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_11_ <br />Findin s <br />Surface water, mine site <br />1. Flows in Bolton, Bush, Sudduth, and Williams Draws will be reduced <br />during mining. After mining has ceased, and reclamation is successful, <br />sediment ponds will be removed, and f]ows wi71 return to baseline levels. <br />2. Following reclamation, it is estimated that a 35% increase in runoff <br />from disturbed lands would occur. Worst case condition for individual <br />receiving streams are: <br />Receiving Streams Percent Vield Increases <br />o ton raw <br />Bush Draw 0.3% <br />Williams Draw 1.2% <br />Sudduth Draw 0.4% <br />As vegetation is successfully reestablished, the water flow increases will <br />decrease with time until natural levels are reestablished. <br />3. Sediment and flow control facilities such as sediment ponds and <br />diversion ditches which detain water will have the effect of increasing the <br />concentration of total dissolved solids in the water due to evaporation. <br />Also, any water pumped from the pits into surface drainages to facilitate <br />operations may contain relatively high levels of dissolved salts, which, while <br />difficult to quantify, might increase in streams draining the mine property. <br />Using data from Williams Draw the permittee has made the following estimate: <br />The average salt discharge of 172.3 grams per day times 62 days gives an <br />assumed annual salt discharge of 10.7 kilograms per year from the mine plan <br />area into Williams Draw. <br />Considering the respective amount of disturbed area tributary to Bolton, Bush, <br />Williams, and Sudduth Draws, the total amount of salt loading on receiving <br />streams is estimated to be about 54 kilograms per year (p 180-126hhhhh, <br />original permit application). <br />This can be broken down into the amount of loading on each individual stream: <br />Bolton Draw 37.0 kg/y r. <br />Bush Draw 3.2 kg/yy <br />Williams Draw 10.7 kg/yr <br />Sudduth Draw 2.7 kg/yr <br />Following mining, pit dewatering will cease, and sediment ponds will be <br />removed. Furthermore, backfilled pits are not expected to discharge to the <br />surface system. Therefore, after final reclamation is complete, salt loading <br />will drop to natural levels. <br />