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Kortes Unit
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Pick Sloan Missouri Basin Program
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Kortes Unit History (60 KB) (pdf)
General Description| Plan| Development| Benefits
General Description

The Kortes Unit of the Pick-Sloan Missouri Basin Project, consisting of Kortes Dam, Reservoir, and Powerplant, is in central Wyoming in a narrow gorge of the North Platte River 2 miles below Seminoe Dam in the Kendrick Project, and about 60 miles southwest of Casper, Wyoming. It was the first unit initiated by the Bureau of Reclamation under the Missouri River Basin Project. The 36,000-kilowatt powerplant generates an average of over 160 million kilowatt-hours annually.

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Water released from Seminoe Dam to Pathfinder Reservoir passes through the Kortes turbines to generate power, which is distributed by the Government-owned interconnected transmission system to localities in the intermountain and Great Plains areas.

The small reservoir storage at Kortes influenced plans for plant operation. Maximum benefits are obtained when Kortes Reservoir remains full and the power releases are coordinated with those from the Seminoe plant to maintain a full reservoir. The Seminoe and Kortes facilities are controlled from the Casper Control Center.

Facility Descriptions
Kortes Dam

Kortes Dam is constructed in the 1,000-foot gorge of the Black Canyon on the North Platte River. The level of water in Kortes Reservoir controls the tailwater elevation of Seminoe Powerplant. The dam is constructed at the optimum location to develop the most head between Seminoe tailwater and Pathfinder high water surface elevation. About 200 of the 300 feet available are used. The concrete gravity structure has a maximum height above foundation rock of 244 feet and contains 147,000 cubic yards of concrete.

The 83-acre Kortes Reservoir is confined to the narrow canyon and provides storage for only 4,765 acre-feet of water. Other principal features include a 50,000-cubicfoot-per-second uncontrolled spillway through the right abutment, and a switchyard on the top of the dam.

The reinforced-concrete powerhouse occupies the entire width of the canyon at the toe of the dam. The plant has three 18,500-horsepower Francis-type turbines and three 12,000-kilowatt generators.

Operating Agencies

The Bureau of Reclamation operates and maintains the dam and powerplant. The Western Area Power Administration (WAPA) operates the switchyard from their dispatch center in Loveland, Colorado.

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The North Platte River valley served as a route to the unsettled West for explorers and traders and for emigrants in search of home sites. The Oregon, California, Mormon, Pony Express, and Overland Trails followed the North Platte and Sweetwater Rivers and crossed the Continental Divide at South Pass.

There were numerous trading posts, army forts, and stage stations located along these trails. Fort Laramie, Fort Steele, and Fort Casper have been restored for their historic value. Settlement in the valley began in the early 1880`s. The first irrigation systems were constructed without large storage reservoirs. Kortes Dam is named after the Kortes Ranch, 2 miles downstream from the present dam location.


Investigations for development of a dam and reservoir at the Kortes site were conducted intermittently after 1933. Based on information obtained during these investigations, the Kortes Unit was included in Senate Document 191.


Kortes power development was found feasible by the Secretary of the Interior as a supplement to the Kendrick Project on November 26, 1941, but it was authorized by the Flood Control Act of December 22, 1944, Public Law 534, which approved the general comprehensive plan set forth in Senate Documents 191 and 475, as revised and coordinated by Senate Document 247, 78th Congress, 2d session.


Construction of Kortes Dam was started in 1946 and completed in 1951. Because of the enormous increase in power demands in the area and power sales commitments, an accelerated power program was developed which consisted of erecting generating equipment and machinery concurrently with the dam and powerhouse construction, placing the generators into service before the powerhouse was completed, construction of temporary transmission facilities, and providing temporary protection for the operating equipment during the construction period.

As a result of this program, two units were placed into service 6 months before the completion of the powerhouse and the dam and 6 months earlier than they would have been without this accelerated program.

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The Kortes Reservoir receives limited recreational use since Kortes Dam and the steep shoreline restrict access in general to the North Platte River immediately below Seminoe Dam. Trout fishing is the main recreational activity at the reservoir. A small boat ramp near Seminoe Dam provides access to the reservoir. Senate Bill 2553 was passed in the 90th Congress authorizing the modification of the operation of Kortes Dam and Powerplant to provide a minimum streamflow of 500 cubic feet per second in the North Platte River between Kortes Reservoir and the normal headwaters of Pathfinder Reservoir. The minimum flow permits maintenance of a fishery in a stretch of the North Platte River, commonly referred to as the `Miracle Mile.`

Kortes Reservoir/Miracle Mile Area
North Platte River Fishery
Seminoe Reservoir

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Last updated: Aug 22, 2012