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SUMMARY (Continued) • be added to control the surface elevation of the canal water. Cross- drainage facilities, consisting of a detention dike and. ditch system, would be constructed to protect the membrane-lined canal. In addition to the moss and debris removal structure installed under Stage One, two new structures would be installed to remove moss, debris, and other material from the" irrigation water and to prevent the buried pipe laterals and measuring devices from clogging. Lateral improvements generally would consist of replacing unlined lateral reaches in the Stage Two area with buried pipe laterals that approximately follow existing alignment and grade. Laterals already lined would not be improved unless needed. Approximately 700 individual laterals are included, with a total length of approximately 490 miles, of which 308 miles (or 63 percent) are presently unlined and would there- fore be placed in pipe. Pipe laterals would be installed in all cases except those in which hydraulics prevent their use; in such cases, they would probably be concrete lined. The pipe sections would range from 6 to 48 inches in diameter. Existing structures, such as drops, road crossings, flumes, turnouts, and canal headgates, would be removed or replaced if necessary. Wildlife measures, including acquisition of 2,090 acres of land • along the Colorado River, would be included to compensate for wildlife habitat losses that could be expected to result from the canal and lateral improvements for the entire Grand Valley Unit. The recommended plan would reduce the salt loading from the unit area by an estimated 143,500 tons annually. Alternative A Alternative A provides for membrane lining the same three reaches of the Government Highline Canal as the recommended plan; however the existing open earth laterals that would be placed in pipe under the recommended plan would be concrete lined under alternative A. As with the recommended plan, existing structures along the canal would need to be evaluated as to their structural and hydraulic soundness and replaced if necessary. Turnout structures would be replaced, and several new wasteway and centerline check structures would be added to control the surface elevation of the canal water. Cross-drainage facilities would be the same as for the recommended plan; however, in this plan, the laterals would be open and concrete lined, so no moss and debris removal structures would be necessary. Conversely, the use of open laterals would require additional safety precautions, so safety fences would be installed along laterals adjacent to schools and recreation areas that may be frequently visited by children. Wildlife measures for alternative A would be the same as for the recommended plan. S-3