Dam risks and benefits: past, present and future

Next Friday, June 5, marks the anniversary of the Teton Dam Flood. Teton Dam Flood Museum Curator Jill Spencer said the event was a lesson to several communities when it comes to dam failure.

“We are foolish, if we ignore our history,” she said. “The Teton flood was a very good learning experience for this entire community and for the communities around us.”

The Teton Dam Flood caused major devastation on June 5, 1976 as the dam filled for the first time. The incident claimed 11 lives and killed more than 13,000 head of cattle.

Spencer said this was a devastation that many people weren’t prepared for.

“They knew the dam had just been finished and it was brand new, it was only eight months old, but they didn’t have any real concept of how much water was behind that,” she said.

Idaho Falls Power and Bonneville County Emergency Management have joined the rest of the nation in increasing risk awareness and the benefits of dams within the community.

Idaho Falls Power assistant manager Bear Prairie said the Idaho Falls dam serves as one of the four hydro-power plants that help keep IFP’s electric rates among the lowest in the nation. It also provides a variety of recreational opportunities such as boating, fishing and picnic areas along the Snake River.

“Hydroelectricity serves over 60 percent of the electricity needs in the Northwest, so it’s a very important resource to the region,” said Prairie.

Bonneville County Emergency Management director Tom Lenderink said it’s important for people to also know the risks, although a dam failures are highly unlikely.
“The people that built these dams and the monitoring that is going on, they do a tremendous job in engineering and the dams are built to last,” he said. “The worst case scenario would be for the Ririe Dam to fail. Even though Ririe seems like a very small dam, it’s much closer than Palisades for most of us.”

Lenderink said the first course of action, in the event of a dam failure, would be a complete evacuation of the area. This would take less than a few hours for most of eastern Idaho.

“If nothing else, get to higher ground and worry about how you’re going to get to where you need to be later.”

Approximately 14,000 dams in the United States are classified as high-hazard potential, meaning that their failure could result in loss of life. Dams can fail for a number of reasons, including over-topping caused by floods, acts of sabotage, or structural failure of materials used in dam construction. The worst dam failure in the United States occurred in 1889 in Johnstown, Pennsylvania. Over 2,200 died, with many more left homeless.