Last weekend, I went to Teton Idaho for the funeral of my uncle. It was good to see family that I haven’t seen for a very long time.
While there, I took a side trip to the site of the Teton Dam Disaster.
I remember vaguely from my youth watching this event unfold on TV and seeing the devastation it caused. Well, I did a little research into this incident and found some very interesting information.
It turns out that the Bureau of Reclamation was in charge of building the dam. Construction began in 1975 to build an earthen dam, and it was completed in November 1976. During construction, many caves and holes were discovered in the strata surrounding the dam site, which was primarily basalt and rhyolite. The solution was to fill these holes with grout and move on with the project.
After the dam was completed, at a cost of roughly $34 million dollars, filling began at the standard rate of a foot a day. Soon after, the winter run-offs began so the filling increased to four feet per day. It took until June 4th, 1976, to fill the dam.
The morning of June 5, 1976 at approximately 7:00am, a new spring was discovered not far downstream from the dam. Not long after, water was seen coming out of the left side of the dam. A construction worker in a DC-5 excavator was pushing dirt over the hole, but soon it was too much for it to handle. By 11:00am, the order was given to evacuate all residents downstream in the nearby towns of Sugar City, Teton, Rexburg, and many others.
Approximately 2,000,000,000 cubic feet of water was flowing out of the dam that was 240 feet deep and several miles long. This destroyed the ecosystems in the Teton River valley, thousands of homes and farms, and killed 14 people and many more injured.
The remains of the dam. The point in the middle is the only part of the dam intact. The breach is on the left where all the water came out. On the right was additional flooding.
This is the Teton River Valley. In the distance is the flood plain where all the damage to the towns occurred. The flood was stopped at the American Falls Reservoir, which barely survived breaching itself.
This is the spillway that was never used. It turns out the dam burst the first day the dam was filled.