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• alternate water sources of comparable quantity and quality. As described in the water augmentation <br />plan, WFC has a 114 acre foot consumptive use right on the Highline Canal which would be used to <br />mitigate the potential 26 acre foot impact on surface water right users from pit inflow drawdown. <br />Impact on oroundwater rights. No surface or groundwater rights have been identified within the <br />New Horizon 2 mine area. Therefore, there will be no direct impact from the approved mining plan <br />on any local water rights. <br />Impact of spoil material on groundwater flow and recharge The mine pit will remain open only <br />until the coal has been removed. Following the short-term water level decline on the groundwater <br />system as a result of pumpage of groundwater inflow to the pit, a potential long-term impact to the <br />local groundwater flow is the period of time necessary for resaturation of the spoil material and <br />reestablishment of a flow gradient. Spoil material at the New Horizon 2 mine will be replaced using <br />techniques which will restore permeabilities of the material. Thus, the mining operation will not <br />diminish vertical or horizontal permeabilities but may increase these permeabilities. As a result, there <br />should be no significant impacts from the mining operation on groundwater flow and recharge rates. <br />The time period required for the spoil material to resaturate should be greatly reduced because of the <br />irrigation recharge as the mined area will be revegetated for an irrigation type of post mining land use. <br />Containment of pit inflow and impacts on water quality. Ail runoff and pit pumpage from <br />disturbed areas will be routed through sedimentation pond 007. The pond is designed and <br />constructed to impound runoff and pit pumpage from areas disturbed by mining and provide sufficient <br />residence time to insure that the pond discharge water chemistry meets the effluent requirements <br />specified in the NPDES Permit. A review of the chemical and flow data indicates that the potential <br />for any discharge from Pond 007 to exceed receiving stream or federal standards is minimal. Past <br />history of mine operations at the Nucla Mine indicate very few exceedances of the standards over the <br />years of operations. As previously discussed, highest pit inflow is predicted to occur in year 5 at <br />approximately 5,600 cubic feet per day. To assess the impact of this inflow on Calamity Draw and <br />the San Miguel water quality, it was assumed that the entire flow was discharged and that the TDS <br />level for the overburden aquifer was representative of the chemical load. The duration of the water <br />quality impacts is relatively short term (5 years) and the significance of the impact is negligible as <br />TDS increases in the range of 0.08 to 1.5 percent are projected on the San Miguel River and Calamity <br />(REVISED 9/99) 2.04.7-47 <br />