the Colorado Department of Natural Resources, Division of Minerals and Geology, which are appendices to the Animas River UAA (Appendices 10A, 10B, 10C, and 10D). The reports are as following: • • • •
Mineral Creek Remediation Feasibility Report, 1997 Cement Creek Remediation Feasibility Report, 1998 Upper Animas Remediation Feasibility Report (Animas River above Eureka), 1999 Upper Animas Remediation Feasibility Report (Animas River below Eureka), 2000 The following is an example of the type of remediation and expected reductions of metal
loading considered by the ARSG: • • • •
Bulkhead – approximately 50% reduction of metal loading Passive Treatment – approximately 30% reduction of metal loading Active Treatment – approximately 85% reduction of metal loading Infiltration Source Control – approximately 50% reduction of metal loading The ARSG believes that these are conservative estimates for these types of remedial
activities. The experience of the WQCD in other parts of Colorado is that similar types of remediation generally produce higher load reductions. Therefore, the WQCD considers the conservative load reduction estimates of the ARSG as an implicit Margin of Safety in this TMDL assessment. The type of remediation chosen for a site was based upon the characteristics of the site. This information is detailed in Chapters 10 and 11, including the associated appendices, of the Animas River UAA.
Discharge Permits
The WQCD’s Permit Tracking System, as of December, 2001, identified seven active Colorado Discharge Permit System (CDPS) discharge permits and eleven inactivated permits in San Juan County. An inactivated permit is one where the activity that required a discharge permit has ceased and is not expected to occur again.
24
Upper Animas River Basin Total Maximum Daily Load Assessment
None of the active discharge permits were considered significant sources of pollutants, specifically metals, by the ARSG and WQCD. Table 9, below, lists the active discharge permits in the basin. The Town of Silverton waste water treatment plant (CDPS CO0020301) was issued a renewal permit effective as of December 2000. As part of their permit, the treatment plant is required to sample for metals on a quarterly basis. The active permits issued to the Sunnyside Gold Corporation were either considered within the context of the Animas River UAA (American Tunnel treatment plant, active remediation projects) or currently are not discharging water from the facility (Mayflower Mill, and Terry Tunnel). Cascade Village does not discharge to the Animas River, and is not considered by the WQCD to be a significant source of dissolved metals. Table 9: Active CDPS Permits in the WQCD Permit Tracking System as of December, 2001 for San Juan County. Permitee Edmunds, Geoffrey H. Silverton, Town Of Silverton, Town Of Sunnyside Gold Corporation Sunnyside Gold Corporation Sunnyside Gold Corporation Sunnyside Gold Corporation
Facility Name Cascade Village Town Of Silverton Water Treatment Plant Mayflower Mill American Tunnel Terry Tunnel Mine Remediation Projects
Permit No. 0039691 0020311 0640008 0000426 0027529 0036056 0044768
Status Active Active Active Active Active Active Active
Category Domestic Domestic Industrial Industrial Industrial Industrial Industrial
Type Minor Minor Minor Major Major Major Minor
5. Water Quality Goals and Targets The water quality goal of this TMDL assessment is the attainment of the adopted Aquatic Life Use Classifications for segments 3a, 4a, 4b, and 9 in the Upper Basin. This includes the biological goals that were established during the May 2001 Rulemaking Hearing for Animas River Basin portion of Regulation No. 34. In order to achieve this goal within twenty years, the numeric water quality standards as adopted by the WQCC in Regulation No. 34 must be attained. For the purpose of this TMDL assessment, the water quality standards for the Upper Basin are referred to as water quality targets. Water quality targets are the measurable and quantifiable aspect of the water quality goal. Attainment of water quality targets is considered the endpoint of a TMDL. The proposed ARSG remediation plan as outlined in the Animas River UAA, if completed, should achieve the
25
Upper Animas River Basin Total Maximum Daily Load Assessment
water quality targets within twenty years. The water quality targets may be modified in the context of the periodic review of water quality standards (Regulation No. 34). Table 10 identifies the segments in the Upper Animas River Basin, their Aquatic Life Use Classification, and their associated water quality goals and targets.
26
Upper Animas River Basin Total Maximum Daily Load Assessment
Table 10: Water quality goals and targets. Aquatic Life Use Segment Classification 2. Mainstem of the Animas River, including all Not Adopted for this tributaries and wetlands, from the outlet of Denver segment. Lake to a point immediately above the confluence with Maggie Gulch, except for specific listings in Segment 1 [Designated Wilderness Areas]. Aquatic Life Use, 3a. Mainstem of the Animas River, including Cold 1 wetlands, from a point immediately below the confluence with Maggie Gulch to immediately above Aquatic life goal of the confluence with Cement Creek. brook trout. 3b. Mainstem of the Animas River, including Not Adopted for this wetlands, from a point immediately above the segment. confluence with Cement Creek to a point immediately above the confluence with Mineral Creek. 3c. Arrastra Gulch including all lakes, tributaries, Aquatic Life Use, and wetlands from the source to the confluence with Cold 2 the Animas River. 4a. Mainstem of the Animas River, including wetlands, from a point immediately above the confluence with Mineral Creek to the confluence with Deer Creek. 4b. Mainstem of the Animas River, including wetlands, from the confluence with Deer Creek to Baker’s Bridge.
Aquatic Life Use, Cold 2 Aquatic life goal of brook trout. Aquatic Life Use, Cold 1
7. Mainstem of Cement Creek, including all Not Adopted for this tributaries, wetlands, lakes, and reservoirs, from the segment. source to the confluence with the Animas River.
