Fears of more flooding arise in a Miami-Dade housing project
Residents in older neighborhoods across South Florida have been fighting new development for decades, but one spot in Northeast Miami-Dade has an objection that could be more common in the future: flooding.
Some residents of the charming, leafy neighborhood of Biscayne Shores, a pocket of unincorporated Miami-Dade, are worried that a new planned development will send stormwater pouring down the street, and into the yards and homes of low-lying neighborhoods.
Modern building codes and elevation standards mean fewer flooding worries for people who would live in the proposed 177-unit residential complex developer Bislot LLC wants to build on the other side of Northeast 108th Street. But the project makes residents of some of the single-story houses nervous. Most of the homes were built in the 1940s and 50s, long before anyone was worried about sea rise, hurricane storm surge and climate-driven deluges.
Dave Hart had a foot of water in his living room after Hurricane Irma in 2017, and he worries what the next storm could bring if his new neighbors are now several feet higher.
“When they concrete that area,” Hart said, pointing to the three houses Bislot owns across the street and the larger corner lot near Biscayne Boulevard, “all of that water is going to drain into this little slip here.”
Miami-Dade County developer rules require builders to design drainage systems that prevent rain run-off from flooding neighbors, but Hart and his fellow homeowners see the math working against them. The complex would replace grassy lawns surrounding the three houses Bislot owns on 108th and the mostly empty lot at the corner.
But there are other important numbers at play as well in a county with a shortage of housing.
The proposed complex needs county approval to more than double the number of residential units allowed on the site from 66 to 177. Bislot has pledged to price at least 10% of the units at the workforce level to be affordable to families of four earning up to $136,000 a year, and county planning staff recommended approval in a November report.
But nearby residents haven’t given up. They are fighting approval of a needed zoning change before the County Commission, citing an existing flooding problem Miami-Dade has yet to fix in the neighborhood, among other concerns, including traffic and noise.
A Bislot representative was not available for an interview, but in an April meeting, a lawyer for the development asked commissioners to wait to consider the project until they had a chance to talk to residents.
“We are working with our residential neighbors to arrive at limitations on the potential development that hopefully everyone can live with,” said Graham Penn.
In a memo on the project, Miami-Dade’s Chief Resilience Officer Jim Murley noted that flooding is more common at this site than other spots in the county and could become more frequent as sea levels continue to rise.
The memo also goes on to explain what many flood managers say is a gap in building code flood standards: The new elevated projects are only built to absorb a routine amount of rainfalls, not the extreme thunderstorms increasingly seen in South Florida — the system that swamped Fort Lauderdale two weeks ago being the latest off-the-scale example. Unless the project incorporates the latest information on increased rainfall and flooding, he wrote, it could also increase flooding in the neighborhood.
“Elevating one area on fill to reduce flood risks may increase flooding risks for adjacent areas if the run-off is not carefully managed,” he wrote. “Typically, a development would be required (or designed) to maintain a certain volume of stormwater on site; however, if there were a strong storm in excess of that design level the additional water would run off site. If adjacent or downstream areas are at a lower elevation, they may experience increased flooding.”
DECADES OF FLOODING
Jane St. Lawrence, a real estate agent, lives in a 1940 house a few doors down from the proposed project site, and she said downpours already mean floods for the neighborhood. She’s convinced a new building’s higher elevations will only make things worse for houses like hers when heavy rain hits.
“If they have to build up the land, where is it going to go?” she asked. “It’s going to go downstream.”
Hart, a retired assistant principal, said he’s had to wait more than a day to flush his toilet when a heavy rain saturates his backyard enough to prevent his 1946 home’s septic tank from properly draining. One recent storm even freed his koi fish from his pond and set them loose in his front yard.
With Biscayne Boulevard off one end of the street and Biscayne Bay on the other, Hart has seen traffic and development build up around the neighborhood while rising sea levels slowly leave the street drains vulnerable to failure during heavy rains.
“There’s a storm drain over there,” Hart says from his front lawn. “But it doesn’t do much.”
Biscayne Shores is an old neighborhood, mostly built in the 1940s before Miami-Dade required the use of fill to elevate homes. Its lowest point is on par with the highest annual tides, known as King Tides.
Sea level rise also affects groundwater, causing a higher water table under the neighborhood with less capacity to absorb rainfall, meaning even a few inches can cause flooding.
But Miami-Dade County’s answer to the concerns so far: Sorry, not much we can do.
The county is doing what it can to help the neighborhood this year by installing new stormwater pumps and a one-way valve on the outfall into Biscayne Bay, which ensures that water can drain out but not leak back in. But the county’s own modeling suggests the fix will become less helpful as sea levels continue to rise or if rainfall gets more severe.
Any more serious fixes to the neighborhood require homes to elevate. Not just more homes, but all of them.
Even raising roads, an increasingly common strategy in South Florida to keep important evacuation roads safe after a deluge or hurricane, isn’t an option for now. Not until more homes come up.
“Once a critical mass of lots is redeveloped in the area, raising roadways to comply with current floodplain standards will also provide a higher level of flood protection. Elevation of roadways, however, is not recommended in the short term given the area’s present topography, as flooding on private lots would be aggravated by a higher roadway elevation during rain events resulting in those private lots retaining more of their own stormwater,” the county wrote in a recent report on flooding in the neighborhood.
This story was produced in partnership with the Florida Climate Reporting Network, a multi-newsroom initiative formed to cover the impacts of climate change in the state.