A new interactive national flood map, developed and released by the non-profit First Street Foundation, identified cities across America that have a significantly higher degree of properties at-risk than government flood maps currently show.
The analysis found that Cape Coral, Florida has the most properties — and the largest percentage of properties — at substantial risk of flooding nationwide: more than 90,000 properties, or almost 70 percent of the city’s stockpile.
Cape Coral is a city of 200,000 on the southwest coast of Florida. So, what makes it America’s most vulnerable city when it comes to flooding? After all, the United States has 95,000 miles of shoreline and 3.5 million miles of river? It has coastal and shoreline megalopolises like New York, Chicago, Miami and Los Angeles.
Well, to start with, Cape Coral might be barely larger than Washington, D.C., but it has 400-hundred miles of canals devoted to waterfront living — more than any other city in the world. The residential lots are small and numerous and configured to put as many as possible on the waterfront.
None of this was a quirk of nature.
Cape Coral was constructed from a mangrove swamp with dredges and draglines in the 1950s. It was designed and marketed to a wide swath of America — and the world — as an opportunity to own a small slice of waterfront paradise on Florida’s southwest coast.
But it was also designed at a time when sea levels were considered to be static.
“The rate of sea level rise here is about four millimeters per year, and it’s accelerating,” James Douglass, a marine scientist at Florida Gulf Coast University in Fort Myers, told Florida Flood Trends.
That means the sea is rising more than an inch every six years.
Much of Cape Coral was built about five feet above sea level and much of it is low-lying.
“You see a lot of people’s backyards at high tide that are just about wet,” Douglass said.
For now, the two major flood risks in Cape Coral are storm surge and heavy rainfall. Like many places, Cape Coral is seeing more intense rain events. It also faces a risk of more intense hurricanes in the future.
Hurricane Irma in 2017 gave Cape Coral a glancing blow. The city also took hits from Hurricanes Charley in 2004 and Donna in 1960. But there’s great concern about what a hurricane pushing a real surge might do to Cape Coral, or what might happen if a major rain event occurred, like the 50 inches of rain Hurricane Harvey dropped on Houston.
The interactive flooding map released recently, called Flood Factor, lets people look up their addresses to get a different assessment of flood risk from the maps prepared by the Federal Emergency Management Agency (FEMA). Florida Flood Trends and First Street Foundation are both funded by the 2040 Foundation.
The top-20 list of cities with most properties at substantial risk of flooding includes three other Florida cities: Tampa (43,000 properties), Jacksonville (29,000 properties), and Lehigh Acres (26,000 properties).