Utility AmerenUE said February 5 it submitted plans to regulators to rebuild the breached upper reservoir of its 408-MW Taum Sauk pumped-storage project in eastern Missouri.
Taum Sauk has not operated since the mountaintop ring dam breached Dec. 14, 2005, releasing 1.4 billion gallons of water down the Black River, injuring nine people, and damaging property. (HNN 12/15/06)
The company said it filed for approval from the Federal Energy Regulatory Commission to begin construction beginning in 2007, with the project (No. 2277) returning to service in 2009. FERC has indicated it would seek public comment on the filing, according to the statement by the utility.
AmerenUE stressed that the reservoir would be rebuilt following criteria used in current dam design and construction practice. It said the work will utilize roller-compacted concrete based on a design by Paul Rizzo &Associates that satisfies FERC guidelines.
ï¿½We would not be returning this plant to service if we were not absolutely certain that our design met, or exceeded, all modern safety criteria,ï¿½ AmerenUE President Thomas Voss said. ï¿½After much analysis, we are now confident that this plant can be returned to service and operated safely to restore a critical source of reliable power to our customers.ï¿½
AmerenUE said the new dam would include safety features including:
o A crest elevation in excess of the highest anticipated water surface, including rain events or high water levels;
o An overflow release structure to protect against damage to the dam in the unlikely event that redundant control systems fail and the upper reservoir overflows;
o Multiple independent lines of defense, including continuous video camera monitoring of the water level and separate instrumentation and monitoring systems that will be dedicated solely to dam safety.
Insurance is expected to cover the cost of rebuilding. However, the company must resolve outstanding issues with state agencies before the plant can come back to service.
Missouri Attorney General Jay Nixon filed a lawsuit against AmerenUE in December, seeking damages. The lawsuit alleges Ameren’s operation of the project led directly to overtopping of the reservoir and its subsequent failure. The filing alleges instruments meant to detect high water levels in the reservoir were improperly positioned and programmed.