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<br />. <br /> <br />. <br /> <br />. <br /> <br />Or. (0 (0 'I 9 <br />0(,"::..1 <br /> <br />GRAND VALLEY UNIT <br /> <br />Back!!round <br /> <br />The Grand Valley Unit (Unit), one of the original four salinity control units authorized <br />for construction by Title II of Public Law 93-320, consists of the Colorado River valley <br />from Palisade, Colorado, to the Colorado-Utah state line. The Unit area contributes <br />approximately 580,000 tons of salt per year to the Colorado River. The salt contribution <br />is caused by seepage from the canal and lateral systems and on-farm deep-percolation. <br />The 200 miles of canals and 500 miles of laterals in the Grand Valley serve <br />approximately 70,000 acres of irrigated lands. <br /> <br />The concept of lining canals and laterals to control seepage and ultimately salt <br />contributions to the Colorado River was tested in an area of the Grand Valley called <br />Stage One. It was estimated that 24,000 tons of salt per year entered the river due to <br />canal and lateral seepage in this 5,700 acre irrigated area. In 1980 - 1982 approximately <br />7 miles of canal were concrete lined and about 34 miles of earth ditch were replaced <br />with 30 miles of pipeline. Stage One post-construction monitoring indicated that the <br />improvements prevented 21,900 tons of salt per year from entering the river. <br /> <br />With the success in the Stage One area, plans were initiated to improve another 320 <br />miles of laterals and about 40 miles of canals as part of Grand Valley Unit, Stage Two. <br />Stage Two construction is expected to control another 139,500 tons of salt per year. The <br />total Grand Valley Unit improvement program is expected to prevent 161,400 tons of <br />salt per year from entering the Colorado River. Table 1 lists the various increments of <br />Grand Valley Unit, Stage Two and the incremental and overall cost effectiveness.. <br /> <br />The estimated costs presented in table 1 are the costs that would be expected if a <br />traditional Reclamation contract competitively bid approach is taken. Similar <br />construction work conducted by the employees of local water user organizations have <br />indicated that it may be possible to perform the improvement work through irrigation <br />entities at considerable savings. Current estimates of the savings range from 40 to 60 <br />percent. As this method of work and the associated cost savings are verified, table 1 <br />costs will be adjusted. <br /> <br />6 <br />