Teton Dam

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The Teton Dam was a dam on the Teton River near Sugar City and Rexburg , Idaho , USA, which failed spectacularly on June 5, 1976. The dam breach caused eleven deaths and financial damage of up to one billion US dollars.

The rupture of the Teton Dam
Remains of the Teton Dam

Coordinates: 43 ° 54 ′ 33 ″  N , 111 ° 32 ′ 20 ″  W.

Map: USA
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Teton Dam​
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United States

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The dam in Teton Canyon about 44 miles (71 km) northeast of the city of Idaho Falls was completed in November 1975 by the Bureau of Reclamation ("Land Reclamation Office "), at the same time began the progressive filling of the reservoir for months. It was a 93 m high earth embankment, the purpose of which was irrigation, electricity generation, flood protection and recreational recreation.

The dam was built in the eastern Snake River Plain on volcanic soil that is approximately 1.9 million years old. The subsoil is very permeable, but cracks but no seepage were noticed on the dam before the break.

Data

  • Construction type: Zonendamm
  • Construction period: 1972–1975
  • Dam height: 305 feet (93 m)
  • Capacity: 288,250 acre-feet (355,550,000 m³)
  • Crown length: 2700 feet (823 m)

Dam break

At the time of the break, the new reservoir was filled for the first time by the meltwater in the spring to almost the planned water level after a slow rise in the fill level over the winter. Two days before the break, water began to seep from the dam, which is usually not uncommon for an earth dam when it happens in designated places. The source outlets could be seen approx. 225 m below the dam.

On the morning of June 5th, around 9:30 a.m., there was a new leak in the right abutment 40 meters below the dam crest. Bulldozers tried unsuccessfully to plug the leak. The local radio and television reporters appeared, and the alarm went off for those below . Two bulldozers were trapped in the eroding embankment and their drivers were pulled to safety with leashes. At 11:57 a.m. the dam broke. By evening, about five hours later, the pool was completely emptied and a third of the dam was washed away.

The valley was flooded over a length of 120 kilometers up to the confluence of the Teton and the Snake River . The towns directly below, like Rexburg, were hit heavily. The city of Idaho Falls below had time to prepare. At the old and unstable American Falls dam , engineers (allegedly) drained the water before the tide came. This dam held out until the tide was over. The cleanup lasted all summer.

Consequences

The breach of the dam sparked wide-ranging controversy over the safety of American dams. A program to review all dams was then carried out. According to information from the Bureau of Reclamation (USBR), all USBR dams are now examined under the strict criteria of a safety program. Each facility is periodically monitored to assess load capacity, seismic stability, internal faults and physical degradation.

The dam was not rebuilt. The site is open to the public and can be visited.

See also

Web links and sources

Commons : Teton Dam  - collection of images, videos and audio files