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North Platte Project History (93KB) (pdf)
General Description| Plan| Development| Benefits
General Description

The North Platte Project extends 111 miles along the North Platte River Valley from Guernsey, Wyoming to Bridgeport, Nebraska. The project provides full service irrigation for about 226,000 acres divided into four irrigation districts. Supplemental irrigation service is furnished to eight water-user associations serving a combined area of about 109,000 acres.

Project features include five storage dams; four diversion dams; one pumping plant; one powerplant; and about 2,000 miles of canals, laterals, and drains. Electric power is generated at Guernsey Powerplant and supplied to the project area by four substations and about 160 miles of transmission lines.

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The North Platte River, fed by many mountain streams rising in the Rocky Mountains of Colorado and Wyoming, is the most important river in southeastern Wyoming and western Nebraska. Its waters are stored and used for irrigation and power development for the North Platte Project, the Kendrick Project, and the Kortes and Glendo Units of the Pick-Sloan Missouri Basin Program. Storage structures for these projects are interspersed along the North Platte River and require close coordination of operations.

Project operation is further complicated by agreements and laws governing water rights. The use and quantity of water are allocated for certain defined purposes - some on a priority basis, some on a proportionate share basis, and some on a geographical source basis.

Facility Descriptions

Waters of the North Platte River must pass through Seminoe and Kortes Dams before flowing downstream to Pathfinder Reservoir where they are joined by the flows from the Sweetwater River. Pathfinder Reservoir has a storage capacity of 1,016,000 acre-feet and holds much of the North Platte Project water. During the nonirrigation season, a small amount of water is released to satisfy other water rights, enhance fish and wildlife, and operate powerplants downstream. During the irrigation season, water is released as required, including water flowing from Seminoe Reservoir to be diverted at Alcova Dam for irrigation on the Kendrick Project.

Pathfinder Dam was one of the first dams constructed by the Reclamation Service. The dam is in a granite canyon on the North Platte River about 3 miles below its junction with the Sweetwater River and about 47 miles southwest of Casper, Wyoming. It is made of granite quarried from nearby hills and is faced with large rectangular blocks laid in horizontal courses. It is an arch dam with a gravity-type section, and has a structural height of 214 feet.

Pathfinder Dike fills a depression in the natural ground surface about 0.25 mile south of the dam. It is an earthfill structure, 38 feet high, with a concrete corewall.

About 180 miles below Alcova Dam and 25 miles below Glendo Dam, Guernsey Dam controls river flow. Water released from Pathfinder Reservoir can be stored at this dam and released to fit varying irrigation demands. Water is released through Guernsey Powerplant.

Guernsey Dam is in a rocky canyon 2 miles upstream from Guernsey, Wyoming. It is a diaphragm- type embankment of sluiced clay, sand, and gravel that forms an impervious core. Its slopes are protected by a thick layer of rock riprap. The structural height of the dam is 135 feet. The original capacity of the reservoir was 73,810 acre-feet, but this has been greatly reduced by silt deposits to about 46,000 acre-feet. The powerplant is on the right bank below the dam and has two generators, each of which had an installed capacity of 2,400 kilowatts and was uprated to 3,200 kilowatts in 1993. Power is transmitted to towns and industries down the valley over transmission lines which are operated and maintained by the Western Area Power Administration.

Since 1909, water for the North Platte Project has been diverted from the river by Whalen Diversion Dam. Water is diverted on the south side of the river into the Fort Laramie Canal and on the north side of the river into the Interstate Canal. The dam is a gravity, concrete ogee weir with an embankment wing which spans the river about 8 miles below Guernsey Dam.

Fort Laramie Canal

This canal has an initial capacity of 1,500 cubic feet per second and winds its way for 129 miles to an area south of Gering, Nebraska, delivering water to farms along its course. It also originally carried water for operating the Lingle Powerplant, which was retired in April 1956. The canal was constructed during 1915-1924.

Interstate Canal and Reservoir System

The Interstate Canal has an initial capacity of 2,100 cubic feet per second. Constructed during 1905-1915, it follows the contour of the land for 95 miles to Lake Alice and Lake Minatare Reservoirs northeast of Scotts Bluff, Nebraska.

The 35-mile long High-Line Canal extends from Lake Alice to the southwest. Diversion capacity is 160 cubic feet per second.

The Low-Line Canal extends from Lake Minatare southwest. It is 43 miles long and has a diversion capacity of 430 cubic feet per second.

Lake Alice, Lake Minatare, Lake Winters Creek, and Reservoir No. 2 are offstream equalizing reservoirs. The reservoirs are fed using water diverted at Whalen Diversion Dam through the Interstate Canal, which ends at Lake Alice. The Reservoir Supply Canal carries water to the other reservoirs, which are usually filled each year before the start of the irrigation season. Natural depressions were made into important reservoirs by building Minatare Dam and the Upper and Lower Dams at Lake Alice. The combined storage capacity of these reservoirs is about 73,000 acre-feet.

