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Surface Water Impacts to surface water from activities within the 5-year permit area include construction of sedimentation ponds, increased salt loading from the waste piles, and increased sedimentation. Drainage from both waste piles, mine water, and disturbed area runoff is routed through a sedimentation pond prior to discharge. All sedimentation ponds are to be.dewatered within a 36 hour period to reduce losses from evaporation and infiltration. Water from WECC's high flow priority rights is stored for later use. Undeveloped springs will be developed to mitigate any loss of flow from existing springs. Any potential loss of downstream flow will be mitigated through diversion and storage of WECC's highflow rights for use in summer months to offset these losses. Both waste piles will be reclaimed contemporaneously to minimize surface disturbance. Impacts to surface water from mining in the 5-year permit term area are not significant. Several potential effects on surface water quality and quantity have been identified from mining in the life of mine area and cumulative hydrologic impact area. Surface water quality may be affected by discharge of mine water from underground workings or by seepage from waste piles. Underground operations may deplete springs and seeps and stream flows by altering goundwater flow, reversing hydraulic gradients, and through subsidence. Withdrawal of water for mine use may deplete surface flows. There are 13 water rights within or near the lease area that are outside the 5-year permit area. An additional 29 downstream rights could also be affected by the life of mine project. A detailed water augmentation plan for the Minnesota Creek basin has been filed with the State water court. The augmentation plan sets up methodology to identify depletions caused by mining operations and establishes compensation for injury to vested water rights. Any loss in streamflow resulting from spring depletion will be compensated for by the augmentation plan. Surface water flows from disturbed areas would carry higher sediment concentrations than natural runoff. Subsidence protection plans are proposed for all tributaries to Minnesota Creek to protect streamflow. The cumulative hydrologic impact assessment (CHIA) indicates that the worst case projection of TDS for the North Fork of the Gunnison would result in a 335 mg/L increase using the 7-day, 10-year low flow (Q7,10) of 32.5 CFS. Utilizing the current monthly average flow, the expected increase would be 5 mg/L. Worst case depletion of springs and seeps could result in a 6.2 percent reduction of low flow runoff. The total estimated water consumed by all mines in the North Fork Drainage Basin is approximately 0.13 percent of the mean annual yield of the river. This indicates that the total coal mining activities within the North Fork of the Gunnison Drainage will have a very minor impact on the quantity of water available in the basin. The impacts to surface water quality and quantity are not significant for either the 5-year permit area or the life-of mine area. -T-