One in Five Texans Lives in a Floodplain
At the same time, higher global temperatures are melting glaciers, increasing sea levels around the world — including in Texas — and making coastlines more vulnerable to storm surges. Between 2000 and 2019, rising sea levels caused the Texas coastline to retreat about 4 feet per year on average, according to a 2021 University of Texas Bureau of Economic Geology report for the Texas General Land Office.
Reem Zoun, director of flood planning at the TWDB, said that to decide how to prevent flooding in Texas, the agency first needed to identify which areas of the state were at the most risk. The analysis identified how many buildings, homes, people, hospitals, roads and agricultural areas are in a floodplain.
The San Jacinto region, which includes Harris County and Galveston, has the most people living in a floodplain: almost 2.5 million people are in a 100- or 500-year floodplain. The Lower Rio Grande region, which spans much of Texas’ southern border and includes the Rio Grande Valley, is next with about 1 million people at risk.
Though floodplains are defined by the Federal Emergency Management Agency, the agency does not map every inch of the U.S. and its maps have long been criticized as out of date and underestimating actual flood risk.
Texas used existing flood data to create the maps that served as a baseline that regions could add to with their own flood hazard maps — if any existed — and supplement with knowledge from local water managers. In regions with very little data, gaps were filled with data from a contracted flood risk modeling data company called Fathom.
Sixty-three of Texas’ 254 counties had no existing flood hazard information prior to the planning effort, according to the TWDB.
In the Canadian-Upper Red region, for example, which includes much of the Panhandle and Wichita Falls, hardly any flood maps existed, while 98% of the Lower Red-Sulphur-Cypress region in the northeast corner of the state had inadequate flood mapping, James Bronikowski, TWDB’s manager for regional flood planning told the board on Tuesday.
The TWDB often functions as a water infrastructure bank and intends to use the planning process to help finance the construction of flood prevention projects with low-cost loans and grants, although the cost of the projects far outweighs the money that’s been dedicated to the agency by lawmakers.
During the 2023 legislative session, lawmakers allocated $625 million to finance flood prevention projects through the Flood Infrastructure Fund. Once the statewide flood plan is finalized, projects will have to be included in the plan in order to access those funds.
Another $550 million of the surplus was allocated to the coastal barrier project that includes the Ike Dike.
Erin Douglas is the climate reporter for The Texas Tribune. This story is published courtesy of the Texas Tribune, a nonpartisan, nonprofit media organization that informs Texans — and engages with them — about public policy, politics, government, and statewide issues.
