The Teton Dam, 44 miles
northeast of Idaho Falls in southeastern Idaho, failed abruptly on
June 5, 1976. It released nearly 300,000 acre feet of water, then
flooded farmland and towns downstream with the eventual loss of 14
lives, directly or indirectly, and with a cost estimated to be
nearly $1 billion.
My parents lived in Idaho
Falls at the time and my Father, a firefighter/EMT with the Idaho
Falls Fire Department took all the pictures you will see on these
web pages. The picture in the title graphic is a view of the
dam and river after it failed. Below is a picture of what it
looked like before the dam failed.
As you can see the
devastation was enormous! The towns below the dam hardest hit
were St. Anthony, Rexburg and Roberts although the devastation was
also seen in Idaho Falls and Blackfoot.
Here is a little history of
what occurred on June 5, 1976:
Teton Dam, a 305-foot high
earth fill dam across the Teton River in Madison County, southeast
Idaho, failed completely and released the contents of its reservoir
at 11:57 AM on June 5, 1976. Failure was initiated by a large leak
near the right (northwest) abutment of the dam, about 130 feet below
the crest. The dam, designed by the U.S. Bureau of Reclamation,
failed just as it was being completed and filled for the first time.
Eyewitnesses noticed the first major leak between 7:30 and 8:00 AM,
June 5, although two days earlier engineers at the dam observed
small springs in the right abutment downstream from the toe of the
dam. The main leak was flowing about 20-30 cubic feet per second (cfs)
from rock in the right abutment near the toe of the dam and above
the abutment-embankment contact. The flow increased to 40-50 cfs by
9:00 AM. At about the same time, 2 cfs seepage issued from the rock
in the right abutment, approximately 130 feet below the crest of the
dam at the abutment-embankment contact.
Between 9:30 and 10:00 AM, a wet spot developed on the downstream
face of the dam, 15 to 20 feet out from the right abutment at about
the same elevation as the seepage coming from the right abutment
rock. This wet spot developed rapidly into seepage, and material
soon began to slough, and erosion proceeded back into the dam
embankment. The water quantity increased continually as the hole
grew. Efforts to fill the increasing hole in the embankment were
futile during the following 2 to 2 1/2 hour period until failure.
The sheriff of Fremont County (St. Anthony, Idaho) said that his
office was officially warned of the pending collapse of the dam at
10:43 AM on June 5. The sheriff of Madison County, Rexburg, Idaho,
was not notified until 10:50 AM on June 5. He said that he did not
immediately accept the warning as valid but concluded that while the
matter was not too serious, he should begin telephoning people he
knew who lived in the potential flood path.
The dam breached at 11:57 AM when the crest of the embankment fell
into the enlarging hole and a wall of water surged through the
opening. By 8:00 PM the flow of water through the breach had nearly
stabilized. Downstream the channel was filled at least to a depth of
30 feet for a long distance. About 40 percent of the dam embankment
was lost, and the powerhouse and warehouse structure were submerged
completely in debris.
At the time of failure, the reservoir was almost full and contained
251,000 acre-feet of water. After the breach the main part of the
reservoir emptied in about 5 hours.
The Teton Dam has never
been rebuilt and the remnants of engineering gone devastatingly bad
can still be seen in Madison County.
Click below to see the
photos my Father took showing the before, during and after effects
of this disaster.