Grapevine

Where flood policy helps most—and where it could do more

Flooding, including the devastation caused recently by Hurricane Helene, is responsible for $5 billion in annual damages in the U.S. That's more than any other type of weather-related extreme event.

To address the problem, the federal government instituted a program in 1990 that helps reduce flood insurance costs in communities enacting measures to better handle flooding. If, say, a town preserves open space as a buffer against coastal flooding, or develops better stormwater management, area policy owners get discounts on their premiums. Studies show the program works well: It has reduced overall flood damage in participating communities.

However, a new study led by an MIT researcher shows that the effects of the program differ greatly from place to place. For instance, higher-population communities, which likely have more means to introduce flood defenses, benefit more than smaller communities, to the tune of about $4,000 per insured household.

"When we evaluate it, the effects of the same policy vary widely among different types of communities," says study co-author Lidia Cano Pecharromán, a Ph.D. candidate in MIT's Department of Urban Studies and Planning.

Referring to climate and environmental justice concerns, she adds, "It's important to understand not just if a policy is effective, but who is benefitting, so that we can make necessary adjustments and reach all the targets we want to reach."