Wyoming State Water Plan, Wyoming Water Development Office
Rafting on Snake River Lake Marie, Snowy Mountains Wyoming Wind River Range picture

U.S. Bureau of Reclamation Projects
Within Wyoming's Portion of the Colorado River Basin

Seedskadee Project

Fontenelle Dam and Reservoir

General Description

The Seedskadee Project, a participating project of the Colorado River Storage Project, is in the Upper Green River Basin in southwestern Wyoming. It provides storage and regulation of the flows of the Green River for power generation, municipal and industrial use, fish and wildlife, and recreation. The basin contains vast mineral resources of coal, trona, oil and gas, and shale that provide the basis for extensive existing and potential industrial development. Towns in the area are Rock Springs, Green River, and Kemmerer.


Unit Descriptions and Facilities
Principal features of the project are the Fontenelle Dam, Powerplant, and Reservoir. The reservoir is operated for municipal and industrial water use, power production, flood control, and downstream fishery and wildlife refuge.

Fontenelle Dam, Reservoir, and Reservoir
The Fontenelle Dam is located on the Green River 24 miles southeast of La Barge, Wyoming. A zoned earthfill structure, the dam is 139 feet high with a crest length of 5,421 feet, and a volume of 5,265,000 cubic yards of material. The spillway consists of an uncontrolled crest, open chute, and stilling basin with a design capacity of 20,200 cubic feet per second. Fontenelle Powerplant is located adjacent to the toe of the dam, with the power penstock branching from the river outlet works. The powerplant consists of one 10,000-kilowatt generator and one 16,000-horsepower hydraulic turbine.

The reservoir has an active capacity of 150,500 acre-feet and a total capacity of 345,360 acre-feet, with a surface area of 8,058 acres. The lake is 20 miles in length when full, and has a shoreline of approximately 56 miles.

Operating agencies
The Bureau of Reclamation operates the Fontenelle Reservoir and Powerplant, and is responsible for recreation facilities. The Fish and Wildlife Service manages the Seedskadee National Wildlife Refuge. The Wyoming Game and Fish Commission manages the reservoir fishery and the fishery in the Green River below the reservoir. The development farm has been transferred to the Wyoming Game and Fish Commission for wildlife management purposes.


The Crow Indians called it the "Seeds-ke-dee-agie," meaning "Sage Hen River," but it was the "Rio Verde" to the Spaniards. To the mountain men it was simply the Green River. In 1812, South Pass was discovered by fur trappers. From 1825 until 1840, the Upper Green River Basin was the crossroads for the mountain men. After the trappers came, the covered wagons moved west along the Oregon Trail. Settlers began homesteading lands near the river in the 1880's.

The Seedskadee Project was originally investigated by the Bureau of Reclamation as a unit of a plan for development in the Upper Green River Basin. This plan was presented in a 1946 report on the Colorado River Basin. The Bureau of Reclamation carried out investigations of the Seedskadee development as an independent project, and in November 1950 prepared a feasibility report on the Seedskadee Project, issued as a supplement to the December 1950 report on the Colorado River Storage Project and participating projects. These two reports were amended in October 1953 by a further supplement that brought construction cost and project benefit estimates up to date. This latter supplement was submitted to the Congress and was the basis for project authorization.

The definite plan report was prepared in April 1959, and in February 1961 was modified to provide for future municipal and industrial water needs. Under the provisions of Title III of the Water Supply Act of 1958 (72 Stat. 319), the Wyoming legislature authorized the Wyoming Natural Resource Board to negotiate a contract for additional capacity in the Fontenelle Reservoir for municipal and industrial water, thus increasing the total capacity of the reservoir to 345,360 acre-feet, with 150,500 acre-feet of active capacity. Following reevaluation studies, the House Committee on Interior and Insular Affairs approved construction of the powerplant and associated works.

On May 21, 1962, the Commissioner of Reclamation issued a stop-order suspending construction of irrigation features of the project until a review of Wyoming projects could be accomplished. In a program to find solutions to serious financial and economic problems encountered on high-altitude irrigation projects, and to provide guidelines for land development and water management, experimental crops were grown on 512 acres of land, using border dike, contour flooding, and circular sprinkling methods. As a result of these experimental farm studies, Fontenelle Dam, originally conceived as an irrigation storage dam, evolved toward storage of water for cities, industry, and fish and wildlife. Irrigation development has been indefinitely deferred.

