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HYDROLOGIC CHARACTERIZATION AND MONITORING PLAN <br />portion of the southeast corner of the SOD area is drained by the north fork of South Prong <br />Creek. <br />An abbreviated summary of the surface water quality data parameters including total dissolved <br />solids (TDS), total suspended solids (TSS), field pH, total iron, dissolved iron, and total <br />manganese is presented in Table 1. The most recently published (WY 2015) surface water <br />quality data and flow hydrographs for the monitoring sites are presented in Appendix B. <br />Complete historical surface water quality and flow data are presented in the Annual Hydrology <br />Reports (HydroGeo, 2002 through 2016a). <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 <br />of the SOD area (Plate 1). The Dry Fork watershed encompasses an area of approximately 7.5 <br />square miles. The main stem of the Dry Fork of Minnesota Creek (Dry Fork) is about 5.6 miles <br />in length, extends from an elevation of 8,720 to 6,700 feet above mean sea level (amsl), and has <br />an average gradient of about 6 percent. The upper Dry Fork drainage is about 2.5 miles long, <br />extends from an elevation of 8,400 to 7,800 feet amsl, 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 <br />Creek and Poison Gulch (Plate 1). <br />Dry Fork has a well-developed alluvial valley floor in low gradient reaches (particularly in the <br />upper reaches of the drainage above Minnesota Reservoir). However, in steeper reaches, the <br />bottom of the drainage is narrow with little, if any, alluvial development. Dry Fork streamflows <br />originate from surface runoff, numerous springs, and diversions from the Deep Creek Ditch <br />Trans -Basin Diversion (Deep Creek Ditch). Deep Creek Ditch transports water from Little <br />Gunnison Creek and surface runoff from the upper Deep Creek drainage to the upper Dry Fork <br />area to provide irrigation water for users in the Minnesota Creek basin. The average annual <br />diversions for the Deep Creek Ditch comprise about 900 acre-feet (ac -ft) (CDWR, 2015). <br />Minnesota Reservoir is located in the Dry Fork drainage and provides up to 467 ac -ft of water <br />storage for local irrigation use. <br />The Dry Fork water quality data collected through WY2015 for select parameters are summarized <br />in Table 1. The water quality data do not indicate any mining -related impacts. The water quality <br />data do, however, reflect natural seasonal variations with respect to levels of iron, manganese, pH, <br />TDS, and TSS being elevated during spring runoff. <br />2.1.2 Deer Creek <br />Deer Creek is a small ephemeral stream that is tributary to Dry Fork (Plate 1). Deer Creek has a <br />watershed area encompassing approximately 1 square mile. The Deer Creek drainage is about <br />1.6 miles long, extends from an elevation of 8,320 to 7,500 feet amsl, and has an average <br />gradient of about 6 percent. <br />MCC began monitoring flows and collecting water quality data in Deer Creek in the spring of <br />2005. The water quality data do not indicate any mining related impacts. The water quality data <br />collected through WY2015 for select parameters are summarized in Table 1. <br />Revised 09/07- PR12; 08/16- TR139 HydroGeo, Inc <br />