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PR-12 Exhibit 71 2 <br />2A 'SURFA(CE WATER HYDROLOGY <br />The SOD and DFL areas include portions of four drainages: Dry Fork, Lick Creek, Deep Creek, and <br />South Prong ,Creek (Map 1). The main SOD area is drained by Dry Fork and Lick Creek and the small <br />northeast arm of the SOD and DFL areas is drained by upper Deep Creek. A small portion of the <br />southeast corner of the SOD area is drained by the north fork of South Prong Creek. An abbreviated <br />summary of the surface water quality data is presented in Table 1. Additional baseline water quality data <br />and hydrographs are presented in Appendix A. <br />2.1 Streams <br />2.1.1 Dry Fork <br />'Dry Fork is a tributary stream to Minnesota Creek and drains the northern section and majority of the <br />SOD area (Map 1). The Dry Fork watershed encompasses an area of approximately 7.5 square miles. <br />The main stem of the Dry Fork is about 5.6 miles in length, extends from an elevation of 8,720 feet to <br />6,700 feet, and has an average gradient of about 6 percent. The upper Dry Fork drainage is about 2.5 <br />miles long, extends from an elevation of 8,400 feet to 7,800 feet, and has an average gradient of about 4.5 <br />percent. The major tributary drainages flowing into Dry Fork in the SOD area include Deer Creek and <br />Poison Gulch. <br />Dry Fork has a well developed alluvial valley floor in low gradient reaches (particularly in the upper <br />reaches of the drainage above Minnesota Reservoir). However, in steeper reaches, the bottom of the <br />drainage is narrow with little, if any, alluvial development. Dry Creek flows originate from surface <br />runoff, numerous springs, and diversions from the Deep Creek Ditch Trans-Basin Diversion (Deep Creek <br />Ditch). Deep Creek Ditch transports water from Little Gunnison -Creek and surface runoff from the upper <br />Deep -Creek drainage to the upper Dry Fork area to provide irrigation water for users in the Minnesota <br />Creek basin. The average annual diversions for the Deep Creek Ditch comprise about 1,000 acre-feet (ac- <br />ft). Minnesota Reservoir is located in the :Dry Fork drainage and provides up to 467 ac-ft of water storage <br />for local irrigation use. The Dry Fork water quality data collected to-date does not indicate any mining- <br />related impacts. The water quality data do, however, reflect natural seasonal variations with respect to levels <br />of iron, manganese, pH, TDS, and TSS being elevated during spring runoff. <br />September 2007 II1'droGeo, Inc. <br />•