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Exhibit 71 Hydrologic Characterization South of the Divide Area and Monitoring Plan 2 . 2.0 SURFACE WATER HYDROLOGY The SOD azea includes portions of four drainages: Dry Fork, Lick Creek, Deep Creek, and South Prong Creek (Map 1). The main SOD area is drained by Dry Fork and Lick Creek and the small northeast arm of the SOD azea is drained by upper Deep Creek. A small portion of the southeast corner of the SOD azea is drained by the north fork of South Prong Creek. An abbreviated summary of the surface water quality data is presented in Table 1. Additional baseline water quality data and hydrographs aze presented in Appendix A. 2.1 Streams 2.1.1 Dry Fork Dry Fork is a tributary stream to Minnesota Creek and drains the northern section and majority of the SOD azea (Map 1). The Dry Fork watershed encompasses an azea of approximately 7.5 square miles. The main stem of the Dry Fork is about 5.6 miles in length, extends from an elevation of 8,720 feet to 6,700 feet, and has an average gradient of about 6 percent. The upper Dry Fork drainage is about 2.5 miles long, extends from an elevation of 8,400 feet to 7,800 feet, and has an average gradient of about 4.5 percent. The major tributary drainages flowing into Dry Fork in the SOD azea include Deer Creek and Poison Gulch. • Dry Fork has a well developed alluvial valley floor in low gradient reaches (particularly in the upper reaches of the drainage above Minnesota Reservoir). However, in steeper reaches, the bottom of the drainage is narrow with little, if any, alluvial development. Dry Creek flows originate from surface runoff, numerous springs, and diversions from the Deep Creek Ditch Trans-Basin Diversion (Deep Creek Ditch). Deep Creek Ditch transports water from Little Gunnison Creek and surface runoff from the upper Deep Creek drainage to the upper Dry Fork azea to provide irrigation water for users in the Minnesota Creek basin. The average annual diversions for the Deep Creek Ditch comprise about 1,000 acre-feet (ac- ft). Minnesota Reservoir is located in the Dry Fork drainage and provides up to 467 ac-ft of water storage for local ircigation use. The Dry Fork water quality data collected to-date do not indicate any mining-related impacts. The water quality data do, however, reflect natural seasonal variations with respect to levels of iron, manganese, pH, TDS, and TSS being elevated during spring runoff. April 2006 AydroGea, Ine.