Bexar County commissioners this week approved a state grant to begin installing flood warning sirens in high-risk areas — a step officials say will add to the county’s flood safety system, but won’t fully address its most dangerous flooding risks.
The funding, provided through the Texas Water Development Board under Senate Bill 3, allocates $1 million to Bexar County and allows for up to $1.25 million with additional approval.
The money is specifically designated for flood warning sirens in areas identified by the state as prone to flash flooding — a requirement that comes in response to last summer’s deadly floods across Texas.
Under the state’s guidelines, sirens must be installed within these designated zones, with priority given to locations where people may be exposed to flooding outdoors — including campgrounds, RV parks and other overnight sites.
In Bexar County, those zones span roughly 800 to 900 miles of waterways, or about 36% of the county’s floodplain, according to San Antonio River Authority officials.
Erin Cavazos, an engineering manager with the River Authority — which is leading the initiative — said the county plans to install sirens in phases before August 2027.
The full cost of installing sirens across all eligible areas has not yet been determined, but officials said it will exceed the state funding that is currently available.
“They do have additional funding that they haven’t determined how it will be allocated,” Cavazos said. “We intend to submit the full cost of the sirens for the whole flash flood-prone area that they’ve identified. $1.25 million will not be enough.”
In total, five to 10 sirens will be installed over the next 16 months or so using existing funding, but officials cautioned that sirens are not designed to address the type of flooding that has caused most of the recent flood deaths in Bexar County.
“Sirens haven’t worked very well with drivers,” Cavazos told commissioners, noting that most flood-related fatalities locally occur at low-water crossings when people attempt to drive through rising water.
Last June, 15 cars were swept off a Loop 410 and Perrin Beitel access road into the creek below on the city’s Northeast Side during flash flooding, resulting in 13 deaths.
That reality has shaped the county’s broader flood response strategy — one that relies less on audible warnings and more on preventing drivers from entering flooded roadways in the first place.
NextGen system’s next steps
Last year, the River Authority entered an interlocal agreement with Bexar County to begin development of a $20 million NextGen flood warning system — an effort officials say offers a more immediate and cost-effective way to reduce flood deaths than large-scale infrastructure projects.
That system is designed to improve how quickly officials can detect rising water and warn the public to reduce deaths on flood prone roadways.
Addressing dangerous low-water crossings directly can cost tens of millions of dollars per location, a scale of investment that limits how quickly those fixes can be made across the county.
Precinct 3 Commissioner Grant Moody said upgrading just two crossings in his precinct would cost as much as the entire NextGen system, while hundreds exist countywide.
“I think this is the most important investment we can make in terms of trying to protect human life,” Moody said. “I’m sure there’s ongoing conversations about how we prioritize those infrastructure dollars in addition to this, but I do think this is our best use of that first $20 million.”
That work has included surveying all existing high-water detection locations in the county, collecting records and inventory on those sites, conducting a risk assessment to identify where new gauges may be needed and beginning work on predictive flood modeling and a public outreach campaign.
The River Authority plans to return to Commissioners Court in May with a capital plan and a request for the next interlocal agreement, which would move the project into the design and, officials hope, implementation phases this summer.
The River Authority has also finished surveying existing sites and has been using that engineering analysis to identify flood risk beyond current gauge locations.
“We have gauge locations, but I would say we’re probably covering a tenth of the area that’s at risk,” Cavazos said. “Our capital plan will include not only the upgrades we’ve been talking about, but also additional gauge locations.”
Some improvements can begin before the full system is built out.
Cavazos said the River Authority is close to deploying upstream-to-downstream alerting, which would allow emergency managers to warn that rising water upstream may soon affect crossings farther down the watershed. For example, drivers along Leon Creek could be warned that flooding upstream could soon impact access roads near U.S. Highway 90.
For Precinct 2 Commissioner Justin Rodriguez, one key question was when the public could expect to see results.
“The floods are not going to wait till 2027,” Rodriguez said, asking whether any short-term improvements could be deployed before the full system is completed.
Cavazos said some of those early changes will come on the informational side.
Currently, residents can monitor flooding conditions through BexarFlood.org, which provides real-time updates on low-water crossings using a color-coded system to indicate whether roads are safe, nearing closure or flooded. Users can also sign up to receive text or email alerts for specific crossings, though the system requires residents to opt in.
About 3,700 users are currently subscribed to at least one location, according to the River Authority.
Flood data is also shared with navigation apps like Google Maps and Waze to help drivers avoid flooded roads, while broader weather alerts are issued through the National Weather Service and local emergency management systems.
The River Authority has launched a regional version of BexarFlood, now branded as SARiverFlood.org, with county-specific domains planned across the region. Officials said the goal is to better serve drivers moving across county lines, especially commuters entering Bexar County from surrounding areas.
But officials said the current system is largely reactive, with each crossing operating as an independent data point based on water levels at that specific location.
As the NextGen system rolls out those data points will become connected and provide earlier warnings as floodwaters move through the region.
At the same time, the agency is preparing a flood-awareness campaign aimed directly at driver behavior. Cavazos said the campaign, expected to launch in May, is based on research showing that warnings about personal danger alone are often not enough to stop people from driving into floodwater. Some of the messaging instead focuses on things drivers may respond to more immediately, such as damage to their vehicles.
Even with those additions, officials said the county will still have to prioritize.
For now, county leaders say the focus remains on reducing risk where they can — even if no single system can eliminate it entirely.
