As an added measure to protect Bexar County from the dangers of flash flooding, the Bexar County Commissioners Court voted to implement a series of improvements and expansions of the county’s flood warning system Aug. 5.

What’s changed

Known as the Next Generation Flood Warning System, the new system will be implemented by the San Antonio River Authority, SARA, and will help streamline stream and rain gauges to help provide more detail in real time, which can be viewed at Bexarflood.org. According to county documents, SARA estimates that the upgrades and expansion of the predictive flood model, PDM, within Bexar County is roughly $22 million and $11.821 million within the City of San Antonio.
These improvements and expansions are designed as a multipronged approach to improve flood readiness. This approach is designed to reduce or eliminate water rescues at low water crossings, leverage technology for an improved early warning system, remove structures from floodplain and floodway and create more resilient systems for future conditions.

Multipronged approach:
  • Flood warning system
  • Resilient flood infrastructure
  • Communications and advocacy
  • Operations and maintenance


The conditions


The flood warning system roadmap introduced by SARA includes three categories—immediate, short-term and long-term.

Immediate:
  • Restore functionality to all gauges and communications
  • Update gauge alert thresholds with additional warning levels


Short-term:
  • Standardize all programmable and communication equipment
  • Install manually closing low-water crossing barricade gates
  • Report to a single server, share data with partners
  • Single command center, shared access with partners
  • Implement and leverage PFM 3.0 for more precise flooding locations and timing


Long-term:
  • Leverage PFM 3.0 to identify future infrastructure needs
  • Automate low-water crossing barricade gates


SARA said the upgrades and expansions are due to a variety of factors, such as Bexar County’s location within the Balcones Escarpment, which can see intense and unpredictable weather, rapid changes in elevation, impervious limestone, erosive soils and steep slopes; and a favorable climate for flash flooding.

The backstory

According to county documents, Bexar County’s past investments in flood control includes a 10-year, $500 million flood control program first commenced in 2007 and an additional $384 million in local flood control projects since 2017. Investments include roughly 80 high water alert life savings technology warning systems that use sensors to detect rising water on roadways.

Additionally, Bexar County, the city of San Antonio, SARA and 20 suburban cities formed an inter-local agency partnership known as Bexar Regional Watershed Management in 2003, which manages regional stormwater issues within the County. The agency has implemented over $2 billion in flood mitigation projects since its creation.