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• 2.04.7 <br />According to the report for the water year October 1993 to September 1994, <br />the average annual discharge of the North Fork of the Gunnison River is <br />330,500 acre feet, which drains 526 square miles with an average elevation <br />of 8,700 feet. This is a water yield of 628 acre-feet per square mile. <br />Water flows and water quality in the North Fork are strongly influenced by <br />water control through Overland and Paonia Reservoirs, by water withdrawal <br />from several irrigation canals, and by reflow from irrigated lands back into <br />the river. Withdrawals at Somerset (Fire Mountain Canal), between Bowie <br />and Paonia (Stewart Ditch), and just above Paonia (Farmers Ditch) withdraw <br />significant flows and cause significant dewatering of the river. Some of this <br />water returns to the river near and below Paonia. <br />Irrigation has significant effects on water volume and quality of the North <br />Fork. It contributes to reduced flows and increased salinity, nutrients, and <br />probably herbicide/pesticide levels. Indirectly, lower flows contribute to <br />higher summer temperatures. The municipality of Hotchkiss (below Paonia), <br />• and several smaller communities along the valley and mesas are also <br />sources of nutrients as the result of effluents from discharges directly into <br />the river and through the groundwater. There is little industrial use or <br />discharge of water to the North Fork, particularly in the upper part of the <br />valley, although several coal mines have operated in the past and are <br />presently operating. <br />The North Fork of the Gunnison River, into which streams draining the <br />Somerset Coal Field flow, is severely affected by human activities, primarily <br />agriculture. Coal mines in the area currently discharge fairly significant flows <br />into the river. The Sanborn Creek Mine, West Elk Mine and Bear No. 3 Mine <br />all discharge mine water to the river. Near Somerset, the water is a calcium- <br />bicarbonate type, typical of runoff from mountain areas, and contains total <br />dissolved-solids concentrations of 100 to 400 mg/I (ref. SOM 1994 AHR). <br />Streams Draining Permit and Adjacent Areas <br />Two tributary watersheds have been identified within or adjacent to the <br />Permit Area: Terror Creek and Hubbard Creek. Large discharges typically <br />occur in March through July, with peak flows occurring in late April or early <br />May. <br />PR-03 2.04 - 31 - 5199 <br />