UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 8 999 IaTnSTREET SUITE 300 DENVER, CO 80202-UB6 Mtp:flwww~pa.gwtmglonOB

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Ref: 8EPR-EP Mark T.Pifher, Director Water Quality Control Division Colorado Department ofPublic Health and ~nviromn 4300 Cherry Creek Drive South Denver, Colorado 80246-1530

Re:

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W

L Approvals Zinc, Lead Fork of the Arkansas River

Dear Mr.Pi&er:

We have completed our review of the total maxi num daily load (TkriDL) as submittfl by your office for the East Fork of the Arkany River, Se nent 16. The TMDL is included in the docuqent entitld, TMDL semt b. E&t Fork Mc~~as'ZLiver~ (cQloradoDepartment of Public Health and Environment, December 3 1,2003). This document was submitted to us for review and approval in correspondence dated January 2/ 2004. In a&rdance with the Clean Waten Act (33 U.S.C. 125 1 ef. seq.), we approve all as@& of the TMDL as developed for the water quality limited waterbody as described in Section1,303(d)(l). Enclosure 1 to this letter provides a summary of the elements of the TMDL and nclosd 2 provides details of our review of the ITMDL.

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Based on our review, we feel the separate TMDL elmen; listed in Enclosure 2 adequhttly address the pollutant of concern, taking into mnsidmtion seasonal variation and a margin of safety. In approving this TMDL, EPA affirms that the TMDL has been established at a level necessary to attain and maintain the applicable watt& quality standards and bas the n v components of an approvable TMDL.

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Thank you for your submittal. Ifyou have any questions concerning this approval, fejel free to contact Kathy Hernandez of my staff at 30313 $2-6 101.

Max H. Dodson Assistant Regional Administrator Office of Ecosystems Protection and Remediation

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FINAL TMDL Segment 1b, East Fork Arkansas River

Colorado Department of Public Health and Environment Water Quality Control Division Assessment Unit 4300 Cherry Creek Drive South Denver, Colorado 80246 December 31, 2003

TOTAL MAXIMUM DAILY LOAD ASSESSMENT East Fork Arkansas River above Birdseye Gulch Segment COARUA01b Lake County, Colorado _____________________________________________________________________ EXECUTIVE SUMMARY Section 303(d) of the federal Clean Water Act requires states to identify water bodies that are water quality impaired. The East Fork of the Arkansas River above Birdseye Gulch, Segment COARUA01b was identified on Colorado‟s 1998 and 2002 303(d) lists as not supporting the use classification for aquatic life due to high levels of lead and zinc. Once listed, the State is required to quantify the amount of a specific pollutant that a listed water body can assimilate without exceeding applicable water quality standards (unless the waterbody subsequently achieves standards via an alternate recognized mechanism). This maximum allowable pollutant quantity is referred to as the Total Maximum Daily Load ("TMDL"). This is the TMDL analysis for the East Fork of the Arkansas River. The stated target, or expected condition, of the TMDL is a reduction in loading of lead and zinc within the upper reaches of Segment 1b of the East Fork of the Arkansas River. Much of the loading to this segment is due to natural and irreversible anthropogenic sources. There is one obvious anthropogenic source that has been identified in this segment, the John Reed Disturbed Wetlands. Remediation of this site is expected to result in a 50% loading reduction of lead and zinc to the segment.

Pollutant

Lead Zinc

TMDL for the East Fork of the Arkansas River Limiting Target/Goal Estimated Flow Beneficial (ug/l) (cfs) Use Aquatic Life 1.44 0.74 Cold 1 Aquatic Life 76.6 (ch) 0.74 Cold 1 76.0 (ac)

Estimated TMDL (lbs/day) 0.0058 0.3037

Percentage Loading Reduction Needed to Meet TMDL Pollutant Current Loading Estimated Percentage of (lbs/day) TMDL Total Load (lbs/day) Reduction Needed to meet Target

Lead Zinc 1.0

0.0082 0.5594 INTRODUCTION

0.0058 0.3037

29% 46%

Section 303(d) of the federal Clean Water Act requires states to identify water bodies that are water quality impaired. Water quality impaired segments are those water bodies or stream segments which are not fully attaining one or more assigned use classification or standard. These segments are currently identified on the Colorado 2002 303(d) List. Once listed, the State is required to quantify the amount of a specific pollutant that a listed water body can assimilate without exceeding applicable water quality standards. A segment or pollutant may be removed from the list if the applicable standard is attained, if implementation of clean up activities via an alternate means will result in attainment of standards, or the original listing decision is shown to be in error. This maximum allowable pollutant quantity is referred to as the Total Maximum Daily Load ("TMDL"). The TMDL is comprised of the Load Allocation ("LA"), which is that portion of the pollutant load attributed to natural background or the nonpoint sources, the Waste Load Allocation ("WLA"), which is that portion of the pollutant load associated with point source discharges, and a Margin of Safety ("MOS"). The TMDL may also include an allocation reserved to accommodate future growth. The TMDL may be expressed as the sum of the LA, WLA and MOS.

