By Zhong-Ren Peng, University of Florida
Back-to-back hurricanes left a nerve-wracking scene on the Florida coast in November 2022: Several homes and even swimming pools were left hanging over the ocean as waves eroded the land beneath them. Dozens of homes and apartment buildings in the Daytona Beach area were deemed unsafe.
The destruction has raised a troubling question: How much property along the rest of Florida’s coast is at risk of collapse, and can it be saved?
As director of iAdapt, the International Center for Adaptation Planning and Design at the University of Florida, I have been studying climate adaptation issues for the past two decades to help answer these questions.
Rising seas, aging buildings
Living by the sea has a strong appeal in Florida – beautiful beaches, ocean views and often pleasant breezes. However, there are also risks, and they are exacerbated by climate change.
Sea levels are expected to rise an average of 10 to 14 inches (25-35 cm) on the US East Coast over the next 30 years and 14 to 18 inches (35-45 cm) on the Gulf Coast as the planet warms. Rising temperatures also increase the intensity of hurricanes.
With higher seas and larger storm surges, ocean waves erode beaches more easily, weaken seawalls, and submerge cement foundations in corrosive saltwater. Together with subsidence or sinking land, they make coastal life more risky.
The risk of erosion varies depending on soil, geology and natural shoreline changes. But it is widespread in US coastal areas, especially Florida. Maps produced by engineers at the Florida Department of Environmental Protection show that most of Florida’s coast faces critical erosion risk.
Aging or poorly maintained buildings and seawalls and older or poor construction methods and materials can dramatically exacerbate the risk.
Designing better building codes
So what can be done to minimize the damage?
The first step is to build more robust buildings and strengthen existing ones according to advanced building codes.
Building regulations change over time as risks increase and construction techniques and materials improve. For example, the Florida Building Code design criteria for South Florida changed from requiring some new buildings to be able to withstand 146 mph sustained winds in 2002 to 195 mph winds in 2021, meaning a powerful Category 5 hurricane.
The city of Punta Gorda, near where Hurricane Ian made landfall in October 2022, showed how homes built to the latest building codes have a much better chance of survival.
Many of Punta Gorda’s buildings had been rebuilt after Hurricane Charley in 2004, shortly after the state updated the Florida Building Code. When Ian hit, they survived with less damage than those in neighboring towns. The updated code required new construction to withstand hurricane-force winds, including having shutters or impact-resistant window glass.
However, even homes built to the latest codes can be vulnerable because the codes do not adequately address the environment on which buildings sit. A modern building in a low-lying coastal area may suffer damage in the future as sea levels rise and the shoreline erodes, even if it meets current flood zone elevation standards.
This is the problem coastal residents faced during Hurricanes Nicole and Ian. Flooding and erosion, exacerbated by sea-level rise, caused most of the damage—not wind.
The dozens of beach houses and apartment buildings that became unstable or collapsed in Volusia County during Hurricane Nicole might have seemed fine initially. But as the climate changes, so does the coastal environment, and a hurricane can leave the building vulnerable. Hurricane Ian damaged seawalls in Volusia County, and some were beyond repair before Nicole struck.
How to minimize the risk
The damage in the Daytona area in 2022 and the fatal collapse a year earlier of a condo tower in Surfside should be a wake-up call to all coastal communities.
Data and tools can show where the coastal areas are most vulnerable. What is lacking are policies and enforcement.
Florida recently began requiring state-funded constructors to conduct a sea-level impact study before beginning construction of a coastal structure. I think it is time to apply this new rule to any new construction, regardless of the source of funding.
A comprehensive requirement for sea-level impact studies should also allow for risk-based enforcement, including barring construction in high-risk areas.
Similarly, vulnerability audits—especially for multistory buildings built before 2002—can check the integrity of an existing structure and help spot new environmental risks from sea-level rise and beach erosion. Before 2002, building standards were low and enforcement was lacking, so many of the materials and structures used in these buildings do not meet today’s standards.
What property owners can do
There are a number of techniques that homeowners can use to fortify homes against flood risks.
In some places, this may mean that the house is raised or improved so that surface water runs away from the building. Installing a sump pump and remodeling with storm-resistant building materials can help.
FEMA suggests other measures to protect against coastal erosion, such as replenishing beach sand, strengthening seawalls and anchoring the home. Engineering can help communities, at least temporarily, through seawalls, dams and increased drainage. But in the longer term, societies must assess the vulnerability of coastal areas. Sometimes the answer is to move.
However, there is a disturbing trend after hurricanes, and we see it with Ian: Many damaged areas see lots of money pouring in to rebuild the same vulnerable places. An important question communities should ask is, if these are already in high-risk areas, why rebuild the same place?
Zhong-Ren Peng, professor of urban and regional planning, University of Florida
This article is republished from The Conversation under a Creative Commons license. Read the original article.