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San Antonio River Authority addresses concerns after deadly floods, focusing on prevention and future safety

Engineer explains what prevention projects are in place and which others are too expensive

The fallout from last week’s deadly flood is still heavy on so many minds.

The speed at which streets flooded, and the widespread effects left South Texans with many questions, so KSAT took those questions to the San Antonio River Authority.

The organization maps and models floodplains, oversees flood infrastructure, and does that in partnership with the City of San Antonio, Bexar County and even the Federal Emergency Management Agency (FEMA).

The organization covers all waterways that contribute to the San Antonio River, including Cibolo Creek, the Medina River, Leon Creek, Salado Creek, and even smaller creeks like Beitel Creek, where most of Thursday’s fatalities happened.

“Plus, there are our downstream counties, Wilson, Carnes, and Goliad counties, where we perform a lot of the modeling for them,” said San Antonio River Authority Manager of Engineering Erin Cavazos.

“They are distributed around the city, and that’s where a lot of the complication comes in during a storm event. Where that intense area is varies every event,” said Cavazos.

This time around, the Northeast Side of San Antonio and Bexar County were particularly hard hit.

“The main unique condition last week was the pockets of really high rainfall that happened over a very short time, and how that moved downstream. That’s how flashy our creeks are. It can go from dry to flooded in 15 minutes,” Cavazos said.

During KSAT’s reporting, neighbors in flooded areas stated that new construction was nearby, and they worried that it contributed to the flooding.

Cavazos said it’s still too early to know.

“Construction adds additional uncertainty. And I think that over the course of investigating what happened, we might find answers to that,” Cavazos said.

The substantial question now surrounds prevention: How can the San Antonio River Authority help prevent this widespread flooding again?

“The prevention would take so much investment. It’s cost-prohibitive. The need is great, but there isn’t enough funding. Some of the more expensive investments are like dams, tunnels and channels. A lot of times, what we want to do would involve having to acquire property, and we just don’t have the space,” Cavazos said.

The San Antonio River Authority already operates and maintains 28 flood retention dams in Bexar County, which hold water and slowly release it over time.

    • Salado Creek – 14 dams
    • Calaveras Creek – 7 dams
    • Martinez Creek – 6 dams
    • Leon Creek – 1 dams

The organization has also invested in prevention in a different way: a system called Bexar Flood, which helps the public identify hazardous low-water crossings.

“There’s a gauge out there, and it starts to show when the water is getting close to the road, it turns a different color, and it sends alerts. Then, when it’s over topping the road, it turns red,” Cavazos explained.

The alerts have been picked up by the traffic app Waze, which allows users to see the Bexar Flood alerts.

“We would love to see it in Google Maps, Apple Maps, and all the mapping applications people use. There are some technical hurdles to work through on those. And we’d also like to see this beyond Bexar County,” Cavazos.

Even before the recent flood, they were already assessing the need to add gauges to the network.

Now, they’ll focus on places like Beitel Creek, where the majority of deaths happened.

“The ones in that area are owned by the City of San Antonio, and we’ll work with them on identifying the best approach to monitoring that creek and understanding the relationship between rainfall and runoff and how quickly it floods,” Cavazos said.

As the organization assesses the floods of last week and what programs and infrastructure could help next time, Cavazos hopes people will be prepared for next time and study the floodplain maps on their website.

“See where the high flood risk is, where you live, and on your routes, like where you go shopping, where you work and where you pick up your kids. Knowing where all of those cross the floodplain is going to help you understand the flood risk in your life,” Cavazos said.


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