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-44- If adequate subsidence protection plans can be designed, then loss of surface water would result only from the first two sources, increased infiltration and loss of springs. This runoff is not entirely lost to the hydrologic system. It would temporarily become a part of the ground water system and would eventually reemerge to the surface. It is difficult to predict where this water would reemerge. It could re-emerge downstream in the same drainage (the Minnesota Creek system) or it could reemerge along the North Fork of the Gunnison. In the latter case, the impact upon water users located along Minnesota Creek is potentially the greatest. In either case, water users located below the confluence of Minnesota Creek and the North Fork of the Gunnison should not be affected. The following stipulation is required by the Division to insure that the applicant analyzes and uses the data gathered under requirements put forth in previous stipulations. Stipulation No. 10 WEST ELK CDAL COt~ANY OR ANY SUCCEEDING OPERATOR OF THE MT. GUNNISON NUMBER 1 MINE, MUST ~Ni'INUE TO SUBMIT TO THE DNISION, AN ANNUAL HYDROLOGIC REPORT. THIS REPORT SHALL INCLUDE AN ANALYSIS OF ALL HYDROLOGIC DATA GA'P[-IERED DURING THE YEAR, AN PSSFSSMENT OF TES IMPACTS OF MINING DURING THE YEAR, AND AN ESTIMATE OF THE PROJECP IMPACTS OF MINING IN THE FOLSOWING YEARS. THIS REPORT SHALL ASSESS THE IMPACTS OF MINING ON THE QUALITY AND QUANTITY OF WATER IN SURFACE STREAMS, SPRINGS, GROUND WATER AQUIFERS, MINE INFLOW AND MINE DISCHARGES. Impacts on Surface Waters The Division, based on review of the permit applications for the mining operations considered in this assessment, has identified several possible affects of mining on surface water quality and quantity . Surface water quality might be affected by the discharge of mine water from underground workings or by seepage from waste rock or coal refuse piles to the stream - alluvial aquifer system. The underground mining operations, by altering ground water flaw, reversing hydraulic gradients, and through subsidence effects, may deplete springs and seeps or stream flows. In addition, the withdrawal of surface water for mine usage may deplete surface flows. Two other possible surface water effects, increased infiltration in the areas overlying underground workings and increased erosion from disturbed areas, were briefly considered but then deleted from further analysis. Although subsidence might logically increase infiltration rates in an undermined watershed (and therefore decrease runoff], the Division is unaware of any literature documenting that this effect actually occurs. Surface flow from disturbed areas would carry higher sediment concentrations than natural runoff. However, Rule 4.05.2 requires that all disturbed flow pass through a properly designed sediment control pond. Effluent from the pond is required to meet NPDES limitations prior to discharge. During operation, monitoring and inspection by the