Williamson County now has more floodplains, study explains why

WILLIAMSON COUNTY, Texas (KXAN) — Williamson County has some preliminary findings from its ongoing Atlas 14 Floodplain Mapping Study. Researchers found that the number of homes near floodplains has doubled since the last time the data was updated.

The county partnered with the Texas Water Development Board for this study with the goal of updating floodplain information with rainfall data released by the National Oceanic and Atmospheric Administration (NOAA) in 2018.

Cindy Engelhardt with Halff Associates, a company assisting with the county’s study, said the study team recorded an additional 1,300 stream miles to the county’s waterways, bringing that number up to 2,800 stream miles.

The study team’s findings suggest there are now 11,500 buildings in or near a floodplain with 35% of those along the new streamways.

Why are there more buildings near floodplains?

Engelhardt said the increased number of homes near floodplains is no surprise given the rapid growth of the county and increased development, along with the study team actively looking to add streams to its count.

She said another goal of the study is to provide the public with updated and accurate information, in part so they can input their address into the county’s floodplain map and see what’s been recorded.

Engelhardt said researchers have also found that while it’s not “raining more” in Williamson County, it is “raining harder.”

She said those heavy rains have given teams an even better idea of where flooding is taking place as floodplains are determined by the amount of rain falling in a certain amount of time.

“We’re not saying Williamson County’s rain is increasing, we’re just saying that the storms that do come through are more intense. So in a 24-hour period, which is how we define floodplains, the rain that is dropping in that time period is more,” Engelhardt said.

County seeks public input

The team’s first draft of the study is now available on the county’s website and will be updated once the study is complete. The county said it anticipates that taking place in 2026.

The county is holding public meetings to gather input on the study and crosscheck findings. Several meetings are taking place already in Georgetown, Round Rock, Hutto and Taylor.

Upcoming meetings and locations are as follows, all meetings are from 5 to 7 p.m.:

• June 6: Williamson County Cedar Park Annex, Judge Williams Courtroom, 350 Discovery Blvd., Cedar Park, TX 78613
• June 10: Walburg Community Center, 4000 FM 972, Georgetown, TX 78623
• June 11: Sonterra MUD Boardroom, 113 Limestone Terrace, Jarrell TX 76537
• June 17: St. Dominic Savio Catholic School (in the library), 9300 Neenah Avenue, Austin, TX 78717

Any questions on the study or information about flooding on private property such as photos or videos can be sent to atlas14@wilco.org or mailed to the Public Affairs Office at 710 S Main Street, Suite 101, Georgetown, TX, 78626.

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