Jackson Lake Dam
Encyclopedia
Jackson Lake Dam is a concrete
and earth-fill dam
at the outlet of Jackson Lake
in northwestern Wyoming
, USA. The lake and dam are situated within Grand Teton National Park
in Teton County
. The Snake River
emerges from the dam and flows about 800 miles (1,287 km) through Wyoming, Idaho
, Oregon
, and Washington to its mouth on the Columbia River in eastern Washington. The chief purpose of the dam is to provide water storage for irrigation in the Snake River basin in the state of Idaho as part of the Minidoka Project
. Jackson Lake is a natural lake but its depth was increased by the dam to provide water storage.
.
The reservoir was created by damming the outlet of the natural glacial Jackson Lake
, with the additional height creating a storage pool for the Minidoka Project
, which provides irrigation water from the Snake River for farmlands in Idaho. Jackson Lake stores and releases water which is collected by Minidoka Dam
and American Falls Dam
more than 100 miles (160.9 km) downstream for diversion to distribution canals. At the time of the dam's construction, Jackson Hole
and the Teton Range
were as yet unprotected from development. Grand Teton National Park was established in 1929, and excluded Jackson Lake. The lake was incorporated into Jackson Hole National Monument
when it was proclaimed by President Franklin D. Roosevelt
under the Antiquities Act
, and became a part of Grand Teton National Park win 1950 when the park was expanded to encompass the national monument lands. When the dam was built there was no attempt to clear the shores of the lake of standing timber, resulting in an unsightly band of dead trees when the waters rose. This vista, and the mudflats created by drawdown of lake waters, were cited in later years in successful arguments against reservoirs in Yellowstone National Park
.
Construction personnel for the dam were housed at a temporary camp that dwarfed the nearby town of Moran, Wyoming
. Supplies came in from the Grassy Lake Road
north of the park, which runs west into Idaho to meet the nearest railhead at Ashton, Idaho
.
5.5 or greater. The dam was upgraded during 1986–1989, and the Bureau of Reclamation now believes it can withstand the “maximum credible earthquake,” a magnitude 7.5 quake on the Teton fault.
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
and earth-fill dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
at the outlet of Jackson Lake
Jackson Lake
Jackson Lake is a lake located in north western Wyoming in Grand Teton National Park. The lake is natural, except for the top 33 feet , which is due to the construction of Jackson Lake Dam, built in 1911. This top level of the lake is utilized by farmers in Idaho for irrigation purposes...
in northwestern 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...
, USA. The lake and dam are situated within Grand Teton National Park
Grand Teton National Park
Grand Teton National Park is a United States National Park located in northwestern Wyoming, U.S. The Park consists of approximately and includes the major peaks of the long Teton Range as well as most of the northern sections of the valley known as Jackson Hole. Only south of Yellowstone...
in Teton County
Teton County, Wyoming
Teton County is a county located in the U.S. state of Wyoming. As of 2010, the population was 21,294. Its county seat is Jackson. Teton County contains the affluent Jackson Hole skiing area...
. The Snake River
Snake River
The Snake is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean...
emerges from the dam and flows about 800 miles (1,287 km) through Wyoming, Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
, Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
, and Washington to its mouth on the Columbia River in eastern Washington. The chief purpose of the dam is to provide water storage for irrigation in the Snake River basin in the state of Idaho as part of the Minidoka Project
Minidoka Project
The Minidoka Project is a series of public works by the U.S. Bureau of Reclamation to control the flow of the Snake River in Wyoming and Idaho, supplying irrigation water to farmlands in Idaho...
. Jackson Lake is a natural lake but its depth was increased by the dam to provide water storage.
History
The first Jackson Lake Dam was a log-crib dam constructed in 1906-7 across the outlet of Jackson Lake, a natural lake. That dam raised the lake level by 22 feet (6.7 m), but the dam failed in 1910. An new concrete and earthen dam was constructed in stages between 1911 and 1916, raising the maximum lake level to 30 feet (9.1 m) above the lake's natural elevation, providing a storage capacity of 847000 acre.ft. The new dam was designed by Frank A. Banks, who would later supervise the construction of Grand Coulee DamGrand Coulee Dam
Grand Coulee Dam is a gravity dam on the Columbia River in the U.S. state of Washington built to produce hydroelectric power and provide irrigation. It was constructed between 1933 and 1942, originally with two power plants. A third power station was completed in 1974 to increase its energy...
.
The reservoir was created by damming the outlet of the natural glacial Jackson Lake
Jackson Lake
Jackson Lake is a lake located in north western Wyoming in Grand Teton National Park. The lake is natural, except for the top 33 feet , which is due to the construction of Jackson Lake Dam, built in 1911. This top level of the lake is utilized by farmers in Idaho for irrigation purposes...
, with the additional height creating a storage pool for the Minidoka Project
Minidoka Project
The Minidoka Project is a series of public works by the U.S. Bureau of Reclamation to control the flow of the Snake River in Wyoming and Idaho, supplying irrigation water to farmlands in Idaho...
