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<br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />Colorado River <br />Water Quality lmprov€',nenl Program <br />FInal Environmental Impact Statement <br />for the Lower Gunnison and Uintah Basin Units <br /> <br />to> <br />>- <br /><::> <br />1'';'' <br /> <br />Lead Agency <br />U.S. Department of Agricultun., 5011 Const-evaden Service <br /> <br />Cooperating Agencies <br />Agricultural Stabilization <br />and Conservation Service, USDA <br /> <br />Bureau of Reclamation <br />Service, USDI <br /> <br />Eovi ronmenta 1 <br />Protection Agency <br /> <br />States and Counties Directly Affected <br />Colorado <br />Delta County <br />Montrose County <br /> <br />Utah <br />Duchesne County <br />Uintah County <br />\t-Iasatch County <br /> <br />Abstract - Lo~er Gunnison Bdsin Unit. The dIScussion of the Lower Gunnison <br />unit sho...'s that irrigated agricultun~ on 171,000 acres, contributes about 840,000 <br />tons of salt to the Colorado River annually. Improved management of irrigation <br />water including land leveling, measuring water onto the field and lining onfarm <br />earthen oitches and off-farm laterals can reduce the river's salt load by as <br />much as 500,000 lons, reducing salinity concentrations at Imperial Dam by 52 <br />milligrams per liter. Local benefits resulting from these improvements would <br />be reflected in reduced costs of production, improved irrigation systems and <br />increased crop yields. A ~orst-case analysis shows improvements to this level <br />could impact up to 13,200 acres of ~etland (in one alternative), that have princi- <br />pally developed as a result of irrigation in the valley for about 100 years. <br />These ~etlands have a habitat value of 461,200 units, The recommended plan, <br />if implemented, would reduce salt loading by 335,000 tons per year, which could <br />impact 3,800 acres of wetlands (10 percent of the ~etlaDds in the Lower Gunnison <br />Basin Unit). <br /> <br />Abstract - Uintah Basin Unit. Onfarm return flow from 205,000 acres of irrigated <br />land in the Uintah Basin Unit presently contributes 177,200 tons of salt to <br />the Colorado River annually. Onfarm irrigation efficiency improvements through <br />better control and management of irrigation ....ater \,:ill reduce the annual salt <br />contributlon by 76,600 tons and increase average annual streamflow by 20,200 <br />acre-feet. This reduces the salt concentration by 10.3 milligrams per liter <br />at Imperial Dam or allo~s the ~ater quality at Imperial Dam to be maintained <br />at the present level ~hil~ developing an additional 86,000 acre-teet of ~ater. <br />Improvement in average onfarm irrigation efficiency from 34 to 51 percent ~ill <br />be accomplished by l} installing and using water conveyance and control structures <br />and measuring devices, 2) using the irrigation system best adapted to the soil, <br />crops and level of management desired, 3) utilizin~ soils information to properly <br />design and layout irrigation systems. and 4) appl~ing the proper amount of water <br />at the proper time to meet crop consumptive use, There are about 49,000 acres of <br />'Wetland '.,;ildlife habitat in the basin. In the recommended plan, about 20,000 <br />acres having an acre value of about 7,600 acres ~ill be converted to upland <br />habitat and about 1,900 acres of upland wildlile habitat having an acre value <br />of 630 acres ...ill be disturbed during construction. wildlife habitat mainte- <br />nance and improvement and better farm crops ~ith grain and corn added to the <br />rotation ...ill be implemented through long term agreements with individual farmers <br />to help offset losses. In addition loss of irrigation lnduced ~etland is minimized <br />by the fact that conservation measures tor salinity control are limited to those <br />acres which have been irrigated for four of the last five years. <br /> <br />Questions on this Supplement should be directed to: <br />Frank Reckendorf. Environmental Resource Specialist <br />~est Technical Service Center, Soil Conservation Service <br />511 S. ~. Broad~ay, Portland, Oregon 97209 <br />Phone - CommerClal: (503) 221-2841 r~rs: 423-2841 <br />