As if handling 22 feet of floodwater in Lake Waco weren’t enough of a headache, lake officials are now sizing up a problem on the back side of the dam that may take millions of dollars to fix.
Heavy rainfall around May 29 caused a section of the earthen dam surface, 4 feet deep and 300 feet long, to slide downhill, said Heath McLane, lake manager for the U.S. Army Corps of Engineers. The “shallow embankment slide” was discovered during a daily inspection, and the affected area was covered with tarps to prevent more rain from infiltrating the soil, McLane said.
McLane said the slide is not thought to endanger the integrity of the dam, and it is similar to slides other Corps dams in the region have occasionally experienced, but it will be taken seriously.
“Earthen slides do raise a concern and require additional monitoring and mitigation,” he said. “It’s something we have dealt with before and have experience in making repairs.”
Corps engineers in coming weeks will assess the damage and make recommendations for fixing the slide. In the meantime, the cost of the fix is unknown, but McLane said it could cost millions of dollars.
He said Corps officials don’t think this slide is related to a slope failure that the lake encountered when it was constructed in the early 1960s. That was caused by an unstable shale formation below the dam, which was later corrected with the addition of massive amounts of dirt.
The Corps late last month closed the popular hike-and-bike trail on top of the dam because of vandalism and trespassing incidents unrelated to the current issue.
“If we hadn’t closed the week before, we would have closed it anyway for this repair,” McLane said.
Waco City Manager Dale Fisseler, a professional engineer, said he was surprised to hear of the extent of the dam slide, but he expects the Corps will do the right thing.
“When they get engaged on a project like that, you know they’re going to make it right,” Fisseler said. “My experience with them on a number of projects is that they really focus on the safety of citizens.”