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Tabetha Lynch, DRMS <br />Page 13 <br />4/30/2015 <br />drainages is limited to spring snowmelt almost exclusively. Discharges from the ponds flow down <br />ephemeral channels which cross an outcrop of the permeable Twentymile Sandstone that is a few hundred <br />feet wide. It is likely that much of the discharge from the ponds infiltrate into this outcrop prior to <br />reaching the Williams Fork River. The Twentymile Sandstone dips northward, away from the Williams <br />Fork River and underneath the Trapper Mine; consequently, the pond discharges that infiltrate into the <br />sandstone flow away from the Williams Fork River as ground water. The potential for contaminating <br />ground water in the Twentymile Sandstone is negligible due to the relatively small volume of water from <br />the ponds compared to the large volume of ground water in the Twentymile Sandstone. Water from the <br />ponds would also be subject to large evaporation losses on this scrubby, south - facing slope. Losses from <br />evaporation and infiltration will prevent significant quantities of surface water from the permit area from <br />reaching the Williams Fork River valley. Ground water from the permit area will not reach the Williams <br />Fork River valley because bedrock dips from the river valley to the permit area. <br />Trapper conducts surface and groundwater monitoring throughout the site in accordance with the permit. <br />Trapper submits an Annual Hydrology Report every year with results of the monitoring. See previous <br />annual hydrology report reviews for an evaluation of their monitoring program. Trapper's surface and <br />ground water monitoring program includes the measurements of constituents which may impact farming <br />practices within the AVF's of the Yampa and Williams Fork River. Given the previous findings that the <br />mining operation will have an insignificant effect on the Yampa and Williams Fork AVFs due to their <br />hydrologic connectivity to these areas, the mining related impacts and trends identified in the annual <br />hydrology reports should have minimal impact to these AVFs. <br />4.24.4 <br />(1) Trapper conducts surface and groundwater monitoring throughout the site in accordance with the <br />permit. Trapper's surface and ground water monitoring program includes the measurements of <br />constituents which may impact farming practices within the AVF's of the Yampa and Williams Fork <br />River. As indicated in the previous section; given the previous findings that the mining operation will <br />have an insignificant effect on the Yampa and Williams Fork AVFs due to their hydrologic connectivity <br />to these areas, the mining related impacts and trends identified in the annual hydrology reports should <br />have minimal impact to these AVFs. <br />(2) -(3) The adequacy of the surface and ground water monitoring program is being conducted as part of <br />the review of section 2.05.6(3) of the permit by yourself and Robin Reilley of DRMS. Trapper's surface <br />and ground water monitoring program includes the measurements of constituents which may impact <br />farming practices within the AVFs of the Yampa and Williams Fork River AVFs. Given the evaluation <br />contained in the permit regarding the hydrologic connectivity of the mine plan area to the Yampa and <br />Williams Fork River, it appears the monitoring program currently in place is adequate to evaluate the <br />surface and ground water system which may impact the Yampa and Williams Fork AVFs. <br />(4)NA <br />