8. Mainstem of Mineral Creek, including wetlands, Not Adopted for this from the source to a point immediately above the segment. confluence with South Mineral Creek. All tributaries on the east side of this segment of Mineral Creek including wetlands, lakes and reservoirs except for Big Horn Creek. Mainstem of the Middle Fork of Mineral Creek including all tributaries, wetlands, lakes and reservoirs from the source to the confluence with Mineral Creek except for Crystal Lake and its exiting tributary to confluence with Middle Fork of Mineral Creek. 9. Mainstem of Mineral Creek, including wetlands, Aquatic Life Use, from immediately above the confluence with South Cold 2 Mineral Creek to the confluence with the Animas Aquatic life goal of River. macroinvertebrates and brook trout travel corridor.
27
Water Quality Target and Qualifier. Attainment of numeric and/or narrative water quality standards in the segment. Reduced metal loads to improve downstream fisheries (segments 3a, 4b). Attainment of numeric water quality standards in the segment. Enhancement of existing brook trout fishery. Attainment of numeric and/or narrative water quality standards in the segment. Reduced metal loads to improve downstream fisheries (segment 4b). Attainment of numeric water quality standards in the segment. Reduced metal loads to improve downstream fisheries (segment 4b). Attainment of numeric water quality standards in the segment. Reduced metal loads to improve downstream fisheries (segment 4b). Brook trout fishery. Attainment of numeric water quality standards in the segment. Enhancement of existing brook trout fishery throughout the segment. Attainment of numeric and/or narrative water quality standards in the segment. Reduced metal loads to improve downstream fisheries (segment 4b). Attainment of numeric and/or narrative water quality standards in the segment. Reduced metal loads to improve downstream fisheries (segment 4b).
Attainment of numeric water quality standards in the segment and water quality that supports aquatic insect habitat, and reduced metal loads to provide a brook trout travel corridor, and improve downstream fisheries (segment 4b).
Upper Animas River Basin Total Maximum Daily Load Assessment
28
Upper Animas River Basin Total Maximum Daily Load Assessment
6. Technical Analysis TMDL Approach A traditional TMDL consists of three components: the Load Allocation (LA), which is the portion of the pollutant load that is attributed to background or nonpoint source pollution; the Waste Load Allocation (WLA), which is the portion of the pollutant load associated with point source discharges; and a Margin of Safety (MOS). A reserve load allocation for future growth in the basin can also be added to a TMDL, although none was developed for this TMDL. The sum of the LA, the WLA, and the MOS represents the TMDL. Ultimately, TMDL implementation is intended to result in the attainment of the aquatic life use designation and attendant numeric water quality standards. In this case, the TMDL implementation is the same as the remediation goals outlined in the Animas River UAA. Remediation and the resultant water quality improvements are anticipated to take a minimum of twenty years from the present. Margin of Safety and Seasonality The margin of safety is the TMDL component that accounts for unknowns or uncertainties in the development of the TMDL. The margin of safety may be explicit (a separate value in the TMDL) or implicit (included in factors determining the TMDL). The magnitude of the margin of safety is reduced by much of the work performed in preparation of this TMDL. Some of the tasks were identified as the result of earlier modeling efforts and some were performed as ongoing data collection efforts. The combination improved the quality of the data available. Specific Margin of Safety components include: • • • •
•
Period of flow record - the number of gages and the period or record provide a sound basis for flow analysis. Water quality data - the water-quality monitoring program provides a sound basis for water quality modeling. Continued modeling – the ARSG is continuing to improve their basin-wide water quality model in order to predict improvements to water quality from remedial efforts. Continued water quality monitoring – the ARSG is continuing to monitor the Animas River and tributaries in the Upper Basin. This information will be utilized to increase the accuracy of the water quality model and TMDL during the next periodic review of water quality standards in 2005. Continued special studies – the ARSG is continuing to propose and conduct special studies to further quantify metal loading in segments where there was some uncertainty to sources. 29
Upper Animas River Basin Total Maximum Daily Load Assessment
•
Conservative load reductions – the WQCD considers the load reductions estimated by the ARSG from remediation projects to be conservative as compared to other remediation projects in Colorado. Therefore, the conservative load reduction estimates are an implicit Margin of Safety. A TMDL was developed for each parameter of concern for each month of the year. These
monthly TMDLs were developed because of the extreme hydrograph of the Upper Basin, and are intended to approximate the monthly low-flow critical condition for aquatic life. Therefore, seasonality is accounted for in this TMDL assessment with the monthly TMDLs.
Watershed Based Approach and Allocation Methodology
Because of the complex nature and inter-relatedness of the water quality in the Upper Animas River Basin, TMDLs are being developed to address the entire Upper Basin for each parameter of concern. This watershed based approach lends itself well to establishing and meeting water quality goals and targets. The TMDLs for the Upper Basin are to reflect the numeric water quality standards developed in the Use Attainability Analysis by the ARSG. The baseline data used to develop the TMDLs were at the four principle stream gages (A68, CC48, MC34, and A72) in the Upper Basin, therefore the TMDLs are expressed as discreet loads at the four gages. Table 11 shows the correlation of the four water gages to the segments. The TMDLs developed for the Upper Basin are expressed as monthly TMDLs, which better express the hydrograph in the Upper Basin.
30
Upper Animas River Basin Total Maximum Daily Load Assessment
Table 11: Segments addressed through TMDLs at water gages. Water Gage
Segment Addressed
A68
Animas River 02, and 03A
CC48
Animas River 07
MC34
Animas River 08, and 09 (former 09B)
A72
Animas River 03B, 04A, 04B
The following describes the Allocation Methodology used to determine the monthly TMDLs at the four principal water gages. 1. Daily Current Condition Loads were calculated from the Current Water Quality Conditions and 15th percentile flows that were agreed to by the WQCD and ARSG in May 2001 (Tables 4, 5, 6, and 7). The Daily Current Condition Loads for the four principal stream gages (A68, CC48, MC34, and A72) are presented in Tables 12, 13, 14, and 15 for each month of the year. Due to data limitations, a Daily Current Condition Load was not developed for lead. 2. Daily Allowable Loads were calculated based upon the promulgated numeric water quality standards, the 15th percentile flows for A68, MC34, and A72. (The reason for not calculating Daily Allowable Loads for CC48 by this method is because there are not Aquatic Life Use Classification numeric water quality standards for the parameters of concern for CC48.) The Daily Allowable Loads for three stream gages (A68, MC34, and A72) are presented in Tables 16, 17, and 18 for each month of the year.
