JEFFERSON CITY, Mo. (AP) -- An Ameren Corp. employee who gave the orders to run a mountaintop hydroelectric plant said his computer readings showed nothing unusual about its water level on an early December 2005 morning, even though water was running over the top of its reservoir.
Attorneys quizzed Ameren power plant dispatcher James Bolding on Monday as the Missouri Public Service Commission embarked on its third week of investigatory hearings into the collapse of the Taum Sauk reservoir.
Utility regulators are looking into whether the reservoir failure -- which washed out Johnson Shut-Ins State Park and seriously injured the park superintendent's family -- highlighted a pattern of safety problems at the St. Louis-based utility.
Ameren already has agreed to pay $15 million under a settlement with federal energy regulators. A state Highway Patrol investigation led to no criminal charges from Attorney General Jay Nixon, who instead is pursuing civil damages in state court. The PSC's investigation is separate from the others, though Ameren attorneys have complained it's redundant.
Bolding, who worked at Ameren's St. Louis office, said he gave the orders to pump water up to the Taum Sauk reservoir and then ordered it to stop slightly below the targeted water level around 5 a.m. on Dec. 14, 2005. The intent was to drain the reservoir at 6 a.m. and sell the electricity it produced.
There was nothing to indicate anything unusual about the reservoir's water level, which was displayed on a 3-foot-by-5-foot plasma screen in his office, Bolding said.
But just after 5 a.m., a 600-foot-wide section of the reservoir wall gave way, after water flowing over its top eroded the wall's base.
Ameren employees had known for more than two months that some of the reservoir's water-level gauges had broken free from the reservoir wall and were floating with the water, resulting in inaccurate readings.
To compensate for what he described as a "slight error" in those readings, Bolding said Ameren had lowered its targeted height for filling the reservoir by 2 feet. On the morning of the failure, Bolding said he ordered the reservoir filling to stop even an inch or so lower than that.
"I felt confident in our routine of filling and lowering the level, and not getting any calls (from plant operators) that water was overflowing, that it was well within the boundaries," Bolding testified Monday during the PSC's administrative hearing.
Bolding, like some other Ameren employees who have testified, said he was unaware that separate safety sensors that were supposed to trigger an automatic shutdown of the pumps had been set so high as to be rendered ineffective. Even so, Bolding said he was not relying on those safety probes when giving his directions to raise and lower the reservoir.