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<br />M <br />en <br />o <br />o <br />C..:> <br />o <br /> <br />Grand Vallev unit Final Environmental Imoact statement <br /> <br />Salinity control for the Grand Valley Unit was planned in two <br />stages. Stage One was completed in 1983, and included the concrete <br />lining of 6.8 miles of the Government Highline Canal. The 1986 <br />FEIS for Stage Two Development of the Unit recommended incremental <br />salinity control measures to be constructed over 20 years, <br />including the membrane lining of three reaches of the Government <br />Highline Canal and the consolidation into pipe or lining of <br />associated open laterals for the systems. The three reaches of the <br />Government Highline Canal to be lined covered the remaining 38 <br />miles of the canal located within the Unit. Of the three reaches, <br />lining of the west end has been completed through the membrane <br />lining of 8 miles and piping of the last mile. <br /> <br />Because of cracks that developed during the first 3 years of <br />operation in the unreinforced concrete lining of Stage One, the <br />FEIS selected the use of membrane (a 20-mil thick polyvinyl <br />chloride sheet covered with layers of earth and gravel) instead of <br />concrete to line the Stage Two segments of the canal. Completion <br />of membrane lining for the west end has provided useful experience <br />related to the membrane lining technology. The alternative use of <br />concrete lining for Reaches 1 and 2 is further analyzed by this EA. <br /> <br />In the Alternatives chapter of the FEIS (Reclamation, 1986), Table <br />5 (p. 18) prioritizes the various recommended measures for the <br />preferred and selected Alternative B according to the cost <br />effectiveness of each measure in removing salts from the river <br />system, which is expressed as cost per ton of salt removed per <br />year. Scheduling of the various measures depends on the relative <br />cost effectiveness in combination with a number of other factors, <br />including the status of organizational efforts for salinity control <br />measures of laterals, the preferences of local water user groups, <br />and the need for a logical construction sequence. Lining for Reach <br />1 is scheduled for construction beginning in 1992. The membrane <br />lining of Reach 2 is not yet scheduled for construction; it is the <br />least cost effective increment of all the salinity control measures <br />recommended for the unit. Lining of the associated laterals, <br />usually by placing them in buried pipe, is also being accomplished. <br /> <br />In the "Rights-of-Way" section of the FEIS (p. 31), it is noted <br />that: <br /> <br />Rights-of-way for existing canals . . . were either obtained <br />under the Congressional Act of August 30, 1890 (the 1890 Canal <br />Act), were purchased outright, or were withdrawn from the <br />public domain. <br /> <br />Most of the canal corridor for Reach 1 was purchased as fee title <br />lands (fee land) prior to construction between 1912 and 1919. <br />Outright purchase of these lands was necessary because the 1890 <br /> <br />4 <br />