3. For A68, MC34, and A72: If the Daily Allowable Load is less than the Current Condition Load, then the Total Maximum Daily Load is the Daily Allowable Load for each month. If the Daily Allowable Load is greater than the Current Condition Load, then the Total Maximum Daily Load is the Current Condition Load. The TMDLs for A68, MC34 and A72 are shown in Tables 19, 20, and 21. The TMDL for lead is the Daily Allowable Load. 4. The Total Maximum Daily Load for CC48 was calculated by taking the Current Condition Load and subtracting the load reduction expected from the proposed remediation projects in the Cement Creek Drainage. The TMDL for the Cement Creek Drainage is shown in Table 22.
31
Upper Animas River Basin Total Maximum Daily Load Assessment
Current Condition Loads Table 12: Current Condition Load at A68. Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Al (tot) Cd (dis) Cu (dis) Fe (tot) Mn (dis) Zn (dis) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) 17 18 29 49 245 567 38 13 39 11 20 14
0.2 0.2 0.4 0.7 1.6 2.3 0.5 0.2 0.3 0.2 0.2 0.2
0.4 0.4 0.9 1.8 8.3 14.1 2.4 1.0 0.9 0.7 1.0 0.5
27 39 55 105 325 701 140 56 54 23 28 28
185 205 334 395 659 956 361 242 289 191 236 227
74 83 140 223 557 746 166 103 102 79 89 78
Table 13: Current Condition Load at CC48. Month
Al (tot) Cd (dis) Cu (dis) Fe (tot) Mn (dis) Zn (dis) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day)
Jan
410
0.1
2.2
718
97
47
Feb
419
0.1
1.9
565
134
49
Mar
455
0.1
3.2
632
175
59
Apr
375
0.2
4.4
468
134
72
May
833
0.7
19.1
1269
256
206
Jun
1423
1.6
46.9
1924
292
353
Jul
490
0.5
13.6
675
183
121
Aug
395
0.3
5.9
507
148
67
Sep
432
0.3
6.1
652
180
80
Oct
340
0.2
2.7
455
131
57
Nov
410
0.2
3.0
626
171
62
Dec
435
0.1
2.6
757
134
53
32
Upper Animas River Basin Total Maximum Daily Load Assessment
Table 14: Current Condition Load at MC34. Month
Al (tot) Cd (dis) Cu (dis) Fe (tot) Mn (dis) Zn (dis) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day)
Jan
435
0.1
4.2
497
50
42
Feb
458
0.1
4.3
533
51
44
Mar
548
0.2
6.5
711
66
67
Apr
669
0.3
8.0
733
115
89
May
858
0.8
16.6
2028
163
213
Jun
1975
0.8
9.9
3466
225
198
Jul
615
0.3
2.2
1146
118
56
Aug
519
0.2
1.9
831
76
60
Sep
615
0.2
1.9
853
73
58
Oct
464
0.2
2.2
740
66
56
Nov
515
0.2
4.8
728
63
60
Dec
445
0.1
4.4
575
53
47
Table 15: Current Condition Load at A72. Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Al (tot) Cd (dis) Cu (dis) Fe (tot) Mn (dis) Zn (dis) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) 809 940 938 990 1616 2784 887 937 961 751 849 816
0.5 0.4 0.8 1.2 2.9 5.4 1.1 0.7 0.8 0.7 0.7 0.4
5.0 5.4 6.2 8.1 16.3 27.7 6.7 3.8 3.1 2.9 4.0 4.5
1118 1016 1486 1830 3387 5011 1739 1415 1232 1217 1301 1346
331 377 504 650 1281 1044 357 331 404 384 391 355
33
170 188 263 387 892 1231 374 249 247 218 213 184
Upper Animas River Basin Total Maximum Daily Load Assessment
Daily Allowable Loads Table 16: Daily Allowable Load at A68. Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Al (tot) Cd (dis) Cu (dis) Fe (tot) Mn (dis) Pb (dis) Zn (dis) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) 69 0.4 1.5 92 194 0.5 66 73 0.4 1.6 97 204 0.5 76 93 0.4 1.9 124 253 0.6 132 130 0.6 2.1 173 322 0.6 207 531 1.6 5.6 707 1110 1.4 538 1320 2.9 11.2 1760 2541 2.6 722 389 0.9 3.5 518 763 0.8 145 198 0.6 2.3 265 429 0.6 90 186 0.6 2.6 248 433 0.7 94 122 0.5 2.0 162 302 0.5 71 117 0.5 2.3 157 312 0.7 80 89 0.4 1.9 119 247 0.6 70
Table 17: Daily Allowable Load at MC34. Month
Al (tot) Cd (dis) Cu (dis) Fe (tot) Mn (dis) Pb (dis) Zn (dis) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day)
Jan
404
0.4
1.7
295
195
0.5
22
Feb
428
0.4
1.6
328
191
0.5
21
Mar
517
0.5
2.0
496
245
0.6
27
Apr
636
0.6
3.0
564
330
0.7
31
May
818
1.3
11.8
1854
923
1.1
135
Jun
1925
2.2
8.3
3151
1984
1.8
109
Jul
571
0.8
3.1
1007
667
0.7
41
Aug
485
0.6
2.6
542
423
0.7
34
Sep
583
0.7
2.9
685
429
0.8
38
Oct
434
0.6
2.5
580
332
0.7
33
Nov
484
0.6
2.4
508
300
0.7
32
Dec
416
0.5
2.0
358
231
0.6
27
34
Upper Animas River Basin Total Maximum Daily Load Assessment
Table 18: Daily Allowable Load at A72. Month
Al (tot) Cd (dis) Cu (dis) Fe (tot) Mn (dis) Pb (dis) Zn (dis) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day)
Jan
770
1.2
5.3
863
575
1.7
114
Feb
901
1.2
