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<br />Colorado River Basin Salmlty Control Program <br /> <br />~, <br />0' <br />:r <br />0:.. <br /> <br />Bdore a preferred alternative can be selected. an environmental assessment will need to be <br />completed. Sewemup ~1esa. located immediately east of Sinbad Valley. is a BL~1 wilderness study <br />area and is also proposed as an outstanding natural area in the resource management plan. The <br />area has high visual sensiti\'uy. both onsite and along a powerHne alignmem. and has peregrine <br />falcons nesting in it. Reclamation has suspended study of this area for salinity control because of <br />the project's small size. potemial environmemal impacts. and marginal cost effectiveness. <br /> <br />Uinta Basin Unit <br /> <br /> <br />The Uinta Basin Unit is located in nonheastern Utah. The area includes ponions of Duchesne and <br />Uima Coumies and is situated between the Uinta Mountains on the nonh and the Tavaputs Plateau <br />on the south. The principal communities within the area are Duchesne. Roose\'elt. and Vernal. <br /> <br />Reclamation has conducted extensive studies in the area. ~10st of the salt pickup from the unit area <br />is from the dissolution of salts from the soil and subsurface materials. principally from soils of <br />marine origin which underlie most of the Uinta Basin. Seepage from conveyance systems and deep <br />percolation resulting from irrigation are the primary processes which dissolve salts from the soils <br />and shales and convey the salts through the groundwater system to natural drainages and ultimate]y <br />to the Colorado River. The Uinta Basin contributes an estimated ~50.000 tons of sail per year to <br />the Colorado River. <br /> <br />Reclamation-Several proposals ha\'e been received under Reclamation's Basinwide Salinity <br />Control Program. Request for Proposals. and have been accepted. Environmental compliance on <br />these plans WIll need to be completed bdore they may be implemented. but several show promise. <br /> <br />l'SDA- The USDA Uinta Basin Salinity Conrro/ Plan was prepared in 1979 and amended in 1987 <br />to include off-fannlateral improvements. In 199Z. the plan was expanded to bring in 10.000 acres <br />of adjoining irrigated lands which were not included in the original plan. The [Olal salt-load <br />reduction goal for this area is 106.800 tons per year. <br /> <br />Since 1987. Implementation has been accomplished under the aUlhorilies of the USDA Colorado <br />Rl..-er Salinity Control Program. The application of salinity reduction practices continues at an <br />increasing rate. The major practices installed are wheel-line sprinkler systems. improved surface <br />systems. underground pipelines and gated pipe. In this area. many groups of fanners are replacing <br />leaking earthen laterals with pipelines which pro..-ide gravilY pressure for onfann sprinkler systems. <br /> <br />Verification Studies-USGS reported in their 'vanonal Warer Summary /990-91. Wafer Supp(\.' <br />Paper 1400. a downward trend in dlssol..-ed solids concentration (salinity) in the Duchesne River. <br />immediately downstream of the project area. They pointed out that much of the base !low of the <br />river was from irrigation return !lows. From table ~a in the appendix of this repon. salinity <br />discharge has dropped from 206.000 IOns in 1981 when USDA first slarted irrigation improvements <br />to 169.000 tons in 1993-a 37.0OCHon reduction. Based on the amount of irrigation improvements <br />installed. USDA estimates that Irrigalion impro..-ements through 199Z have reduced the salinity <br />discharge by about 55.500 tons per year (/993 Join! Emlllanon Report). Recent srudies have also <br /> <br />63 <br />