THE WOODLANDS, Texas — Leslie Martinez heard the floodwaters before she saw them. They rushed across the lawn, seeped around the doors and into the house.
It was 2:15 a.m. Aug. 28, three days after Hurricane Harvey made landfall. Her young daughter was asleep in her arms. Martinez’s first reaction was to spread towels around the floor.
After all, Martinez recalled, the homebuilder had assured her that “flooding was not even a possibility” when she and her husband purchased the house in this planned suburban community north of Houston in 2011.
They would never have bought here otherwise. Flood insurance, of course, was neither required nor needed.
Now, with the rains outside lashing and the water inside rising, the family took refuge on the second floor. Later that day, rescue boats came and ferried them to safety.
The flooding forced Martinez and her husband, John Ahearn, to borrow money from their parents and accept a donation from their daughter’s school. It left them feeling furious and betrayed.
“I’m scared that it’s going to continue happening,” Martinez said, even as she wondered how they had become the victims of something they had been told had a vanishingly small chance of coming to pass in such a short time since the purchase.
What they did not know was that their home, and those of many of their flooded-out neighbors in this new section of the Woodlands, had been built on land that not long ago lay squarely in a flood plain.
A New York Times examination found that in the years leading up to Hurricane Harvey, with a surging local economy fueling demand for new upscale housing, the developers of the Woodlands had used a wrinkle in the federal flood-mapping system — along with many dump trucks’ worth of dirt — to lift dozens of lots out of the area officially deemed prone to flooding.
What they had done, in effect, was create gerrymandered maps of risk.
In Martinez’s case, documents show, the land was raised less than 10 inches above the level that, under federal flood-insurance rules, would have required the family to be notified of their risk and purchase insurance. Other lots in their area were raised as little as 1.2 inches above that height.
No one has suggested that the developers broke any laws, and the company that owns the Woodlands says it followed all applicable regulations and standards. But the experiences of Martinez’s family and their neighbors show that even when the mapping rules are followed to the letter, the results can be disastrous.
The adjustment process began as a way to correct the wild inaccuracies in the maps that form the basis of the federal flood-insurance program, which was created in the 1960s to protect homeowners from catastrophic loss. Increasingly, though, the changes have also become a way for developers to build on low-lying land.
Across the country, documents show, the Federal Emergency Management Agency, which runs the insurance program, has granted more than 150,000 map changes in the past five years. In some cases, lots were raised, and in others, levees, drainage systems, water-detention ponds and other methods changed the calculated flood risk for a swath of land.
Many of these changes were unquestionably appropriate. But in the Houston area, a Times analysis of FEMA documents shows, at least 6,000 properties in redesignated zones were damaged during the flooding caused by Harvey.
“This is all about engineers doing things for developers rather than for the public,” said James B. Blackburn, codirector of the Severe Storm Prediction, Education and Evacuation from Disasters Center at Rice University in Houston.
Blackburn, who was involved in early designs of the Woodlands, added, “It would be nice to know that you were only 2 inches above the flood plain. You know, that’s not a lot of margin for error on these maps. Yet all the federal protection for flood insurance gets removed.”
What happened in the Woodlands underscored one of the great lessons of Harvey’s assault on Houston: the profound vulnerability of a metropolis with an ethos of untrammeled development built, essentially, on a swamp.
To Martinez and her neighbors, the cruel twist was that it could happen here — in a community founded in 1974 as a kind of anti-suburbia by oil and gas billionaire George P. Mitchell.
If the Woodlands was a community apart, rich with woods, lakes, trails and streams, Mitchell was its benevolent dictator, whose vision of building quality and environmental balance fostered a reputation of a development where the flood risk was extremely low.
Mitchell sold his company’s stake in the Woodlands in 1997, and the community has been steered by a succession of publicly traded companies — most recently, Howard Hughes Corp., which bought a major stake in 2010 and acquired the rest the next year.
Don Hickey, a 37-year resident of the Woodlands who was an early employee of Mitchell, said people paid more to live here in part because they felt they would be safe.
Hickey, who works in real estate finance and is collaborating with fellow homeowners to get their flooding problems fixed, summarized the situation in caustic terms, saying, “The developer had an economic benefit to more aggressively develop land around the flood plain or spend less money on flood control.”
The company says quality has not slipped during the transition of ownership.
“Since development began at the Woodlands more than four decades ago, it has strived to be a model master-planned community. While ownership has changed, what has never changed — nor will ever change — is our strict adherence to standards and our commitment to our communities,” said Grant Herlitz, president of Howard Hughes Corp.
Hurricane Harvey, the company argues, was an exceptional flooding event, and all map revisions followed federal and local guidelines. “To the extent that standards are reevaluated, we will do as we have always done and act in accordance with any new regulations,” Herlitz said.