1.1

Segment 1b; East Fork of the Arkansas River

The East Fork of the Arkansas River, subject of this TMDL, begins its journey in Lake County, Colorado at 12,500‟ above mean sea level (amsl) in the high basin formed by Mount Arkansas to the north and Mounts Buckskin and Democrat along the Continental Divide (Map 1). From its source, the river flows northward just over three miles, through riparian and shrub wetlands generally through U.S. Forest Service ("USFS") managed lands. The river then flows approximately 1.75 miles while turning west, then south toward the mainstem of the Arkansas River near Leadville, Colorado. This nine mile segment of the East Fork of the Arkansas River is identified as Segment 1b of the Upper Arkansas River subbasin by the Colorado Water Quality Control Commission ("WQCC") and the Colorado Water Quality Control Division ("WQCD") for purposes of Colorado use classifications and water quality standards. The segment encompasses a watershed area of approximately 31.5 square miles and is part of Arkansas Headwaters Hydrologic Unit Code 11020001. The segment's water body identification ("WBID") is COARUA01b and the segment is described as the “mainstem of the East Fork of the Arkansas River from its source to a point immediately above the confluence with Birdseye Gulch”. The assigned use classifications are “Aquatic Life Cold Water 1, Recreation 1a, Water Supply”. Segment 1b was identified on Colorado‟s 1998 and 2002 303(d) lists as not

supporting the use classification for aquatic life due to high levels of lead and zinc. The segment also was listed as partially supporting of the water supply use classification because of high dissolved manganese. Temporary modifications to the standards for lead (Pb), zinc (Zn), and manganese (Mn) were 6.5 ug/l, 137 ug/l, and 90 ug/l respectively, and were approved for the segment on November 30, 1998. In the July 2002 Arkansas River Basin rulemaking hearing, the WQCC extended the temporary modifications for lead and zinc to December 31, 2007. The temporary modification for manganese was deleted due to changes to the Basic Standards, Regulation No. 31 in 2000. Manganese was subsequently deleted from on the 2002 303(d) list in March 2003 because the ambient water quality is meeting the water quality standards for both water supply and aquatic life.

1.2

Discharge Permits and Property Ownership

Currently, there are no active Colorado Discharge Permit System ("CDPS") permitted discharges into Segment 1b of the Arkansas River. One discharge permit to the segment, CDPS Discharge Permit CO-0029840, was inactivated by the Climax Molybdenum Company ("Climax") in October 1988. No other permitted sources are present within the segment. Photo 1 shows the location of several key elements within the upper portion of the segment. The Climax property line is at the WQCD upstream sampling station 7199 (Map 1). Lands upstream and downstream of this point are mix of private lands, patented mining claims, and lands managed by the U.S. Forest Service ("USFS"), the U.S. Bureau of Land Management ("BLM"), and the Colorado Department of Transportation ("CDOT").

2.0

PROBLEM IDENTIFICATION

The East Fork of the Arkansas River watershed and surrounding region lies within the Colorado Mineral Belt and is heavily influenced by natural mineralization and by historic mining activities. A brief historical summary of the area serves to place present lead and zinc loading to the segment in perspective. 2.1

History

During the late 19th century and well into the early 20th century, exploration for, and production of, minerals was a continuous, extensive, and important activity throughout the mineral belt of central Colorado. Uncountable mining and milling operations sprouted anywhere natural mineralization and mineral resources could be located. The Consolidated Ten Mile Mining District ("District") is one such area where extensive mineralization occurs. The District, located in Lake, Eagle, and Summit Counties, encompasses about 45

square miles of mountainous terrain along the Continental Divide between roughly Copper Mountain to the north, to just south of Fremont Pass to the south. The District, formally established in the 1870s, includes mines surrounding the historic townsites of Recen, Kokomo, Robinson, Carbonateville, and Climax, and the upper reaches of the Arkansas River. From the earliest placer gold discoveries in the 1860s, intermittent periods of active mining and lulls occurred within the district. The District produced silver, molybdenum, lead, zinc, copper, and gold ores. Prior to approximately 1900, silver and lead were the primary commodities. After 1900, zinc and molybdenum ores produced the highest values. 2.2

Geology and Mining

Geology and mineralization in the District is highly complex, and generally of three types: massive sulfide replacement deposits, veins, and high-temperature deposits characterized by magnetite, garnet, and molybdenite occurring as veins, disseminations, and replacement bodies. Sulfide mineralization containing various concentrations of lead, zinc, silver, copper, gold, and molybdenum is predominant throughout the District. Excluding Climax (with its surface mining in recent years), mining operations in the District were underground and relatively small compared to districts in the Leadville, Central City, San Juan, and Cripple Creek areas. Small “poddy” ore bodies and veins were exploited by shafts, adits, and declines. Typical of the period, mills were constructed at or near the principal mine entrance or entrances where several adits or shafts were in the near vicinity. Briefly and simply, these mills crushed and reduced the raw ores to polymetallic concentrates that could be shipped to and processed by distant smelters more economically. The fine waste material remaining, defined as “tailing” or “tailings”, was deposited adjacent to or directly down-gradient of the mill, much as domestic wastes of the time were sent to the nearest moving water body. In that period prior to modern environmental laws, regulations, and considerations, gravity was the principal disposal method for mining wastes. Climax Molybdenum has the most recent presence in the watershed and continues to maintain its facility. No active mining is taking place at the present time. 2.3

TMDL Scope and Priority

Lead and zinc are the pollutants of concern considered in this TMDL. This TMDL addresses that upper portion of Segment 1b of the Arkansas River that does not meet the water quality standards for the established aquatic life use classification for lead and zinc. The 1998 and the 2002 303(d) lists rate the segment priority as “High”. Recently completed and planned remediation efforts within the watershed are expected to reduce metals loading to the segment, allowing either attainment of table value standards ("TVS") or justifying adoption of ambient quality based standards to

be adopted pursuant to Regulation 31.7(1)(b)(ii). Ambient quality based standards could be justified based on an adjustment to account for natural or irreversible manmade sources. 2.4

