U.S. is reducing floodplain development in most areas

The perception that the U.S. has not been able to curb development in flood-prone areas is mostly inaccurate, according to new research from climate adaptation experts.

A national survey of floodplain development between 2001 and 2019 found that fewer structures were built in floodplains than might be expected if cities were building at random. Data indicates that the average city now avoids new construction in floodplains, a finding that bucks conventional wisdom.

Communities in two states, Florida and Louisiana, are exceptions. These states are responsible for most of the floodplain construction in the U.S. this century. Much of the available land in these states is in either coastal or riverine floodplains, and the economies of both states largely depend on proximity to water.

Researchers focused on New Jersey and found that more than three-quarters of Garden State towns reduced floodplain development since 2000. About a quarter of the state’s communities eliminated floodplain development. They did through “routine municipal practices” such as zoning changes and permit denials.

A caveat to the research is that flood zones were delineated by Federal Emergency Management Agency flood insurance maps, which researchers say are outdated.