Updated April 27 at 3 p.m.

Changes to flood plain maps will soon go public in Cedar Park and Leander as both cities are in the process of a massive overhaul of the Federal Emergency Management Agency’s guide to area flooding.

In the past few months, the cities teamed with other area municipalities and entities, such as the Upper Brushy Creek Water Control and Improvement District and Williamson County, to make changes to local maps and inform residents on what to do if their property is impacted.

Including a house in a designated flood plain can result in additional costs in the form of mandatory flood insurance if a resident or business owner’s property is added to the flood plain. Some properties have also been removed from the high-risk flooding list.

Many factors go into identifying flood plain designations between map updates. Local officials said several heavy rain events in the past several years, along with continued local development, have given the cities a much better look at where the water goes and where concerns exist.

The Upper Brushy Creek district is responsible for operation and continuous updates of 23 dams in Williamson County. Most of the dams are located in Round Rock, Leander, Cedar Park and Hutto. Ruth Haberman, Upper Brushy Creek general manager, said the district continues to work with local emergency responders to refine data.

Updates include the modernization of two dams, work that Haberman said should start toward the end of 2017 and finish at the end of 2018.

“That completes the original [dam update] program,” Haberman said. “In the meantime, the two remaining district dams were reclassified to high hazard, based on downstream impacts in the event of a dam failure, not based on the condition of the dam. One of those dams already meets state requirements, but we will need to evaluate the other for remediation needs and funding opportunity.”

Haberman said the district has initiated a watershed-wide evaluation to develop a long-term capital remediation plan to address infrastructure maintenance and repair needs.

With much-valued information from the improvement district, Cedar Park, Leander, Round Rock, other surrounding communities and Williamson County all feed their information to FEMA and its National Flood Insurance Program. The goal of the federal flood program, according to FEMA’s website, is to reduce the impact of flooding on private and public structures by providing affordable insurance to property owners and encouraging communities to adopt and enforce flood plain-management regulations.

Not only does the map revamp allow cities to have updated data, but it also provides accurate information that cities and communities can use when assessing development, said Michael Lafferty, Leander assistant flood plain manager. The Upper Brushy Creek WCID started a flood-protection plan in 2012.

“There’s been so much work in and around this area; (the district) decided that all communities should work with the [improvement district] to get the data moved into a comprehensive model that could be used for flood maps,” he said.

Leander City Engineer Wayne Watts said the 2008 maps, which are currently the most recent, did not restudy the area but instead used updated topographic information to adjust floodplain boundaries based on calculations made in 1990.

“In 1990, this city had 3,500 people in it,” Watts said. “It’s got 49,000-plus today. You can imagine the changes. And that applies across Williamson County.”

Cedar Park, which has also seen growth, had engineering officials compile their own survey results to send to FEMA, according to the city.

Flood plains and updating the maps

A flood plain is the flat, low area of high-risk land adjacent to waterways, such as rivers and creeks, that has a 1 percent or greater chance of being hit by water in any given year—also known as a 100-year-flood. 

A flood plain is beneficial for filtering storm water and decreasing the severity of floods, allowing the water to safely flow back to the rivers, streams and developed drainage systems with minimal danger to life and property.

FEMA developed its first maps in the 1980s, said Round Rock City Engineer Danny Halden. He said Round Rock has done a good job over the years of identifying and protecting growth near the city’s flood plains, which have been tested recently when quick, heavy bursts of rain hit.

“Updating the maps is quite a process,” Halden said. “There is a lot of data, and there have been a lot of changes.”

In the past few months, a technical advisory committee with the improvement district met with officials from Leander, Cedar Park, Round Rock, Hutto, Austin, Pflugerville and Williamson County on the mapping. Leander signed a resolution in support of the project, and neither Cedar Park nor Leander had any financial obligation to the remapping process outside of normal surveying costs, representatives from both cities said.

“We helped them with getting the models, working the data, seeing how it matched up with what we had in the city,” Lafferty said. “After going through all the review processes, it went to FEMA in December 2015.”

The cities received a preliminary flood map from FEMA on Jan. 30, and Leander is now working with an engineering firm to review the flood plain and suggest changes based on recent developments. Other cities also are reviewing the information.

“We’re working with the other cities and entities to coordinate information,” said Jennie Huerta, spokesperson for Cedar Park.

The next step is a consultation coordination officer meeting among the different entities. The meeting could happen at any time and is set up by FEMA.

After the meeting, FEMA hosts a 90-day public comment period, during which individuals or businesses may refute or comment on the maps.

“Appeals have to have scientific basis. You can’t just say, ‘I don’t think I’m in the flood plain,’” Lafferty said. “It has to have some modeling or evidence behind the appeal.”

Leander also will submit data during the comment period. Watts said the map data is a snapshot the improvement district took in 2012. The city has reviewed the preliminary map and is working to address additional data that has been collected since plans were submitted, helping “protect some of our citizens who might otherwise be placed in the flood plain,” he said.

“We have to make sure that we don’t have citizens who are inadvertently identified as being within the flood plain when they truly are not and they’re not subject to flooding,” Watts said. “Particularly, we do not want them to have their mortgage company come back to them and be required by federal law to mandate that they buy flood insurance.”

Flood plain designation

If a property is in the designated flood plain, then it has high-risk for severe flooding. Special insurance is required, either purchased by the homeowner through their agent or assessed to the homeowner through federally backed or issued mortgages. The latter often costs much more.

Flood risks have designations of high risk, moderate to low risk, and undetermined risk areas as categories. Although it is mandatory to have insurance in the high-risk category, floods may happen in the moderate and undetermined risk areas. Flood insurance is available to all homeowners.

“This is a large-scale overview of area between Leander and Hutto,” Lafferty said. “A lot of people think, ‘I’m not in the flood zone; I don’t have any flood risk.’ There’s local drainage programs that can cause flooding that would not be captured by this. This is a snapshot. In 10 or 20 years when this area is restudied, it could change again.”

Round Rock Farmers Insurance agent Philip Gunter said he lived in a flood plain for 17 of his 20 years in the area.

“Seven years ago, our home flooded, so not only did I live on a flood plain and have a flood policy, I also had a major flood claim where we had to vacate our house,” Gunter said. “It was a major lifesaver.”

Gunter said homeowners’ policies do not cover floods. The policies he sells as a flood insurance specialist are always through the FEMA program. He said roughly 10 percent of his clients include flood insurance policies. He no longer lives in a flood plain, but he urges those who do to purchase the security of a policy through their agent.

“No homeowners’ policy I’ve ever seen covers a flood,” Gunter said. “And flood policies don’t cover what a standard home policy covers.”

City officials said they will get as much information to the public as possible in April and May to help residents understand what they need to do if they are in a designated flood plain. 

To ensure those affected by the map revision process have an opportunity to give input, a public comment and appeal period is expected to run from June through August. After that, FEMA will allow a six-month compliance period while new maps are printed and distributed, according to the agency. No comprehensive updates are expected for another 10 years.