This story published online Tuesday, Dec. 13, and appeared in print Wednesday, Dec. 14.

Two months after Hurricane Harvey, the city of Houston spent $10.7 million to get nearly 60 damaged houses out of the flood plain.

A week later, developers went to City Hall, asking to build 900 new houses in it.

Meritage Homes, one of the nation's largest homebuilders, proposed a 151-acre development at the former Pine Crest Golf Course in northwest Houston, 2 miles east of Addicks Reservoir. It's on Brickhouse Gully, where city and county officials had already bought out more than 30 homes to reduce flooding before Harvey. They are in the process of buying 15 more.

Part of the Meritage plan was about to slip through City Council largely unnoticed before Cynthia Neely, a member of an anti-flooding group, raised an uproar.

"Why are we doing this if we're just going to repeat the process and let it happen in a new development?" Neely wondered. "It makes no sense."

UPDATE: Houston City Council unanimously backs plan to build homes in flood plain

The Meritage proposal would not just be in the flood plain but also along a more critical and vulnerable area: a floodway, loosely defined as the center of the wider flood plain. It's where water moves fastest during a 100-year storm.

Experts on flooding agree that it's a terrible idea to build in or along these channels of cascading floodwater. But Harris County and Houston have allowed 20,000 parcels worth $13.5 billion to be developed in or along them, a Houston Chronicle investigation reveals.

Structures in and near floodways cause water to pile up behind them. They raise the overall height of floodwaters after major rains, pushing water across more land, just as ice cubes displace water in a glass.

About 75 percent of buildings on those 20,000 parcels in or along the floodways were built before 1985, before the first 100-year flood elevations for Harris County were published. But about 1,400 structures, on floodway parcels valued at $4.2 billion, were built in the city and county since 2008, seven years after Tropical Storm Allison exposed the city's vulnerabilities, the Chronicle's investigation shows. More than half of those have Houston addresses.

Consider Buffalo Bayou, Houston's prime conduit for floodwaters from the Katy prairie to the Houston Ship Channel. In some places, the floodway is barely wider than the bayou itself, but downtown, where Buffalo and White Oak bayous converge, it is nearly 10 times larger — about 1,000 feet wide. It encompasses all of the University of Houston-Downtown complex on Main Street, which suffered an estimated $8 million in damage during Harvey.

The structures along floodways include some of the county's most valuable homes, and some of its key businesses; HP Enterprises is leaving its $110 million property on Cypress Creek after two floods in two years.

They include dense developments, such as the perennially flooded apartments around Greenspoint in north Houston and smaller ones such as Banana Bend in east Harris County, where the county is buying out 34 homeowners after Harvey.

Building in harm's way About 1,400 structures have been built on floodway parcels in Harris County since the city of Houston scrapped a prohibition on floodway development. More than half of those have Houston addresses. Bigger, darker dots have more structures within the parcel. Click on each dot for details. Source: FEMA/Harris County Appraisal District | Data compiled and analyzed by Matt Dempsey | Map created by Rachael Gleason

Experts look at the floodway development and wonder how it was allowed to happen.

"You need to stay the heck out of the floodway, completely," said Bill Robison, retired chief hydrologist for Tulsa, Okla. "There's no business ever building anything in a floodway other than a bridge to get over the floodway."

SOLUTIONS: After Hurricane Harvey, could Houston's leaders learn from Tulsa?

Even building along the edges of a floodway contributes to problems. The thousands of properties up and down the ditches and waterways of Houston act like levees. They force floodwaters into narrower paths, creating jet-like torrents, said Alan Lulloff, chief scientist for the flood plain managers association.

People living there get trapped during storms, creating dangers for rescuers such as Alonso Guillen, a volunteer from Lufkin who died during Harvey when his borrowed boat flipped under the Interstate 45 bridge at Cypress Creek.

Houston's miracle is its inexorable progress, through boom and bust. But its failure to guide that progress with zoning and other regulation has allowed repeated floods to inflict far more damage than they otherwise would have.

Republican Ed Emmett, Harris County judge since 2007, lamented that the county, under state law, has little power to regulate land use. It is now attempting to force builders to elevate new structures above the level of a 500-year storm, instead of the 100-year standard, but it can't tell them where to build.

His mission now: Get the Legislature to recognize that unincorporated Harris County, with 1.7 million people, is unlike any other in the state, and can't get a handle on its expensive flooding problems unless the state gives it authority to levy sales taxes and enforce additional rules such as building inspections — or even the prohibition of construction — in flood-prone areas.

He knows what he's up against in Texas.

"We live in a world where any kind of government control is looked upon skeptically," he said. "I'm starting with the overarching view that we should convert (large parts of the flood plain) to green space. How we are going to get there, I don't know."

