Navigating Design & Constructability Risks During Construction of Secord Dam

Secord Dam, built in the 1920s for hydropower and recreation, required major rehabilitation after the 2020 flood event which caused catastrophic failure (breach) of downstream dams (Edenville and Sanford), which revealed insufficient hydraulic capacity and structural deficiencies at Secord Dam. Key challenges included outdated design standards, lack of as-builts, complex geometry, limited access, and the need to maintain flows during construction. A phased approach was used to reduce design and construction risk, including river rerouting, staged embankment & spillway restoration, and real-time monitoring. The main structural challenge—the right training wall—was addressed using tiebacks, micropiles, pile caps, and supported by temporary external bracing. During construction, the original weir design proved unworkable due to spatial and thermal constraints, leading to a revised multi-lift concrete approach with dowels. Continuous coordination among the design team, contractor, and owner enabled real-time problem-solving, design flexibility, and safe prestressing of a century-old structure, ultimately enhancing dam safety and resilience. This paper presents the lessons learned from navigating design and constructability risks during the Secord Dam rehabilitation, with a focus on structural stability, sequencing, and collaboration between the owner, engineer, and contractor.