The more than 400-foot (120 m) tall concrete-arch gravity dam is owned by the United States Bureau of Reclamation (USBR) and operated by the Owyhee Irrigation District.
[3] Former Oregonian and then United States President Herbert Hoover dedicated what was the highest dam of its type in the world on July 17, 1932.
[5] Owyhee's construction served as a prototype for the larger Hoover Dam on the Colorado River,[5] including the use of refrigeration to cool the concrete.
[9] Owyhee has a unique spillway located part way up the dam that utilizes a 60-foot (18 m) in diameter tunnel to send excess water to the river below during Spring run-off.
[12] The United States Bureau of Reclamation owns the facility, and the Owyhee Irrigation District operates the dam.
Annual precipitation is low, averaging less than 10 inches per year, and diurnal temperature variation is very high in the summer.
[14] The total drainage area of the dam and reservoir is 10,900 square miles (28,000 km2) in Eastern Oregon and western Idaho.