Sylvester Turner, a former Democratic state representative, said he couldn't speak to what happened in Houston before he was elected mayor in 2016. But he relies on the mantra that it's "a post-Harvey world" — and that all of the city's flood plain regulations are under review.

As former Mayor Bill White learned a decade ago, they can be difficult to change.

'Their answer was no'

After Allison caused $9 billion in damage and 41 deaths in 2001, White's administration looked for some way to limit future flood damage. In 2006, the City Council took a big, broad step, prohibiting all new buildings in the floodway.

That ordinance lasted as long as it took for people to figure out what it really did.

Bruce Norcini was the first property owner to stumble upon the floodway prohibition, which, like many laws, passed with no fanfare and nary a protest.

He had constructed three houses in Shady Acres, northwest of downtown. He was trying to sell a desirable lot on 21st Street off White Oak Bayou when he found the city wouldn't approve any building permits there. As a result, the appraised value of two of his lots dropped from $70,000 to $4,000.

Nearby resident Rita Amador, now 94, saw her home equity — which the cancer patient intended to use to pay for assisted living care — dry up overnight. No one would buy her old house and now no one would buy the lot, either.

Norcini hired an eminent domain attorney and formed a coalition of affected property owners. He said they did everything they could think of to get city officials to negotiate.

"I said, 'You guys can't do this. Let's work it out,'" Norcini recalls. "Their answer was no."

After lawsuits claimed that the prohibition amounted to an unjust taking of the property, the city backed down.

Experts say the city should have been able to craft an ordinance to stop people from building in floodways. San Antonio, for example, doesn't allow new structures even in the wider 100-year flood plain. It allows people to use their land for other things — farming, parking lots, golf courses.

"You allow compatible uses and you disallow stupid uses," said Chad Berginnis, director of the Association of State Floodplain Managers in Madison, Wis. Litigation such as Norcini's is rare because courts have established that as long as people have some reasonable use of the property, it's not a taking, said Edward Ziegler, a University of Denver law professor and author of a multi-volume treatise on zoning law.

"A good lawyer can figure out how to do it and how to minimize development and not get sued," he said.

Bruce Norcini poses in Houston near town homes that now stand on land along W. 21st Street that he once owned. In 2006, the city prohibited building in floodways. Overnight, it rendered Norcini's property on W. 21st Street worthless. Norcini and others sued and forced the city to rewrite the ordinance. less Bruce Norcini poses in Houston near town homes that now stand on land along W. 21st Street that he once owned. In 2006, the city prohibited building in floodways. Overnight, it rendered Norcini's property on W. ... more Photo: Melissa Phillip/Houston Chronicle Photo: Melissa Phillip/Houston Chronicle Image 1 of / 8 Caption Close What’s in Houston's worst flood zones? Development worth $13.5 billion 1 / 8 Back to Gallery

More floodway development

When Norcini and the coalition saw their property values drop in independent appraisals, the Harris County Tax Assessor's Office did its own study, showing floodway property values could drop by $250 million overall, reducing local tax revenues by $6 million. The county estimated the prohibition affected roughly 10,000 properties in the floodway, including nearly 2,400 houses.

White, in a recent interview, acknowledged there's no reason to build in a floodway. But given the potential hit to taxpayers on reduced values and legal settlements, it would have been irresponsible to forge ahead with the prohibition, he said. After settling five lawsuits for tens of thousands of dollars, the city struck down the ordinance in 2008.

His successor, Mayor Annise Parker, was city controller at that time. "I think we were going in the right direction," she said. "But a lot of policy is influenced positively and negatively by litigation, and the determined few can drive the policy for the many."

Norcini likes the reworked ordinance, which allows people to build in floodways if they put the building on piers, dig out dirt to account for the space taken up by the piers and produce an engineering study showing that the construction will have minimal impact on flood levels.

"Build high, build strong," he said. "I think that's a pretty good answer."

Development in and near floodways has continued.

Since 2008, about 1,400 structures have popped up on parcels on or along Harris County floodways, and more than half of those have Houston addresses, according to the Chronicle's analysis. Some of those buildings are directly in a floodway and some are elsewhere inside a parcel that has a floodway running through it.

The prohibition episode was a loss for people who wanted to see a sea change in attitudes about flood control after Allison. In just five years, the city, collectively, had gone from underwater to "it'll never happen again."

During a 2008 episode of his radio show, Dan Patrick, then a Republican state senator and now lieutenant governor, dismissed any genuine public safety basis for the floodway prohibition.

"We're not talking about people who are living in areas that constantly flood," said Patrick, a strong advocate for the rights of property owners. "We're talking about a lot of these homes are in areas that have never flooded. In a hundred years, they've never flooded! ... But the city has said, 'Well, you might flood.'"

Personal floodway experience

Norcini sold his lot after the prohibition was lifted. Another builder put a townhouse in. During Harvey, water spilled into the garage. In a testament to Norcini's view — build high, build strong — only the garage was affected because the living areas were elevated to 100-year flood plain standards.