5.6
752
597
1.8
132
Mar
898
1.5
6.7
1211
735
2.1
199
Apr
938
1.7
7.4
1581
959
2.2
265
May
1554
3.2
12.7
3101
2460
3.1
662
Jun
2703
5.1
19.0
4456
4876
4.1
913
Jul
813
2.0
7.9
1493
1717
1.8
197
Aug
881
1.7
7.0
1186
1148
1.9
156
Sep
920
1.9
8.2
1002
1186
2.3
179
Oct
713
1.5
6.6
1000
892
1.9
151
Nov
886
1.5
6.7
1023
828
2.0
148
Dec
777
1.3
5.9
1062
675
1.8
127
Total Maximum Daily Loads Table 19: Total Maximum Daily Load at A68 Al (tot) Cd (dis) Cu (dis) Fe (tot) Mn (dis) Pb (dis) Zn (dis) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) Jan 17* 0.2* 0.4* 27* 185* 0.5 66.1 Feb 18* 0.2* 0.4* 39* 204 0.5 75.8 Mar 29* 0.4* 0.9* 55* 253 0.6 131.7 Apr 49* 0.6 1.8* 105* 321 0.6 207.4 May 245* 1.6 5.6 325* 659* 1.4 537.6 Jun 567* 2.3* 11.2 701* 956* 2.6 721.8 Jul 38* 0.5* 2.4* 140* 361* 0.8 145.2 Aug 13* 0.2* 1.0* 56* 242* 0.6 90.0 Sep 39* 0.3* 0.9* 54* 289* 0.7 94.4 Oct 11* 0.2* 0.7* 23* 191* 0.5 71.3 Nov 20* 0.2* 1.0* 28* 236* 0.7 79.9 Dec 14* 0.2* 0.5* 28* 227* 0.6 70.1 *Current Condition Load Month
35
Upper Animas River Basin Total Maximum Daily Load Assessment
Table 20: Total Maximum Daily Load at MC34 Month
Al (tot) Cd (dis) Cu (dis) Fe (tot)† Mn(dis) Pb (dis) Zn (dis) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day)
Jan
404
0.1*
1.7
295
50*
0.5
22
Feb
428
0.1*
1.6
328
51*
0.5
21
Mar
517
0.2*
2.0
496
66*
0.6
27
Apr
636
0.3*
3.0
564
115*
0.7
31
May
818
0.8*
11.8
1854
163*
1.1
135
Jun
1925
0.8*
8.3
3151
225*
1.8
109
Jul
571
0.3*
2.2*
1007
118*
0.7
41
Aug
485
0.2*
1.9*
542
76*
0.7
34
Sep
583
0.2*
1.9*
685
73*
0.8
38
Oct
434
0.2*
2.2*
580
66*
0.7
33
Nov
484
0.2*
2.4
508
63*
0.7
32
53*
0.6
27
Dec 416 0.1* 2.0 358 *Current Condition Load † Fe (tot) TMDL is the surrogate for pH in Segment 9.
Table 21: Total Maximum Daily Load at A72 Al (tot) Cd (dis) Cu (dis) Fe (tot) † Mn(dis) Pb (dis) Zn (dis) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) Jan 770 0.5* 5.0* 863 331* 1.7 114 Feb 901 0.4* 5.4* 752 377* 1.8 132 Mar 898 0.8* 6.2* 1211 504* 2.1 199 Apr 938 1.2* 7.4 1581 650* 2.2 265 May 1554 2.9 12.7 3101 1281* 3.1 662 Jun 2703 5.1 19.0 4456 1044* 4.1 913 Jul 813 1.1* 6.7* 1493 357* 1.8 197 Aug 881 0.7* 3.8* 1186 331* 1.9 156 Sep 920 0.8* 3.1* 1002 404* 2.3 179 Oct 713 0.7* 2.9* 1000 384* 1.9 151 Nov 849 0.7* 4.0* 1023 391* 2.0 148 Dec 777 0.4* 4.5* 1062 355* 1.8 127 *Current Condition Load † Fe (tot) TMDL is the surrogate for pH in Segment 4a. Month
36
Upper Animas River Basin Total Maximum Daily Load Assessment
Table 22: Total Maximum Daily Load at CC48 Month
Al (tot) Cd (dis) Cu (dis) Fe (tot) Mn(dis) Pb (trec)** Zn (dis) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day)
Jan
405
0.1
1
660
97
5.8**
41
Feb
414
0.1
1
507
134
5.8**
43
Mar
450
0.1
2
569
175
6.3**
50
Apr
352
0.1
4
259
134
6.3**
41
May
807
0.4
8
945
256
19.0**
106
Jun
1389
1.3
23
1372
292
43.7**
118
Jul
465
0.2
6
390
183
14.6**
45
Aug
372
0.1
5
281
148
8.3**
32
Sep
426
0.1
4
571
180
8.3**
60
Oct
335
0.1
2
397
131
5.8**
51
Nov
405
0.1
2
559
171
6.8**
51
Dec
430
0.1
2
695
134
6.3**
44
**Pb TMDL is based upon the agricultural standard of Pb=100(trec) µg/l.
Waste Load Allocations
The ARSG identified 33 draining adits that are currently targeted for remediation as outlined in the Animas River UAA. The WQCD recognizes, as stated below, that the Upper Basin remediation plans are considered an Adaptive Management situation. The following table, Table 23, shows the current metal loading from the 33 identified draining adits subdivided into three main sub-basins of the Upper Basin. Table 23 also shows the estimated metal loading reduction for each site that may be attained upon remediation. The estimated metal loading reductions are based upon the best professional judgment of achievable reductions upon implementation of site-specific remediation plan or Best Management Practices. The estimated metal loading reductions for the 33 identified draining adits are not intended to be, nor should be considered, pollutant effluent limits in any future regulatory decision or action. Tables 24 and 25 show the current metal loading, the post-remediation metal loading, and the load reductions from remediation for the three sub-basins for the high flow condition and the low flow condition of the Upper Basin.