Water Quality Goals

The desired endpoint of the TMDL for Segment 1b of the East Fork of the Arkansas River is to reduce the loading of lead and zinc to the segment so that the segment achieves water quality standards. Achievement of these goals should occur after the remedial program for the John Reed wetland site is completed and post-project monitoring has been initiated in 2003. This project and post-project monitoring is discussed in Section 7.0. 2.5

Water Quality Target / Expected Condition

The stated target, or expected condition, of the TMDL is a reduction in loading of lead and zinc within the upper reaches of Segment 1b of the East Fork of the Arkansas River. Much of the loading to this segment is due to natural and irreversible anthropogenic sources. The John Reed site is the obvious anthropogenic source available for remedy in the upper segment. Remediation of this site as described in Section 7.0 is expected to result in a loading reduction of lead and zinc to the segment. It is unlikely that loading reductions will be to a level meeting TVS. In this event, a Use Attainability Analysis "(UAA") may become necessary to determine the appropriate standards. Actions to be completed by Climax within the segment in 2003 are expected to reduce loading. Therefore, the expected condition for the segment following remedial activities will be an improvement over the present condition.

3.0

WATER QUALITY STANDARDS

As previously noted, Segment 1b is classified for the uses of Aquatic Life Cold Water 1, Recreation 1a, and Water Supply. The WQCC initially adopted ambient based standards for lead and zinc in Segment 1b in 1982. After the change from the total recoverable to dissolved method of analysis in the mid-1980s, the WQCC deleted the ambient based standards and adopted TVS with temporary modifications for lead and zinc. These temporary modifications have been revised and extended at various Arkansas River Basin hearings, most recently in 2002 when temporary modifications were extended to December 2007. Table 1 presents a summary of the water quality TVS and the temporary modifications in place for the segment. A summary of the ambient water quality is also included in Table 1 for comparison to the current standards. The TVS for lead and zinc are based on an average hardness value at low flow for the segment of 60 mg/l (n=90). The TVS are calculated by using the hardness-based

equations specified in Regulation No. 32. The TVS for both lead and zinc include acute and chronic standards. These are intended to protect aquatic species for direct toxicity and sub-lethal affects. For lead, the chronic standard is an order of magnitude more stringent than the acute standard. The chronic standard therefore is selected as the water quality target. The acute and chronic zinc standards are essentially the same and therefore cited as target levels. 3.1

Use Protection

Although water quality values for lead and zinc in Segment 1b exceed TVS, ambient water quality in the segment is protective of the Class 1 Cold Water Aquatic Life Use Classification established by the WQCC. Aquatic life surveys consisting of fishery and benthic macroinvertebrate investigations show that populations of trout and benthic macroinvertebrates exist at sustained and healthy levels. A viable trout population consisting primarily of brook trout, diverse in size structure and high in density (2188 fish/ha) and relative weight inhabit Segment 1b. Diverse macroinvertebrate populations include high mean densities of Ephemeroptera (mayflies) and Plecoptera (stoneflies), two taxonomic families that require high quality water and habitats. 3.2

Ambient Water Quality

Water quality data collected by the WQCD, the Colorado Department of Wildlife ("CDOW"), and Climax was used to evaluate the ambient water quality conditions of Segment 1b. Data was collected by the WQCD from 1993 through 2000 with extensive sampling during the 1998-1999 period. The CDOW collected data at one station, EF0 (located at the same location as WQCD 7197) from 1995 through 2001 with the majority of sampling occurring from 1998 through 2001. Climax has collected water quality data from three stations on the segment since 1992. All sampling station locations are shown on Map 1 and Table 2. The data used in this analysis was from 1996 through 2003 at all stations. The period of record ("POR") used to calculate the TMDL was from the most recent period of record from 1998 through 2003. This period of record is representative of water quality in this segment. Table 1 compares the ambient conditions with TVS. Appendices B and C provide the dated raw data by station that was incorporated into this TMDL. As Map 1 illustrates, only WQCD station 7199 is upstream of the influences of the John Reed site. WQCD station 7198a is below the John Reed site but upstream of the Climax Storke Yard influence. This station was the focus of loading reduction in this TMDL. Table 1. Comparison of Ambient Water Quality to Water Quality Standards for TMDL Metals; Segment 1b Arkansas River.

Table Value Standards (TVS) (Based on Hardness=60 mg/l)

Lead (ug/l)

Zinc (ug/l)

1.44

76.6

Table 1. Comparison of Ambient Water Quality to Water Quality Standards for TMDL Metals; Segment 1b Arkansas River. Lead (ug/l)

Zinc (ug/l)

Temporary Modifications

6.5

137

Ambient Condition 85th percentile of entire segment (POR: 1996-2003)

2.0 (n=125)

139 (n=160)

Ambient Condition 85th percentile of entire segment (POR: 1998-2003)

1.4 (n=94)

119.7 (n=128)

Ambient Condition 85th percentile of data at station 7198a (POR: 1998-2003)

2.05 (n=14)

140 (n=21)

As seen from Table 1, ambient water quality for the entire POR from 1996 through 2003, calculated as the 85th percentile of the data for lead (2.0 ug/l; n=125), while significantly less than the temporary modification of 6.5 ug/l, is higher than TVS. Ambient zinc levels (139 ug/l; n=160) exceed both TVS and the temporary modification. The more recent period of record shows that lead is meeting the TVS for the entire segment, but not at station 7198a just below the John Reed Claim. Data analyses show that zinc is the metal species of most concern in Segment 1b of the East Fork of the Arkansas River. The following table lists the sampling stations used in this analysis. Table 2. Sampling Stations for Upper Arkansas River Segment 1b. Station Number