But the house — and every other structure along the floodway that was surrounded by water — raised the overall flood height and disrupted the flow of floodwaters, said Lulloff, chief scientist for the flood plain managers association.

"Allowing new development that increases flood elevations and velocities on existing development injures others and, therefore, violates their property rights," Lulloff wrote in a 2013 paper.

Among other things, that paper concluded that fully developing the floodway fringes on sections of Cypress Creek — and many stretches are fully developed already — speeds up the water flow by as much as 45 percent, inflicting far more damage.

White said that was the reasoning behind the city's prohibition.

It "was not to protect homeowners from themselves," he said. "The reason was to protect (other) people ... from flood damage."

Parker, who followed White in office, said the city had every right to prevent one person's development from harming others.

"If what you're doing jeopardizes theassets of your neighbors, the state has a right to intervene," she said.

Before Harvey, Norcini and others had already helped increase the density of that part of Shady Acres, dividing lots into smaller ones, according to court and appraisal district records, and the same thing happened all over town. Today, that stretch of 21st Street is packed with townhouses where yards once were.

White built his own home in 1998 on piers at the edge of Buffalo Bayou's floodway, west of Loop 610 in Memorial, one of Houston's wealthiest neighborhoods. When Harvey came and the bayou rose 18 inches into the house, he threw some clothes into a backpack, grabbed some important papers, and waded into waist-deep water.

He was less than 100 feet from the floodway where he wanted to prohibit building. But for all practical purposes, he was standing in the floodway ­— not the one on the map, but the real floodway where water moves during a storm.

"Nature," Lulloff said, "doesn't care about those maps."

Determined to stay

Gladys Thompson is a rare holdout on 21st Street, two lots over from what used to be Norcini's property. She has resisted the temptation to sell her lot to developers eager to divvy it up and build townhomes. At $401,000, the lot is worth 15 times the market value of her home. She and her late husband built it on a concrete slab in the White Oak Bayou floodway in the 1950s. She doesn't want to leave now.

Her living room is a football field away from the bayou, just inside the Loop on the northwest side. When Harvey came, it was in the bayou, under more than 4 feet of water.

She evacuated about 4 a.m., before the flood came, and didn't come back for two months. Even after this ordeal, Thompson, 92, decided to move back in. Her son, Curtis Thompson, 72, was gutting the place in October and lugging in new drywall, one of several family members who chipped in to help her rebuild. He said Gladys will buy flood insurance — for the first time — and gamble that she and her sons won't need it in their lifetimes.

It's their choice to stay in the floodway. They had built there before the term was even coined.

But City Hall soon will be making the choice whether Meritage, six miles west of Thompson's house, can build homes of up to $500,000 along the Brickhouse Gully floodway. It starts as a ditch less than half a mile to the north before spreading out across the old golf course and then draining into White Oak Bayou to the east. About 12 square miles drain into the gully, long known as a problem area to flood control officials.

Preliminary estimates from the city show Harvey damaged more than 2,300 homes and apartments in the Brickhouse watershed. There were more than 100 federal flood insurance claims in the watershed after Harvey, according to the flood control district.

The city approved the original Meritage site plan in September 2016, six years after a report from the flood control district estimated that about 2,700 structures along Brickhouse Gully would flood in a 500-year storm, and that homes there were already flooding every few years. The developers plan to elevate the homes out of the 500-year flood plain, not just the 100-year.

Then came Harvey.

The way forward Structures in and near floodways can make overall flooding worse. So what could Houston and Harris County do? Experts say the following options, along with reducing flooding, can result in lower flood insurance premiums for everyone in the community, regardless of whether they are in a flood plain: — Prohibit new structures or major improvements to structures in floodways Currently, local rules allow buildings in floodways if they meet certain elevation and engineering requirements. But other cities have limited floodway development to uses such as golf courses, farms and parking lots, a restriction that has survived legal challenges from property owners. — Redraw the maps. Mapped floodways in Texas come with a baked-in flaw: They allow buildings to encroach on the fringes of the floodway to the point that the overall water level in a flood rises 1 foot higher than it would if the buildings weren't there. Four other states allow almost no rise in flood levels, and four others allow less than half a foot. The result is a wider mapped floodway where development is restricted. Some cities have removed the floodway concept altogether, prohibiting all buildings in the 100-year flood plain. — Increase elevation standards in the flood plain. The entire flood plain, including the floodway, does its job of storing and carrying away floodwater a lot better when there's nothing in the way. Houston requires 1 foot of "freeboard," meaning buildings must be elevated at least 1 foot above the 100-year flood elevation. FEMA offers credits toward flood insurance discounts for communities that require up to 3 feet of freeboard. Sources: FEMA CRS Coordinator's Manual, Association of State Floodplain Managers, Chapter 19 of the Houston City Code

In early November, the City Council held off on approving a municipal utility district for the subdivision — Spring Brook Village — after the Chronicle published a story. The district would be able to issue bonds to finance improvements.

