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is located in the immediate proximity of Fond 002, suggests that a portion of the pond bottom may <br />intersect or immediately overly the top of the IBxia Shale. Hydraulic commtmicatron or direct <br />• contact with the Levis Shale would cause water rn,.iity degradation and increased salt <br />concentrations. <br />Discharges from sediment Ponds 001 and 002 should significantly affect the chemistry of Dry Creek <br />below the loadout because coal paste conductivities, which are worst case indications of runoff <br />Mater a+°l lty, arB 2 t0 7 t1me9 lO1PBr tllall t)le L'60B1V1[Ig Htream (Dry Creek) Opi]dnCt1V1t1e9. ThB <br />potential for pond discharges era generally quite small. Pond 002 discharged during spring <br />runoff in 1996, the first observed discharge since 1987 and Pond 001 typically only discharges in <br />the spring when receiving streamflows would be considerably granter and would readily dilute the <br />pond discharge. In conclusion, the loadout will not measurable impact the water quality of Dry <br />Creek or any potential water use. <br />In addition, CDAG requested HGT run coal leachate analyses to further evaluate potential impact <br />to Dry Czaek and alluvial water quality. The column leach teats were performed by ACZ <br />Laboratories, inc. on samples of new and old coal using extraction Method 1312. Four Leachate <br />tests were performed, one with new opal, txo with old opal, and one xithout opal to verify <br />control levels. Twenty-five chemical parmmtare ware analyzed fot, including those with <br />sr..,wa..a. for the ranch of the Yampa River Dry Creek is tributary to. The results of the four <br />column leach teats are presented in Attachment 15-2. Both the new and old opal leachate <br />parameter concentrations appear to be quite fawrabla. Only one parameter, boron for the new <br />. coal, exceeds the Yampa River ar...n...+ of 750ug/1. For the parameters TDS and SOS, both the <br />receiving stream and alluvial background levels are significantly higher (6 to 53 times higher). <br />Boron levels in the alluvium, including that portion represented by the vex alluvial well, are <br />comparable to or exceed the leachate boron levels. Table 15-1 presents the coal leachage xater <br />quality OCCL¢1nr190I1 against the Yampa 9tIeam Hra...+.,.av, <br />To evaluate coal ato~cpile lanchate impacts on the Dry Creek xatar quality, tan-year, seven-day <br />high and low flown ware detamained and mixed with calculated lanchate volumes. The ten~yani hrgh <br />£1011 fOr Dry Creek wag determined using 8 r'dgre99i.On egnatlOn development by the USGS Sn Weter- <br />Reaourcaa Investigation Peport 85-4086 for northwest Colorado dra+~~ s (ICircber et. A1., 1985). <br />The ZHQTa891.on equation 19~ <br /> <br />/~/~' o/ <br />3 Revised 10/97 <br />