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Creek Basin. Of the total 140 acres of basin azea within the permit boundary, only about 24 acres are disturbedby the mine. This azea is a small fraction of the total drainage area of 27.4 squaze miles upstream of the mine on Oak Creek. Average annual yield from the mine area is estimated at 7,900 acre-feet. Runoff from the permit area is estimated at 25 ac-ft, or 0.3 percent of the total annual stream flow of Oak Creek above the mine. The estimated mean minimum flow is 5 cfs. Seasonal runoff hydrographs for both streams show peak discharge occurring in April, May, and June as a result of snowmelt runoff: Low flows in both streams begin in the late summer and extend through the winter months until the onset of spring runoff. A large portion of the permit azea has been previously mined, replacing consolidated overburden with spoil materials. Deep percolation of precipitation through the spoils has created a water table aquifer which abuts against the now buried highwall, or box cut, near the foot of the previously mined slope. Numerous springs have formed as a result. These springs emanate along a relatively steep slope above the alluvium on the east side of Trout Creek. Water quality conditions upstream of the mine indicate that dissolved iron, manganese and other tracemetalsallhaveoccasionallyexceededreceivingstreamstandazds. Baseline dataindicateminor changes in water quality occur between upstream and downstream stations on both Trout and Oak Creeks. This is probably due to the impacts of past mining activities. The baseline quality of the water in Oak Creek is generally poorer than that in Trout Creek above the permit area because of the extensive mining that has occurred in the Oak Creek drainage during the past century. Land se Current and historic land use in the vicinity of the operation has been coal mining, livestock grazing and wildlife habitat. Historically, coal has been extracted from the mine azea by both surface strip and underground methods. Imgated cropland in the area is limited to portions of the Trout Creek alluvial body, and to the Yampa River floodplain. Non-imgated crops are grown on sloping upland areas, as well as on some alluvial bottom lands. No cropland will be disturbed by the mining operation. T~soi I Topsoil within the permit azea is discontinuous in the West and Center Ridge Areas, due to previous surface mining operations. The operator has estimated that approximately nine inches of topsoil will be replaced on 132 acres in the West Ridge Area. In the Moffat Area, approximately 375 acres of reclaimed lands will be topsoiled to a depth of 9 inches. Vegetation Vegetation in the vicinity of the mine is characterized by three vegetative types; mixed brush, Edna Mine 7 permit Renexal No. 3