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Annual Hydrology Report <br />April 28, 1988 <br />' Page 20 <br />2.3.3 Ldine Water Management and L:q~act Assessment <br />' The discussion of the mine water system and hydrologic impact assessment is <br />organized by the four sources of water: <br />1) North Fork water <br />2) sanitary wastewater <br />3) mine water, and <br />4) runoff from disturbed areas. <br />l Use and discharge of water from these sources is studied for its potential to <br />J1 affect the North Fork. <br />North Fork Water <br />During Water Year 1982 the conditional right to withdraw water from the <br />North Fork was deemed absolute. When this water right is in priority, <br />water can be pumped from the intake point to the freshwater storage pond(s) <br />within the surface facilities area. In average years, this water right is <br />expected to be out of priority from July to September, but in 1977 it would <br />have been out of priority from April to September. In water year 1986 <br />WDCC's Mt. Gunnison Pipeline water right met quadrennial diligence for the <br />conditional poction and an additional portion was deemed absolute by the <br />Division 4 water court bringing the absolute portion to 0.88 cfs. <br />The 10-acre-foot capacity pond provides for water storage during the term <br />of permit; two ponds are anticipated for subsequent permit terms. Water <br />can also be stored in Sediment Ponds MB-1, MB-2, and MB-3 under a separate <br />decree. Storage is usually limited to the maximum sediment level <br />elevation. Transfer to FW-1 is possible as outlined in the M & R Plan. <br />Average withdrawals aze not expected to exceed 50,000 gpd during the term <br />of permit and are likely to be on the order of 45,000 gpd, depending on <br />production levels and requirements. During 1987 average withdrawal was <br />16,600 gpd for 250 working days. <br />Water from the freshwater pond(s) is either treated to meet potable and <br />sanitary water requirements, used and then treated as sanitary waste water, <br />or it is withdrawn for dust suppression in the mine is which case it then <br />becomes mine water. WF~C's Mt. Gunnison Pipeline water rights were out of <br />priority during water year 1987 for approximately two weeks in September. <br />Due to the low production schedules, this did not cause a problem. Average <br />daily low flows in the North Fork during Water Year 1987 was 75 cfs during <br />5 days in September, 1987. The maximum withdrawal at the intake is 460 gpm <br />with both pumps operating. 'Luis is less than 1.3~ of the observed average <br />daily low flow in the river during the water yeaz, were the pumps operating <br />during low flow conditions. <br />Sanitary Waste Water <br />A sanitary waste water treatment plant was constructed and completed in the <br />fall of 1982. <br />