37
Upper Animas River Basin Total Maximum Daily Load Assessment
Table 23: Current Loads and Estimated Potential Reductions (in percentage) from Adits (Waste Load Allocations) developed by the ARSG in the Animas River UAA. Estimated Current Contributing Current Contributing Load (lbs/day) during Load (lbs/day) during Load the Low Flow Season Reduction the High Flow Season in percent after Remediation Cement Creek Basin Al Cd Cu Fe Mn Zn Al Cd Cu Fe Mn Zn Mogul Mine 50% 1 0.0 1.7 14 4 2 1 0 0.7 5 1 3 Silver Ledge Mine 50% 25 0.1 0.6 222 33 15 4 0 0 56 11 3 Grand Mogul Mine 50% 15 0.2 5.3 33 10 27 1 0 0.2 0 0 1 Mammoth Tunnel 50% 1 0.0 0.0 14 2 8 1 0 0 16 2 0 Anglo-Saxon Mine 50% 0 0.0 0.0 15 10 2 0 0 0 15 5 1 Joe & Johns Mine 50% 0 0.0 0.2 1 1 1 0 0 0 1 0 0 Big Colorado Mine 50% 1 0.0 0.0 3 3 0 1 0 0 6 0 0 Porcupine Mine 50% 0 0.0 0.0 14 5 1 0 0 0 10 5 1 Evelyn Mine 50% 1 0.0 0.0 2 0 0 2 0 0 3 0 0 Lewis Property 50% 0 0.0 0.4 2 0 1 0 0 0.4 2 0 1 Mineral Creek Basin Al Cd Cu Fe Mn Zn Al Cd Cu Fe Mn Zn Kohler Mine 50% 33 0.4 31 321 10 91 28 0.3 28 264 8 78 North Star Mine 50% 0 0 0.1 6 16 4 1 0 0.2 6 11 3 Junction Mine 30% 13 0.1 2.2 126 3 14 0 0 0.1 3 0 0 Bandora Mine 50% 0 0 0.1 5 4 10 0 0 0 2 2 4 Upper Bonner Mine 90% 1 0 0 1 1 1 2 0 0 2 1 1 Ferrocrete Mine 50% 2 0 0 31 5 1 3 0 0 32 7 1 Paradise Mine 50% 28 0 0.1 246 20 2 28 0 0.1 246 20 2 Brooklyn Mine 30% 1 0 0.2 8 2 2 1 0 0.2 8 2 2 Bonner Mine 50% 1 0 0 1 1 1 2 0 0 2 1 0 Lower Bonner 50% 1 0 0 1 0 0 2 0 0 2 1 1 Little Dora Mine 85% 1 0.3 0.9 5 653 48 0 0 0 0 2 0 Animas River Basin above A68 Al Cd Cu Fe Mn Zn Al Cd Cu Fe Mn Zn Vermillion Mine 50% 0 0 0.2 2 1 9 0 0 0.1 1 0 3 Columbus Mine 30% 1 0 0.3 3 0 9 0 0 0.1 1 0 4 Lower Comet Mine 50% 2 0 0.1 2 2 1 2 0 0 1 1 1 N. side of California Mtn. 50% 4 0 0 1 5 2 4 0 0 1 5 2 Sound Democrat Mine 50% 0 0 0.1 0 4 1 0 0 0 0 2 0 Mountain Queen Mine 50% 0 0 0.2 1 0 1 0 0 0.1 0 0 0 Silver Wing Mine 85% 0 0 0.1 0 0 0 0 0 0.3 1 1 1 Bagley Mine 50% 0 0 0 0 13 7 0 0 0 0 6 3 Senator Mine 50% 0 0 0 21 7 0 1 0 0 23 14 2 Royal Tiger Mine 80% 5 0 0.8 0 3 7 0 0 0.1 0 0 0 Pride of the West Mine 50% 0 0 0 0 0 3 0 0 0 0 0 2 Little Nation Mine 50% 0 0 0 9 2 1 0 0 0 4 1 0 Name of Draining Adit
38
Upper Animas River Basin Total Maximum Daily Load Assessment
Table 24: Estimated metal load reductions in the three sub-basins from remediation at the high flow condition. Sub-Basin and Loads Cement Creek Sub-Basin at CC48 Total Load from ARSG Identified Draining Adits Estimate Post-Remediation Load from ARSG Identified Draining Adits Estimated Load Reduction from ARSG Identified Draining Adits Mineral Creek Sub-Basin at MC34 Total Load from ARSG Identified Draining Adits Estimate Post-Remediation Load from ARSG Identified Draining Adits Estimated Load Reduction from ARSG Identified Draining Adits Animas River Sub-Basin at A68 Total Load from ARSG Identified Draining Adits Estimate Post-Remediation Load from ARSG Identified Draining Adits Estimated Load Reduction from ARSG Identified Draining Adits
Al (tot) Cd (dis) Cu (dis) Fe (tot) Mn(dis) Zn (dis) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day)
44
0.29
8.3
320
68
57
22
0.15
4.2
160
34
28
22
0.15
4.2
160
34
28
81
0.85
34
750
714
175
42
0.32
17
398
129
73
39
0.53
17
352
585
102
14
0.14
1.8
39
39
39
5.9
0.06
0.7
19
18
19
8.4
0.08
1.1
19
20
20
39
Upper Animas River Basin Total Maximum Daily Load Assessment
Table 25: Estimated metal load reductions in the three sub-basins from remediation at the low flow condition. Sub-Basin and Loads
Al (tot) Cd (dis) Cu (dis) Fe (tot) Mn(dis) Zn (dis) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day)
Cement Creek Sub-Basin at CC48 Total Load from ARSG Identified Draining Adits Estimate Post-Remediation Load from ARSG Identified Draining Adits Estimated Load Reduction from ARSG Identified Draining Adits Mineral Creek Sub-Basin at MC34 Total Load from ARSG Identified Draining Adits Estimate Post-Remediation Load from ARSG Identified Draining Adits Estimated Load Reduction from ARSG Identified Draining Adits Animas River Sub-Basin at A68 Total Load from ARSG Identified Draining Adits Estimate Post-Remediation Load from ARSG Identified Draining Adits Estimated Load Reduction from ARSG Identified Draining Adits
9.8
0.07
1.3
113
25
12
4.9
0.03
0.7
57
12
6
4.9
0.03
0.7
57
12
6
65
0.31
29
566
54
93
32
0.15
14
282
26
46
33
0.16
14
283
28
47
8.3
0.07
0.7
33
30
18
4.1
0.04
0.3
17
15
9
4.2
0.03
0.4
17
16
9
