POCATELLO — American Falls Dam, a 94-foot-high composite concrete and earth gravity-type dam on the Snake River in Power County near the town of American Falls, will undergo maintenance and rehabilitation in 2020 and 2021. The dam was originally completed in 1928 and was reconstructed and replaced under the authority of the Bureau of Reclamation’s Safety of Dams Act in 1978.
With a storage capacity of 1,700,000 acre-feet, American Falls Reservoir is the largest reservoir of the Minidoka Project. The dam and reservoir comprise a multipurpose facility from which principle benefits include irrigation, power generation (through a power plant owned and operated by Idaho Power Company), flood control, fish and wildlife resources and recreation. About 889,282 acres of land downstream of American Falls on the Snake River Plain area are irrigated annually with water stored in American Falls Reservoir.
The planned construction activities will address the need for replacement and repair of deteriorating concrete on the spillway, spillway gate operator decks, downstream dam face, adits and stilling basin structures, which have experienced degradation over 40 years in service. Construction activities will consist of the hydro-demolition, cutting, removal and replacement of existing damaged concrete and reinforcing on these components and replacement or modification of an existing drain grate in the stilling basin. Construction will take place from June to November 2020 and mid-July to November 2021.
In preparation for this project, the Bureau of Reclamation completed an Environmental Assessment to examine the potential effects of the proposed actions. Based on the results of the EA, Reclamation has issued a Finding of No Significant Impact.
The final EA and FONSI were prepared in accordance with the National Environmental Policy Act and are available at https://www.usbr.gov/pn/programs/ea/idaho/americanfalls/index.html. To request a copy, please contact Amy Goodrich, Bureau of Reclamation Natural Resource Specialist at 208-383-2250 or via email at email@example.com. Individuals with questions about the overall project may contact Nicole Carson, Bureau of Reclamation Project Manager, at 208-678-0461 x16 or via email at firstname.lastname@example.org.