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<br />SUMMARY <br /> <br />IRRIGATION <br /> <br />Operation of the development alternatives would not affect the <br />amount of water diverted for irrigation use within the study <br />area, including private irrigation diversions as well as the <br />UVRP. The Montrose and Delta Canal (M&D) and the Loutzenhizer <br />Canal would receive the majority of their water supply from the <br />Uncompahgre River with development. Under the no-action <br />alternative, about 59 percent of the water supplies delivered to <br />these canals would be derived from the Gunnison River. Under any <br />of the development alternatives, about 35 percent would be <br />derived from the Gunnison. Conversely, the Selig, East, <br />Ironstone, and Garnet canals would receive higher percentages of <br />Gunnison River water. Senior water rights for private irrigation <br />diversions along the Gunnison and Uncompahgre Rivers would <br />continue to be honored. <br /> <br />RIVER MORPHOLOGY <br /> <br />Without development, the Gunnison River between the North Fork <br />confluence and Delta would be expected to become narrower and <br />more stable due to the effects of existing upstream water storage <br />projects. Changes being caused by the Aspinall Unit on the <br />Gunnison River upstream from the North Fork would continue. <br /> <br />With development, more of the riverbed would be exposed. The <br />principal time that this would occur is in the nongrowing season. <br />This would limit encroachment of riparian vegetation and wetlands <br />during periods of low and intermediate flows. Scouring during <br />high flow periods would maintain the channel. <br /> <br />Without development, the Uncompahgre River upstream of the study <br />area would become a narrower and more stable river under the <br />influence of Ridgway Reservoir. Within the study area <br />(downstream from the South Canal), the bank erosion that now <br />occurs would continue, and bank stabilization by individuals and <br />local governments would continue. <br /> <br />With development, bank erosion in the Uncompahgre River between <br />the South Canal and the proposed tailrace would decrease together <br />with the river's potential to scour encroaching vegetation. <br />Between the proposed tailrace and Delta, the river would become <br />more unstable and significant additional bank erosion would occur <br />unless bank protection was initiated. To reduce this erosion, <br />bank stabilization would be performed by the Sponsors before <br />development in areas found to be most susceptible to erosion. <br />Changes in erosion would be monitored during operations, and <br />further bank stabilization would be completed where necessary. <br /> <br />S - 9 <br />