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Lake Canal Reservoir Company Agenda Item 7b <br />September 9, 2009 (UPDATED September 16, 2009) <br />Page 3 of 5 <br />water decreed for storage in Gray Reservoir No. 3. The water court entered a ruling decreeing the <br />alternate locations on November 10, 2004. <br />Project Description <br />The Borrower considered a couple alternatives for the two reservoirs. <br />South Gray Reservoir options were: 1.) Do Nothing; 2.) Install a toe drain system to control seepage <br />as needed to avoid a dam safety restriction. <br />Gray No. 3 options were: 1.) Da Nothing; 2.) Complete rehabilitation; 3.) Breach the dam <br />Gray No. 3 breach required review of a couple different options in order to deal with the impact of <br />the access road which runs along the top of the dam. The options were: a.) Re-route the access road; <br />b.) Maintain the existing alignment of the access road through the breached dam area <br />SELECTED PROJECT - Install tae drains on South Gray dam and breach Gray No. 3 and route <br />access road around the breach. <br />South Gray - To address the seepage issue in the dam the following is planned: <br />To control the seepage a toe drain system will be installed consisring of a perforated PVC pipe <br />surrounded by a filter layer of C33 sand. The drain will be placed about 6 feet below grade. Toe <br />drains are proposed from the spillway to approximately 450 feet to the east along the dam. <br />Gray No. 3- The breach of Gray No. 3 will require the following activities: <br />1. Provide a breach of adequate size to pass the 100-year flood.. <br />2. Dam breach proposed is at a 3:1 slope with a breach width of 65 feet. <br />3. The dam access road will be re-routed to the downstream toe of Gray No. 3 and South Gray due <br />to the impact to the current access road by the breach exca~ation. <br />4. Excess excavated material from the breach will have to be spoiled in the reservoir area and the <br />disturbed areas seeded to prevent erosion. <br />5. The existing outlet works will have to be demolished and buried in the reservoir. <br />6. The azea downstream of the breach will have to be graded to provide a spillway through the <br />breach to Box Elder Creek. <br />7. Riprap and bedding will be placed at the confluence with Box Elder Creek to limit erosion. <br />Engineering and construction costs are estimated at: <br />Construction Cost $ 300,000 <br />Contingency @ 20% $ 60,000 <br />Engineering Fees 73 000 <br />TOTALS $ 433,000 <br />Final design is expected to be complete in February 2010 and construction is projected to occur in <br />the falUwinter of 2010. <br />