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<br />001964 <br /> <br />3.2.3 Water Quality <br /> <br />According to Brogden et. AI. (1979), there is significant concerns in respect to surface and <br />ground water quality in primary drainages of the San Juan River such as the Mancos River <br />Drainage. Accumulations of heavy metal, salts, and elements such as selenium cause <br />contamination in Reclamations project-affected rivers and man made reservoirs. Subsequent <br />bioaccumulation in the food chain can cause problems for the endangered fish species in the San <br />Juan River (Colorado Pikeminnow, razorback sucker). Increased loading of the San Juan River <br />and its tributaries degrade water quality and cause harm for all aquatic species. (p. 5, BO <br />MWCD, March 1998) <br /> <br />The subject water and associated irrigated properties are thoughtto ha.ve substantially lower <br />concentration levels of salts and selenium; and contribute relatively little of those contaminants <br />to the San Juan River systems through return flows. ThisjspflItially due tot,he higher elevation <br />of the properties, which have historically been shown tocontmn lower levelscof contaminants, <br />than the lower lying reaches of the Mancos River prainage; and the relatively small aIIlounts of <br />irrigation water and methods of irrigation, which havearesultanpow intercept and transport rate <br />for contaminants found below the plow zone. Since theselandshave.been irrigated for an <br />extended period of time, elements have already been leached from them. In general it is <br />expected there will be an increase in irrig~tion efficiency and Which will reduce transport of <br />contaminant issues. (Stan Power, Personnel Communications, February f002) <br /> <br />Reclamation believes that there will not be ariincreasein,9?ntamin,ants in the Mancos River <br />System and the San Juan River as a result of these carriagecoTItracts, because there are no new <br />depletions or new irrigationlands. <br /> <br />3.2.4 Turbidity <br /> <br />It is assumed that turbidity isimportant as it affects the interaction between introduced fishes and <br />the endemicCdlorado'Ri ver fishes., Because these endemic fishes have evolved under natural <br />conditiQI).s of high turbidity, it is conc;luded that the retention of these highly turbid conditions is <br />an important factor for theseendanget(edtishes. Reduction of turbidity may enable introduced <br />-" '," -. ',-, '.,-, -,-"-"." <br />species to&Wn a competitive'~4ge whjch could further contribute to the decline of the endangered <br />Colorado Riverfishes. (p5-6;:eO MWCD, March 1998) It is expected that there will be no <br />changes in turbiciity, since these non-project water usages are historic. <br /> <br />3.3 Hydroelectric Gen~.ration <br /> <br />At Jackson Gulch Darb., the District operates a hydroelectric plant (260 kwh turbine connected <br />to one 260 hp generators) to generate the small amounts of power required by project facilities. <br />Design data and economic feasibility for the facility were based on historical averages of 26 cfs <br />and 92 feet of elevation during high and low extremes (11 years data, 1979-1990, during 5 <br />months of irrigation May-September). Annually, the hydroelectric facility utilizes irrigations <br />flows up to a maximum of 33 cfs. <br /> <br />13 <br />