Missouri's Taum Sauk Pumped Storage facility breaches; loses 1 billion gallons of water in 20 minutes

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At 5:12am on December 14, 2005, the upper reservoir of the Taum Sauk Pumped Storage hydropower project breached.

The failure released one billion gallons of water - a weight of 8 billion pounds, and more than the entire City of St. Louis consumes in two days - over twenty minutes. The St. Louis Post-Dispatch is covering the breach in depth.

The project is in rural Missouri, about 120 miles southwest of St. Louis near Lesterville in Reynolds County. The flood crashed through the home of the superintendent of Johnson's Shut-in State Park, injuring his three children. No other injuries have been reported, although the town of Lesterville was temporarily evacuated.

The upper reservoir - which can hold 1.5 billion gallons of water - is not part of the Black River's riverbed. It actually sits in a carved-out berm on top of the aptly named Proffit Mountain.

AmerenUE, the project owner, reported that the reservoir has been leaking for two years, although they believed the problem was on the mend. No seismic activity or abnormal rainfall precipitated additional pressure to open the leaks and cause the breach.

The Federal Energy Regulatory Commission licenses this facility under docket P-2277. According to the docket, available online in FERC's eLibrary, FERC inspected the project's safety within the past three months and certified in October that the project was satisfactorily compliant. FERC also agreed with AmerenUE's assessment that the leaks from the floor of the upper reservoir appeared to be "dramatically" lessening.

The project had just begun the permitting process to receive a new license and begin compliance with modern environmental laws. AmerenUE planned to use the traditional licensing process, no longer available without special permission from FERC.

About Pumped Storage

The Taum Sauk project is called a "pumped storage" facility because it generates power on the margin. Pumped storage facilities have at least two reservoirs, one at higher elevation than the other. Dam managers release water from the higher reservoir when power is most needed and profitable, usually early morning, then pump water back from the lower reservoir to the upper reservoir at less profitable times.

It is not a closed system - the project loses water to evaporation, aquifers, seepage, and basic environmental requirements to keep water in the river below the project. When the water loss was greater, however, AmerenUE had simply not placed minimum flows in the Black River below the dams. Minimum flows were expected to be a core issue for locals in the upcoming licensing process.

For more information, please contact Dan Sherburne at the Missouri Coalition for the Environment.