Arrowrock Dam

Civil engineers tested the technological limits of the time to design and construct this engineering marvel. The Arrowrock Dam served as a proving ground for design elements and construction methods that would later be incorporated into other large dams in the west. It was the first United States Bureau of Reclamation dam to use Ensign Valves to control the flow through the outlet works.

The Arrowrock Dam, a concrete arch dam located on the Boise River 22 miles upriver from Boise, Idaho, serves as an essential water storage facility supplying irrigation water to thousands of acres of fertile farmland in the Treasure Valley. At the time of its dedication in 1915, the Arrowrock Dam was the highest dam in the world at 350 feet, a title it would hold until 1925 when it was surpassed by the Schraeh Dam in Switzerland. Civil engineers tested the technological limits of the time to construct this engineering marvel.

The Arrowrock Dam served as a proving ground for design elements and construction methods that would later be incorporated into other large dams in the western United States. The dam was the first United States Bureau of Reclamation dam to use Ensign valves to control the flow from the outlet works. While working on the Arrowrock Dam, Supervising Engineer Frank Crowe developed a grid system of delivering concrete pneumatically and an overhead cable system for rapidly delivering construction material throughout the construction site. Crowe later went on construct many more dams, including the Hoover Dam, where he utilized the systems he developed while working on the Arrowrock Dam.