Laserfiche WebLink
The following table describes the data and results of the mass-balance <br />calculations. <br />Q TDS <br />FISH CREEK (cfs) (m9/1) <br />Fish Creek above Cow Camp Creek 10.6 610 <br />Cow Camp Creek 0.2 2245 <br />Bond Creek 0.2 2245 <br />Fish Creek below Bond Creek 11,0 670 <br />Fish Creek below Bond Creek 11.0 670 <br />Trout Creek above Fish Creek 15,0 245 <br />Trout Creek below Fish Creek 26.0 460 <br />Yampa River below Fish Creek 427,6 154 <br />GRASSY CREEK <br />Yampa River above Grassy Creek 427.6 154 <br />Grassy Creek above Yampa River 0.84 2341 <br />Yampa River at Hayden, Colorado 428.4 158 <br />In order to determine how the dissolved solids concentration in a stream <br />affects environmental quality, a criteria for assessing material damage to the <br />hydrologic regime is required. Existing standards for salt loading are based <br />on the potential for material damage to crops through sub-irrigation or flood <br />irrigation. Moderately sensitive species can withstand irrigation by water <br />with a specific conductance of 1 mmho/cm (equivalent to 730 mg/1 TDS). As the <br />table above illustrates, receiving stream concentrations of TDS below <br />Seneca II Mine influence are below this standard in the irrigable streams <br />(ie: Fish Creek, Trout Creek and the Yampa River). <br />The conclusion which can be drawn from this analysis is that the cumulative <br />impact to surface waters within the Yampa River basin above Hayden, Colorado <br />from the Seneca II Mine and the other mines in the basin is insignificant, <br />The mining activities as proposed will not preclude the use of surface waters <br />downstream of the mine from beneficial uses including agriculture, water <br />supply, recreation and aquatic habitat. The operations within the basin will <br />not incur material damage to the prevailing hydrologic balance in this system. <br />Ground Water <br />A. Sand Wash Basin <br />The mines located in the southeastern portion of the Sand Wash Basin which are <br />considered in this analysis include a portion of the Seneca II Mine, the <br />Seneca II-W Mine, the Meadows No. 1 Mine, and the Grassy Gap Coal Mine. <br />Three probable effects of mining to the aquifers in the Sand Wash Basin have <br />been identified: (1) the interruption of the disturbed aquifers due to <br />removal of coal and overburden during surface mining activities; (2) the <br />recharge to undisturbed portions of the coal and overburden aquifers by <br />developed spoils aquifers; and (3) the recharge to alluvial aquifers by <br />discharges from developed spoils springs. <br />_p 7_ <br />