, which provides irrigation water from the Snake River for farmlands in Idaho. Jackson Lake stores and releases water which is collected by Minidoka Dam
Minidoka Dam
The Minidoka Dam is an earthfill dam on the Snake River in south central Idaho. The dam, originally completed in 1906, is east of Rupert on county highway 400; it is 86 feet high and nearly a mile in length, with a wide overflow spillway section. The dam and power plant were listed on the...
and American Falls Dam
American Falls Dam
The American Falls Dam is a concrete gravity-type dam located near the town of American Falls, Idaho, on river mile 714.7 of the Snake River. The dam and reservoir are a part of the Minidoka Project on the Snake River Plain and are used primarily for flood control, irrigation, and recreation...
more than 100 miles (160.9 km) downstream for diversion to distribution canals. At the time of the dam's construction, Jackson Hole
Jackson Hole
Jackson Hole, originally called Jackson's Hole, is a valley located in the U.S. state of Wyoming, near the western border with Idaho. The name "hole" derives from language used by early trappers or mountain men, who primarily entered the valley from the north and east and had to descend along...
and the Teton Range
Teton Range
The Teton Range is a mountain range of the Rocky Mountains in North America. A north-south range, it is on the Wyoming side of the state's border with Idaho, just south of Yellowstone National Park. Most of the range is in Grand Teton National Park....
were as yet unprotected from development. Grand Teton National Park was established in 1929, and excluded Jackson Lake. The lake was incorporated into Jackson Hole National Monument
Jackson Hole National Monument
Jackson Hole National Monument was a wildlife reserve in Jackson Hole, the majority of which is now a part of Grand Teton National Park in Wyoming, United States. It was created by executive order by Franklin Delano Roosevelt in 1943, and met with considerable opposition from Wyoming legislators....
when it was proclaimed by President Franklin D. Roosevelt
Franklin D. Roosevelt
Franklin Delano Roosevelt , also known by his initials, FDR, was the 32nd President of the United States and a central figure in world events during the mid-20th century, leading the United States during a time of worldwide economic crisis and world war...
under the Antiquities Act
Antiquities Act
The Antiquities Act of 1906, officially An Act for the Preservation of American Antiquities , is an act passed by the United States Congress and signed into law by Theodore Roosevelt on June 8, 1906, giving the President of the United States authority to, by executive order, restrict the use of...
, and became a part of Grand Teton National Park win 1950 when the park was expanded to encompass the national monument lands. When the dam was built there was no attempt to clear the shores of the lake of standing timber, resulting in an unsightly band of dead trees when the waters rose. This vista, and the mudflats created by drawdown of lake waters, were cited in later years in successful arguments against reservoirs in Yellowstone National Park
Yellowstone National Park
Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...
.
Construction personnel for the dam were housed at a temporary camp that dwarfed the nearby town of Moran, Wyoming
Moran, Wyoming
Moran is an unincorporated community in south central Teton County, Wyoming, United States, which serves as one of the principal fee collection entrances to Grand Teton National Park. It lies in Grand Teton National Park northeast of the city of Jackson, the county seat of Teton County, at the...
. Supplies came in from the Grassy Lake Road
Grassy Lake Dam
Grassy Lake Dam is a small dam operated by the U.S. Bureau of Reclamation in Teton County, Wyoming, immediately to the south of Yellowstone National Park. The dam lies in a corridor of Bridger-Teton National Forest that runs between Yellowstone and Grand Teton National Parks. The dam structure and...
north of the park, which runs west into Idaho to meet the nearest railhead at Ashton, Idaho
Ashton, Idaho
Ashton is a city in Fremont County, Idaho, United States. It is part of the Rexburg, Idaho Micropolitan Statistical Area. The population was 1,129 at the 2000 census. The district is noted for seed potato production and bills itself as the world's largest seed potato growing area.-Geography and...
.
Reinforcement
The U.S. Bureau of Reclamation conducted studies on dams in 1976 and determined that Jackson Lake Dam was susceptible to failure in case of an earthquake of magnitudeRichter magnitude scale
The expression Richter magnitude scale refers to a number of ways to assign a single number to quantify the energy contained in an earthquake....
5.5 or greater. The dam was upgraded during 1986–1989, and the Bureau of Reclamation now believes it can withstand the “maximum credible earthquake,” a magnitude 7.5 quake on the Teton fault.
Dam facts and figures
The dam is owned and operated by the U.S. Bureau of Reclamation, which maintains the water level above the lake’s natural elevation for downstream irrigation.- Type: Concrete gravity dam with earthen embankment wings
- Drainage area: 1824 square miles (4,724 km²)
- Lake elevation:
- Normal full pool: 6760 feet (2,060.4 m)
- Maximum pool: 6769 feet (2,063.2 m)
- Minimum pool: 6730 feet (2,051.3 m)
- Maximum water surface: 6770.3 feet (2,063.6 m)
- Usable storage (6730–6760 ft): 847000 acre.ft
- Crest elevation: 6777 feet (2,065.6 m)
- Crest length: 4920 feet (1,499.6 m)
- Crest width: 24 feet (7.3 m)
- Base width: 72 feet (21.9 m)
- Structural height: 65 feet (19.8 m)
- Hydrostatic headHydrostatic headWhen generating hydropower, the head is a general term used to describe the distance that a given water source has to fall before the point where power is generated. Ultimately the force responsible for hydropower is gravity, so a hydroelectricity plant with a tall/high head can produce more...
: 42 feet (12.8 m)
External links
- U.S. Bureau of Reclamation: Jackson Lake Dam
- U.S. Bureau of Reclamation: Minidoka Project
- University of Wyoming: The Operation and Management of Jackson Lake Dam
- U.S. Army Corps of Engineers: Jackson Lake Dam and Lake Hydrologic Data
- U.S. National Park Service: The Snake River: Responses to Jackson Lake Dam (PDF)