What Happens When Flood Maps Don’t Illustrate True Risk

3/25/25 – Eight years after Hurricane Harvey and a massive region-wide effort to update flood maps, FEMA still features maps on its website based on decades-old data that don’t come close to showing true flood risk. The old maps cause confusion among buyers who may not understand their limitations. And that helps developers pursue and profit from risky ventures.

Three-Year Delay for New Maps and Still Counting

FEMA has yet to release maps based on more recent Atlas-14 data developed after Hurricane Harvey. Harris County Flood Control District (HCFCD) anticipated release of FEMA’s new preliminary maps three years ago and release of the final maps by now.

Harris County and Federal officials did not respond to requests for information about the release of updated flood maps.

Delays Contribute to Confusion about Safety of New Developments

The delays have contributed to confusion about the safety of new developments near or in floodplains.

Take, for instance, the lawsuit between the City of Houston and one of the area’s largest developers. According to a Texas Supreme Court decision released last Friday, the Signorelli Companies want to develop more than 500 lots near the San Jacinto East Fork as part of The Commons of Lake Houston.

Even though plats show most of the lots outside the current 500-year floodplain, floodplains will reportedly expand by 50-100% when the new flood maps come out. At that point, most if not all the lots will likely be deep in the floodplain.

So, the City imposed higher elevation requirements for homes in anticipation of the new flood maps. That triggered a property-rights lawsuit by the developer, which claimed the City’s requirements made the property “undevelopable.”

Sometimes We Just Never Learn

Sometimes, it feels as if we just never learn. I understand a developer’s desire to make money from its land. But unsuspecting homebuyers could lose their life savings. Worse, more people could die.

Flood insurance is becoming unaffordable for many. Insurance companies are fleeing high-risk areas.

And we haven’t even mentioned yet the costs of flood mitigation, disaster relief, buyouts, and restoration of the natural ecosystems–that already protect people for free.

In my opinion, for the public good, some land just shouldn’t be built on.

The Commons of Lake Houston Proposal

The flood map for the Commons area on the East Fork was last updated in 2007. It is based on Pre-Atlas-14 data acquired after Tropical Storm Allison in 2001. New Atlas 14 rainfall data is 30-40% higher than previous estimates and represents the current best efforts of scientists.

The map below shows the extent of those 100- and 500-year floodplains in 2007 maps as dotted lines superimposed over a proposed new section of the Commons called the Crossing.

Two Pictures Worth 2,000 Woods

These two pictures, sent to me by nearby residents of existing homes on higher ground in the Commons, illustrate the problem.

Think such a flood can’t happen again your lifetime? That Harvey was a thousand-year storm?

It almost happened again last May in a no-name storm a month before the start of hurricane season. The screen capture below shows historical data from an HCFCD gage just upstream from the Commons. Note the last three entries.

That no name storm produced flooding almost five feet higher than Imelda and only about four feet lower than Harvey. It was the second highest flood at that location since HCFCD started keeping records!

Will We Repeat Mistakes of the Past?

The thing about floodplains is that they keep growing with upstream development – especially as other developers push into wetlands near rivers and streams. And the area upstream from the Commons is growing very quickly.

At some point (like now), it may make more sense to donate this land to an organization such as the Bayou Land Conservancy, Houston Parks, or Texas Parks and Wildlife. That would offer the developer tax benefits, help protect the public, and provide recreation. It would even likely add value to homes on higher ground.

Posted by Bob Rehak based on 3/25/25

2765 Days since Hurricane Harvey

The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.

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