Jackson Lake Dam

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Jackson Lake Dam. View is to the west.
Jackson Lake Dam. View is to the west.
Jackson Lake Dam. View is to the northwest.
Jackson Lake Dam. View is to the northwest.

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. Jackson Lake is a natural lake but its depth was increased by the dam to provide water storage.

Contents

[edit] History

The first Jackson Lake Dam was a log-crib dam constructed in 1906 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. The new dam was designed by Frank A. Banks.[1]

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 magnitude 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.

[edit] 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: 1,824 square miles (4,724 km²)
  • Lake elevation:
    • Normal full pool: 6,760 feet (2,060.4 m)
    • Maximum pool: 6,769 feet (2,063.2 m)
    • Minimum pool: 6,730 feet (2,051.3 m)
    • Maximum water surface: 6,770.3 feet (2,063.6 m)
  • Usable storage (6730–6760 ft): 847,000 acre feet (1 billion m³)
  • Crest elevation: 6,777 feet (2,065.6 m)
  • Crest length: 4,920 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 head: 42 feet (12.8 m)

[edit] References

  1. ^ The United Press. Builder of Grand Coulee To Retire and Live Near It. The New York Times, September 12, 1950.

[edit] External links

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Snake River Dams

Coordinates: 43°51′27.53″N 110°35′22.34″W / 43.8576472, -110.5895389