Almost 32 years ago, the Teton Dam in southeastern Idaho failed against the force of a 17-mile long, 270-foot deep reservoir. Eight months of stored stream flow and snowmelt crashed down the valley in less than six hours, swallowing the communities of Rexburg, Teton, Newdale and Sugar City. Eleven people died and the wall of water caused as much as $1 billion in damage, according to local reports.
Now, the dam may be resurrected.
Last month, the Idaho Department of Water Resources set aside $400,000 to study the feasibility of rebuilding the dam across the Teton River Canyon. The resulting reservoir would provide agricultural and drinking water as well as hydropower and recreation, says Dave Tuthill, director of the state’s Department of Water Resources.
“Fifty years ago we had enough water,” says Tuthill. “But we have been experiencing many years of drought in Idaho, so we have a heightened awareness for a need for additional water supplies.” Increased urbanization and the likelihood of a hotter, drier future have also made Idaho thirstier.
The state’s study will investigate whether a new dam can be built safely in the porous rock that contributed to the first dam’s collapse, as well as whether or not another reservoir is the best remedy for Idaho’s dry times. The state will also consider recharging aquifers and diverting water to storage areas, such as nearby lakes.
Before the dam was completed in 1976, conservation groups including Trout Unlimited and the Sierra Club filed a lawsuit to halt the project. Today, eco-groups criticize the idea of rebuilding the dam, saying it would disrupt seasonal flows critical to the spawning cycles of native Yellowstone cutthroat trout. The cutthroat prefer flowing water to lakes or reservoirs.
In addition to harming trout and aquatic species, the reservoir would drown bald eagle nesting grounds and block deer and elk from their wintering areas in the Teton Canyon, says Kim Goodman, project director with Trout Unlimited.
Even studying the revival of the Teton Dam is a misuse of money, Goodman says. “We’re spending state and federal funds to find out if (the dam) is feasible or not. But we already proved this dam is not feasible. Its failure was the ultimate sign.”
Instead, say conservationists, the state could work with irrigators to conserve Teton water, create an incentive-based water trading system, and increase the capacity of existing dams like the Minidoka on the Snake River.
Of the more than 600 dams the Bureau of Reclamation has built during the past century, the Teton Dam has been the only dam to fail.
“It had a very profound effect not just on Reclamation but on the whole Department of Interior,” says Diana Cross, acting deputy regional director with the Bureau. “After that, the dam safety program was created. We now have a safety record second to none.”
Nonetheless, after the 1976 incident, rebuilding the dam might be a hard sell.
“Just the other day, I was visiting a friend in the area,” says Goodman. “I said, ‘(The flood) seems so fresh in people’s minds.’
‘Yeah,’ he said, holding back tears. ‘I was one of the people in the helicopter rescuing people in Sugar City and Rexburg when the flood hit.’ Can you imagine if it had happened at night? It is amazing that only 11 people died in that disaster.”
The author is an intern for High Country News.
For more information about the 1976 flood, see these links: http://simscience.org/cracks/movies/tetonf.mov