Load Allocations Load Allocations are generally considered the source or sources of pollutants from nonpoint sources. The WQCD has historically considered mine waste sites, which are not associated with an active mining operation or do not have a discreet conveyance of pollutants to the waters of the State, to be non-point sources of pollution. This approach to mine waste sites was continued in this TMDL assessment. The ARSG identified two types of Load Allocations in the Upper Basin. The first type of Load Allocation is the pollution caused by water flowing over and through hydrothermally altered geologic terrain in the Upper Basin and the non-targeted mine waste sites. The WQCD choose to refer to this portion of the Load Allocation as the Undifferentiated Load Allocation. The Undifferentiated Load Allocation can be subcategorized into 1) natural runoff sources (i.e. weathering of natural geologic features) and 2) anthropogenic related sources other than the targeted mines wastes sites (e.g. non-targeted wastes, roads, construction and grazing impacts). The second type of Load Allocation is referred to by the WQCD as Quantified Load Allocations. The Quantified Load Allocations are the estimated post remediation loads for 32 40
Upper Animas River Basin Total Maximum Daily Load Assessment
mine waste sites in the Upper Basin that were developed by the ARSG. The ARSG, due to their methodology as describing loads from mine waste sites, estimated the Quantified Load Allocations as pounds per year. The Quantified Load Allocations are listed in Table 26 below.
41
Upper Animas River Basin Total Maximum Daily Load Assessment
Table 26: Current Loads and Estimated Potential Reductions (in percentage) from mine waste sites (Quantified Load Allocations) developed by the ARSG in the Animas River UAA.
Site Name
Estimated Load Reduction Mine Waste Current Mine Waste Load Allocation (lbs/year) in percent Condition Load (lbs/year) after Remediation
Cement Creek Basin Galena Queen Mine Kansas City #2 Mine Hercules Mine Upper Joe & Johns Mine Grand Mogul (East) Mine Kansas City #1 Mine Black Hawk Mine Lead Carbonate Mine Henrietta 3 Mine Ross Basin Lark Mine Pride of the Rockies Mine Henrietta # 7 Mine
90% 40% 90% 40% 35% 40% 50% 55% 20% 10% 90% 45% 40%
Al Cd Cu Fe 154 36.8 832 6,895 159 7.1 39 3,979 163 30.6 168 6,712 2 0.1 2 19 47 2 29 745 82 1.2 19 1,618 82 0.5 6 124 120 0.8 27 1,228 217 0.7 107 4,972 9 0.3 18 234 18 0.8 40 886 7 0.1 0 383 101 0.8 25 1,685
Mogul Mine
35%
51 1.2 32 942
Mineral Creek Basin
Al Cd Cu
Brooklyn Mine Bullion King (Lower) Mine Upper Browns Trench Congress Shaft Brooklyn (Upper) Mine Upper Browns Mine Little Dora Mine
90 90 40 40 20 90 30
58 641 27 11 661 82 94
Brooklyn (Lower) Mine
20
110 0.6
Animas River Basin above A68
0.8 6 0.1 0.2 3.1 0.3 0.4
Mn Zn Al Cd Cu Fe Mn Zn 0 6137 15.4 3.68 83.2 689.5 0 613.7 0 1172 95.4 4.26 23.4 2387.4 0 703.2 0 4711 16.3 3.06 16.8 671.2 0 471.1 0 23 1.2 0.06 1.2 11.4 0 13.8 0 385 30.55 1.3 18.85 484.25 0 250.25 0.2 282 49.2 0.72 11.4 970.8 0.12 169.2 0.1 108 41 0.25 3 62 0.05 54 0 179 54 0.36 12.15 552.6 0 80.55 0 113 173.6 0.56 85.6 3977.6 0 90.4 0 49 8.1 0.27 16.2 210.6 0 44.1 0 168 1.8 0.08 4 88.6 0 16.8 0.1 7 3.85 0.055 0 210.65 0.055 3.85 0 159 60.6 0.48 15 1011 0 95.4 0 261 33.15
0.78
20.8
612.3
Al
Cd
Cu
Fe
117 118 5.8 190 629 64.1 3 9 16.2 11 20 6.6 176 163 528.8 6 25 8.2 471 66 65.8
0.08 0.6 0.06 0.12 2.48 0.03 0.28
Fe Mn Zn
8 993 14 9,945 8 198 16 109 38 9,909 5 1,610 43 452
9 672 122 105
0 169.65 Mn
Zn
0.8 99.3 11.7 1.4 994.5 19 4.8 118.8 1.8 9.6 65.4 6.6 30.4 7927.2 140.8 0.5 161 0.6 30.1 316.4 329.7
11.8 62.9 5.4 12 130.4 2.5 46.2
88
0.48
7.2
537.6
97.6
84
Fe Mn Zn
Al
Cd
Cu
Fe
Mn
Zn
0.8 8 225 1 165 1 123 393 172 131 0.3 1 8 43 73 0.1 1 0 7 18 0.6 3 14 32 95 0.2 7 80 57 70 0.8 24 13 73 141 0.4 13 612 99 95 1 15 1 50 255
16.8 49 1.5 0.1 1.6 0.6 1.7 8.1 16.1
0.48 0.5 0.03 0.01 0.06 0.02 0.08 0.04 0.7
4.8 61.5 0.1 0.1 0.3 0.7 2.4 1.3 10.5
135 196.5 0.8 0 1.4 8 1.3 61.2 0.7
0.6 86 4.3 0.7 3.2 5.7 7.3 9.9 35
99 65.5 7.3 1.8 9.5 7 14.1 9.5 178.5
4
0.23
1
0
53.6
66.4
Al Cd Cu
Ben Butler Mine Silver Wing Mine Tom Moore Mine Eagle Mine Lucky Jack Mine Clipper Mine Buffalo Boy Mine Ben Franklin Mine Caledonia Mine
40 50 90 90 90 90 90 90 30
28 98 15 1 16 6 17 81 23
Sunnyside Mine
90
40 2.3 10
0 536 664
42
Upper Animas River Basin Total Maximum Daily Load Assessment
