Harris County to draw up new flood maps
Work set to begin early next year with $6.5M in FEMA funds
More than a year after Hurricane Harvey showed the Houston area’s floodplain maps were outdated and inaccurate, Harris County is prepared to begin the years-long process of drawing new maps.
Commissioners Court on Tuesday agreed to accept $6.5 million in federal FEMA funds to complement $8 million in local dollars to create new maps, to be completed by 2023.
“We’re excited about that, and it’s going to be a big undertaking,” said Russ Poppe, executive director of the Harris County Flood Control District. He added the county already has begun the search for contractors.
A Houston Chronicle investigation found that of the more than 204,000 county homes and apartments that flooded during Harvey, nearly three in four were outside the 100-year floodplain. In those zones, which have a 1 percent chance of flooding in a given year, homeowners are required to purchase subsidized flood insurance through the federal National Flood Insurance Program.
County Judge Ed Emmett said there is no need to wait for new maps to complete the more than 230 projects included in the $2.5 billion flood bond voters approved in August.
“The maps are really more important to the homeowners and business owners and insurance than they are to our projects,” Emmett said. “Flood Control knows that the projects are needed to prevent flooding.”
He said the redefined floodplains will be essential to planning future development and assessing flood risk in communities. For years, he said government and private developers failed to keep track of where creeks and bayous drained, and where water flowed when waterways crested their banks.
The redrawn maps also will allow the county to more fairly enforce its new floodplain building codes. In the year after Harvey, Houston and Harris County added new requirements for floodplain development.
The county’s flood control district hopes to hire contractors through the end of the year to begin work in January. Director of Operations Matt Zeve said engineers hope to complete the new maps, which will cover nearly 800 miles of waterways, by 2023.
The new maps will cover Harris County’s 23 watersheds, including bayous, creeks, the San Jacinto River, Addicks and Barker reservoirs and Galveston Bay.
Zeve noted that the last time Harris County mapped its floodplains, starting in 2001, the project took six years. With better technology, the county now can do it in four.
Engineers will use LiDAR, a laser-based system used to measure land elevation, as well as Atlas 14, a tool developed by the National Oceanic and Atmospheric Administration, to study hypothetical flood-producing rainfall events.
“It’s a better product for the public,” Zeve said.
With the approval of several additional projects by Commissioners Court on Tuesday, the flood control district has begun work on about 40 flood bond projects, or about 17 percent of the total.