Bexar County officials demonstrated on Tuesday a new railroad-style flood gate system designed to automatically block drivers from entering flooded roadways — part of a broader $21 million “NextGen” flood warning network that officials hope will prevent future flood deaths across the region.
The new flood gates use upstream water sensors, flashing warning lights and lowered gate arms to close roads when rising creek levels make roadway conditions dangerous.
The county’s older High-Water Alert Lifesaving Technology, or HALT, flood warning system primarily relies on flashing warning beacons activated by rising water near crossings. This new system features towers that add another layer of prevention when drivers approach a flooded road.
“This is a continuation of our HALT system, except upgraded … with these railroad light crossing arms, we are basically taking the decision out of the driver’s hands,” County Manager David Smith said. “That arm comes down and you pretty much have to turn around.”
Officials said 15 locations currently include the new railroad-style gate arms, with additional crossings expected to receive the upgrades as the network expands.
The HALT network currently includes 198 flood warning and gauge locations across Bexar County.
According to Smith, roughly 170 of those locations are currently active and connected to the broader NextGen network, while the remaining sites are expected to be refurbished and upgraded by 2028.
The upgraded system now feeds real-time crossing information into BexarFlood.org, where residents can monitor roadway conditions and sign up to receive text or email alerts for specific flood-prone crossings near their homes or commute routes.
An expanded regional system is also available at sariverflood.org and includes data for Bexar, Goliad, Karnes and Wilson counties.
“You can take steps today,” Smith said. “Subscribe to the HALT locations you want to get text messages for.”
Smith said many drivers underestimate how little water it takes to lose control of a vehicle during flooding events. According to the National Weather Service, roughly 12 inches of moving water can carry away most vehicles, including trucks and SUVs.
“Once it floats, you’ve lost control,” Smith said. “It can be rapid, it can be slow, but you’re out, you are no longer in charge of where that vehicle goes.”
Precinct 1 Commissioner Rebeca Clay-Flores credited Smith with helping push the NextGen system forward following last year’s deadly flooding season.
But Smith said the idea for the expanded system emerged after the San Antonio River Authority completed a technical assessment of the June 2025 Beitel Creek flooding near Loop 410 and Perrin Beitel, where 15 vehicles were swept into floodwaters during an overnight storm that killed 13 people.
“What struck me from that was just how accurate their modeling was,” Smith said.
Smith approached Derek Boese, general manager and CEO of the River Authority, and asked whether the agency’s flood modeling could be expanded countywide and used proactively rather than reactively.
Boese told him much of the watershed modeling work was already underway, leading to broader discussions about developing a predictive flood warning system capable of identifying dangerous crossings before floodwaters reached the roadway.
Nearly a year later, the expanded system is now operating and will eventually allow meteorologists and emergency managers to use watershed modeling, rainfall data and storm movement in real time to determine when specific crossings are expected to overtop — allowing roads to close before flooding reaches drivers.
“They will have the hydraulic models in place to tell them, well, at two inches an hour over Polecat Creek here in West Bexar County, that means you’ll have this low water crossing on Keller Road over-topped within 90 minutes,” Smith said. “They can predict that ahead of time and close the road before the flooding hits there at all.”
County leaders and the River Authority formally showcased the new technology alongside a proclamation event for Flood Awareness Day, where officials also unveiled a new regional public safety campaign called “Floods Don’t Care” ahead of an active stretch of severe weather expected across South Central Texas this week.
The campaign comes ahead of an active stretch of severe weather expected across South Central Texas this week and is aimed at encouraging drivers to avoid flooded roads and take warnings seriously during heavy rain events.
“Floods don’t care if you drive a Tesla or an F-150,” River Authority Vice Chairman Jim Campbell said. “What we can do is install infrastructure like this that gives us a fighting chance.”
Bexar County Judge Peter Sakai echoed that sentiment as he proclaimed May 19 as Flood Awareness Day in Bexar County.
“We owe this community more than remembrance,” Sakai said. “We owe it preparation, urgency and action.”
