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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 />Project Service Area and Facilities <br /> <br />The LID provides water for both irrigation and augmentation to a 12,818.9 acre service area in <br />Logan County. The LID begins west of Merino, Colorado and extends to the. Northeast of <br />Sterling, Colorado as presented in Figure 1. The LID serves landowners under the following <br />ditch systems: South Platte Ditch Company, Farmers Pawnee Canal, Davis Brothers Ditch <br />Company, Springdale Ditch Company, and the Schneider Ditch Company. LID also delivers <br />water for augmentation to the South Platte Well Users, Pawnee Well Users, and Logan Well <br />Users for replacement of well pumping within the service area. The irrigated acreage within the <br />service area is primarily used to grow corn, alfalfa, sugar beets, pinto beans, and feed crops. <br /> <br />Hydrology and Water Rights <br /> <br />The Prewitt Reservoir is an off stream reservoir, which diverts water from the South Platte River, <br />just upstream of the Morgan/Logan County line. The Prewitt receives water under Priority 75A <br />for storage of 32,300 acre feet of water at a rate of 695 cfs with an appropriation date of May 25, <br />1910. The Prewitt also has Priority 75R for refill of up to 34,960 acre feet of water with an <br />appropriation date of December 31, 1929. A summary of Prewitt Reservoir's water rights along <br />with specifications of the reservoir is presented in Appendix E. <br /> <br />Project Description and Alternatives <br /> <br />The purpose of this project is to construct an emergency spillway to provide unrestricted <br />overflow to pass flows resulting from the Probable Maximum Precipitation (PMP). The Prewitt <br />Spillway project began approximately 6 years ago with the initiation of a hydrological study and <br />an investigation of the area surrounding the reservoir. The hydrology study was completed by <br />W.W. Wheeler and Associates, Inc. and has been approved by the State Engineer Office <br />(SEO). The investigation of the area adjacent to the reservoir revealed a natural depression <br />near the mouth of the inlet canal which would carry most of the flow from the PMP, but was not <br />low enough to bring the reservoir back down to its full storage level. The Prewitt Operating <br />Committee and management considered four alternatives in order to reach the current spillway <br />design. The four alternatives considered are: <br /> <br />1. The no-action alternative. <br />2. Lower the current natural depression. <br />/ 3. Construct a pipe spillway near the west center area of the reservoir. <br />4. Construct a pipe spillway in the dam near the outlet. <br /> <br />Alternative No. 1 was considered unacceptable since it means the Prewitt Reservoir storage <br />would be further restricted by the SEO. <br /> <br />Alternative No.2 was ruled out because any alteration of the natural depression would require <br />the purchase of substantial right of way to route the PMP flow to the South Platte River. <br /> <br />Alternative No. 3 was ruled out because the cost of this alternative and Alternative 4 were <br />almost identical, but this alternative would once again require purchase of some right of way. <br /> <br />Logan Irrigation District <br />Emergency Spillway Feasibility Study <br />March 30, 2006 <br /> <br />Page 7 of 12 <br />