The San Antonio River Authority Floodplain Viewer
Click image to access River Authority Floodplain Viewer.
The River Authority Floodplain Viewer engages users in an interactive floodplain map, displaying the Federal Emergency Management Agency’s (FEMA) National Flood Hazard Layer (NFHL) data. Together with its many Bexar Regional Watershed Management (BRWM) partners, the San Antonio River Authority performs engineering studies to develop the data used in these digital maps, providing basic information about the floodplains in Bexar, Wilson, Karnes and Goliad counties. To download FEMA Flood Data Sets, please visit https://msc.fema.gov/portal/advanceSearch
What is the “base flood?”
The base flood, or 100-year flood, is the flooding event that statistically has a 1-percent chance of occurring in any given year. Thus, the base flood can also be called the “1-percent annual chance flood.”
The San Antonio River Authority Floodplain Viewer outlines the 1-percent annual chance flood boundaries—indicating that those areas will be inundated by a flood event that has a 1-percent chance of being equaled or exceeded in any given year. The San Antonio Floodplain Viewer also shows moderate flood hazard areas, which are represented between the limits of the base flood (1 percent annual chance) and the 0.2 percent annual chance (or 500-year) flood.
By no coincidence, the Special Flood Hazard Area (SFHA)—as defined by FEMA—is the land area covered by the floodwaters of the base flood—that is the 1-percent annual chance flooding event. This is important because the National Flood Insurance Program’s (NFIP) floodplain management regulations are enforceable in the SFHA, including the mandatory purchase of flood insurance.
FEMA encourages everyone to get flood insurance, even if you don’t live in a high-risk flood zone. While governments are doing all they can to alleviate the impact of floods, everyone should play a role in protecting themselves.
To learn more about flood insurance, click here to visit the FEMA National Flood Insurance Program site.