The Boysen Dam is a rockfill dam on the Wind River 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 ...

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

. The dam lies at the head of

Wind River Canyon Wind River Canyon is a scenic Wyoming canyon on the Wind River (Wyoming), Wind River. It is located between the towns of Shoshoni, Wyoming, Shoshoni and Thermopolis, Wyoming, Thermopolis and is a popular stop for visitors to Yellowstone National P ...

through the

Owl Creek Mountains The Owl Creek Mountains are a subrange of the Rocky Mountains in central Wyoming in the United States, running east to west to form a bridge between the Absaroka Range to the northwest and the Bridger Mountains to the east. The range forms the bo ...

in western Wyoming and creates

Boysen Reservoir Boysen Reservoir is a reservoir formed by Boysen Dam, an earth-fill dam on the Wind River (Wyoming), Wind River in the central part of the U.S. state of Wyoming. It is near the town of Shoshoni, Wyoming, Shoshoni in Fremont County, Wyoming, Fre ...

. It is owned by the U.S. Bureau of Reclamation and furnishes irrigation water supply to the

Bighorn Basin The Bighorn Basin is a plateau region and intermontane basin, approximately 100 miles (160 km) wide, in north-central Wyoming in the United States. It is bounded by the Absaroka Range on the west, the Pryor Mountains on the north, the Bigho ...

as well as providing flood control and

hydroelectric power Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

History

The first dam to be built at the Wind River Canyon site was actually in 1908, when Asmus Boysen supervised the construction of a small concrete run-of-the-river structure that generated 710

kilowatt 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 of electricity. This early dam, located just downriver of the present Boysen Dam, silted up by 1925 and was removed in 1948. As early as 1904, the Bureau of Reclamation also made investigative forays into the area for the construction of a dam, although a final report was not completed until 1942. Initially, by a suggestion of the

U.S. Army Corps of Engineers The United States Army Corps of Engineers (USACE) is the military engineering branch of the United States Army. A direct reporting unit (DRU), it has three primary mission areas: Engineer Regiment, military construction, and civil wor ...

, the Boysen Dam would be built right over the site of the old dam, but the location was changed to about upstream in order to reduce cost.

Construction

Preliminary work for construction of Boysen Dam was begun on September 9, 1946 and included the installation of government buildings, an employee camp, warehouses, electrical transmission lines and the relocation of U.S. Highway 20 and the Chicago, Burlington and Quincy Railway to bypass the construction site. The contract for the dam itself and the rerouting of the rail line was awarded to the Morrison-Knudsen Company for $13.9 million. Most of the preparatory work including foundation excavations and the various camp facilities were completed by the end of autumn 1947, and official groundbreaking was on September 19 of that year. In February 1948, excavation of the river diversion tunnel began and work continued on the relocation of the railway, which would run ''under'' the dam and portions of the future reservoir through a tunnel long. By March 1949, the diversion tunnel was successfully complete and the rail realignment mostly finished despite several minor setbacks including a rockslide and a fire that destroyed the concrete mixing plant. On December 23, 1949 a

cofferdam A cofferdam is an enclosure built within a body of water to allow the enclosed area to be pumped out or drained. This pumping creates a dry working environment so that the work can be carried out safely. Cofferdams are commonly used for constru ...

across the Wind was finished and the river began flowing through the diversion tunnel, allowing work to proceed on the main section of the dam. As the embankment rose, the train tunnel was completed and opened on September 5, 1950 and work begun on the dam's power plant. Contracts for clearing the reservoir area were awarded beginning in September and came out to about $637,000. Construction on the powerhouse continued through 1951 and equipment began coming into the dam site beginning in July of that year. The total cost of the generators and other apparatus came to $604,501. The embankment of the dam was completed a month later, and on October 11, 1951, the diversion tunnel was sealed and Boysen Reservoir began to rise. The powerhouse was finished in December 1951 and the entire dam was completed on February 16, 1952 at a cost of $18,576,405. The dam was declared operational on December 11, 1952.

Structure and operations

Boysen Dam is an earth and rock fill structure high from the foundations and long. The

hydraulic head Hydraulic head or piezometric head is a measurement related to liquid pressure (normalized by specific weight) and the liquid elevation above a vertical datum., 410 pages. See pp. 43–44., 650 pages. See p. 22, eq.3.2a. It is usually meas ...

is only about because of the great depth to bedrock from the riverbed, thus necessitating a large amount of excavation for the dam foundations. The reservoir has a storage capacity of , of which is reserved for annual flood storage and for agricultural and municipal uses. The dam provides electricity for regions of Wyoming ranging from Alcova to

Thermopolis Thermopolis is the county seat and most populous town in Hot Springs County, Wyoming, United States. As of the 2020 U.S. Census, the town population was 2,725. Thermopolis, Greek for "hot city", is home to numerous natural hot springs, in which ...

. The dam also serves an important purpose of flood control, and has prevented about $75 million of damages from its completion to 1998. Its

spillway A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure tha ...

is a concrete lined, over the crest structure controlled by two

radial gate The Tainter gate is a type of radial arm floodgate used in dams and canal locks to control water flow. It is named for its inventor, the Wisconsin structural engineer Jeremiah Burnham Tainter. Tainter, an employee of the lumber firm Knapp, ...

s with a capacity of .

Energy Generation Data

File:A-energy-01.svg, Boysen Dam Average Monthly Energy Generation (mwh) 1988-2020 File:Y-energy-01.svg, Boysen Dam Total Yearly Energy Generation (mwh) 1988-2020

References

External links