The Federal Energy Regulatory Commission has instructed AmerenUE to proceed with a plan for stabilizing the upper reservoir at the 408-MW Taum Sauk pumped-storage project (No. 2277) near Lesterville, Mo.
The northwest corner of the mountain-top dam failed Dec. 14, releasing a 1.5-billion-gallon flood into a rural area including Johnsons Shut-Ins State Park. Three children were injured. AmerenUE said instrument failure during pump-back operations likely led to the breach.
AmerenUE said March 21 it filed a request with the Missouri Department of Natural Resources for a permit to implement the plan, which would be completed by this summer. Officials of Ameren Corp. in St. Louis, the licensee’s parent company, said no decision would be made about rebuilding the project until FERC and other agencies complete investigations into the 700-foot rupture.
AmerenUE’s safety initiative includes phased-in projects to:
o Establish safe slopes in the breached area and a safe working area along the top of the dike;
o Remove concrete parapet wall panels at the top of the dike to allow access by equipment used to stabilize the slopes;
o Rebuild access roads and construct a new road and ramp to provide access for heavy equipment into the upper reservoir;
o Remove all silt and remaining liner material inside the upper reservoir, in addition to concrete debris and exposed rebar in the breached area; and
o Design, build, and install a cover and hatch for the vertical shaft that carries water back and forth between the project’s lower and upper reservoirs.
State, federal agencies eye dam safety issues
Gov. Matt Blunt ordered the Department of Natural Resources to study state dam regulation following the breach. While FERC oversees Taum Sauk, the governor’s office noted the incident raised questions about state regulation of Missouri’s dams. Several dam safety bills have been introduced or revived in Congress as a result of incidents at Taum Sauk and in Hawaii and Massachusetts.
In February, AmerenUE announced it resolved all claims with the family of park Superintendent Jerry Toops, who lived below the reservoir at the bottom of Proffit Mountain. Toops, his wife Lisa, and the couple’s three children were swept away from their home by floodwaters pouring from the upper reservoir. The children were hospitalized and treated for injuries.
AmerenUE said it made restitution to the family for hardships suffered as a result of the incident. The St. Louis Post Dispatch reported that while terms were not disclosed, the family’s lawyer indicated the settlement would more than cover the children’s college educations and future medical needs.