Florida codes keep new homes ‘high and dry.’ Do they make flooding worse for neighbors?

Lance Peterman’s home in the Fort Lauderdale neighborhood of River Oaks flooded earlier this month during record-setting rains. It wasn’t the first time for him or many of his neighbors. But he heard a different story when he chatted with the owners of some newer homes built on elevated lots along his street.

“They were high and dry,” said Peterman, 56. “Nothing like the rest of us.”

It’s become a common sight in development-crazed South Florida: Shiny new homes popping up in neighborhoods of low-slung older homes — almost always constructed on land raised by trucked-in gravel. The added elevation has become standard thanks to decades of stricter building codes and a growing understanding that Florida buildings need to rise to withstand storms and floods of the future.

But neighbors like Peterman wonder — especially after the latest “rain bomb” to hit Fort Lauderdale — if the standards to raise new construction make flooding worse for surrounding older homes.

Peterman said his family has owned their home since 1972. It’s flooded several times since, he said, getting more common and intense in the last decade. He believes all the new development in the neighborhood, including dozens more homes, a church, a McDonald’s and a hotel, has something to do with that.

He’s not alone. The Biscayne Shores neighborhood in Miami-Dade County is fighting a new residential development with the same logic, that a new, higher building will flood the older, lower homes.

“To me, it’s going to be a nightmare,” said Dave Hart, who lives in a 1944 house near the proposed project site just off Biscayne Boulevard. “Where is the water going to go? They’re tearing up earth and putting cement on it.”

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According to the Florida Building Code, properly designed buildings and homes shouldn’t cause flooding for neighbors. Construction standards typically call for them to include swales or other features to handle runoff from the property — no matter how much higher they’re built.

But that’s the critical keyword: properly.

Complaints of new development worsening flooding in surrounding areas are common across South Florida, and floodplain experts say it underlines a problem with perhaps the leading strategy for coping with flooding driven by climate change. There can be damaging ripple effects from an approach to new construction summed up as “fill and build.”

“It falls into that bucket of stuff we know is a problem but don’t fix,” said Del Schwalls, a Florida-based floodplain management consultant. “We spend 20 years complaining about it instead of plugging the holes.”

An unintended ripple effect

The difference between old and new homes in River Oaks is just the latest example of an unintended flaw in Florida’s efforts to build communities more resilient to flooding, one long known but also left largely unaddressed.

Back in 2019, for example, Florida International University produced a study for the Florida Building Commission on the potential impacts of climate change on the state’s building stock. Only in a footnote at the end did it note: “New research may be needed” when it comes to the use of fill in flood-prone areas.

Unlike in the Keys or other barrier island communities, where homes are built on stilts, higher homes in South Florida’s urban areas are usually elevated by gravel or dirt — a mix known as fill.

READ MORE:Threat from below: Sea rise is pushing up groundwater — and flood risks for South Florida

It’s perhaps the oldest building technique in Florida. From day one, developers took the muck, rock and soil left from draining and developing the Everglades to elevate roadbeds and neighborhoods.

Now, as sea level rise pushes tides inland and raises groundwater levels, many swathes of land are at an even higher risk of flooding when the skies open up. Science suggests that as the atmosphere warms, extreme rain events like the one in Fort Lauderdale last week could get more common — and even more extreme.

Fill — much of it lime rock mined on the western border of Miami-Dade County in what was once the Everglades — is a key ingredient in Miami-Dade’s “climate action strategy.”

The county lists building on fill as one of the five major paths forward for adapting to sea level rise. And last year, the county added a new policy that requires elevating county roads, canal banks and land parcels higher to avoid flooding — all using fill.

That’s not the case in some other flood-prone communities. Charleston, South Carolina, for example, actually banned the practice earlier this year for properties that are zero to six feet above sea level, despite pushback from the development industry there.

That same rule would make waves in South Florida, where the average elevation is about six feet.

But Miami-Dade, and most government regulators in South Florida, see positives in the use of fill. Obviously, it protects the new structures. And as sea rise shrinks the gap between groundwater and the surface, adding a few feet of fill makes more space for the ground to absorb water.

“I’ve created room for that water to hide and go back to the water table and get it off the street,” said Vince Seijas, director at large of the Florida Floodplain Managers Association.

It also keeps underground pipes from sitting in water that’s getting increasingly salty, which can shorten the life of sewage and drainage systems. But Seijas acknowledges it can be “a double-edged sword.”

“Now I have that extra storage capacity, but what happens to that extra runoff?” he said. “Elevation is good and it helps to an extent, but then you create that disparity with the existing inventory.”

That disparity can mean the difference between a dry house and water filling yards or seeping under doors.

Don’t flood your neighbors

Florida’s building code does include standards intended to deal with the problem of elevated land next to low spots — at least in part. The newest code allows fill, even in flood-prone areas, as long as it doesn’t send water or waves toward another building. And most places in Florida also have a “no adverse impacts” rule,” which means new development is not supposed to worsen conditions for neighbors.

