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Expected surface water effects include increased evaporation losses <br />from sediment ponds, which are assumed to be offset by increased <br />runoff from impervious areas such as haul roads and structures, and <br />increased total dissolved solids and total salt loads in receiving <br />streams. The effect of surface water runoff from the Meadows No. 1 <br />Mine on water quality in the Yampa River is negligible due to the <br />small quantity and good quality, since no water is discharged <br />unless it meets NPDES effluent limitations. Therefore, effected <br />water quality in the Yampa River would remain suitable for both <br />flood irrigation and domestic use. <br />C. <br />Water Quality Standards and Effluent Limitations <br />Section 2.05.3 of the permit application includes information <br />regarding protection of the hydrologic balance. To meet effluent <br />standards, surface water runoff is routed through sedimentation <br />ponds. Runoff on the reclaimed pit area is routed to Sediment <br />Ponds No. 1 and No. 2, or through the Northwest Impoundment and <br />Explosives Storage Area pond. These structures are depicted on Map <br />6 of the approved permit application package. <br />Runoff from the facilities yards is directed to the Yampa River <br />sediment pond, located on the south side of the Yampa River, as <br />shown on Map 6 of the permit application package. <br />With one exception in 1991, effluent from these sedimentation ponds <br />has not exceeded Colorado Department of Health standards. On <br />April 15, 1991, discharge from the Yampa River sedimentation pond <br />had oil and grease concentrations of 200 mgl1. Since there were no <br />mine-related activities in the facilities area, the excess oil and <br />grease was attributed to vandalism. <br />D <br />Surface and Ground Water Monitoring <br />The applicant will conduct monitoring of surface water in a <br />manner approved by the Division. The monitoring plan was <br />submitted under 2.05.6(3)(b)(iii> and includes the following: <br />NPDES discharge samples will be checked for pH, settleable <br />solids, and flow on a monthly basis at the ponds located at the <br />base of the pit, below the facilities area, and below the area <br />where the explosives magazine was previously located (NPDES <br />discharge points 001, 002, and 003). Quarterly samples of <br />discharge from these ponds will be analyzed for iron, <br />manganese, electrical conductivity, total dissolved solids, <br />sulfate, total suspended solids, and settleable solids. In <br />addition, a spring and seep survey will be conducted twice <br />annually in June and August (4.05.13(2)). <br />Ground water monitoring and surface water monitoring on the <br />Yampa River were discontinued with the approval of Technical <br />Revisions 3 and 4. The decision was made after considering the <br />operator's demonstration that 1) disturbed area runoff is <br />sampled at NPDES discharge points prior to entering the Yampa <br />River, 2> base flow in the Yampa is great enough to ensure <br />-13- <br />