Staff from the U.S. Army Corps of Engineers completed safety inspections of both the Clearwater Lake and Wappapello Lake dams following Wednesday night’s earthquake in the region, something officials said is a routine safety procedure.
“Following a local reported 4.0 magnitude earthquake, a precautionary walk-over inspection of all flood-damage reduction facilities at Wappapello Lake was completed on the morning of Nov. 18,” said U.S. Army Corps of Engineers St. Louis District Public Affairs Specialist J.P. Rebello.
The inspection, Rebello said, did not turn up anything of concern.
“No defects, changes or potential concerns were observed or reported,” he said.
At Clearwater Lake, a local Corps team quickly got to the dam Wednesday night to ensure its safety.
“Last night, we got the alert from the U.S. Geological Survey (USGS) at 9:32 that there was seismic activity in the area. By 9:36, we requested to dispatch a team out to the dam,” said Jay Townsend, chief of public affairs for the USACE Little Rock District.
By 11:09 p.m., Townsend said, the team had finished its initial inspection and reported back to dam safety officials in Little Rock.
“Certainly, credit goes to the local project office at Clearwater to react as it did at night,” Townsend said.
The inspection, Townsend said, involves crews looking for damage and water issues.
“What they do is quickly go out and do a visual inspection of the dam,” he explained. “With preliminary inspections, what they’re looking for is seepages or leakage in areas where there’s typically not water.
“They can walk through the galleys and can walk through the earthen embankments.”
Every dam also has piezometers, Townsend said, to measure water pressure in various areas, and those can be looked at during inspections as well.
In addition, dams also have seismic detection systems inside their structures, he said.
“The guys that built these dams 50 and 60 years ago had the foresight to put these instruments in place, and they’ve been updated over the years,” Townsend said.
“If any of that stuff is triggered beyond normal dam safety protocol, then it might require further inspection, but in this case, it was not,” he reported. “Everything looks good and is operating as intended.”