Rainbow Dam is a hydroelectric dam on the
Missouri River
The Missouri River is a river in the Central United States, Central and Mountain states, Mountain West regions of the United States. The nation's longest, it rises in the eastern Centennial Mountains of the Bitterroot Range of the Rocky Moun ...
, high and long, located six miles northeast of
Great Falls in the
U.S. state
In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its so ...
of
Montana
Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...
.
History
The dam is named for the downstream
Rainbow Falls, a waterfall that is the third of the five
Great Falls of the Missouri. Built in 1910, the dam furnishes water to an eight-unit hydroelectric plant with a capacity of 36
megawatt
The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work ...
s.
As the dam's power plant is located over a half-mile downstream, the flow of water over Rainbow Falls and downstream Crooked Falls is significantly reduced during the dry season. The water from the penstocks re-enters the river a few hundred yards east of Crooked Falls.
Montana Power Company
The Montana Power Company (MPC) was an electric utility company based in Butte, Montana, which provided electricity to Montana consumers and industry from 1912 to 1997.
History
The Montana Power Company was founded in 1912 by John D. Ryan, the ...
acquired the dam when it was founded in 1912,
PPL Corporation
PPL Corporation is an energy company headquartered in Allentown, Pennsylvania in the Lehigh Valley region of eastern Pennsylvania. The company is publicly traded on the New York Stock Exchange as and is part of the S&P 500. As of 2022, the compa ...
purchased it in 1997 and sold it to
NorthWestern Corporation
NorthWestern Energy Group, Inc. is a utility company that serves South Dakota, Nebraska, and Montana that is based in Sioux Falls. , the company serves approximately 718,000 customers. The company's corporate headquarters are located in Sioux Fa ...
in 2014.
See also
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Ryan Dam
References
External links
*
Historic American Engineering Record
Heritage Documentation Programs (HDP) is a division of the U.S. National Park Service (NPS). It administers three programs established to document historic places in the United States: Historic American Buildings Survey (HABS), Historic American E ...
(HAER) documentation, filed under End of Rainbow Dam Road, Great Falls, Cascade County, MT:
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Buildings and structures in Cascade County, Montana
Dams completed in 1910
Dams in Montana
Dams on the Missouri River
Gravity dams
Historic American Engineering Record in Montana
NorthWestern Corporation dams
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