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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />1. Environmental concerns over wetlands protection and endangered species habitat <br />have effectively stopped current lining plans just upstream of Drop 3. (Einal <br />, Environmental. Impact Statement/Final EIR. AAC Lininii Proiect, USBR, March, <br />1994). <br /> <br />2. Much of the AAC outside of existing lining plans flows through developed <br />agricultural and urban areas. Land acquisition for a parallel channel may be <br />prohibitively expensive. Concrete lining of the current channel is not feasible for the <br />same reason as the existing project; the AAC cannot be removed from service for <br />more than a few days. <br /> <br />The 1984 USBR report estimated that 51,400 acre-feet of water per year could be conserved by <br />lining the entire length of the East Highline (EHL) Canal. However, approximately 40,000 acre- <br />feet are recovered annually through the existing IID EHL Seepage Recovery Program. Most of <br />the remaining seepage losses occur in the first 25 miles of the EHL, upstream of the Mulberry <br />Lateral. Lining the EHL is problematic for three reasons: <br /> <br />1. As with the AAC, upstream reaches of the EHL cannot be removed from service for <br />more than a few days. <br /> <br />2. The EHL is bordered on the west by developed agricultural lands, and for part of the <br />distance, by a 230KV power line. The EHL is bordered on the east by some farm <br />land and some sensitive environmental areas. A parallel canal alternative for the <br />entire 25 miles would be cost prohibitive due to these factors alone. <br /> <br />3. Storage in the existing earth-lined channel is critical to District water control and <br />management. The existing channel would either have to be lined as is, or additional <br />storage facilities would have to be constructed. <br /> <br />Specific reaches of the EHL with high seepage losses, that are not served by a seepage collection <br />system could be identified and lined. However, having a mix of lined and unlined segments <br />along a main canal may eventually limit water conservation opportunities, create maintenance <br />problems and negatively affect the operation and management of the canal. Any lining along the <br />EHL will require the careful selection of candidate reaches based on a detailed analysis of <br />operational effects, methods and timing of construction, and estimated cost effectiveness. <br />Additional analyses, possibly in the form of soil and water investigations, are required to assign <br /> <br />Draft: Subject To Revision 12/21/95 <br /> <br /> <br />32 <br />