Seedskadee Project is one of the initial group of participating projects authorized with the Colorado River Storage Project by the act of April 11, 1956 (70 Stat. 105).

Construction of Fontenelle Dam commenced in June 1961 and was completed in April 1964. In September 1965, after the reservoir had filled to capacity, water passing through relief cracks in the right abutment carried away part of the downstream embankment. The reservoir was evacuated and a repair program undertaken and completed in 1967. The reservoir was refilled in the winter and spring of 1968. Construction of Fontenelle Powerplant and appurtenant facilities was started in February 1963, and completed in January 1966. Power generation commenced in May 1968.


Domestic, Municipal, and Industrial
Initial deliveries of municipal and industrial water to the State of Wyoming under the contract of June 14, 1962, began in 1974. Further negotiations with the State were completed on December 27, 1974 for additional municipal and industrial deliveries.

Recreation and Fish and Wildlife
The Seedskadee National Wildlife Refuge was established by the Fish and Wildlife Service in 1965. The refuge lies along 35 miles of the Green River, approximately 6 miles below Fontenelle Dam and 20 miles northwest of the town of Green River. The refuge will provide habitat for waterfowl, and ultimately 18 wildlife management units will be developed. About 13,250 acres of Federal and private land have been acquired with plans to bring the refuge to a total of about 22,000 acres. A substantial fishery has developed in the reservoir and in the stream between the reservoir and the Flaming Gorge Reservoir. Both the stream and reservoir are stocked with rainbow and brown trout. In the stream below the reservoir, a whitefish population is sustained as a result of natural spawning.

Recreation facilities constructed on the west shore of the reservoir near Fontenelle Creek include sites for camping and picnicking, a boat ramp, parking, sanitary facilities, and drinking water. The reservoir has a surface area of 8,000 acres. The lake is 20 miles long when full and has a shoreline of about 56 miles.

Hydroelectric Power
Commercial power generation commenced in May 1968. The powerplant and switch yard at Fontenelle Dam with transmission lines interconnected with the Colorado River Storage Project transmission system at the Flaming Gorge Powerplant. Fontenelle Powerplant is located adjacent to the toe of the dam, with a 10- foot power penstock branching from one of three river outlet works discharge conduits. The turbine has a water discharge capacity of 1,585 cubic feet per second. Fontenelle Powerplant provides maximum generation of power from regulated base load river flows depending upon water availability. Flows/generation vary from 350 cubic feet per second/1 megawatt at low seasonal head to 1,550 cubic feet per second/11 megawatt at peak runoff periods

Region (Map) Upper Colorado
State Wyoming
County Lincoln
Project Seedskadee
Dam type Earthfill
Location 24 mi SE La Barge, WY
Watercourse Green River
Reservoir Fontenelle
Construction Date 1960-1963
Normal Water Surface Elev 6506 ft
Hydraulic Height 114 ft
Service Spillway Type:
Uncontrolled Crest Yes
Morning-Glory No
Crest Length 300 ft
Gated No
Capacity at Elev 6513.1 ft, 20,000 cfs
Auxiliary Spillway No
Capacity at Elev. 0 cfs
Outlet Works Capacity at:
Elevation 6513.1.0 ft., 16,800 cfs
Crest Elevation of Dam 6,519 ft
Structural Height of Dam 139 ft
Crest Length 5,421 ft
Top of Joint Use 6,506 ft
Top of Active Conservation 6,506 ft
Top of Inactive Conservation 6,484.9 ft
Top of Dead Storage 6408 ft
Drainage Area 4,175 sq mi
Hydrometeorological Report HMR
Flood Type General
Probable Maximum Flood (PMF) Report:
Peak Inflow 6,200 cfs
Inflow Volume 841,000 acre-ft
Flow Duration 20 days
PMF Routing MWS Elev x.0 ft
Initial Routing Elev x.0 ft
Study Date: 3/30/1981