FLOOD PLAINSThe U.S. Is Finally Curbing Floodplain Development, New Research Shows
Over the past century, the United States has built millions of homes along coastlines and rivers, developing on land that is all but destined to flood. At the same time that the warming of the planet has raised sea levels and increased rainfall, annual flood damages have surged in recent decades in large part because more homes are in flood-prone areas now than ever before.
Over the past century, the United States has built millions of homes along coastlines and rivers, developing on land that is all but destined to flood. At the same time that the warming of the planet has raised sea levels and increased rainfall, annual flood damages have surged in recent decades in large part because more homes are in flood-prone areas now than ever before. In coastal cities like Carolina Beach, North Carolina, most homes sit in a federally-designated flood zone, which tees them up for massive flood events like that which dropped more than a foot of rain on the city this week.
Experts have portrayed this widespread risky construction as an intractable problem, alleging that “home sales in flood zones are booming,” that “more Americans are moving into flood … hot spots,” or pointing out “rapid urban growth in flood zones.” News coverage, including that of this publication, has largely followed this lead.
But new research from some of the country’s leading climate adaptation experts, which was published last week in the academic journal Earth’s Future, suggests that academics and journalists may have drawn the wrong lessons from the last few decades of coastal development. A national survey of floodplain development between 2001 and 2019 has found that the U.S. actually built fewer structures in floodplains than might be expected if cities were building at random. This means that, if anything, the average city now actively avoids floodplains, contrary to conventional wisdom. Indeed, in the 21st century most towns and cities in the U.S. built very little or not at all in flood-prone areas. The vast majority of floodplain construction — the kind that grabs headlines and feeds the pessimistic narrative — has taken place in just two states: Louisiana and Florida.
A separate paper just published by the same researchers in the journal Oxford Open Climate Change found that it doesn’t take a sea change for a town or city to effectively limit floodplain development. According to the paper, which is focused on New Jersey, more than three-quarters of Garden State towns reduced floodplain development after the turn of the last century, and around a quarter eliminated it altogether. They did this not by passing any big legislative reforms or climate policies but instead through what the paper calls “routine municipal practices” — things like zoning changes and permit denials.
