Last Updated on October 14, 2025
We’re introducing a new blog series called “When Rivers Rise Fast” to support our community in preparing for and responding to flash floods.
This series will provide valuable information, including a detailed look at the new flood warning system we’re implementing, and a clear explanation of what flash flooding is and why it’s so dangerous. We’ll also highlight essential tools and resources available to the public, empowering you to plan safer routes and avoid flood risks when you’re on the road. In the third post of the series, we’ll spotlight our agency and explain our role in flood management.
The San Antonio River Authority (River Authority) serves as your behind-the-scenes flood safety partner, providing the technical expertise that drives both emergency response and long-term planning. We approach flood protection in two key ways: protection and preparedness.
What We Do:
- Work with the Federal Emergency Management Agency (FEMA) to map floodplains and model how water moves during storms
- Give data to partners (like the City of San Antonio and Bexar County) so they can use public funds to fix flood problems
- Lead the Bexar Regional Watershed Management Partnership (BRWM) to improve flood response through local government collaboration
Protection: Infrastructure + Nature-Based Solutions
In our flood risk model, protection means using man-made structures to guide and control where water flows. This includes:
- Mapping floodplains with FEMA to identify areas with higher flood risk.
- Modeling water flow during storms to inform improvements to stormwater infrastructure
- Working with local governments to support smart, regional solutions.
- Coordinating the Bexar Regional Watershed Management (BRWM) Partnership to improve response.
Walker Ranch Dam, one of many earthen dams maintained by the River Authority, releases water during a flood in 2018.
How Earthen Dams Work
- Built from natural soil and powered by gravity – no electricity needed
- Hold back rising water and slowly release it downstream through a built-in outlet
- Help protect homes, roads, and lives from sudden flash floods.
Stream restoration projects improve water quality, stream bank stability, and groundwater recharge while boosting safety and ecology. Restoration helps reverse these problems and improves life across the entire watershed
Sulfur Creek before and after stream restoration construction. Did you know? When streams are damaged, they can cause dangerous flooding, lower water quality, become unsafe for fishing or recreation, and damage roads, storm drains, and sewers.
- Low Impact Development (LID): The River Authority supports these smart design strategies that manage stormwater and reduce pollution. When used early in project planning, LID is cost-effective and eco-friendly.
Examples of LID:
- Permeable pavement
- Stormwater-harvesting Cisterns
- Bioretention and rain gardens
- Green roofs
- Keeping native plants and soil in place
These methods:
- Slow down and soak in stormwater
- Filter out pollution before it reaches streams
- Prevent street flooding during small storms
- Improve water quality and protect wildlife
The Pullman Market parking lot in San Antonio utilizes “green parking” by incorporating a central landscaped bioswale for stormwater management.
The River Authority’s Escondido Creek Parkway (pictured above during a rain event) incorporates LID features to help manage stormwater during rain events while providing recreational opportunities like a splashpad, trails, and open space.
Preparedness: Staying Ahead of the Storm
The River Authority works closely with government agencies to help residents get prepared before a flood ever happens.
Our goal is to help communities prepare before the rain falls. We do this through:
- Data sharing
- Public education
- Partnerships with city and county emergency services
River Authority engineer Robert Nolen talks with community members during a Draft Maps Open House at the Hardberger Park Urban Ecology Center.
Resources
These sites offer simple tools and tips to protect your home, your family, and your property.
Dig Deeper into Flood Basics, Emergency Preparation, and Recovery Tools
Property Flood Risk and Flood Insurance Tools and Information
- Check Your Address on the Draft Floodplain Maps
- More Flood Insurance Info + How to Prepare Your Home
Stay tuned for part four of our “When Rivers Rise Fast” series on real-time tools to check during a storm, publishing on October 3, 2025.
