On the Snake River near Rupert, on County Highway 400, north of
Minidoka dam was the first Reclamation Service project in Idaho.
It is an earthfill dam eighty-six feet high and nearly a mile long.
Construction began in 1904; most of the canals and laterals were
finished by 1906. Between 1908 and 1909 the first federal power
plant in the northwest was installed at Minidoka. Costs far exceeded
estimates. By 1909 the total cost for the dam had reached $5.8 million.
The Minidoka dam was the first of five dams built in the Minidoka
project. The Minidoka Project proposed to bring water into the southeastern
areas of Idaho near the cities of Rupert and Burley. These uninhabited
sagebrush deserts now boast some of the richest farmland in the
Minidoka farmers had electricity long before other rural areas.
Farmers and nearby townspeople formed cooperative utility companies,
built their own distribution systems, and contracted for power from
the dam, selling it to themselves.
1974 the dam and power plant were placed on the National Register
of Historic Places. The power house is open to the public on weekdays
as well as weekends during the summer. Walcott Park, close to the
dam, is a popular picnic area. Headquarters for the Minidoka National
Wildlife Refuge is adjacent to the park. The 25,000 are refuge was
established in 1909 by president Teddy Roosevelt.
The Minidoka Project supplies a supplemental water supply to more
than 1 million acres of land. The five reservoirs have a storage
capacity of 2,784,600 acre-feet. The Minidoka Dam itself provides
for irrigation, power production; flood control, recreation, and
fish and wildlife resources. The reservoir created by the dam is
called Lake Walcott, named after a Reclamation engineer. It has
a storage capacity of 210,000 acre-feet. The lake extends 26 miles
up the Snake River and has a shoreline of 80 miles. There are two
sections to the spillway. One is an uncontrolled overflow weir section
and the other is a controlled section using radial gates. The spillway
is 2385 ft long. At the dam water is diverted into a canal on each
side of the river. The North side canal supplies the Minidoka Irrigation
District with water. It is an 8-mile long gravity canal and lateral
stem with an initial capacity of 1700 cubic feet per second. The
south side canal is 13 miles long and has an initial capacity of
1325 cubic feet per second. It is a canal system with three large
pumping plants; each plant lifting water 30 ft for a total of 90
ft. This canal serves water to the Burley Irrigation District. The
concrete power plant has nine generating units with a total capacity
of 27700 kilowatts.