Can Miami Beach Hold Its Ground Against King Tides?

A city must decide whether to retreat or stand and fight when rising seas come crashing in.

Extensive flooding after a storm in Miami Beach, June 2009

Credit: iStock

Around this time last year, the Atlantic was gushing over Miami Beach’s seawalls and up through storm drains, turning low-lying Indian Creek Drive into a briny river. So-called king tides made headlines, and Al Gore famously said, “I was in Miami last fall during the supermoon, one of the highest high-tide days. And there were fish from the ocean swimming in some of the streets of Miami Beach and Fort Lauderdale and Del Rey. And this happens regularly.”

Located on a barrier island off the southeastern coast of Florida, Miami Beach is ground zero for sea-level rise. This year, though, as seasonal king tides return, the city is hoping to stay dry while it demonstrates climate adaptation is possible with bricks, mortar, and human ingenuity. One can admire that kind of grit, but any long-term solution is still untested, and legitimate questions are surfacing: For how long should we keep fortifying infrastructure, and at what point do we pack up and leave?

Miami Beach has so far spent about $150 million of the $400 million the city says it needs to save itself from the sea. Stormwater fees have increased twice during the past three years to raise the first $200 million. The funds are being funneled into elevating major roads and constructing seawalls on the island’s vulnerable western coast, in addition to installing water pumps and check valves, which were lacking last year.

The buildings in neighborhoods that have the improvements will remain dry, says Bruce Mowry, Miami Beach’s city engineer, who came to Florida from California three years ago to tackle the flooding. “As long as we have a good power source and the electric pumps are running, I believe the city is safe for the time being,” he says. “If we get a hurricane, all that drops.”

The 25 water pumps now installed in Miami Beach (55 more to go) have enough capacity to manage a storm that brings 7.5 inches of rain within 24 hours, but they would be overwhelmed by anything more. Hurricane Matthew, for instance, recently swamped streets in South Beach and Sunset Harbour, though some of the pumps were off-line due to repairs. Scientists predict that climate change may cause hurricane frequency to diminish while intensity increases. Even so, planning for those conditions is still chock-full of uncertainty, and sea-level rise can be even more squirrely to prepare for than weather.

Recent predictions by the Southeast Florida Regional Climate Change Compact—a collaboration of government officials from Miami-Dade, Broward, Monroe, and Palm Beach counties—indicate that by the end of the century, the sea could rise as high as six and a half feet above the 1992 mean level. That means up to 12 inches by 2030, and 34 inches by 2060. Even though those predictions fall on the conservative side, such changes would submerge the whole island.

No one wants Miami Beach to disappear, says Mark Davis, director of the Tulane Institute on Water Resources Law and Policy, but if the models are correct, that’s the direction in which South Florida and many low-lying coastal communities are headed.

“It’s going to take more than wishful thinking and millions or even billions of dollars of public works,” Davis says. “If people continue to live in these places, it’s going to take a whole rethinking of how we do so.”

That’s not to say people aren’t thinking creatively already. Miami Beach has been updating building codes for new construction and major renovations. Thus far, its city council has increased the height of seawalls and raised the minimum elevation for peoples’ yards and for the lowest floor of any new building. And for sustainability purposes, all new construction larger than 7,000 square feet must be certified at the minimum standard of LEED Gold.

Outside-the-box ideas are being tossed around as well. One example is to design new buildings with unusually high ceilings on the ground floor so that the floor can be raised when flooding becomes an issue.

Because no blueprint exists for flood-proofing cities in Florida, where low-lying areas sit atop foundations of porous limestone, Miami Beach must develop its battle plan in real time. Davis points to cities like New Orleans for instruction. A roughly $100 billion plan is currently being drawn up to help secure that city and its coastal wetlands. The fact that the population of New Orleans has shrunk significantly in recent decades, however, complicates matters. Fewer people now bear the financial burden of maintaining infrastructure that once supported twice as many.

Residents also have to take care of their own property, and those in poorer communities often struggle to afford flood insurance prior to disasters or to rebuild their homes after them. The cost of insurance has been rising along with sea levels, which widens the gap between residents with a financial buffer and those at risk of losing it all.

“Then the question is not whether we can relocate communities but whether we are stranding them,” says Davis, who hopes one day we can look back and be proud of how we help people who don’t have the means to leave. “Change is coming fast, and the bottom line is this: Are we going to be managed by those changes, or are we going to manage them? There won’t be any hiding from the results.”

Flood-mitigation plans follow two routes. The first is to build and support, as seen in Miami Beach and New Orleans. The second is to make adjustments over a longer period, including the possibility of migrating people and infrastructure away from the rising tide.

Nicholas Pinter, a professor of earth and planetary sciences at the University of California, Davis, describes a three-part “sniff test” that’s typically used for river floodplains but can also be applied to coastal communities. Taller and broader levees are good for preexisting infrastructure that’s high in value and concentrated. Miami Beach might qualify because, according to the Organization for Economic Co-operation, it has $416 billion worth of assets at risk. It’s a different story for much of the rest of Florida.

At this point in time, it’s easier to find funding for defensive engineering than it is for retreating. Just look to Soldiers Grove, Wisconsin, for proof. In the 1970s, after decades of continual damage from the Kickapoo River flooding, the Army Corps of Engineers proposed to protect the town with a $3.5 million levee—more than three times the town’s asset value. The residents rejected the expensive exercise, requesting to be relocated instead. It took years for federal agencies to cobble together enough money to find a new home for Soldiers Grove. Relocation to higher ground nearby began in 1979 and was finished four years later.

Earlier this year, Louisiana’s Isle de Jean Charles became the first U.S. community to receive federal funding for relocation due to climate-related flooding. According to an article in the New York Times, the town’s 80-plus residents, all belonging to the Biloxi-Chitimacha-Choctaw tribe, will learn where they’re heading sometime next year.

When asked about whether resettlement was possible for Miami Beach, city engineer Mowry is firm: “Managed retreat is not in the city’s vocabulary.”

This type of unyielding conviction in human ingenuity makes Harold Wanless, chairman of the department of geological sciences at the University of Miami, shake his head. “We’re sticking our head down and our other end up,” he says. To appropriately anticipate sea-level rise, he suggests local governments render maps for every six additional inches of sea-level rise. That will help determine which areas are most at risk—and when, and at what cost, to protect them.

About 13 miles south of Miami Beach, Coral Gables is doing just that. The city is currently assessing its vulnerability and drafting a document that considers the legal ramifications of sea-level rise. It includes a section on relocation.

“We don’t want to retreat, but it’s in the legal document,” says Matthew Anderson, LEED Green Associate for the city of Coral Gables, noting the document is the first of its kind. “Every action has a reaction, and we want to make the best decisions for making our community resilient to sea-level rise.”

On November 14, we’ll see the largest supermoon rise since 1948. As its gravitational pull tugs powerfully at the ocean, Miami Beach’s pumps will be ready and waiting for the coming king tides. If only climate change were as predictable as the moon.

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