Matthew Zeve, director of operations for the flood control district, said nearby homeowners have filled his inbox with complaints about the project, but the district had to evaluate it based on current requirements, which were on the books before Harvey. They require that any development not create worse flooding, upstream or down, during a 100-year storm, a rainfall that has a 1 percent chance of happening in a given year.

"This could take that flood every day," said Robert Moore, director of land development for Meritage.

The company's engineering firm submitted a memo to city officials on Nov. 1, saying its model shows that even in a Harvey-like storm, water wouldn't overtop the street curbs. Those calculations haven't been reviewed by the flood control district, and aren't required to be, Zeve said.

The Meritage memo relies on rain gauge data that showed the site got about 36 inches of rain during Harvey. But the amount of rain — and the speed at which it fell, which is critical in drainage calculations — varied widely across Southeast Texas. Nederland, outside Beaumont, set a new U.S. rainfall record for a tropical storm, at 64.5 inches.

Meritage officials emphasize that because their drainage plan improves flood storage and runoff over the existing golf course, areas downstream along Brickhouse Gully will be better off in any storm than they are today.

But the cumulative impact of building along the county's floodways over time is that flooding gets worse, Zeve and the other experts said. And adding houses along Brickhouse Gully means sacrificing an alternative: green space with even more detention capacity.

Zeve said he wishes MetroNational, which sold the land to the developers, would have offered to sell it to the flood control district. MetroNational said the district never raised the idea.

"I'd love to build a big old hole in the ground right there and try to reduce flood risks on Brickhouse Gully," Zeve said. "Now does that make MetroNational any money? It might make them some money, but they probably make a lot more money doing single-family residential, and they're a business and they have profit goals, so they make those decisions."

It's impossible to equip Harris County with flood control that would protect everything against a storm of Harvey's scale, Zeve said, but area officials acknowledge that the current 100-year design standards are out of date. They've approved upgrading to the 500-year standard, and the city could follow suit.

Moore said Meritage intends to meet new standards should the city adopt them.

"No one wants to build the development of tomorrow to yesterday's standards," he said. "If we've misjudged or aimed too low, we'll find a way."

Rebecca Elliott and Mike Morris contributed to this report.

About our investigation: "Developing Storm"

Hurricane Harvey was the most destructive storm in Houston's history. The late-August storm dumped up to 60 inches of rain on southeast Texas, but the resulting damage was multiplied by actions taken ­– and not taken – during the past 50 years. Our seven-part series explains why the storm's damage was both a natural and man-made disaster.

To analyze development in and near floodways, the Houston Chronicle first sought city and county data about buildings inside floodways. While both issue construction permits for those buildings, neither keeps data on how many were built before current permitting rules were in place, or how many non-permitted structures exist.

The Chronicle then obtained floodway boundary data from FEMA and a database of every parcel in the Harris County Appraisal District, and overlaid the parcels on a map of floodway boundaries to determine which parcels were located entirely inside floodways or had floodways running through them.

The Chronicle then relied on the county database to see which of the floodway parcels had construction on them, and in what years. The analysis captures any parcel that has construction on it and intersects a floodway, regardless of whether the construction was inside the floodway or elsewhere inside the parcel.

Parcel values were based on the appraisal district's values for 2017. Floodway boundaries were based on FEMA's flood insurance rate maps for 2017.

Mark Collette finds the information the government and corporations don't want you to see. Contact him at mark.collette@chron.com. Follow him on Twitter at @ChronMC.

Matt Dempsey is the data reporter for the Houston Chronicle's Investigations team. He joined the Chronicle in 2014 and has worked on several major projects, including the investigation on the dangers of chemical plants. Matt previously worked for the Arizona Republic and Atlanta Journal-Constitution. Contact him at matt.dempsey@chron.com. Follow him on Twitter at @mizzousundevil.

Multimedia by Houston Chronicle staff

Data analysis by Matt Dempsey

Interactives by Rachael Gleason

Audience engagement by Rachael Gleason

Design by Jordan Rubio

Get engaged

— Where do we go from here? Seven Houston-area leaders discussed flooding causes and solutions at a Greater Houston After Harvey forum hosted by the Houston Chronicle in early December. Watch Wednesday night's keynote address by Jim Blackburn, co-director of Rice University's Severe Storm Prediction, Education and Evacuation from Disasters (SSPEED) Center. Read his thoughts on living around water.

— Sign up for our Facebook community to share your Harvey story, engage with other community members and ask our reporters questions.

— Join the discussion on Twitter: #HoustonAfterHarvey.

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