Boysen Dam
Encyclopedia
The Boysen Dam is a rockfill dam on the Wind River
in the U.S. state
of Wyoming
. The dam lies at the head of Wind River Canyon
through the Owl Creek Mountains
in western Wyoming and creates Boysen Reservoir
. It is owned by the U.S. Bureau of Reclamation and furnishes irrigation water supply to the Bighorn Basin
as well as providing flood control and hydroelectric power.
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 7131 feet (2,173.5 m) 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
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 in to 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.
is only about 117 ft (35.7 m) because of the great depth to bedrock from the riverbed, thus necessiating a large amount of excavation for the dam foundations. The reservoir has a storage capacity of 952400 acre.ft, of which 520679 acre.ft is reserved for annual flood storage and 144229 acre.ft for agricultural and municipal uses. The dam provides electricity for regions of Wyoming ranging from Alcova
to Thermopolis
.
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
is a concrete lined, over the crest structure controlled by two radial gates with a capacity of 25000 cuft/s.
Wind River (Wyoming)
The Wind River is the name applied to the upper reaches of the Bighorn River in Wyoming in the United States. The Wind River is long. The two rivers are sometimes referred to as the Wind/Bighorn.-Course:...
in the U.S. state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...
of Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
. The dam lies at the head of Wind River Canyon
Wind River Canyon
Wind River Canyon is a scenic Wyoming canyon carved out by the Wind River. It is located between the cities of Shoshoni and Thermopolis and is a popular stop for visitors to Yellowstone National Park. It is accessible by U.S. Highway 20 and Wyoming Highway 789. It was designated as a Wyoming Scenic...
through the Owl Creek Mountains
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 boundary between the Bighorn Basin to the north and the...
in western Wyoming and creates Boysen Reservoir
Boysen Reservoir
Boysen Reservoir is a reservoir formed by Boysen Dam, an earth-fill dam on the Wind River in the central part of the U.S. state of Wyoming. It is near the town of Shoshoni in Fremont County...
. It is owned by the U.S. Bureau of Reclamation and furnishes irrigation water supply to the Bighorn Basin
Bighorn Basin
The Bighorn Basin is a plateau region and intermontane basin, approximately 100 miles wide, in north-central Wyoming in the United States. It is bounded by the Absaroka Range on the west, the Bighorn Mountains on the east, and the Owl Creek Mountains and Bridger Mountains on the south...
as well as providing flood control and hydroelectric power.
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 kilowatts 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 Boysen Dam would be built right over the site of the old dam, but the location was changed to about one and a half miles (2.4 km) 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 and North Western RailwayChicago and North Western Railway
The Chicago and North Western Transportation Company was a Class I railroad in the Midwest United States. It was also known as the North Western. The railroad operated more than of track as of the turn of the 20th century, and over of track in seven states before retrenchment in the late 1970s...
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 7131 feet (2,173.5 m) 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
Cofferdam
A cofferdam is a temporary enclosure built within, or in pairs across, a body of water and constructed to allow the enclosed area to be pumped out, creating a dry work environment for the major work to proceed...
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 in to 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 220 feet (67.1 m) high from the foundations and 1143 ft (348.4 m) long. The hydraulic headHydraulic head
Hydraulic head or piezometric head is a specific measurement of water pressure above a geodetic datum. It is usually measured as a water surface elevation, expressed in units of length, at the entrance of a piezometer...
is only about 117 ft (35.7 m) because of the great depth to bedrock from the riverbed, thus necessiating a large amount of excavation for the dam foundations. The reservoir has a storage capacity of 952400 acre.ft, of which 520679 acre.ft is reserved for annual flood storage and 144229 acre.ft for agricultural and municipal uses. The dam provides electricity for regions of Wyoming ranging from Alcova
Alcova, Wyoming
Alcova is a census-designated place in Natrona County, Wyoming, United States. It is part of the Casper, Wyoming Metropolitan Statistical Area. The population was 20 at the 2000 census. The center of population of Wyoming is located in Alcova...
to Thermopolis
Thermopolis, Wyoming
Thermopolis is the largest town in, and the county seat of Hot Springs County, Wyoming, United States. As of the 2000 census, the town population was 3,172....
.
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
Spillway
A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically being the river that was dammed. In the UK they may be known as overflow channels. Spillways release floods so that the water does not overtop and damage or even destroy...
is a concrete lined, over the crest structure controlled by two radial gates with a capacity of 25000 cuft/s.