WSP04698 - Laserfiche WebLink

Home Browse Search

. ~ en f,) 00 . . such as safety and cultural resources. UVWUA overhead will be approximately 6%. Total overhead used in the cost estimates is assumed to be 14%. 2. Description of the Revised Plan for the Main Canals The revised plan includes the pvc membrane lining of each main canal. Each canal design also includes an over excavation quantity to account for anticipated mucky conditions after the canals are drained, and to account for the fact'that a'rarge portion of the canal alignments cut into potentially unstable shale bedrock. The design slope was generally flatter than the existing grade; and for this reason, in combination with the canal over excavation, large amounts of borrow material would be required. Another consequence of the design canal' slope is that more drop structures would be required than presently exist. Most major existing waterway structures such 'as 'tunnels, siphons and flumes would be retained. A few of these existing major structures, as well as some existing concrete-lined canal sections, were included in the UVWUA's last R&B Program constructed in the 1980's and therefore are not included in this study. A few existing bridges and road crossings, which are in good condition, would also be utilized; however, the bulk of the existing bridges are in poor shape and would be replaced with new bridges or road crossings. Other existing structures such', asc -- turnouts and drops would be replaced. Materials from the structures to be removed or replaced would be either disposed of or salvaged. Each canal would be equipped with a flow measurement device. In general, existing methods of wasting excess canal flows - would be utilized. The design capacity would be usually reduced immediately downstream of a lateral turnout where canal flow is lower. Canal flood protection would be provided in accordance with policies developed during the current salinity control work being done in the Grand Valley. The current flood protection would be replaced in-kind with some improvements made to the culverts and drains. Cross-drainage facilities were designed to pass the following storm floods: the 10-year frequency storm for canal reaches with capacities of 50 cfs and below; the 25-year frequency storm for canal reaches with capacities of greater than 50 cis; and, the 50-year frequency storm for the South Canal. All canal reaches would be fenced on both sides. No cattleguards, safety ladders or deer escape ramps would be needed for PVC membrane-lined sections. 9