7. Implementation Implementation of the TMDLs for the Upper Animas River Basin is dependent upon initiation and eventual completion of the ARSG proposed remediation plan as outlined in the Animas River UAA. The intent of this TMDL assessment is that water quality targets will be attained at the stream gages (A68, MC34, CC48, and A72) after completion of the 65 remediation projects. However, this TMDL may need to be amended in the future if new conditions arise, which is often referred to as an Adaptive Management Approach by the EPA. The ARSG, WQCD, and other agencies will continue to monitor water quality in the Upper Basin. The WQCD will review the water quality data and the TMDLs in the Upper Basin as part of its water quality standards triennial review process. The next water quality standards review is scheduled for November, 2005. Implementation of mining remediation projects is problematic to achieve for interested third parties such as the ARSG. Difficulties in terms of ownership, access, and liability are possible when working on historic mining sites. The ARSG is working to find ways to provide incentives, and encourage landowners to be involved in remediation projects. As well, the ARSG is seeking approaches to allow “Good Samaritans” to provide assistance in remediation without facing undue liability for their actions.
Adaptive Management Approach
Implementation of the TMDLs for the Upper Basin is dependent upon initiation and eventual completion of the ARSG proposed remediation plan as outlined in the Animas River UAA. The WQCD recognizes that the remediation plan developed in the Animas River UAA is ambitious and projected to take place over twenty years. The WQCD also recognizes that the remediation plan developed in the Animas River UAA may change due to financial considerations, new pollutant source discoveries, new remediation technologies, further characterization, or other unforeseen circumstances. Therefore, the WQCD considers this TMDL assessment to be a situation where an Adaptive Management Approach would be appropriate. An Adaptive Management Approach for the Upper Basin is an acknowledgement between the WQCD, the ARSG, and other interested parties that the remediation plan developed
43
Upper Animas River Basin Total Maximum Daily Load Assessment
in the Animas River UAA can be revised based upon new and relevant information or circumstance. There are two basic scenarios that could occur as remediation progresses in the Upper Basin: Adaptive Management Approach Scenario 1) the remediation plan is revised due to new information or circumstances, but the water quality goals and targets outlined in this TMDL assessment are not changed; Adaptive Management Approach Scenario 2) new information or circumstances require changes to the water quality goals and targets outlined in this TMDL assessment. Should a different Adaptive Management Approach Scenario arise as remediation progresses, it will be addressed by the ARSG and WQCD as appropriate. The remediation plan may need to be revised by the ARSG due to new information or circumstances in the Upper Basin without altering the water quality goals and targets outlined in this TMDL assessment (Adaptive Management Approach Scenario 1). For example, should a new remediation site or sites be targeted for remediation in lieu of a previously targeted remediation site or sites, the WQCD would agree to the change as long as the same approximate load reduction is accomplished by remediation of the new targeted sites as would have been by the previously targeted remediation site or sites. Thus, the water quality goals and targets would still be attained by the TMDL assessment should all remediation projects be completed. Such a revision should be accounted for within the TMDL assessment as an amendment submitted to the WQCD. Therefore, regardless of how the remediation plan progresses, the ambitious environmental improvement intended by this TMDL assessment for the Upper Basin remains unaltered. As remediation progresses in the Upper Basin, the water quality goals and targets that were developed during the 2001 water quality standards review, and utilized to develop this TMDL assessment, may need to be adjusted due to new financial considerations, new pollutant source discoveries, new remediation technologies, or other unforeseen circumstances (Adaptive Management Approach Scenario 2). If such a situation should occur, the water quality standards will have to be adjusted through the formal WQCC water quality standards review process. If changes to the water quality standards are adopted by the WQCC in the future, the TMDL will be adjusted to reflect those changes in terms of water quality goals and targets. This scenario is significantly more rigorous in terms of burden of proof than Adaptive Management Approach Scenario 1, and would require approval of the EPA and concurrence with other interested parties.