Location

Latitude

Longitude

7199

East Fork Arkansas River above Climax/John Reed Site

39.21‟128”

106.10‟212”

7198a (Clx 1)

East Fork Arkansas River above Climax Storke Area; Below John Reed Site

39.21‟27”

106.10‟286”

Table 2. Sampling Stations for Upper Arkansas River Segment 1b. Station Number

Location

Latitude

Longitude

7198 (Clx 3)

East Fork Arkansas River below Storke and Highway 91

39.21‟71”

106.10‟77”

7197 (Clx 2 and CDOW EF0)

East Fork Arkansas River below Gravel Pits

39.21‟664”

106.11‟777”

7196

East Fork Arkansas River above Chalk Creek

39.21‟66”

106.13‟331”

7196a

Chalk Creek

39.20‟971”

106.13‟223”

7194

French Gulch

30.21‟13”

106.12‟807”

7194a

English Gulch

39.19‟686”

106.12‟993”

7192

East Fork Arkansas 39.18‟853” River above Birdseye Gulch Birdseye Gulch North 39.18‟397” Channel

106.13‟435”

7192a

4.0

106.133‟249”

SOURCE ANALYSIS

The ambient water quality was examined spatially to see if there were any obvious sources of lead and zinc that could be investigated. It was found that the major source of zinc and lead is located in the upper watershed above the Storke Yard. The data presented in the figures below use the POR from 1996 through 2003. 4.1.1 Lead Changes in lead concentrations through the segment are shown on Figure 1. Lead is at or below TVS at WQCD station 7199 located at the uppermost Climax property line. At station 7198a just downstream of the John Reed wetland, the concentration rises, exceeding TVS. In the vicinity of station 7197 just downstream of the Climax property line, lead again attains TVS for the remainder of the segment. Lead does not exceed the temporary modification of 6.5 ug/l on an annualized basis. The point of highest concentrations is at or just below station 7198a. This station is just below the influences of the disturbed John Reed wetland site. Seasonality did not appear to be a

significant factor in lead concentrations in Segment 1b, and exceedances of the TVS were found at a variety of times throughout the year. Figure 1: Lead Concentrations in the East Fork of the Arkansas River, COARUA01b 10 9 8

Pb (ug/l)

7 6 Lead Concentration (ug/l)

5

TVS

4 3 2 1 0 7199

7198a (Clx 1) 7198 (Clx 3) 7197 (Clx 2)

7196

7192

Station

4.1.2 Zinc Data for zinc show trends generally similar to those for lead as noted in Figure 2. Zinc is below the TVS at WQCD station 7199. At station 7198a just below the disturbed John Reed wetland, zinc levels rise, exceeding the temporary modification of 137 ug/l. As with lead, zinc levels trend downward rapidly past the disturbed John Reed wetland area, and meet the TVS at or just below the lower Climax property line. Again, exceedances of the zinc TVS were found throughout the year and seasonality was not considered in this assessment.

Figure 2: Zinc Concentrations in the East Fork of the Arkansas River, COARUA01b

200 180 160 140

Zn (ug/l)

120 Zinc Concentrations (ug/l)

100

TVS

80 60 40 20 0 7199

7198a (Clx 1) 7198 (Clx 3) 7197 (Clx 2)

7196

7192

Station

4.2

Results of the Source Investigation at the Historic John Reed Claim

Several investigations of loading sources within the upper portions of the Segment 1b watershed were conducted prior to initiating the TMDL process. The results of these investigations determined that the principal source of zinc and lead to Segment 1b was slightly contaminated alluvial groundwater surfacing near the top of, and percolating through, a small disturbed wetland area on the north side of the segment. This small disturbed wetland coincides with the historic John Reed mill site and is shown on Map 1 and in Photos 1 and 2. The John Reed never was operated by Climax. The claims on which the site is located were acquired by Climax as part of property consolidation efforts in the 1960s and early 1970s.

Photo 1. The upper Arkansas basin and that portion of Segment 1b showing the positions of several key elements, including Climax property, the John Reed disturbance, and the water quality monitoring stations above the Climax Storke Yard.

Briefly, the John Reed, owned by the long-defunct Burmah Gold Mining Company of Denver, milled sulfidic zinc/lead/silver ores beginning in the 1890s. The mill was operated intermittently from approximately 1897 until approximately 1926 when the structures burned. The small mill probably dates to the late 1890s. Photo 3, digitally extracted from a vintage postcard dated prior to 1926, shows the remnants of the mill and some of the area of the down-gradient disturbance.

Photo 2. Overview of the disturbed John Reed wetland in relation to historic mining/milling activities; Segment 1b, East Fork of the Arkansas River.

Photo 3. Circa 1920s photo of John Reed mill structure and the mill tailings depositional area below leading to Segment 1b of the Arkansas River. Viewed to the southeast and upstream from Fremont Pass. The present day Storke Yard is in the lower right corner.

