Minidoka Dam and Powerplant Minidoka Dam is a multi-purpose structure providing for irrigation, power production, flood control, recreation, fish and wildlife conservation and flood control for the lower portion of the Minidoka Project. The dam is located on the main stem of the Snake River, 13-miles northeast of Rupert, Idaho and is a zoned earth and rockfill structure constructed, operated and maintained by the Bureau of Reclamation. It has a structural height of 86 feet, a hydraulic height of 74 feet, and a crest length of 4,475 feet. The Lake extends 26 miles up the Snake River and has a shoreline of 80 miles. The reservoir serves as a storage and regulating reservoir as well as a diversion point for two canals.
Water is diverted at the dam into a canal on each side of the river.
The North Side Canal delivers water to the Minidoka Irrigation District, and the South Side Canal delivers water to the Burley Irrigation District and to a small acrea. The spillway section extends for 2,385 feet in an irregular line and has a capacity at elevation 4245.0 feet of 89,000 cfs. Nearly all of the inflow to the Snake River within this tributary area between dams enters the river from its southern tributaries. Although some precipitation does occur in the Snake River Plain to the north of the Snake, most precipitation infiltrates into the very porous lava flow areas or is lost in sinks. No major tributary stream enters the Snake River from the north between the two dams.