Florida codes keep new homes ‘high and dry.’ Do they make flooding worse for neighbors?
Lance Peterman’s home in the
“They were high and dry,” said Peterman, 56. “Nothing like the rest of us.”
It’s become a common sight in development-crazed
But neighbors like Peterman wonder — especially after the latest “rain bomb” to hit
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
“To me, it’s going to be a nightmare,” said
In one
According to the Florida
But that’s the critical keyword: properly.
Complaints of new development worsening flooding in surrounding areas are common across
“It falls into that bucket of stuff we know is a problem but don’t fix,” said
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,
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
It’s perhaps the oldest building technique in
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
Fill — much of it lime rock mined on the western border of
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.
That same rule would make waves in
But
“I’ve created room for that water to hide and go back to the water table and get it off the street,” said
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
“Whatever you’re going in to do, you have to demonstrate along with it that you’re not impacting any of your neighbors,” said
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.
READ NEXT: Climate change could make freak events like Fort Lauderdale’s rain bomb more common
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
Take
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
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
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
“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
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
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
The biggest part of the project? Elevating thousands of homes — on piles, not fill.
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