Operational practices of the John Reed were typical of that period. Waste rock and low grade ores were deposited directly outside and below the mine openings. Hand-

sorted higher grade ore was directed to the mill where concentrates were produced, and fine-grained mill tailing was piped or sluiced directly down-gradient. At the John Reed site, waste rock and mill tailings were deposited below the mill at the head of the wetland area where the material quickly eroded into the wetland toward the Arkansas River. Typical of the geological characteristics throughout the District, ore material milled at the John Reed was sulfidic. Once exposed to the climatic conditions of the area, the exposed waste rock and, particularly the fined-grained tailings, produced acid rock drainage ("ARD"), mobilizing zinc and lead. Likewise, snowmelt and precipitation percolating naturally through surficial soils have contacted natural sulfide mineralization, producing acidic conditions. As these acidic waters containing lead and zinc moved through the wetland toward the Arkansas River, vegetation died where areas were most acidified. In addition, during the past century, tailings have been deposited throughout the down-gradient wetland area in various places depending upon surface flow patterns and surface-subsurface structural blockages such as boulders and outcrops. An investigation by the WQCD in 2001 originally stated that sources contributing to the impairment of Segment 1b above Birdseye Gulch were a combination of natural sources and man-induced irreversible sources, and that present water quality classifications and standards were unattainable. In initiating the investigation, WQCD staff collected water quality samples from the segment at several locations above and below the Climax mine Storke area (Map 1). This data, along with Climax and CDOW data, were assessed and WQCD concluded that the segment is impacted by zinc and lead from sources above any Climax related disturbances (above the Climax Storke Yard). It was concluded that the sources of the elevated metal species are historic inactive mining impacts in the watershed along with a combination of natural and irreversible man-induced sources. As discussed in this TMDL, comprehensive water quality sampling shows that zinc and lead levels increase above TVS at the sampling point directly downstream of the point where the disturbed wetland drains to the river (Map 1, Station 7198a). At a point within and just below Climax property, levels of lead and zinc in the segment attain TVS. 4.3

Other Sources

Aside from the John Reed site, other potential sources of loading to the segment include historic mining related activities above Climax property, naturally occurring non-point sources on private and federally managed lands (USFS and BLM), runoff from Colorado Highway 91, and stormwater. 4.4.1 Historic Mining Influences Exploration and mining activities in the upper reaches of Segment 1b began during

the peak of the activity in the District in the early 1880s. A review of mineral surveys (Colorado State Office, Bureau of Land Management) for the upper portions of the segment show that a number of patented placer, lode and mill claims exist, each with some form of anthropomorphic feature related to mineral development. Several of these claims (survey dates in paren.) including the inactive Hess mine and their recorded features include: •

MS 1939 (1888) - Upper Arkansas Placer - Tunnel, Shaft, Buildings; Hess mine located on this claim.



MS 1938 (1888) - Triune Placer - 2 Cuts, Tunnel



MS 12657 (1898) - Littler Lode - 2 Tunnels



MS 8658 (1894) - Scott No. 3 Placers - Mill (just north of the river), Ditch, Flume, Pump Station, Shops, Adits



Hess mine - Near top of drainage; upstream of WQCD station 7199 (Photo 1). - Inactive - Draining adit; no CDPS permit

While there is no present evidence of direct point or non-point source discharges from these sites (with the exception of the Hess mine), the possibility of discharges of metal-bearing sediments over the past 100-120 years, particularly during periods of high precipitation, cannot be eliminated. Likewise, erosion of sediments to the Arkansas River from even very small waste rock dumps over that time frame is likely. Such sediments may have become embedded in the rivers substrate and entrained behind beaver dams and along embankments where loading over long time periods can occur. The data do not indicate that such loading above the John Reed site presently is significant, but it must be recognized as a potential source. There is restoration potential for these sources, but it is unlikely that any remedial activity will be planned. 4.4.2 Roads Roads within the District property have been evaluated to determine which roads should be used during remedial activity. In addition, Best Management Practices will be used to keep additional metals loading from entering the stream from the roads that will be used during remediation. 4.4.3 Non-point Sources As discussed, Segment 1b lies within a steep region of recognized natural

mineralization. As such, the natural minerals mobilized from precipitation events, snow-melt, and colluvial activity are readily available to the river, directly and indirectly. Local geology directly affects the water quality of the segment when surface and run-off waters contact exposed areas of sulfide mineralization and when mineralized sediments are washed into the system. Other natural features of the watershed such as the two small unnamed tributaries draining from Mount Arkansas to the south and beaver ponds throughout the upper reaches also contribute natural loading to the segment.

5.0

TECHNICAL ANALYSIS

5.1

Data Collection and Analysis

The history of data collection, number of samples, and ambient water quality for Segment 1b is discussed in Section 3.2. Data collected by WQCD, CDOW, and Climax for lead and zinc were evaluated at the 85th percentile level (ambient conditions). The analysis did not indicate significant seasonal variation. Appendices B and C present the databases utilized in this TMDL for lead and zinc respectively. 5.2

Hydrology

Concentrations of pollutants in surface waters are indirectly related to flow. Typically, the higher the stream flow, the lower the concentration. Conversely, lower the flow the greater the concentration of contaminants. Therefore, the low flow condition instream usually becomes the critical condition for the analysis and survival of aquatic life. 5.2.1

Flow Data

Empirical flow data for the upper portions of the segment are minimal and scattered. Flow data are not available on a monthly basis for the upper portion of the segment. Instream flow measurements were taken by WQCD at stations 7199 and just upstream of 7198a on September 14, 2001. This latter station was labeled as 7199a for this single flow event and was located just below the John Reed wetland but above station 7198a. Calculated flows for each station on that date were 8.02 cfs and 6.5 cfs, respectively. Because 2001 and 2002 were years of extreme drought in the watershed, these data could be used as representative low flows for this upper reach of the segment, but due to the small size of this data set, data from a USGS gage located further down the watershed was used to estimate low flows for this TMDL. A low flow analysis was done for this segment using USGS Data. This analysis in presented below. 5.2.2

