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<br /> <br />no longer be needed to retain runoff. At this point, <br />the runoff from the reclaimed surface will drain unrestricted into the <br />receiving streams. <br />Estimated increase of flow in receiving streams. Based upon 35~ increase <br />in runoff from disturbed sites. <br />Receiving Streams Percent Yield Increases <br />Bolton Draw 2. 7q <br />Bush Draw 0.3~ <br />Williams Draw 1.2~ <br />Sudduth Draw 0.4a <br />These seem to represent a worst case condition. Any actual increase <br />would probably be less. <br />The sediment pond effluent limitations on total suspended solids is <br />set at 30 mg/1 by NPDES standards. This effluent limitation will have <br />the effect of requiring Kerr Coal's mining operations to release water <br />which is actually lower in sediment load than national baseline levels. <br />This condition may, in turn, have the effect of causing erosion down- <br />stream from the mine plan area to regain the natural level of sediment <br />load. This effect has been suggested on a theoretical basis at several <br />mine sites. However, it has yet to be documented either by the Division's <br />inspectors or by the companies. Should the erosion occur, it would <br />begin immediately downstream from the discharge points from the ponds. <br />Given the infrequent nature of stream flow in this area, it would not <br />spread rapidly, and could be mitigated if it occurs. <br />2 <br />Salt Loading <br />Sediment and flow control facilities such as sediment ponds and diversion <br />ditches which detain water will have the effect of increasing the concen- <br />tration of total dissolved solids in the water due to evaporation. Also, <br />any water pumped from the pits into surface drainages to facilitate <br />operations may contain relatively high levels of dissolved salts, while <br />difficult to quantify, might increase in streams draining the mine property. <br />Using data from :dil2iams Draw the applicant 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 14 7 kilograms per year from the mine plan <br />area into Williams Draw. <br />Considering the respective amount of disturbed area tributary to each of <br />Bolton, Bush, Williams, and Sudduth Draws, the total amount of salt Load- <br />ing on receiving streams is estimated to be about 54 kilograms per year. <br />(p Z80-126hhhhh) <br />This can be broken down into the amount of Loading on each individual stream. <br />Bolton Draw <br />Bush Draw <br />[Williams Draw <br />Sudduth Draw <br />37.0 .ti.l ograms/ yr . <br />3.2 kg/yr <br />10.7 kg/yr <br />2.7 log/yr <br />-8- <br />