AmerenUE: Reservoir wasn't weakened by Sept. 25 overflow

AmerenUE launched a counteroffensive Thursday to persuade the public that it responsibly operated a hydroelectric plant where a reservoir ruptured Dec. 14.

The utility released a summary of a report it submitted to the Federal Energy Regulatory Commission about a Sept. 25 incident where water washed over the top of the reservoir. In a news release, AmerenUE said the overflow at that time was caused by high winds from the remnants of Hurricane Rita and "slightly elevated reservoir levels."

The incident wasn't serious enough to report to the federal agency, which is responsible for watching over the operation of the plant, AmerenUE said.

"The Sept. 25 event was significantly different from the Dec. 14 reservoir failure that resulted in significant flooding," chief operating officer Thomas Voss said in the prepared statement. "In addition, contrary to news reports, the integrity of the reservoir structure was not weakened by the Sept. 25 wave action."

When the reservoir failed Dec. 14, more than 1 billion gallons of water rushed out of the Proffit Mountain reservoir. The cascade stripped trees from the mountain before entering Johnson's Shut-Ins State Park, where it toppled hundreds more trees and destroyed a home, injuring five people inside.

The reservoir provided water for the Taum Sauk Hydroelectric Plant. Water pumped up Proffit Mountain was stored until needed to power turbines that generated electricity. As water passed through the turbines, it returned to the Black River, where a dam creates a lake to retain the water for pumping back up the mountain.

After water went over the top of the reservoir Sept. 25, a plant superintendent sent an e-mail to several AmerenUE supervisors warning that damage from the overflow could cause an eventual failure. The overflow had washed away rock at the base of the reservoir, leaving trenches a foot deep in some areas.

The Dec. 14 rupture occurred when water level sensors failed, allowing too much water to be pumped into the reservoir. As water flowed over the top of the reservoir, it eroded the earth-and-rock wall at the same point where water went over Sept. 25.

In the news release issued Thursday, AmerenUE said "the company has found no evidence to indicate that water had ever been pumped over the top of the upper reservoir prior to Dec. 14."

The wall collapsed shortly after 5 a.m. that day. The water hit the home in Johnson's Shut-Ins as the family of park superintendent Jerry Toops was sleeping. His three children were hospitalized but have since been released.

The Federal Energy Regulatory Commission is investigating the reservoir failure. AmerenUE issued the news release in an attempt to quiet media reports that it has been irresponsible, spokesman Mike McCleary said.

"Once we filed this report, we felt we should respond to a lot of the allegations," McCleary said. "We are cooperating fully with all parties involved."

In addition to the media reports, Gov. Matt Blunt on Monday called on Attorney General Jay Nixon to pursue criminal or civil action against the utility.

Nixon is pushing his own investigation, as is the Department of Natural Resources, which operates the park and is responsible for protecting the water quality of the Black River.

The federal energy agency did not return a call seeking comment.

AmerenUE is paying for the cleanup of Johnson's Shut-Ins as well as planning for treatments that would reduce sediment clouding the Black River. "The company has always accepted full responsibility for the Dec. 14 breach," Voss said.

The investigation of the breach isn't focusing on whether AmerenUE wants to avoid blame for the breach, DNR deputy director Kurt Schaefer. "It is an issue of whether or not this was an avoidable situation," he said. "While I recognize they have taken responsibility for everything since, the issue that is pending is what occurred beforehand."

The resource agency investigators turned reports over to Nixon's office Wednesday and Thursday, Schaefer said. And the agency today will likely approve AmerenUE's plan to use alum treatments to reduce sediment in the Black River, he said.

The attorney general's investigation is independent of the DNR work and was underway before Blunt called for court action, spokesman John Fougere said. He declined to comment on specifics of the investigation.

rkeller@semissourian.com

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