Low Flow Analysis

The annual 1E3 and 30E3 (one day in three years and three day in thirty years

respectively) low flows were calculated for one station in the watershed using United States Environmental Protection Agency (EPA) DFLOW software, and daily flow data from the East Fork of the Arkansas River. A watershed area correlation was used to estimate flows further up the watershed to be used in the TMDL calculations. The river flow was data taken from the USGS Gage # 07079300 located near Leadville on the East Fork of the Arkansas River at Highway 24. The watershed area above the gaging station is 49.9 square miles and the flow/watershed area record was from 19901999. The watershed area above Birdseye Gulch is 31.48 square miles, and the watershed area above station 7198a is 5.36 square miles. The watershed areas were calculated using a model 620000 K&E planimeter, from four 1:50,000 scale county maps: Lake, Summit, Eagle, and Park counties. The low flows were estimated using the ratio of the flow to watershed area at the gage and relating that to the smaller watershed areas of interest in this TMDL. The annual and monthly acute (1E3) and chronic (30E3) low flows at a point in the East Fork of the Arkansas River at Highway 24 are presented below in Table 3: Low Flows for the East Fork of the Arkansas at the USGS Gage Station 07079300, East Fork of the Arkansas River at Highway 24.

Table 3: Low Flows for the East Fork of the Arkansas River at Highway 24 at the USGS Gage 07079300 Low Flow (cfs)

Annual

Jan

Feb

Mar

Apr

May

Jun

Jul

1E3

6.4

7.2

6.6

7.1

7.1

13.0

21.0

30E3

6.7

6.7

7.3

7.3

13.0

19.0

5.2.3

6.8

Aug

Sep

Oct

Nov

Dec

12.0

9.0

8.7

11.0

8.8

6.4

12.0

8.9

8.9

9.8

9.4

7.4

Flow Data Used in the Analysis

The data used in the TMDL calculation are the estimated low flows as calculated above Stroke Yard and below the John Reed Claim. The data from this station indicates that a significant source of lead and zinc are located above this station. This low flow data is presented below in Table 4. Table 4: Estimated Low Flows for the East Fork of the Arkansas River above Storke Yard (WQCD Station 7198a) Low Flow (cfs)

Annual

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

1E3

0.70

0.79

0.73

0.78

0.78

1.43

2.3

1.32

0.99

0.96

1.21

0.97

0.70

30E3

0.74

0.75

0.74

0.8

0.8

1.43

2.09

1.32

0.98

0.98

1.08

1.03

0.81

6.0

TMDL ALLOCATION

6.1

Allocation Methodology

As noted above, increased levels of lead and zinc over TVS are a result of both natural and historic mining and milling practices in the watershed. Based upon the TVS for lead and zinc at a mean hardness of 60 mg/l at low flow, a target has been set. In order to reach this target, loading allocations have been assigned to the various sources. The loading reduction allocations for the John Reed are the only ones that are examined in this TMDL. Allocations for other sources are not addressed by this TMDL. The loading analysis is addressed with the following methodology. Total Maximum Daily Loads ("TMDL") A TMDL is comprised of the Load Allocation ("LA"), which is that portion of the pollutant load attributed to natural background or the nonpoint sources, the Waste Load Allocation ("WLA"), which is that portion of the pollutant load associated with point source discharges, and a Margin of Safety ("MOS"). The TMDL may also include an allocation reserved to accommodate future growth. The TMDL may be expressed as the sum of the LA, WLA and MOS.

TMDL = WLA + LA + MOS TMDL = Sum of Waste Load Allocations + Sum of Load Allocations + Margin of Safety

Waste Load Allocations "(WLA") There is one identified point source to this segment. The Hess Mine is a draining adit located in the upper portion of this segment above Climax property. This is an inactive mine with no CDPS permit. There is no information regarding flows and concentrations from this draining adit. Load Allocations ("LA") All other sources that were examined are considered non point sources and therefore are accountable to load allocations. Margin of Safety ("MOS") The MOS used in the TMDL analysis is implicit and resides in the conservative assumptions utilized in the calculations and management response to removal of the source materials, and post-remediation water quality monitoring that will be performed.

The conservative assumptions used in the analysis include the use of the 85th percentile of the data in establishing ambient conditions. Mean hardness was used in calculation of hardness based TVS. The TMDL addresses worst case conditions in terms of metals concentrations. Additionally, the use of a mean hardness value represents a conservative element. Finally, the TMDL is based on an estimated stream flow which is considerably lower than that recorded by the WQCD during low flow conditions. This will tend to overestimate the loading reductions. The TMDL equation becomes the following:

TMDL = Sum of Load Allocations (LA), where each LA= Target x Flow x Conversion Factor, LA (lbs/day) = Water Quality Standard, TVS (ug/l) x Flow (cfs) x 0.0054

6.2

TMDL for Lead and Zinc Table 5: TMDL for the East Fork of the Arkansas River

Pollutant

Lead Zinc

Limiting Beneficial Use Aquatic Life Cold 1 Aquatic Life Cold 1

Target/Goal (ug/l) 1.44

Estimated Flow (cfs) 0.74

Estimated TMDL (lbs/day) 0.0058

76.0

0.74

0.3037

Table 6: Current Loading at Station 7198a Pollutant

Lead Zinc

Concentration (85th percentile at Station 7198a) (ug/l) 2.05 140

Estimated Flow (cfs)