44
Upper Animas River Basin Total Maximum Daily Load Assessment
Integration of future CDPS Permits and TMDLs
The ARSG has raised the possibility that new point source discharges may occur as the result of future mining or milling activities located within the Upper Basin, and the possible future expansion of Silverton or other communities in the Upper Basin. The Division recognizes that any new mine-related discharge permit written for an existing draining adit that previously did not have a CDPS permit would be beneficial to downstream water quality since either Best Available Technology (“BAT”) limits or numerical stream standards, whichever are lower, would be imposed on the new discharge. Until remediation addressing the ARSG identified draining adits and mine waste sites is completed, there is no assimilative load capacity for the load remaining after appropriate treatment. In this type of situation, the Division feels it is important to create incentives to clean up existing non-permitted mine discharges and will support the treatment of these effluents at a level no more strict than BAT or the receiving stream numeric standards. By requiring that any such discharge meet the water quality standard, it is assured that the discharge will, in fact, dilute instream concentrations of the non-attaining parameters. Any new discharge will therefore neither contribute to nor cause non-attainment of instream water quality standards. The attainment of the adopted numerical standard concentrations, which are based upon meeting biological goals for the establishment and sustainability of aquatic life, is considered as beneficial to the aquatic environment of the Upper Basin as meeting the total maximum daily loads described in this document.
8. Public Involvement The Total Maximum Daily Load Assessment for the Upper Animas River Basin was noticed in the February CDPHE Water Quality Information Bulletin for public comment. The TMDL was available through the Water Quality Control Division by request, and was available on the WQCD internet site. There were three commenters during this period: Animas River Stakeholder’s Group, U.S. Environmental Protection Agency, and Earthjustice. Several modifications were made to the TMDL assessment based upon these comments. The comments are available upon request. The WQCD subsequently decided to notice the TMDL assessment for a second public comment period (April 1, 2002 to April 30, 2002).
45
Upper Animas River Basin Total Maximum Daily Load Assessment
Public Involvement through the ARSG The ARSG have met as a public forum, open to any interested person or party since 1994. The ARSG has been the primary group involved in coordinating data collection and analysis, and developing the remediation scenarios that are the foundation of this TMDL. The public has also had the opportunity for involvement with the WQCC water quality standards hearings regarding these segments. In addition, the compilation of the Clean Water Act Section 303(d) Lists has been a public process. Listed below are the current and former participants in the Animas River Stakeholder’s Group: Private Citizens River Watch Network, Inc. Root and Norton Assayers San Juan County Commissioners San Juan County Historical Society Silver Wing Co., Inc. Silverton, Town of Southern Ute Tribe Southwestern Colorado Water Conservation District St. Paul Lodge Sunnyside Gold Corp. TUSCO U.S. Army Corps of Engineers U.S. Bureau of Land Management U.S. Bureau of Reclamation U.S. Environmental Protection Agency U.S. Forest Service U.S. Geological Survey
Colorado Center for Environmental Management Colorado Department of Public Health & Environment Colorado Division of Minerals and Geology Colorado Division of Wildlife Colorado Geological Survey Colorado River Watch Colorado Water Quality Control Division Durango and Silverton Narrow Gauge Railroad Durango, City of Echo Bay Mines Ltd. Fort Lewis College Friends of the Animas River Gold King Mines Little Nation Mining Mineral Policy Center Mining Remedial Recovery Co. OSIRIS Gold
9. Responsive Statements The Upper Animas River Basin TMDL was held to public notice twice (February and April 2002). The first public notice draft generated two commenters, EPA and Earthjustice. Both commented that the lack of a TMDL for dissolved Pb was inappropriate. A TMDL for dissolved Pb was developed and added to the second public notice draft. EPA commented that more
46
Upper Animas River Basin Total Maximum Daily Load Assessment
explanation of the Margin of Safety, seasonality of the TMDL, and remediation goals was needed. These three points were expanded upon in the second public notice draft. The second public notice draft generated one commenter, Earthjustice. Earthjustice commented that the historic policy of the WQCD to not require a CDPS permit for inactive mine waste sites was not in compliance with the federal Clean Water Act. In order to clarify the WQCD’s position the following sentence on Page 39 was modified from “The WQCD has historically considered mine waste sites, which are not associated with an active mining operation or have a discreet conveyance of pollutants to the waters of the State, to be non-point sources of pollution” to “The WQCD has historically considered mine waste sites, which are not associated with an active mining operation and do not have a discreet conveyance of pollutants to waters of the State, to be non-point sources of pollution.” Furthermore, it is the Division’s intent that the TMDL reflect a watershed-based approach built upon local community efforts intended to address the water quality problems. The TMDL incorporates wasteload allocations and load allocations that are assigned to significant pollutant sources. The Division is committed to undertaking remedial actions identified in the TMDL using the full range of appropriate regulatory and non-regulatory mechanisms. Currently, discussions are underway which may result in a congressional appropriation directed at funding these efforts. Alternately, or in combination with any such monies, the Division may potentially undertake funding remedial activities using federal CWA section 319 monies. Current EPA program guidance (see Supplemental Guidelines for the Award of Section 319 Nonpoint Source Grants to States and Territories in FY 2002 and Subsequent Years, EPA, September 5, 2001) mandates that half of available §319 funds be allocated to restoration of impaired waters. A funding prerequisite is EPA approval of one or more TMDLs for the listed segments. We believe that use of §319 funds to remediate abandoned mine sites provides an expeditious solution to an otherwise intractable environmental problem. It should also be noted that an active, cooperative water quality monitoring program involving the BOR, USGS, and ARSG is ongoing. The Division considers this ongoing water quality monitoring project to be an important component of the TMDL implementation strategy.
47
Upper Animas River Basin Total Maximum Daily Load Assessment
10. Appendix Figure 1: Location of the Animas River Basin in Colorado.
48
Upper Animas River Basin Total Maximum Daily Load Assessment
Figure 2: Stream segmentation of the Upper Animas River Basin
49
Upper Animas River Basin Total Maximum Daily Load Assessment
Figure 3: Location of the four principal stream gages in the Upper Basin
50
Upper Animas River Basin Total Maximum Daily Load Assessment
Figure 4: ARSG proposed remediation sites.
51
Upper Animas River Basin Total Maximum Daily Load Assessment
Upper Animas River Basin TMDL Responsive Statements
52
