Sevier Bridge Dam Rehabilitation: A Work of Resourceful and Collaborative Engineering

Sevier Bridge Reservoir, located in central Utah, has provided primary storage of Sevier River water for over 120 years. The reservoir is formed by a 92-foot-tall, 1,340-ft-long earth embankment dam, creating the largest privately owned impoundment in the state of Utah. Sevier Bridge Dam and its reservoir (also referred to as Yuba Lake) enable irrigation of 55,000 acres of agricultural land and is thus vital to local communities and the regional economy. Sevier Bridge Reservoir is a key part of a reservoir system that provides cooling water used at the Intermountain Power Plant, a facility that supplies power to millions of residents and businesses in multiple states. The second phase of rehabilitation for Sevier Bridge Dam to mitigate deficiencies was recently completed. This work included construction of a stability berm, ground improvement using granular columns to mitigate a liquefaction hazard in the foundation soils, and a new spillway. Hydraulic modelling of the reservoir, its spillway, and downstream drainage system demonstrated that a reoriented spillway could pass the probable maximum flood without needing to replace an existing highway bridge near the spillway or modify downstream water reservoir systems. Innovative use of technologies by the designers and collaboration of stakeholders led to the successful implementation of cost-effective solutions and the project being recognized by the Association of State Dam Safety Officials with its 2025 National Rehabilitation Project of the Year award.