Wetlands, Flooding, and the Clean Water Act

In 2020 the Environmental Protection Agency narrowed the definition of waters of the United States, significantly limiting wetland protection under the Clean Water Act. Current policy debates center on the uncertainty around wetland benefits. We estimate the value of wetlands for lood mitigation across the United States using detailed lood claims and land use data. We find the average hectare of wetland lost between 2001 and 2016 cost society $1,840 annually, and over $8,000 in developed areas. We document significant spatial heterogeneity in wetland benefits, with implications for lood insurance policy and the 50 percent of isolated wetlands at risk of losing federal protection.

Automated summary

In 2020, the EPA narrowed the definition of "waters of the United States", resulting in increased uncertainty around wetland protection. Using flood claims and land use data, researchers estimated the economic value of wetlands for flood mitigation in the United States. The study found significant spatial heterogeneity in wetland benefits, which has implications for flood insurance policy and the protection of isolated wetlands at risk.