“Whatever you’re going in to do, you have to demonstrate along with it that you’re not impacting any of your neighbors,” said Marina Blanco-Pape, director of Miami-Dade County’s water management division.

New construction is supposed to be able to handle stormwater runoff — at least from relatively routine rainfall — within the confines of the property. And adding fill requires changes too. The formula works this way: For every cubic yard of dirt added to a property, regulations require developers to make plans to deal with that same amount of water.

For big projects like a new housing development, developers have room to design for that. It can typically include a man-made lake or a series of deep swales to catch runoff from elevated homes.

But when it comes to redeveloping a single property in an older neighborhood, things can get trickier. And that’s because so many of South Florida’s existing homes are old — and low.

Most of Miami-Dade’s old homes were built long before there were drainage standards, so they’re not up to snuff. Add the intensified rainfall, higher groundwater levels and higher tides brought by climate change, and it’s a recipe for more flooding.

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And when one (or several) homes in a row of low houses get elevated, the lowest point where water used to collect is now concentrated on only a few properties, which may now experience more flooding.

So is that the new, higher home’s fault? Blanco-Pape said although it may seem like it to homeowners, in the eyes of flood regulators, it actually means the lower homes need to fix their drainage.

“That doesn’t mean that the property is flooded by the next-door neighbor, that means that property needs to have some improvement in how they retain or manage their own stormwater,” Blanco-Pape said.

Whether or not a new development heightens flood risks for its neighbors is a touchy subject in South Florida, where lawsuits over the issue aren’t uncommon.

Take Miami Beach, where raising roads has produced similar impacts, leading to lawsuits over increased yard flooding.

Decades ago, building codes were designed to direct rain runoff from homes and yards to drain into the street, where the stormwater system sucked it away. But, as some West Avenue landlords argued in a lawsuit against Miami Beach, those raised roads effectively short-circuited the original drainage system.

Other than general language about new development not flooding neighbors, floodplain manager Seijas said the building code is pretty ambiguous. It specifies that runoff can only flow to “an approved location, and they leave it open,” he said.

There is also the question about the level of rainfall a property is designed to absorb. Old properties were built before any standards existed. And even new properties are only designed to handle so much — maybe a couple of inches in a single day. Anything more is likely to flow to the lowest nearby location — streets, or sometimes neighbors’ yards if the local municipal drainage system gets overwhelmed.

With those systems designed to handle an average Florida rainstorm’s worth of water, that can happen multiple times during a rainy season. Fort Lauderdale’s floods, and the regular flooding in places like Sweetwater and Downtown Miami, are an example of the potential damage when the drainage can’t keep up with nature.

Some floodplain experts, like Schwalls, want to see updated rules about building on fill that address the concerns — or at least do a better job of protecting low-lying neighbors. He said current regulations don’t focus enough on hydrology, which is how runoff moves across land and where it might wind up.

“That issue isn’t really addressed even though it sounds like it is in the regulations,” Schwalls said. “The regulations are behind the science.”

What about older homes?

Eventually, as sea levels rise and the government’s flood maps, which guide development, continue to update, homes and buildings in South Florida will have no choice but to elevate.

“That’s a foregone conclusion,” Seijas said.

But the reality is that step could take decades, even with South Florida’s high rate of redevelopment. Most residents can’t afford the tens or hundreds of thousands of dollars it takes to elevate an old home or build a newer, higher house. And the short-term solutions, like flood barriers or landscaping that absorbs floodwater, are just that, short-term.

“This is really one of the remaining issues we’re going to have to look at as a matter of equity for the people who find themselves in these situations,” said James Murley, Miami-Dade County’s chief resilience officer.

One limited solution is to use government cash to buy the most flood-prone properties and possibly take them out of future development. But that’s been tough to pull off in Miami-Dade.

READ MORE: Buyouts take flood-prone Keys properties off the market. There are more sellers waiting

The county took too long to buy out 10 homes flooded by Hurricane Irma and had to give back the federal funds earmarked for the project, but not before developers snapped some up. Afterward, Miami-Dade OK’d even more dense development on one of the most flooded properties.

Right now, Murley said, the county’s big bet is on the federal project to protect Miami-Dade’s coastline from future storm surge, the back bay project. It’s likely that the final version — mostly paid for by the federal government — will include cash to elevate thousands of homes in the county.

However, that’s a decade away, at best.

In the Florida Keys, where elevation on stilts is already common, mainly because of the threat of hurricane storm surge, fill has long fallen out of favor for homes. In fact, the federal government recently approved a multi-million dollar project to protect the island chain from future storm surge.

The biggest part of the project? Elevating thousands of homes — on piles, not fill.

Miami Herald Staff Writer Doug Hanks contributed to this story.