CHARLOTTE — Swinging cranes and clawing excavators have reshaped the landscape, elevating Charlotte’s skyline, expanding its girth and transforming this former cotton-shipment town into the South’s financial hub and one of America’s fastest-growing cities.

But the Queen City also has been steadily unbuilding itself, bulldozing houses and razing apartment complexes along its creeks, ripping up a mall parking lot to reveal a hidden waterway and then stripping away its concrete banks, all in a bid to prevent the flash flooding that turns communities into deathtraps.

The county has removed 460 structures and replaced them with absorbent grasslands, winning national praise as a prototype for regional flood planning that anticipates the impact of projected development and the growing effects of extreme weather. The innovative strategy was ahead of the curve when it launched in the 1990s, by calculating future flood risk and then purchasing — and demolishing — vulnerable homes, businesses and office buildings.

But the region is facing more-complex challenges as climate change threatens bigger and more-lasting deluges. Six out of North Carolina’s seven wettest storms have occurred in the past 20 years. In June, after an 11-inch downpour upstream, the Catawba River burst its banks here in a catastrophe that can’t be cured by opening up a few extra acres of flood plain.

“We just can’t engineer ourselves out of this problem,” said Bill Hunt, a civil engineer at North Carolina State University who predicts that more-drastic steps will become necessary to move entire communities out of danger.

“What Charlotte has done works very well for 2- or 3-inch rains,” Hunt said. “But we don’t have tools to fix 11- or 12-inch rains.”

The program, operated jointly by the city of Charlotte and Mecklenburg County, has provided 700 households with voluntary buyouts, replacing their houses and apartments with almost 200 acres of open land that can flood safely. It also gives technical and financial assistance to homeowners looking to elevate their properties above flood level.

The effort is backed by a utility fee levied on impervious surfaces in homes, government centers and office buildings. The buyout program has cost $64 million, though officials estimate that it has saved $28 million in property damage and now-unnecessary services like emergency rescues. Charlotte-Mecklenburg Storm Water Services expects the savings will reach $300 million from the homes it has already purchased.

About 85 percent of homeowners who have gone through Storm Water Services’ appraisal process have accepted the buyout. Properties are chosen based on flood risk and an assessment of the financial impact that would follow.

As officials toured the recently flooded Catawba River area last month, they pointed out houses they hope to buy and others that will have to be raised above their current rooflines. They picked out telltale signs of June’s flood: a cushion caught high up in a tree; faint lines of organic matter stuck on windows indicating the high-water mark; branches tangled around a tree trunk, revealing the direction the torrents flowed.

It’s all part of their detective work, figuring out how the floodwater behaved so they can advise residents whether they should consider elevating their homes or taking a buyout.

Bill Strain understood some of the flood risk when he bought a two-story house on Riverside Drive in February. The former police officer had whiled away many a summer day at a nearby Fraternity of Police campground, where he watched the Catawba River surge and swirl. But this was his dream house, with a back porch 6 feet above the water and a dock for his powerboat reaching out beyond. Strain and his wife moved in just weeks before June’s deluge, which inundated them and more than 40 other nearby households.

Now, Strain, 72, is at work with power tools, ripping his walls back to studs and replacing flooring piece by piece. He has dismissed talk of a buyout, but welcomes representatives from Storm Water Services, hoping instead that they will help him secure grants to elevate his house by about 12 feet.

“They ain’t getting rid of me,” said Strain, even as his neighbors reached different conclusions.

On one side, Ken Morgan has already taken a buyout and left. He is sorry his home will be demolished but content with the deal from Storm Water Services, based on the pre-flood fair market value minus damages, which allowed him to buy another house, mortgage-free, 10 miles away.

“I’m done playing along the river,” said Morgan, 60. “I didn’t want to live with that threat anymore, jacked up or not.”

The neighbors on Strain’s other side feel stranded. Their home was already elevated, but with two children, they needed extra space, so the family installed a video studio and bathroom on the ground floor. The floodwaters wrecked it all. And although they signed up for a buyout, they don’t think they’ll get one.

“Since we didn’t have total loss to our property, we weren’t a priority,” Sabrina Hilario, 43, said. Instead, they hope to sell their house.

Not everyone trusts Storm Water Services, believing its goal may simply be to oust them and create a park, or suspecting that it is in cahoots with the behemoth Duke Energy, which controls the river’s flow through hydroelectric dams. Hilario and others say they plan to file a class-action lawsuit against the company. (A representative of Duke Energy said the company complies with federal licensing requirements for water levels.)

Storm Water Services is working on offers to buy out a dozen homes in the area. Morgan and two others have completed the process. Several others are in the works.

The riverine flooding is a new challenge for a program whose work on urban creeks has attracted attention among communities looking to mitigate their own risk, like Louisville, Kentucky, which implemented a “quick buy” program about five years ago, and Virginia Beach, which is threatened by a combination of sea-level rise and development.

“We have been looking across the country,” said Erin Sutton, emergency manager for Virginia Beach, “and Charlotte keeps floating to the top.”

Congress also appears to be recognizing the dangers that lie ahead. In a rare act of bipartisanship, the House and Senate have pending legislation that would make it easier for communities to set up similar programs to buy people out or elevate their homes by leveraging federal funds.

The key to Charlotte-Mecklenburg’s success has lain in developing a more forward-looking means of mapping and assessing flood risk than the Federal Emergency Management Agency. In 2000, Charlotte-Mecklenburg became the first U.S. community to show where flooding is likely to happen in the future based on projections of upstream development.

“The point,” said David Canaan, director of Mecklenburg County Storm Water Services, “is looking into the future.”

The program also has stood out for its ability to fund prompt buyouts with the stormwater utility fee levied on impervious surfaces. By comparison, FEMA’s buyout program takes on average five years, according to the Natural Resources Defense Council, by which time many residents have invested money and sweat equity into rebuilding and have little incentive to leave, setting up a cycle of repeat flooding.

The Charlotte-Mecklenburg program continues to look at ways to hone preparedness, experimenting with cheaper — and thus more numerous — flood gauges that will allow residents to learn promptly of impending dangers.

The refreshed flood plains have been turned into public amenities — stream-side trails, sunken rain gardens, waist-high grasslands that provide a sanctuary for migrating butterflies — and a haven from harried urban life.

“The creeks and the nature and the animals, it’s just a beautiful place to come,” said Kathy Halverson, who paused on a pedestrian bridge near where more than 60 houses once stood to marvel at a pair of ducks dabbling in Little Sugar Creek below.

Those who don’t accept a buyout see their surroundings change. Carol Thompson’s brick home on Charlotte’s Briar Creek now sits in a sea of green, where she once had neighbors. Thompson, who has lived there for 30 years, did not believe she could find as nice a property with the buyout money.

“Why tear it down?” said Thompson, who has built up flood protections around her house’s foundation.

In the Catawba River neighborhood, several residents seem hesitant to move, saying they moved there — some into fishing shacks or trailers that they adapted into homes — because they valued the waterfront so highly. They have spotted speculators wandering the neighborhood, looking to get a quick deal in a spectacular setting.

Even if all 40 of the flooded homes were demolished, the newly open land would do little to stanch the vast quantity of water that came down the river in June, carrying runoff from several other counties before it reached Riverside Drive.

Strain is keenly aware of the benefits the Storm Water Services program brings — and also senses injustice. In other parts of the county, even on the hill above what remains of his dream house, new homes are going up as Charlotte continues its rapid expansion.

“They let the high-dollar guys build all these developments, and the little guys who’ve been here for 50 years are flooding and being moved out,” Strain said.

“And they say that’s progress.”

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