1906 28.5mw Minidoka Dam on Snake River for Irrigation

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Minidoka Dam is a storage and diversion dam for two different irrigation canals.

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These would be the gates for the Gravity Canal that is on the south side of the dam. In April, they are opening the gates to start the irrigation season.

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Three pump houses pump the water up 30' (9m) for a total of 90' (27m).

Photo via uidaho, "Minidoka Dam and Reservoir near Rupert", Archival Idaho Photograph Collection, University of Idaho Library Digital Collections, Public Domain

nps
"Today, the multi-faceted Minidoka Project, which provides irrigation water to more than one million acres, counts a total of seven dams and thousands of miles of canals, laterals and drains. Still at the core is the more than 100-year-old Minidoka Dam, significant as the Bureau of Reclamation’s first embankment dam and the first Federally-built dam in the Pacific Northwest to include a powerplant to supply electricity. Minidoka Dam stands only 86 feet [26m] high, but its spillway, designed to handle the great flow of the Snake River, is made of concrete and stretches 2,300 feet [701m] long, or nearly one-half of a mile."
"Over the years, Minidoka Dam has undergone additions and repairs, including the current reconstruction of its spillway. A sixth generating unit was installed in the powerplant in 1927, and a seventh in 1942. Then, in the early 1990s, work began on a new powerplant, with Units 8 and 9 added in 1997. Reclamation retired the original five generators from service but preserved them as museum pieces in the original powerhouse building, where visitors still can see them."

Bureau of Reclamation posted four photos with the comment:

⚡ Hydropower: Meet the Bureau of Reclamation’s oldest.  

More than a century of hydropower history lives at Minidoka Dam in southern Idaho.  

The original Minidoka Powerhouse began generating electricity in 1909, making Minidoka the oldest operating hydropower facility operated by the Reclamation.  

Here’s this historic powerhouse by the numbers:  

⚡ 28 megawatts of generating capacity  

⚡ 4 generators across two powerhouses  

⚡ About 100 million kilowatt-hours of average annual generation  

⚡ Enough electricity to supply approximately 7,000 to 10,000 homes for a year

Minidoka Dam is 86 feet tall and stretches 4,475 feet — about 0.85 miles — across the Snake River.  

💡 Fun fact: Construction on Minidoka Dam began in October 1904. By April 1910, the nearby communities of Burley, Rupert and Heyburn were receiving both irrigation water and electricity from the Minidoka Project.  

More than a century later, Minidoka is still generating power.  

Dam impressive. Powerfully Reclamation. ⚡  

📸1: Water flows from the Minidoka Powerhouse into the Snake River near Rupert, Idaho. 

📸2: Minidoka Dam switchyard, Minidoka Irrigation District headworks, and the Minidoka Powerhouse along the Snake River near Rupert, Idaho. 

📸3: Generating units line the interior of the Minidoka Powerhouse near Rupert, Idaho. 

📸4: Minidoka Powerhouse operates along the Snake River near Rupert, Idaho.

Brett Wanamaker shared

usbr
"The combined generation capacity of all four units is 28.5 megawatts, with a combined flow of 8670 cubic feet per second."
In 2015, the new $21.3m spillway with radial gates replaced the original spillway that used stop logs.