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Executive Summary <br />A feasibility level study was made to evaluate the benefits of constructing an augmentation <br />reservoir near the Colorado - Nebraska state line. The purpose of the reservoir would be for <br />providing supplemental flows to the South Platte River to insure compliance with the compact. <br />The supplemental flows are intended to allow GASP well owners to continue to divert water. <br />The study is an extension of a previous study that evaluated several uplands reservoir sites on the <br />south side of the river. The site in this study is located on the north side of the river between the <br />towns of Sedgwick and Ovid. <br />The project was evaluated as either a recharge project similar to the Tamarack project or as a <br />standard storage project that would make controlled releases back to the river. Recharge would <br />provide limited benefits based on the stream depletion analysis that was completed. A storage <br />reservoir with controlled releases would provide much greater impact in reducing compact calls. <br />Water supplies would be delivered to the reservoir through either the Peterson Ditch by gravity <br />or by pumping the GASP Ovid wells located approximately %2 mile to the south of the reservoir <br />site. <br />Permitting issues were evaluated. The project site has jurisdictional wetlands which will require <br />obtaining an individual 404 permit. Preliminary meetings with the Corps of Engineers received <br />indication that they would be supportive in issuing, a permit for this project in light of the <br />environmental benefits that the river would see. <br />Preliminary cost estimates were prepared for the project. These include the reservoir <br />embankment and appurtenant structures, a release structure on the Peterson Ditch, a pumping <br />pipeline /manifold system from the GASP wells, land acquisition costs and permitting costs. The <br />total cost of the project to develop 2,200 acre -feet of water storage would be approximately <br />$1,700,000. The long term annual cost ranges between $750 to $800 per acre -foot. <br />The proposed reservoir was evaluated using the past 30 years of historic flow records for the <br />South Platte River. Based on these records there is sufficient water available for diversion <br />during the winter months to allow this project to operate under a junior diversion decree. The <br />proposed project would be able to supplement compact requirements an average of 24 days per <br />year. <br />• <br />• <br />