Wetlands, Flooding, and the Clean Water Act

This study estimates the value of wetlands in flood mitigation in the United States, finding that each hectare of wetland loss costs our communities on average $1,840 annually, spiking to $8,000 in developed areas.



Aug. 23, 2021 (Updated January 24, 2022)


Working Paper

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1 minute


In 2020 the EPA 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 flood mitigation across the US using detailed flood 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 flood insurance policy and the 50% of ‘isolated’ wetlands at risk of losing federal protection.

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