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findings. <br />Monitoring data in Colowyo's Annual Hydrology Reports (AHRs) indicate that there have been <br />no significant impacts on water quantity of these streams due to mining operations at the Mine. <br />The data for flow in Taylor Creek below the mine (monitoring point LTC on Map 10) and data <br />for flow in Good Spring Creek below the mine (monitoring point LGSC on Map 10) indicate <br />small decreases in flow since 1982; however, these decreases are not statistically significant <br />(very low R2 values). <br />On a smaller than regional scale, some impacts are expected. The sizes of drainage areas for <br />some ephemeral and intermittent creeks within the mined area will be changed, thus altering <br />runoff quantities. Other expected changes include: <br />• Hydraulic transmissivities within backfilled pits will be altered, thus changing the <br />hydrologic balance. <br />• Base flow in creeks may be reduced during mining and for several years after mining. <br />• Peak flows in creeks will be reduced due to pits. <br />• Natural springs might experience increased or decreased flow or be completely <br />eliminated. <br />The Mine's consumption of surface water will possibly affect the agricultural practices on a <br />minor portion of the Good Spring Creek valley floor. However, since Colowyo owns the <br />property to be withdrawn from irrigation and since these lands are not an integral part of any <br />ranching or farming operation, the effect will be minimal. Exhibit 7 of the approved permit <br />discusses the water rights augmentation plan for the mine. <br />Potential Effects on Surface Water Quality <br />The 1982 Findings Document projected that no significant adverse impacts to surface water <br />quality from mining operations will occur in or adjacent to the permit area. <br />However, with construction of the South Taylor Pit, some impacts are anticipated. Spoil spring <br />development and increased salinity due to leaching in the backfilled South Taylor pit area is <br />anticipated to be the most significant impact to the hydrologic balance in and adjacent to the <br />mine area. Spoil spring development is likely in the southeast portion of the South Taylor pit <br />area, generally located in the NW1 /4 of Section 21 in T3N, R93W. Degraded spoil water will <br />move down gradient through undisturbed strata and emanate as springs on the steep hillsides. <br />This degraded water will mix with flow in the East Fork of Good Spring Creek, as represented <br />by the surface water monitoring site EFGSC. Colowyo has provided calculation of salinity <br />increases in Good Spring Creek down gradient of the confluence of the West Fork of Good <br />Spring Creek in Section 2.05.6(3)(b)(iii) of Volume 12. Impacts to irrigated areas immediately <br />downstream of EFGSC are possible and are discussed the alluvial valley floor section of this <br />document. <br />Proposed Decision and Findings of Compliance January 2012 <br />Permit Renewal 06 Page 136 <br />