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• All the inflow water will be pumped from the mine to an existing sediment <br />basin for treatment before it is discharged into the North Fork. Discharged <br />water will meet all sampling and monitoring requirements as specified in the <br />Colorado Wastewater Discharge Permit number CO-0000132. <br />The operator owns two water rights that allow diversion of water from the <br />Gunnison River for municipal and mining purposes. The operator estimates that <br />the operation will consume the following amounts of water from this source: <br />1. Moisture added to coal, 4% by weight = 22.1 ac. ft./yr <br />2. Dust suppression = 2.9 ac, ft./yr <br />3. Showers and personal use = 3.6 ac, ft./yr <br />Total = 28.6 ac. ft./yr <br />Surface water drainage from the surface facilities associated with the mining <br />operation is controlled by four sediment ponds. One additional pond will be <br />used to control discharges from the underground operation (as previously <br />described). The worst-case evaporative losses from these sediment ponds is <br />estimated to result in an annual depletion of 1.8 acre-feet. <br />The annual depletion estimated to occur from the mining operation is the sum <br />of the 28.6 acre-feet for operational needs and an evaporative depletion of <br />• 1.8 acre-feet, which gives a total of 30.4 acre-feet. <br />BASIS FOR OPINION <br />This Biological Opinion addresses the average annual depletion of <br />approximately 30.4 acre-feet of water from the upper Colorado River. <br />Water depletions in the Upper Colorado River Basin have been recognized as a <br />major source of impact to endangered fish species. Continued water withdrawal <br />has restricted the ability of the Colorado River system to produce flow <br />conditions required by various life stages of the fishes. Impoundments and <br />diversions have reduced peak discharges by 50 percent since 1942 while <br />increasing base flows by 21 percent in some reaches. These depletions along <br />with a number of other factors have resulted in such drastic reductions in the <br />populations of Colorado squawfish, humpback chub, bonytail chub and razorback <br />sucker that the Service has listed these species as endangered and has <br />implemented programs to prevent them from becoming extinct. <br />Colorado Sauawfish <br />The Colorado squawfish evolved as the main predator in the Colorado River <br />system. The diet of Colorado squawfish longer than three or four inches <br />consists almost entirely of other fishes (Vanicek and Kramer 1969). The <br />Colorado squawfish is the largest cyprinid fish (minnow family) native to <br />North America and, during pre-development times, may have grown as large as <br />six feet in length and weighed nearly 100 pounds (Behnke and Benson 1983). <br />• These large fish may have been 25-50 years of age. <br />