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pond. This water right is expected to be out of priority from July to <br /> September. <br /> The freshwater pond (FW-1) has a ten acre-foot capacity. Average <br /> withdrawals from the North Fork of the Gunnison are not expected to <br /> exceed 400,000 gallons per day (gpd) during the term of the permit and <br /> are likely to be on the order of 200,000 gpd. The freshwater pond is <br /> filled during spring runoff and kept full until water rights are out of <br /> priority. The water is either treated to meet potable and sanitary water <br /> requirements, used and then treated as sanitary waste water, or <br /> withdrawn for dust suppression in the mine and becomes mine water. <br /> The potential effects of this water diversion on North Fork flows are <br /> developed for both flow rates and flow volumes. With the existing <br /> pump capacity, 450 gallons per minute (gpm), this diversion would <br /> result in a measurable change in flow for low flows with return periods <br /> of about 200 years or greater. Additionally, during the extreme low <br /> flow periods, MCC's water rights would be out of priority and <br /> diversion would not be undertaken. <br /> It is presumed that any change in flow that is less than five percent and <br /> within the measurement error of a stream gauge would not result in a <br /> hydrologic impact. Table 4 of this document shows the estimated <br /> percent changes in North Fork flow volumes due to withdrawals for <br /> projected mine requirements. <br /> The NPDES permit allows for a discharge of 10,000 gpd, based on a <br /> 30-day average, from the sanitary waste water treatment plant. The <br /> potential impact of discharge of waste water effluent would be greatest <br /> when the dilution ratio for effluent is smallest. <br /> The quality of mine water is considered good and offers no problem for <br /> treatment and discharge. Mine water discharge is treated in <br /> sedimentation pond MB-1 and/or MB-2R. B Seam inflow amounts are <br /> expected to be similar to the mine water inflow amounts of the F Seam. <br /> Overland runoff passes over disturbed areas within the permit area to <br /> one of the six sedimentation ponds, mentioned previously in this <br /> section. This water may be discharged to the North Fork or stored <br /> when water rights are in priority. From previous Annual Hydrology <br /> Reports, it appears that these discharges have had no adverse effect on <br /> the North Fork. In fact, the quality of the discharge usually exceeds the <br /> quality of the North Fork. <br /> 45 <br />