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Water Quality Monitoring Plan Climax Molybdenum Company <br /> Version R4 Permit No M-1977-493 <br /> 3.1.6 Surface Water Monitoring Sites <br /> Climax established surface water monitoring sites in the East Fork Arkansas River at locations both <br /> upstream and downstream of mine facilities (Arkansas #1 and Arkansas #2, respectively). Monitoring <br /> parameters and schedule are in Section 4, and water quality monitoring data which have been submitted <br /> in Annual Reports to DRMS are included in Appendix B-5. <br /> 3.2 Eagle River Watershed <br /> As illustrated on Figure 1, the Eagle River Watershed is located in the western portion of the Climax site <br /> below the crest of 1 Dam. The land adjacent to the Climax property is primarily National Forest Land <br /> managed for various uses by the U.S. Forest Service (USFS). <br /> 3.2.1 Existing and Potential Future Uses of Groundwater <br /> Groundwater in the upper Eagle River Watershed within the Climax Mine property boundary occurs <br /> primarily in the areas downstream of the former Robinson Tailings Storage Facility (TSF) and Robinson <br /> Lake. Significant and continuous groundwater flow in alluvium and bedrock within the valley upgradient of <br /> the Eagle Park Reservoir is unlikely as groundwater flow is intercepted by Robinson Lake and the <br /> groundwater cut-off wall associated with the Robinson Lake Seepage Collection system. <br /> The WQCC has not adopted classifications or site-specific groundwater standards in the Eagle River <br /> Watershed in the vicinity of Climax. Within this area, current and future domestic or agricultural <br /> development of groundwater would not be likely given the site location and climate conditions. The current <br /> use of groundwater is limited to recharge of the East Fork Eagle River and Eagle Park Reservoir,which are <br /> classified for aquatic life, recreation, water supply, and agricultural uses. However, the quantity of <br /> groundwater recharge is very small in comparison to the overall storage volume of Eagle Park Reservoir or <br /> the average annual total reservoir recharge, as demonstrated by the results of a mass balance mixing <br /> model performed in 2016 (Tetra Tech, 2016a). The mixing model was performed to evaluate the potential <br /> loading of constituents to Eagle Park Reservoir if groundwater quality equaled the proposed NPLs and is <br /> included as Appendix C to this WQMP for reference. <br /> 3.2.2 Location and Description of Classified Stream Segments <br /> Eagle River basin, Segment 3, contains all tributaries to the Eagle River, including wetlands, from the <br /> source to the compressor house bridge at Belden. Exceptions include Segment 4 — the main stem of <br /> Homestake Creek from the confluence of the East Fork to the confluence with the Eagle River and Segment <br /> 1 —all tributaries and wetlands to the Eagle River system within the Gore Range—Eagle's Nest and Holy <br /> Cross Wilderness Area. <br /> Segment 3 of the Eagle River basin is classified as Aquatic Life Cold 1, Recreation E, Water Supply, and <br /> Agriculture by WQCC. <br /> 3.2.3 Potential Contamination Sources and EPFs <br /> The Eagle River Watershed is bounded on the east by 1 Dam, the western embankment of the former <br /> Robinson TSF, and contains two fresh water reservoirs (Eagle Park and Chalk Mountain), as well as <br /> Robinson Lake, which stores process water for use in the mill. Reclaimed process water decanted from <br /> the TSFs is conveyed to Robinson Lake via the Tenmile Tunnel. Potential contaminant sources and <br /> established environmental protection facilities (EPFs) within this portion of the site are identified and <br /> EPP—Appendix C March 2018 6 <br />