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-zo- Base Flaw Downstream of Refuse Site + Outflow from Surface Facilities = 1,054 mg/1 TDS at 0.7 cfs. The concentration of TDS is projected to increase from 755 mg/1 to 1,054 mg/1 for the worst case. This condition could exist only during the non-irrigation season, so the increase is not considered significant to irrigation use of the stream water. The alluvium along the Colorado River directly adjacent to the Harvey Gap Drainage could be negatively impacted by the increased level .of TDS. During the snowmelt period, the alluvium is recharged by the surface water system. Therefore, the alluvium immediately adjacent to Harvey Gap could experience a rise in the level of TDS from early spring to April 15 (start of outflow from the Grass Valley Reservoir). The W. Shafto Well (Table 1) completed in the Colorado River alluvium has a TDS level of 760 mg/1. The worst case quality projected for Harvey Gap Water is 1,054 mg/l. As this is an extreme projection of worst case and should not exist for long periods of time, any degradation of water quality within the alluvium should not be significant. The worst case condition of TDS increase was also projected for the irrigation season. The lowest outflow from the reservoir during this period is projected as 7 cfs (from the hydrograph submitted in the permit application, page 536). A water quality of 330 mg/1 TDS for this discharge is used (from Table 1). Using the predictive equation previously presented, and merging this flow and concentration with outflow from the refuse disposal pond, gives a result of: Reservoir Low Outflow + Outflow from Refuse Disposal Pond = 352 mgll at 7.1 cfs Carrying this downstream and using the previous assumptions for outflow from the surface facility pond gives: Low Flow Downstream of Refuse Site + Outflow from Surface Facilities = 371 mg/1 TDS at 7.2 cfs During the irrigation season, the worst case increase in TDS is predicted as rising from 330 mg/1 at the Reservoir Outlet to 352 mg/1 downstream of the mine. This rise is insignificant and would have no effect on the usability of the water. Table 1 shows the coal seam water chemistry to have high levels of sulfates relative to the surface water of the area. Due to dilution from the subcrop seep and dilution within the surface water system, little rise in sulfates in the stream is expected. Also, the ionic balance of the stream should not be impacted.