Northport Canal

Water for the Northport Canal is conveyed 80 miles through the Tri-State Canal of the Farmers Irrigation District.

The Northport Canal, a continuation of the privately constructed Tri-State Canal, was designed to irrigate 16,170 acres in the Northport Division. The canal is 27 miles long and has a diversion capacity of 250 cubic feet per second.

The Tri-State Canal diverts water, stored in project reservoirs, from the North Platte River in Nebraska.

Operating Agencies

The Pathfinder and Guernsey Reservoirs and Guernsey Powerplant are operated and maintained by the Bureau of Reclamation. Whalen Diversion Dam is operated by the Goshen Irrigation District for the other districts on a cost-sharing basis. The distribution systems are operated by the districts which they serve.

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In the early days the trade route to the west beyond the Rocky Mountains followed the North Platte River. Many historic trails wound their way from the east along the North Platte and Sweetwater Rivers to cross the Continental Divide at South Pass. Stage stations, trading posts, and army forts were scattered along the trails but, with the advent of the railroad in the late 1860`s, the trails began to disappear. Two old forts, Fort Laramie and Fort Casper, have been restored for their historical value.

Settlement of the North Platte Valley in western Nebraska began in the early 1880`s. Rainfall was scarce when needed, and small private irrigation systems were built without storage reservoirs. The lack of facilities to hold the early spring runoff meant that the river could not supply sufficient water during the growing season and some of the projects failed.


In 1895, Nebraska enacted an irrigation district law permitting the formation of districts with power to assess lands for irrigation improvements. Shortly after the Federal Reclamation Act was passed in 1902, the Reclamation Service began studying the North Platte Project. The project was authorized in 1903, and surveys were started to determine the location of irrigable lands. As the work proceeded, it became apparent that storage must be provided to reclaim any considerable area. Further investigations led to the selection of the Pathfinder Dam site as the most favorable storage location.


The project, originally called Sweetwater Project, was authorized by the Secretary of the Interior on March 14, 1903. Guernsey Dam and Powerplant were approved by the President on April 30, 1925.


Construction started in 1905 on Pathfinder Dam and the Interstate Canal. By 1915, work on the Interstate Canal and Reservoirs was completed and work had started on Fort Laramie Canal. Lingle Powerplant and the Northport Canal system were started in 1918. All canal construction was completed by 1925. Guernsey Dam was started on June 1, 1925, and completed in July 1927.

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About 335,000 acres of sagebrush and rangeland have been transformed into productive farmland. Agriculture is the basic income-producing activity. From the first irrigation, the project has produced alfalfa, corn, potatoes, and sugar beets steadily and abundantly. Dry beans also have become an important crop.


Guernsey Reservoir has developed foot trails and campgrounds. Many of the facilities are outstanding examples of work performed by the Civilian Conservation Corps (CCC) in the 1930`s. A fine museum, also built by the CCC, houses exhibits pertaining to the area. The dam, powerplant, and all CCC structures are included in the National Register of Historic Places. Other activities enjoyed by visitors to the area are picnicking and boating.

Pathfinder Reservoir is used for boating and fishing, primarily for cutthroat, rainbow, and brown trout. Pathfinder Dam, one of the first dams built under the 1902 Reclamation Act, is also listed in the National Register of Historic Places because of its pioneering role in reclaiming arid lands and the innovative engineering required in its construction. The dam is also listed as a Wyoming Historic Civil Engineering Landmark. An information center with exhibits about the dam and surrounding area is maintained near the dam.

Picnic grounds, a swimming beach, and boat docks are available at Lake Minatare; fishing is good for walleye, trout, and perch.

For specific information about any of these recreation sites, click on the name below.

Guernsey Reservoir
Lake Alice
Lake Minatare State Recreation Area
Pathfinder Reservoir
Pathfinder National Wildlife Refuge
Winters Creek Lake

Hydroelectric Power

Electricity is supplied to many towns, rural cooperatives, and industries in the project area.

Flood Control

Project reservoirs have been effective in reducing damage to property and loss of life from floods. A direct result of flood control is the increased utilization of river valley lands made safe and productive by the regulation of riverflows. Pathfinder Reservoir has a surcharge capacity of 188,493 acre-feet and has prevented $8.7 million in flood damages since its construction. Guernsey Reservoir has no allocated flood control or surcharge capacity; however, it has prevented $439.0 thousand in flood damages since its construction.

The North Platte Project has provided an accumulated $9,171,000 in flood control benefits from 1950 to 1999.

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Last updated: Apr 05, 2013