Current Loading (lbs/day)

0.74 0.74

0.0082 0.5594

Table 7: Percentage Loading Reduction Needed to Meet TMDL Pollutant

Current Loading (lbs/day)

TMDL (lbs/day)

Percentage of Total Load Reduction

Lead Zinc 7.0

0.0082 0.5594

0.0058 0.3037

Needed to meet Target 29% 46%

RESTORATION PLANNING AND IMPLEMENTATION PROCESS

The percentages of loading reduction necessary to meet TVS for lead and zinc are listed in the table above. Restoration of the disturbed John Reed wetland area is expected to account for a 50% reduction of the total loading of lead and zinc into the segment. There are several sources that have been discussed that are contributing to the elevated levels of metals in the East Fork of the Arkansas River that could be reduced. With the lack of flow data available and the diffuse nature of non point source loading, it becomes difficult to distribute appropriate loading reductions to each source. In addition, there is no information regarding the flow or water quality of the discharge from the Hess Mine to determine its impact on the East Fork of the Arkansas River, but the segment is meeting TVS below this influence. The estimated allocations of loading reductions are presented in Table 7. Table 8: Allocation of the Loading Reductions to Various Sources Source % Allocation Notes John Reed Disturbed 100% of total This is the only source where Wetlands reduction an implementation plan has been established. Additional nonpoint 0% of total All reversible sources of lead sources from natural or reduction and zinc have been previously irreversible remediated. No implementation anthropogenic sources plan has been established for the reduction of remaining sources in this area that are natural and/or irreversible anthropogenic sources Hess Mine 0% TVS are attained below the Hess Mine.

7.1

Previous Water Quality Improvements in the Watershed

Climax has had a direct presence within the watershed of Segment 1b since the early 1950s. Between the early 1950s and the 1970s, Climax accessed the underground Storke level of the Climax ore body via shaft and other infrastructure development in the Storke Yard area (Map 1, Photo 1). Briefly, these activities included surface facilities (offices, shops, change house, ventilation facilities, conveyance/crushing, etc.) necessary to support underground mining. In addition, aggregate for use in the underground mine‟s concrete production plant was extracted from pits in the river bottom near the southwestern property boundary, and several small settling basins

were constructed just below Highway 91 to catch and hold suspended solids and washdown materials from the Storke Yard crushing facilities and air scrubbing equipment. These ponds, constructed in the 1960s, were decommissioned in 1982 when the Storke wastewater pump station was activated. Water management in this portion of the segment during the period of Storke level activities consisted of routing a section of the Arkansas River through the Storke yard in a pipe along the southern portion of the area. In addition, the river was routed into a diversion structure around the settling basins and the aggregate pits. Discharges from the aggregate pits occurred under the now inactive CDPS permit.

7.1.1

Specific Improvements

Since the 1980s a number of Climax activities have occurred within Segment 1b that have improved both water quality and the watershed in general. • The settling basins were removed and reclaimed. This project removed a potential source of contamination from the Arkansas River watershed and allowed restoration of the original stream channel. • The aggregate pits were reclaimed as ponds that presently support a viable population of large brook trout and have improved the aesthetics of the valley. • The Arkansas River channel below the Storke Yard was reconstructed in the late 1980s, and the channel area was reclaimed. • The 5-shaft pumpstation was installed and placed into operation. This pumpstation moves water from the flooded underground workings at Climax to the water treatment system in the upper Tenmile Valley. • The Storke Yard infrastructure was demolished and the Storke Yard area reclaimed in the 1990s. Partial reclamation financial warranty release for this area was approved by the Colorado Division of Minerals and Geology in the late 1990s. • Waste rock was removed from the upland areas of the John Reed mine and the site reclaimed in the 1990s. This project has contributed to lessening the loading of metals into the down-gradient wetland areas.

7.2

Rehabilitation of the John Reed Disturbed Wetland

The significant source of lead and zinc loading to the segment originates from the historic John Reed site. Climax has undertaken a project to reduce this loading source. The source investigation identified sulfidic mill tailings and waste rock in the small (2.5 acres) wetland between the John Reed mill site and the Arkansas River as

the primary source of lead and zinc loading to Segment 1b. Climax intends to remove the tailings and waste rock material and rehabilitate the impacted wetland during the construction season of 2003. This project will involve “surgical” removal of the identifiable acid-producing materials from the river edge to the top of the wetland followed by the placement of growth media and seeding/planting of wetland vegetation species native to the area. Storm water Best Management Practices (BMP) will be deployed during all elements and phases of the project to protect Segment 1b and the surrounding wetland and riparian areas. The entire work plan is addressed in a separate document, Climax Molybdenum Company, Climax Mine: Work Plan: Disturbed Wetlands Restoration; Segment 1b of the Arkansas River, January 28, 2003. 7.3

Rehabilitation of Other Sources

Currently there are no plans in place for the reduction of load allocations from the other sources. As part of continued monitoring and assessment by the WQCD, rehabilitation of other non-point sources can be considered on a case-by-case basis if water quality is not improving over time. Water quality monitoring will be performed by Climax and the WQCD as described below. WQCD will analyze the data and determine whether additional remediation, if possible, is necessary to attain water quality standards. If the remaining anthropogenic sources are deemed irreversible, the WQCD may propose that the WQCC adopt ambient based water quality standards for the segment.

