Kingsley Dam Resurfacing in Early Design Stages
The Central Nebraska Public Power & Irrigation District board of directors have retained RJH Consultants of Englewood, Colo., as the firm that will design the slope protection replacement project on the face of Kingsley Dam.
RJH provided the board with several preliminary alternatives for slope protection repairs. The options ranged from completely replacing the existing slope protection with pre-formed concrete blocks to an approach that would only be a temporary repair and provide a short-term solution to the areas showing damage. However, the consultant’s investigation has determined that the existing riprap is undersized and lacks proper bedding over a much larger area of the dam, and that a full dam refacing will ultimately be required.
One option being studied is to replace the riprap with concrete-faced soil-cement which could provide a cost effective long-term solution. Currently, the consultant is at the 50% design phase of the project. This design would require removing all the riprap on the facing of the dam and replacing it with the concrete-faced soil-cement. Replacement of the current facing with a properly designed and filtered riprap system is also being considered. The area of the dam that must be resurfaced is roughly the equivalent of 30 football fields.
A timeline of when the project is scheduled to begin is still being determined by the consulting firm, and the next four months will be spent working with national experts to decide on the best solution for the project. Initial estimates for the cost of the repairs range from $80 million to $200 million and the start date is likely to be no earlier than 2025.
Central officials stress that the dam is safe, and the work to reface the dam is part of the District’s responsibility to ensure continued safe operation well into the future.