New flood insurance map to affect hundreds


A seven-year collaborative effort to update a decade-old flood map that determines if a federally backed mortgage is legally mandated to purchase flood insurance is in the final stages of development in Williamson County.

The new map, developed and published by the Federal Emergency Management Agency is based off a watershed study by the Upper Brushy Creek Water Control and Improvement District, will affect hundreds of Round Rock and Williamson County residents as their properties move in or out of the dictated flood risk zone.

FEMA’s flood insurance rate zone map is used by insurance companies to determine if flood insurance is legally mandated for a property. This map shows the flood plain information for the Upper Brushy Creek WCID watershed, which covers most of southern Williamson County, and the San Gabriel River watershed that runs through the rest of the county.

In Round Rock alone city engineers estimate that approximately 300 of 500 total structures that are on the existing flood insurance rate map will be removed from the upcoming FEMA map. Those structures are now likely to be relieved of federally mandated flood insurance policies.

Structures, according to Round Rock flood plain administrator Danny Halden, are likely houses, though it is impossible for the city to determine if they are elevated off the ground to make them safer from floodwater. The city additionally cannot determine if the structure is a storage building or a shed.

Only federally backed mortgages are mandated to purchase flood insurance if the property is located inside the flood insurance rate area. If a house is already paid off or is paying a mortgage that is not backed by a federal lender then the legal mandate does not apply to that property.

Hutto city officials found that more properties are poised to move into the amended flood risk area. According to the city of Hutto, 110 platted lots that were previously not in the flood plain are now in the area of mapped flood risk, as opposed to 38 platted lots that are set to leave the flood plain. It is unclear if there are any structures located on those lots.

The Upper Brushy Creek WCID Flood Protection Plan published in June 2016 identified a total of 927 structures inside the district’s 500-year flood depth grid. That included 824 single-family homes, 10 multifamily properties, 10 public facilities and 83 commercial properties. The 500-year flood has a 0.2 percent chance of occurring during any given year.

Williamson County is reporting a similar trend in its unincorporated areas. According to numbers provided to Community Impact Newspaper, 228 structures in unincorporated areas in Williamson County will leave the flood plain—more than the identified 143 structures previously outside of the flood plain that are soon expected to be within its boundaries.

“As we’re studying it and keeping an eye on it we’re letting folks know when they’re coming in for a permit where [the flood plain]is and how we expect it to impact their property,” said Terron Evertson, flood plain administrator for Williamson County.


Property owners that are about to be moved into the new flood insurance rate map flood plain will likely have to buy some form of flood insurance. According to the FEMA website, Congress mandates identified flood-risk properties purchase flood insurance if their corresponding mortgages are federally backed.

A vast majority of mortgages are federally backed. If one’s mortgage is financed through Freddie Mac, Fannie Mae or the Federal Housing Authority, it is federally backed and subject to Congressional mandate.

FEMA officials say the map is expected to become official by fall 2019, though local officials caution the process has already been delayed several times. At the time of the map’s official adoption, affected property owners will be required to carry flood insurance.

If property owners have not yet already been contacted by their insurance carriers, FEMA and local officials urge residents to reach out to their city or county flood plain administrator to see if their property may be affected.

“The more that communities and homeowners know about this process, the better we can work together to make sure that we build safely and resiliently and are prepared for flooding and other natural disasters,” Larry Fordham, acting regional insurance liaison for FEMA Region 6, wrote in an email.

Fordham outlined several cost-mitigating options for property owners now under mandate to purchase flood insurance, such as the Preferred Risk Policy. The policy is the National Flood Insurance Program’s preferred policy for homeowners and, according to Fordham, provides the best coverage for the lowest cost if purchased before the new map becomes official.

None of the governing bodies or agencies involved in this mapping have an estimate on how much this may cost property owners as a whole across Williamson County.

Across the board FEMA and local officials recommend flood insurance even for those outside of the identified flood plain, warning that flood damage—however unlikely—can be extremely costly for a homeowner.

“Weird events happen, and events that happen outside of the FEMA limit occur,” Halden said. “If [property owners]live closer to a creek they need to delve into things and understand their risk. … Sometimes people think a line on a map is a line that is never going to be crossed.”


The area’s flood insurance rate map was last updated in 2008, according to Evertson, and even then it used old, spotty data.

“There really hasn’t been new analysis done since 1991,” Halden said. Per Halden the flood insurance risk map currently on the books is based off data that was collected nearly 30 years ago.

“Round Rock is such a fast-growing community we’re dealing with, [and]we’ve got the old maps that are effective,” Halden said. “[Now] we have this preliminary information, which seems like better information.”

The new flood insurance rate map is built off new watershed data collected and compiled by Upper Brushy Creek WCID. The WCID received grant funding from the Texas Water Development Board in 2011 to develop a flood protection plan and more accurately map the area’s watershed. The watershed study was also partially funded by FEMA itself.

Williamson County and multiple municipalities, including Round Rock and Hutto, participated in compiling data. For the first time in three decades, the floodplain maps were developed using recent development information, detailed topographical data and modern technology, creating the most accurate and technologically advanced watershed study the region has ever had.

“It has been an incredible collaborative effort. I don’t know if there’s been an effort like this. I think we’re really fortunate. We’re going to have one of the best products out there,” said Alysha Girard, general manager of Upper Brushy Creek WCID.

Local officials reached out to FEMA to use the WCID’s watershed data to build Williamson County’s newest flood insurance rate map, a request FEMA granted.

“[Williamson County] is a rapidly growing area,” said Larry Voice, civil engineer for FEMA Region 6. “When a lot of the data was being developed there it wasn’t a highly populated area. … As you have more people in there it becomes important to really get a precise answer there.”

FEMA will soon release revised maps based off flood plain appeals. According to FEMA no public comments were received, though at least one developer appealed to the agency through the city of Round Rock.

The city of Round Rock itself filed “four or five” appeals, per Halden.

Local agencies will receive the revised preliminary map sometime this spring, according to Voice, and the agency will then file a letter of final determination. Within six months of that action the new flood insurance rate map will become effective and the majority of properties located inside the flood plain will require flood insurance.

“We strongly encourage [residents]to look at this new data and understand it,” Voice said. “We caution them not to be overconfident if they’re not in the flood area and not get insurance anyways.”

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Iain Oldman
Iain Oldman joined Community Impact Newspaper in 2017 after spending two years in Pittsburgh, Pa., where he covered Pittsburgh City Council. His byline has appeared in PublicSource, WESA-FM and Scranton-Times Tribune. Iain worked as the reporter for Community Impact Newspaper's flagship Round Rock/Pflugerville/Hutto edition and is now working as the reporter for Northwest Austin.
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