LIVINGSTON, Texas – Nearly a week after the Trinity River Authority declared a “potential failure watch” for the Lake Livingston Dam, we’re learning about the damage done during flooding earlier this year.
Near-historic rainfalls resulted in flooding throughout SE Texas. Along the Trinity River, communities were hit hard with the flow being released from the Lake Livingston Dam.
According to data obtained by KPRC 2′s Gage Goulding, the dam set a record for water flowing from its spillway at 124,000 cfs.
Last Friday the Trinity River Authority issued the potential failure watch after discovering damage to the dam as a result of the high flow event.
It took nearly a week for leaders at the Trinity River Authority to explain what happened and the repairs needed to strengthen the dam, which recently received an unsatisfactory assessment, the lowest rating, during a May inspection filed with the U.S. Army Corps. of Engineers.
According to documents filed with federal regulators, the dam has several different damages from the flooding.
The first problem was discovered on May 10 during an evaluation by an engineering firm, according to documents filed with the Federal Energy Regulator Commission.
As a result, the Trinity River Authority activated its Emergency Action Plan (EAP) on May 16 for a “Non-Failure (Abnormal) Condition.” This issue was outlined to be a partial failure of the left downstream training wall as well as erosion adjacent to the training wall.
A training wall is a wall that guides the flow of water. This training wall is downstream, or on the spillway side of the dam.
Fast forward to June 26 and another special inspection yields an even more concerning find. After several unsuccessful attempts to inspect the dam, crews discovered an alarming concern in the “stilling basin.”
A stilling basin is an area on the downstream side of a spillway that helps break the turbulent flow of water.
“Trinity River Authority (TRA) staff closed all spillway gates for a short time to allow for closer inspection and depth measurements in the stilling basin,” engineers wrote in a June 26th report filed with federal regulators. “These inspections and measurements revealed significant scour in the stilling basin that threatens the integrity of the dam. This is an emergency condition that requires immediate action.”
It’s this call for immediate action that prompted the “Potential Failure Watch.”
Since then the Trinity River Authority has been working to fix the issues.
According to Trinity River Authority General Manager Kevin Ward, crews discovered that the force of the water removed all of the rip rap, a layer of large stones, and clay the whole way to the apron of the dam.
“Under current flow there is no threat,” Ward told KPRC 2′s Gage Goulding on a phone call late Wednesday.
Ward went on to explain that repairs are already in progress.
Roughly 100 truckloads of large rock are being brought in daily as crews work around the clock.
On top of that, crews already began pumping concrete to fix the training wall erosion noted in the mid-May findings.
If all goes well, crews will begin pumping additional concrete into the bottom of the dam’s stilling basin to begin permanent repairs from the flooding.
With Hurricane Beryl potentially making an impact in SE Texas, Ward says crews are attacking the most critical areas of concern first so they can weather the storm.
All permanent repairs are forecast to be completed by July 22.