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the Stewart Ditch landslide. Average daily low flows in the North Fork during Water Year 1986 was 80 cfs orb January 15, 1986. The maximum withdrawal at the intake is 460 gpm~'rSitih both pumps operating. This is J less than 1.38 of the observed average daily low flow in the river during the water year, were the pumps operating during low flay conditions. Sanitarv Waste Water J A sanitary waste water treatment plant was constructed and cronq~leted in the fall of 1982. .DU'7J c~~ During Water Year 1986 discharge from the waste water treatment plant averaged 4870~gpd. This discharge is about 0.018 of the average daily flow of 80 cfs observed in the North Fork during the year. Analysis presented in the quarterly reports show ,monitoring results from discharges from the waste water treatment plant as required under NPDFS Permit No. ~-0038776. The results of analysis suggest the waste water discharge has no measurable effect on water quality in the North Fork Gunnison River. Mine Water Mine inflows during Water Year 1986 were small. The total mine water inflar was 31.2 acre ft. during the year. The total water exiting the mine is estimated to be 28.8 acre feet. The quality of mine water is considered good and offers no problem for treatment and dischazge. ] Mine water was discharged exclusively from Sylvester Gulch. Table 1.4--1 shows the results of discharge sampling. Mine water inflow for Water Year 1987 is expected to be similar to that experienced during Water Yeaz 1986. Mine water would be expected to have water quality characteristics similar to that reported in Table 1.4-1 and l 1.4-2 in 1987. t Because of the small quantity of mine water anticipated, any discharge from ponds could normally be dominated by water quality characteristics of disturbed azea runoff as described in the following section. ' Runoff from Disturbed Area Overland runoff Fran snowcnelt• and precipitation within the disturbed areas ' is routed to one of six sediment ponds on the mine site. The six sediment ponds are designed to contain the predicted runoff from a statistically determined 10 year, 24 hour precipitation event as well as a calculated sediment storage volume. The ponds are also designed to safely pass the overflow fran a 25 year, 24 hour precipitation event. The Mt. Gunnison Mine site receives much of its annual precipitation from snowfall during the winter months. When warmer weather begins in late February, March or I April, most runoff to the sediment ponds is fran sna++melt. It is entirely possible for a volume of runoff greater than the 10 year, 24 hour precipitation event to result fran snowmelt or snowmelt coupled with asmall I precipitation event. (18)