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reclamation increase is 1% of the annual yield, and salt Zoading would be at the rate of 7.6 kg/yr, Williams Draw would be subject to a 2I% reduction by sediment ponds, a 2% post-reclamation increase, and a salt Loading of 21.4 kg/yr. In Sudduth Draw no additional sediment ponds would be built and the flow reduction would remain 3%, following reclamation flow would be increased by 1%, and anticipated salt loading would be 5.9 kg/yr. In Bolton Draw, the most affected watershed, the calculated effects would severely overestimate probable effects. Areas of existing disturbance have already been reclaimed, or soon will be reclaimed. By the time anticipated future mining in this watershed is conducted, reclamation of existing disturbances will be complete, and probably the sediment control facilities will have been removed. The most severe effects in Bolton Draw have probably already occurred. FIVDING - The proposed operations have been designed to prevent material daaage to the hydrologic balance outside the permit area. All of the effects identified in the analysis are short-term alteration of the hydrologic balance. (see summary of Probable Hydrologic Effects). The analysis has identified no irreversible, adverse effects on the hydrology of surrounding areas. Probable Hydrologic Consecuences - SUMMARY OF SURFACE WATER EFFECTS 1. Runoff and Erosion During mining, disturbed areas would be susceptible to erosion and runoff. Mitigated by sediment control system. Sediment control cannot be z•emoved until revegetation is successful and erosion rates drop to natural levels. While the sediment ponds are present, they will reduce runoff to the receiving streams. (p. 780-126eeeee) Receiving Stream Bolton Draw Bush Draw Williams Draw Sudduth Draw Percent Detention 16.8 5.4 17.9 2.9 This effect would be temporary, and would cease when sediment ponds are removed. Following reclamation, the disturbed site would, for a short period of time, be susceptible to erosion, and would temporarily have increased runoff rates. These problems are rectified with time as the reseeded areas develop with plant root growth and as the fresh topsoil becomes settled and stabilized. Contour furrows will be used to retain water from precipitation as much as possible within seeded areas during reclamation (would also reduce erosion). During the early years following reclamation all of the runoff should be retained by the contour furrows. At the end or the bonding period, vegetative cover will be established and the topsoil stabilized, and contour furrows and sediment ponds wiZ1 -7-