7.4

Monitoring

In order to insure that the TMDL is adequately protective of the segment, and to evaluate the degree of success of the John Reed project in reducing loading of lead and zinc to the segment, monitoring is required. Monitoring will be conducted, by Climax, quarterly for two years following completion of the John Reed wetland rehabilitation project at existing sampling stations 7199, 7198a, and 7197 (Map 1). Climax will also collect flows two times per year at high and low flow periods. Although sampling may be conducted at additional stations shown on the map on a periodic basis, the three stations specified will show the success of the loading reduction project at the John Reed site. Proposed sampling parameters include: pH, hardness, lead and zinc. A report of findings will be developed and submitted to the WQCD at the end of the monitoring period. WQCD will also monitor these sites twice a year for 2 years. 8.0

Conclusion

As discussed, attainment of TVS for lead and zinc within the upper reaches of

Segment 1b of the East Fork of the Arkansas River is the goal of this TMDL. A loading reduction of 29% is necessary to reach the TMDL of 0.0058 lbs/day for lead. A loading reduction of 46% is necessary to reach the TMDL of 0.3037 lbs/day for zinc. Actions to be completed by Climax within the segment in 2003 are expected to reduce loading significantly. However, while these activities will improve the segment substantially, they may not reduce loadings to a level meeting the TVS. Additional investigation of the appropriate standards will be conducted at this time. Attainment of remedial goals should be measured at Station 7198a located below the John Reed wetlands area and above the Storke Yard. The evaluation should be performed following completion of the load reduction project (late fall-winter, 2003) and after two complete years (late fall-winter, 2005), allowing the project area to stabilize.

11.0

PUBLIC INVOLVEMENT

The public has had opportunity to be involved in the Water Quality Control Commission (WQCC) Hearings since 1996 when the WQCC adopted ambient-based standards. Throughout the years the WQCC has adopted new, temporary modifications for this segment where the public has had the opportunity to get involved. Opportunities have also been available through the 303d Listing process which also has a public notice period for public involvement. Public involvement was also achieved through collaboration with Climax Molybdenum, the principal landowner and largest entity potentially affected by the TMDL. A draft of this TMDL was noticed in the Water Quality Bulletin for the month of October 2003 for public comment. Comments were provided by Climax Molybdenum Mine concerning the possible applicability of the TMDL analysis as a basis for establishment of ambient based standards should TMDL implementation not result in attainment of the Table Value Standards currently assigned to the receiving water. The Division will respond to that concern if and when monitoring performed post-TMDL implementation indicates that Table Value Standards are not attained.

10.0

SELECTED REFERENCES

Bergendahl, M.H., and A.H. Koschmann. 1971. Ore Deposits of the KokomoTenmile District, Colorado. USGS Prof. Pap. 652. 53 p. Climax Molybdenum Company, Climax Mine: Segment 1b of the Arkansas River; General Information and Preliminary Review, October, 2002. Climax Molybdenum Company, Climax Mine: Work Plan: Disturbed Wetlands Restoration; Segment 1b of the Arkansas River, January 28, 2003. Dempsey, S., and J.E. Fell, Jr. 1986. Mining the summit: Colorado‟s Ten Mile District, 1860-1960. Univ. of Oklahoma Press. 306 p. Filipek, L., A. Kirk, and W. Schafer. 1996. Control technologies for ARD. Mining Env. Management. December 1996. 5 p. Schneider, E.J. and R.A. Elliott. 1997. Voluntary remediation of inactive mine and mill tailings sites in Rico, Colorado. Tailings and Mine Waste „97. Ft. Collins, Colorado. 613-622. Struhsacker, D.W., and J.W. Todd. 1998. Abandoned mine land initiative: Reclaiming inactive and abandoned mine lands - What really is happening. Publ. National Mining Assn. Unk. nd. Abandoned mine reclamation at the upper Blackfoot mining complex, Lewis and Clark County, Montana. USBMCSUM doc. 13 p. U.S. Army Corp of Engineers (COE). 1987. Corps of Engineers wetland delineation manual. Wetlands Res. Prog. Tech. Rep. Y-87-1. Department of Army, Washington, D.C. WQCC 2002: Colorado Department of Public Health and Environment, Water Quality Control Commission, 2002 303(d) List of Impaired Waters, 2002.

WQCC 2002: Colorado Department of Public Health and Environment, Water Quality Control Commission, Classifications and Numeric Standards for the Arkansas River Basin, Regulation No. 32, Amended January 30, 2003. WQCC 2000: Colorado Department of Public Health and Environment, Water Quality Control Commission, The Basic Standards for Methodologies for Surface Water, Regulation No. 31, 5 CCR 1002-31, Amended September 10, 2001.

Appendix A ACRONYMS amsl BLM CDOT CDOW CDPHE CDPS Climax Clx cfs EF LA lbs/day Mn Pb TVS TMDL ug/l USFS USGS WLA WQCC WQCD Zn

above mean sea level Bureau of Land Management Colorado Department of Transportation Colorado Division of Wildlife Colorado Department of Public Health and Environment Colorado Discharge Permit System Climax Molybdenum Company Climax (usually when referring to sampling stations) cublic feet per second East Fork Load Allocation pounds per day Manganese Lead Table Value Standard Total Maximum Daily Load micrograms per liter United States Forest Service United States Geologic Survey Waste Load Allocation Water Quality Control Commission Water Quality Control Division Zinc

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