C150104 Feasibility Study - Laserfiche WebLink

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I I I I I I I I I I I I I I I I I I I -L Executive Summary A feasibility level study was made to evaluate the benefits of constructing an augmentation reservoir near the Colorado-Nebraska state line. The purpose of the reservoir would be for providing supplemental flows to the South Platte River to insure compliance with the compact. The supplemental flows are intended to allow GASP well owners to continue to divert water. The study is an extension of a previous study that evaluated several uplands reservoir sites on the south side ofthe river. The site in this study is located on the north side of the river between the towns of Sedgwick and Ovid. The project was evaluated as either a recharge project similar to the Tamarack project or as a standard storage project that would make controlled releases back to the river. Recharge would provide limited benefits based on the stream depletion analysis that was completed. A storage reservoir with controlled releases would provide much greater impact in reducing compact calls. Water supplies would be delivered to the reservoir through either the Peterson Ditch by gravity or by pumping the GASP Ovid wells located approximately Y2 mile to the south of the reservoir site. Permitting issues were evaluated. The project site has jurisdictional wetlands which will require obtaining an individual 404 permit. Preliminary meetings with the Corps of Engineers received indication that they would be supportive in issuing a permit for this project in light of the environmental benefits that the river would see. Preliminary cost estimates were prepared for the project. These include the reservoir embankment and appurtenant structures, a release struc;ture on the Peterson Ditch, a pumping pipeline/manifold system from the GASP wells, land a1cquisition costs and permitting costs. The total cost ofthe project to develop 2,200 acre-feet of water storage would be approximately $1,700,000. The long term annual cost ranges between $750 to $800 per acre-foot. The proposed reservoir was evaluated using the past 30 years of historic flow records for the South Platte River. Based on these records there is sufficient water available for diversion during the winter months to allow this project to operate under a junior diversion decree. The proposed project would be able to supplement compact requirements an average of 24 days per year.