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<br />t- <br />ee <br />t"". <br /> <br />.~~ <br />~..." <br /> <br />ENVIRONMENTAL IMPACT STATEMENT <br /> <br />SUMMARY <br /> <br />C <br />'I~-,^ <br />';:>~'l <br />:~;; . ~-_:~/ <br />.'.;.:." <br /> <br />of the river water. Reservoir plans would reduce streamflows in most <br />months although average July and August flows would be increased. <br />Downstream water rights would be honored under the candidate plans. <br /> <br />Reservoir alternatives would affect water quality. Sediment would <br />settle out in the reservoirs under plans 3 and 9 resulting in cleaner <br />water downstream. Suspended metals in the Gunnison River could also <br />be expected to settle out and would remain trapped in reservoir sedi- <br />ments. Salinity concentrations would increase by 4.4 mg/L under plan 3, <br />by 0.9 mg/L under plan 8, and by 16.4 mg/L under plan 9 as measured at <br />Imperial Dam on the Lower Colorado River. Water temper'atures in the <br />Gunnison River would be decreased in the spring and early summer because <br />of reservoir storage. <br /> <br />V eget at ion <br /> <br />The project area is characterized by desert shrubs with scattered <br />areas of Jun1per trees and by a band of shrubs and cottonwood trees along <br />the Guimison River that result from better moisture conditions. Table <br />S-2 summarizes long-term vegetation impacts that could occur in the <br />project area. Plans 3 and 9 would adversely impact the threatened <br />Unita Basin hookless cactus but would not be expected'to jeopardize the <br />existence of this species. <br /> <br />Vegetation type <br />Desert shrub <br />Agriculture <br />Deciduous tree <br />dominated wetland <br />Deciduous shrub <br />dominated wetland <br />Pinon- juniper <br />Total -1,085 <br />1/ Changes shown are in <br />the project. <br />~/ ACreage shown would be acquired and protected. <br /> <br />Table S-2 <br />Vegetat"ion impacts <br />(acres) <br />Future <br />without <br />-10 <br />-350 <br /> <br />1/3 <br />-3,707 <br />-665 <br /> <br />"1;./7 <br />902 <br />276 <br /> <br />Plan <br />L/8 <br />902 <br />276 <br /> <br />1/9 <br />-3,910 <br />-902 <br /> <br />-375 <br /> <br />-637 <br /> <br />258 <br /> <br />258 <br /> <br />-1,009 <br /> <br />-350 <br /> <br />-260 <br />-33 <br />-5,302 <br />addition <br /> <br />207 207 <br />10 10 <br />1,653 1,653 <br />to future changes <br /> <br />-475 <br />-302 <br />""6,598 <br />without <br /> <br />Wild life <br /> <br />The most significant impact under all alternatives would result from <br />changes in the shrub and tree-dominated wetland vegetation that, although <br />limited in extent, provides valuable habitat for wildlife. Losses of <br />this vegetative cover would be greatest under plans 3 and 9 while plans <br />7 and 8 include measures to preserve this type vegetation. Plans 3 and 9 <br />would largely eliminate wetlands along 24 and 34 miles of the Gunnison <br />River respectively. Plan 9 would inundate riverbottom lands in the <br />Escalante Creek State Wildlife area. The reservoir habitat created <br /> <br />vii <br />