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<br />OD1515 <br /> <br />Affected Environment & Consequences <br /> <br />3-3 <br /> <br />3.1.1 <br /> <br />General Impacts to the Region <br /> <br />Under the No Action alternative, changes in the Valley are expected to continue. <br />Increased residential and light industrial developments are expected to occur. No major <br />water projects are anticipated; however, operation of existing facilities, especially the <br />Aspinall Unit, is expected to be more directed toward the protection and recovery of <br />endangered fish species. Agriculture should continue to be important to the local <br />economy. Development alternatives will result in short-term impacts, including <br />vegetation clearing, erosion, and disturbance caused by construction, and long-term <br />operational impacts related to decreased flows in the Gunnison River and increased flows <br />in the Uncompahgre River. <br /> <br />3.2 <br /> <br />Streamflow <br /> <br />3.2.1 <br /> <br />Derivation of Streamflows <br /> <br />Existing and with-project streamflows have been determined using a water budget model <br />of the system, The system in comprised of the Gunnison and Uncompahgre Rivers, <br />several small streams tributary to the Uncompahgre River, 7 major irrigation canals, and <br />several smaller irrigation canals that divert flow from the Uncompahgre River. The <br />period of study for this water budget model was 1952 through 1996, a period of 45 years. <br /> <br />Streamflows in the Gunnison and Uncompahgre Rivers have been gauged by the US <br />Geological Survey (USGS) for many years. The Gunnison River gauge below the <br />Gunnison Tunnel has been in continuous operation since 1903. Gauges on the <br />Uncompahgre River have been in operation since the 1930s. Since gauge operation <br />began, major dams have been constructed in the upstream reaches of both rivers. These <br />dams are Blue Mesa, Morrow Point, and Crystal, which are on the Gunnison River and <br />collectively comprise the Aspinall Unit and the Ridgway Dam on the Uncompahgre <br />River. <br /> <br />In the early 1980s, the Bureau of Reclamation (Reclamation) studied the effects of <br />different Aspinall Unit operations to Gunnison River streamflows. A simulation of <br />Gunnison River streamflows from the period 1952 to 1981 was a result of this study. The <br />simulation presented Gunnison River flows had the Aspinall Unit been operating during <br />that period. A similar simulation study was performed for the Uncompahgre River.! <br /> <br />The Sponsors utilized Reclamation's Gunnison River data, and supplemented these data <br />with actual gauge records from 1982 through 1996. In addition to the simulation and <br /> <br />The Blue Mesa Reservoir began operation in 1965; Morrow Point in 1972, and Crystal Dam in 1979, <br />and Ridgway Dam began operation in 1985, <br /> <br />AS Lateral Hydropower Project <br /> <br />July 2000 <br />