Elwood Dam Seepage Repair Construction Underway
An important piece to the Central Nebraska Public Power and Irrigation District’s irrigation project is getting a face lift as construction is underway on a seepage mitigation project of Elwood Dam at Elwood Reservoir.
Elwood Dam, constructed in the 1970s, consists of a main earthen embankment dam, two earthen saddle dams, a pump station, an inlet-outlet canal and a conduit that is surrounded by an earth fill embankment. Central stores irrigation water and recharge water in Elwood and water is conveyed into and out of the reservoir through the inlet-outlet conduit and the E-65 canal.
Water levels fluctuate routinely at Elwood Reservoir but in recent years Central has operated the reservoir at higher elevations for groundwater recharge purposes. In the summer of 2019, significant seepage was observed near the toe drain and right abutment of the embankment around the inlet-outlet.
Central hired RJH Consultants to evaluate potential dam safety issues related to the seepage at the inlet/outlet embankment and near the main dam. Based on evaluations, RJH concluded that uncontrolled seepage posed credible dam safety issues and that a seepage mitigation system (SMS) should be installed. Central retained RJH to develop a design for the SMS and prepare documents for bidding.
After getting design approval from the state, BSB Construction of Curtis, Neb., was awarded the bid as the contractor to handle construction of the project.
Work began in September with removal of trees from below the dam. Work around the pump station began on November 1. The projected timeline to finish the project is August 2024.
The cost of the project is expected to be $6 million. Central has received two financial commitments from other partners that benefit from storage in the reservoir to help offset some of the total cost of the project.