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<br />Finding of No Significant Impact <br /> <br />Glen Canyon Powerplant Uprating <br /> <br />The proposed action would not constitute a Federal action having <br />significant environmental impacts, <br /> <br />Project impacta are summarized below:, <br /> <br />1. Maximum flows from the powerplant in the Colorado River below Glen <br />Canyon Dam would increase from 31,500 cfs to 33,100 cfs, Utilization <br />of the increased capacity from uprating the generators would cause <br />higher flows than those presently occurring approximately 7 percent <br />of the time, These flows would be of short duration (usually less <br />than 4 hours), and would be dampened as they lllove down the river, <br /> <br />During periods of increased flows, wetted perimeter along the river <br />between the dam and Lees Ferry would increase by an average of 2 feet <br />horizontally, or 2 inches vertically. This increase in wetted <br />perimeter would not cause any significant erosion of streamside <br />vegetation, <br /> <br />The present pattern and duration of flows below 14,000 cfs would not <br />be changed from present operations, and the present sources of ground <br />water that support, riparian vegetation would not be altered; there- <br />fore, impacts on existing riparian vegetation or the terrestrial <br />species that inhabit it would not be measurable, <br /> <br />2, The increase in flows would occur at the high end of the flow pattern <br />and would not affect the minimum flows. The water from the reservoir <br />would come from the same penstocks as at present; therefore, there <br />would be no change in the temperature or the chemistry of the water, <br />Habitat simulation models showed essentially nO change in useable <br />area for fish, Based upon this information, no measurable impact is <br />expected on the quality of fishery resources below the dam. <br /> <br />3. Using data cited in paragraphs 1 and 2 above, plus other studies con- <br />ducted by the U.S, Fish and Wildlife Service and the Bureau, it was <br />concluded that there would be no impact on threatened or endangered <br />species because of the uprating, This was confirmed by the U,S. Fish <br />and Wildlife Service which provided the Bureau with a nonjeapordy <br />opinion on the humpback chub and the peregrine falcon (letter dated <br />April 2, 1982) in compliance with Section 7 of the Endangered Species <br />Act, <br /> <br />i <br />