SAN ANTONIO – A report of over one hundred pages analyzing the June 12 floods in San Antonio, when 13 people were killed, was released Thursday.
The flood majorly affected the Perrin Beitel area on the Northeast Side on June 12, where 11 bodies were later found.
One body was also found several miles upstream from the search area, and one was found in the U.S. Highway 90 Leon Creek area, according to San Antonio fire officials.
The Bexar County Medical Examiner’s Office later identified all of the people killed in the floods.
>> Remembering the victims of the June 12 floods in San Antonio
In the aftermath of the flood, the City of San Antonio launched an investigation into the causes of the deadly floods and the extensive damage to its infrastructure.
An engineering company, called “Kleinfelder,” was hired by the city to assist with the investigation.
Justin Murray, who works with Kleinfelder, presented the report to the city council on Thursday.
“The single biggest reason that the June 12 event happened was the rainfall,” Murray said.
25-year rainfall event
According to the analysis, the storms on June 12 were consistent with a 25-year rainfall event.
Original Texas Department of Transportation design plans from 1979 indicate the Loop 410 westbound access road, where flood depths and velocities were the highest, was built at an elevation “vulnerable to overtopping” in a quarter-century flood event.
“Had there been a risk assessment requirement, potentially it would have elevated that sort of overtopping and then something could be done,” Murray said.
The company’s study also found that there were no identifiable requirements in June that would have implemented some accommodation for flooding in the Perrin Beitel Creek.
Recommended actions
The study recommended the installation of staff gauges as well as advanced signage and flashing lights at the Loop 410 westbound frontage road and the Austin Highway underpass.
“Signage placement should allow for safe detour options and prevent vehicles from entering flooded areas,” the company wrote in the report.
The report also suggested enhancing emergency response protocols through collaboration with the city’s Public Works Department, Transguide, TxDOT, the San Antonio Police Department and the San Antonio Fire Department.
“I think that holistic review will also be really important as we communicate to our constituents about the ways in which we are identifying, prioritizing and of course funding these,” Mayor Gina Ortiz Jones said.
The new protocols could utilize existing gauge data to trigger road closures and public alert notifications in real-time. According to the analysis, flood gauges should be relocated to the downstream faces of crossings to improve early detection of floodwaters.
The report emphasized the expansion of “sensor networks,” which include rain gauges, cameras and automated barriers. It also advised identifying and prioritizing maintenance requirements within vegetation areas in flood-prone areas.
“This is not something we are going to be able to fund internally ourselves,” Jones said. “It’s going to be really important that we continue to work with our state and federal delegation to ensure we have sufficient resources for these major projects.”
Vegetation in Perrin Beitel Creek
The June 12 floods occurred in the summer, when foliage is at its peak, the analysis states.
“The woody forb species, along with Hackberry, Live Oak, and Elm stands with boughs which lie within the depths calculated contributed to increased roughness.”
The company noted that within the areas of dense vegetation along Perrin Beitel Creek, there are sections that are prone to flooding.
The water flow is not continuous and instead happens in isolated “segments or pools.”
According to the analysis, the pools are approximately several feet deep and form in low-lying areas where water collects during rainfall.
The entire report is available for viewing below.
More coverage of this story on KSAT