Seminoe Dam

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Seminoe Dam
Spillways full open following heavy snowmelt, June 2011
USA Wyoming location map.svg
Red pog.svg
Location of Seminoe Dam in Wyoming
CountryUnited States
Location Carbon County, Wyoming
Coordinates 42°09′21″N106°54′30″W / 42.15583°N 106.90833°W / 42.15583; -106.90833 Coordinates: 42°09′21″N106°54′30″W / 42.15583°N 106.90833°W / 42.15583; -106.90833
StatusIn use
Construction began1936
Opening date1939
Owner(s) U.S. Bureau of Reclamation
Dam and spillways
Type of dam Concrete thick gravity-arch
Impounds North Platte River
Height295 ft (90 m) [1]
Length530 ft (160 m) [1]
Width (crest)15 ft (4.6 m) [1]
Width (base)85 ft (26 m)
Dam volume210,000 cu yd (160,000 m3) [1]
Spillways 1
Spillway typeGated concrete tunnel
Spillway capacity48,500 cu ft/s (1,370 m3/s) [2]
Creates Seminoe Reservoir
Total capacity1,017,279 acre⋅ft (1.254795×109 m3) [2]
Catchment area 7,210 sq mi (18,700 km2) [2]
Surface area20,291 acres (8,211 ha)
Maximum water depth206 ft (63 m) [1]
Power Station
Hydraulic head 166 ft (51 m) [3]
Turbines 3x 15 MW
Installed capacity 45 MW
Annual generation 96,406,970 KWh (2007)

Seminoe Dam is a concrete thick-arch dam on the North Platte River in the U.S. state of Wyoming. The dam stores water for irrigation and hydroelectricity generation, and is owned and operated by the U.S. Bureau of Reclamation. It is the uppermost dam on the North Platte River and is located directly upstream from the Kortes Dam. It lies in a narrow, isolated canyon formed by the North Platte cutting through the Seminoe Mountains about 40 miles (64 km) northeast of Rawlins. The 295-foot (90 m) dam forms Seminoe Reservoir, which covers more than 20,000 acres (8,100 ha) when full. [4] Seminoe State Park is adjacent to the reservoir. The small village of Seminoe Dam abuts the dam and reservoir, and provides residence for the dam attendants and park services personnel.



This dam was first proposed in the 1930s as part of the Bureau of Reclamation's Kendrick Project, which would regulate the flow of the North Platte River in order to improve agriculture in the valleys surrounding Casper, Wyoming. Originally known as the Casper-Alcova Project, it was authorized by the National Industrial Recovery Act on June 16, 1933 in response to the Great Depression. The project was renamed the Kendrick Project on August 9, 1937 in honor of Wyoming politician John B. Kendrick. [5]

Seminoe Dam and Reservoir from the air SeminoeDam.jpeg
Seminoe Dam and Reservoir from the air

In 1934, Winston Brothers Company and Associates won the construction contract of Seminoe Dam. Groundbreaking of the site was on February 20, 1936, with preliminary blasting and excavations. The diversion tunnel for the North Platte was completed on January 17, 1937, with one fatality, and by May of that year, a cofferdam was completed to a sufficient height to divert the river into the new channel. Concrete pouring began on January 19, 1938, and the last bucket was emptied on December 21, 1938. Water storage began on April 2, 1939, when the outlet tunnels were closed. The dam's power station was finished and the entire project was declared operational on August 3, 1939. A total of two deaths and several serious injuries resulted from the construction, and a pair of active faults that cut across the canyon near the dam site had to be excavated and filled in. [5]

On March 25, 1969, a helicopter experienced engine problems and crashed into the rocky canyon near Seminoe dam killing Bureau of Reclamation employees David McMillan and Howard Leroy Gates. (Altoona Mirror, April 21, 1969)

When the project was first completed, it delivered water to just 600 acres (240 ha), but has progressed steadily, and by 1980 supplied irrigation water to 22,581 acres (9,138 ha) in the Casper valley. [3]

The dam is suffering from a degrading Alkali–silica reaction that has damaged its structural integrity. [6]


The Seminoe Reservoir is stocked with fish by the Wyoming Game and Fish Commission, and is open to boating and fishing, although access to the shoreline is limited and sometimes difficult due to the lack of development and distance from major cities.

See also

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  1. 1 2 3 4 5 "Dimensions". Kendrick Project. U.S. Bureau of Reclamation. 2008-08-30. Retrieved 2011-02-27.
  2. 1 2 3 "Hydraulics and Hydrology". Kendrick Project. U.S. Bureau of Reclamation. 2008-08-30. Retrieved 2011-02-27.
  3. 1 2 "Kendrick Project". U.S. Bureau of Reclamation. 2009-12-22. Retrieved 2011-02-27.
  4. "Seminoe Reservoir". Platte River Basin Water Atlas. Wyoming State Water Plan. Retrieved 2011-02-27.
  5. 1 2 Klajic, Leisl A. (2000). "The Kendrick Project (Casper-Alcova)" (PDF). Bureau of Reclamation History Program. U.S. Bureau of Reclamation. Retrieved 2011-02-27.