ASDSO Marks Tenth Anniversary of Destructive Missouri Dam Failure

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Consequences could have been must worse; timing likely saved lives.

Lexington, KY: “The tenth anniversary of the Taum Sauk dam failure serves as a reminder of the very real need for constant vigilance in dam safety,” said Lori Spragens, Executive Director of the Association of State Dam Safety Officials.

In the early morning hours of December 14, 2005, the Taum Sauk Upper Reservoir Dam failed, sending a destructive wall of water through Johnson’s Shut-Ins State Park, one of Missouri’s most popular recreational areas. Fortunately, no one was killed by the torrent, but it demolished the home of Park Superintendent Jerry Toops, and swept him, his wife Lisa, and their three young children into a patch of trees about a quarter mile from where their home once stood. Two truck drivers crossing the highway below the dam also narrowly escaped with their lives. (Southeast Missourian, 12/15/05 -

Situated on top of Proffit Mountain in southeast Missouri, the Taum Sauk Upper Reservoir was one of two reservoirs comprising a pumped storage hydroelectric energy center owned and operated by Ameren Missouri. The upper dam failed when instrumentation that regulated water flow into the upper reservoir malfunctioned, causing excess water to be pumped into the reservoir until it overtopped.

As the 55-acre reservoir washed over the dam, a 680 foot-wide section of the earthen embankment failed suddenly, releasing a 40 to 50 foot-high wall of water down the mountainside, stripping vegetation and soil down to the bedrock. The floodwaters inundated State Highway N, pushed vehicles from the road, ripped apart the occupied home of the state park superintendent, and covered the state park campground—fortunately empty at the time of the failure—with up to 40 feet of water. The combination of water and sediment caused significant property and environmental damages to the park and limited recreational uses of the Black River for months.

“This dam failure is a prime example of an event that could have been much worse. Had it not occurred in the winter, dozens of campers would likely have been killed; likewise, had it not occurred in the early morning hours, additional vehicles would likely have been on the highway that flooded. The Toops family and the two truckers swept from the road were extremely fortunate to have survived,” said Spragens.

While the people caught in the flood have recovered from their injuries, Johnson’s Shut-Ins State Park suffered permanent environmental damages. In a settlement reached nearly two years after the failure, the dam owner agreed to pay $177.35 million to the State of Missouri for loss of tourism revenues and damages to park lands and natural resources. (Ameren, 11/28/07 -

Ameren incurred additional expenses rebuilding the dam, which now incorporates multiple redundant systems to ensure that a repeat of the overtopping event never occurs.

“Dam maintenance and upgrades cost a lot,” said Spragens, “but they are much less expensive than cleanup, repairs, and restitution following a dam failure.”

The Association of State Dam Safety Officials ( is a national, non-profit organization dedicated to improving dam safety through research, education and communication. In conjunction with the Federal Emergency Management Agency, ASDSO created a set of two “Living With Dams” booklets—“Know Your Risks” and “Extreme Rainfall Events”—to explain how individuals can learn more about dams in their communities and how communities can prepare for extreme rainfall events. Both are available at

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Lori Spragens
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