The Odland Dam provides opportunities for recreation like boating and fishing, and it had undergone frequent minor repairs for decades. The Golden Valley County Water Resource District asked Barr to inspect the dam, consider a range of repair alternatives, and recommend a solution. Barr conducted structural and geotechnical inspections of the earthen dam embankment and 100-foot-wide concrete spillway. The results influenced the board and design team to consider more comprehensive repairs or replacement in lieu of continued small-scale repairs.
Barr completed hydrologic modeling to estimate the inflow design flood (IDF) that confirmed the existing primary and auxiliary spillways were sufficient to pass the IDF while maintaining appropriate freeboard. We also completed a dam breach analysis to confirm the hazard classification. Using the results of the inspection and hydraulic modeling, Barr facilitated a four-hour value-based-design workshop with a small design team. The session resulted in the creation of a comprehensive list of potential solutions. High-level construction cost estimates were also developed for three viable alternatives determined during the session.
We presented descriptions, sketches, construction cost estimates, and pros and cons for each alternative to the board, with one alternative recommended as best value. The board selected replacing the existing primary spillway and raising the auxiliary spillway as the most cost-beneficial and long-term solution. Barr was then retained to develop final design of the selected concept, which we completed—along with civil layout design and development of drawings and specifications for permitting, funding (with which we provided significant assistance), and construction. Project construction began in August 2021; completion is expected in November 2021.