Wetlands Save Millions of Dollars in Flood Damages During U.S. Hurricanes

Over the course of a decade, Hurricanes Katrina, Sandy, and most recently, Matthew illustrated the incredibly destructive power of storm surge and floods even against extensive defensive infrastructure. SNAPP Coastal Defenses Working Group has now released a pioneering study, Coastal Wetlands and Flood Damage Reduction, that quantifies how much protection natural coastal habitats provide during hurricanes.

Using the latest modeling techniques, scientists from the conservation, engineering, and insurance sectors studied the impacts of storm surges along the Northeastern coastline during Hurricane Sandy in 2012. The study found that, where wetlands remained, they reduced the average damage from Sandy by more than 10%. In total, Northeastern coastal wetlands prevented US$625 million in property damages. Wetlands are critical buffers, not just for catastrophic hurricanes but also for all storms in the region. In Ocean County, NJ, the conservation of salt marshes is predicted to reduce average annual coastal property losses by more than 20%.

By quantifying the economic value of natural defenses, they can be more effectively included in risk models and coastal management.

“This work shows the unlikely yet powerful benefits of collaboration between insurers, engineers and conservationists in identifying solutions to reduce risks to people, property and nature. The work highlights where we can find innovative financing opportunities and incentives for conserving and restoring coastal wetlands, which plainly put is good for the environment and good for business.”

              -Michael Beck, Nature Conservancy’s Lead Marine Scientist,
              SNAPP Coastal Defenses PI

The magnitude of the benefits was surprising given how many coastal wetlands already have been lost throughout the region. The study revealed that even relatively small, thin bands of wetlands serve as an effective first line of defense and proved that restoration will build coastal resilience. This research shows that we can measure the value of these natural defenses and include them in risk and engineering models—thereby making them an integral part of coastal development and habitat restoration decisions.

The SNAPP Coastal Defenses Working Group also developed guidelines for communities on how to use assess the value of natural coastal habitats in flood risk reduction in partnership with the World Bank: Managing coasts with natural solutions: guidelines for measuring and valuing the coastal protection services of mangroves and coral reefs.


Coastal Wetlands and Flood Damage Reduction: Using Risk Industry-based Models to Assess Natural Defenses in the Northeastern USA.
Narayan, S., Beck, M.W., Wilson, P., Thomas, C., Guerrero, A., Shepard, C., Reguero, B.G., Franco, G., Ingram, C.J., Trespalacios, D.
2016. Lloyd’s Tercentenary Research Foundation, London.

Managing coasts with natural solutions: guidelines for measuring and valuing the coastal protection services of mangroves and coral reefs.
Wealth Accounting and the Valuation of Ecosystem Services Partnership (WAVES). Waves technical paper.
Beck, M.W. and G-M Lange (Editors)
2016. Washington, D.C. : World Bank Group.

FACTSHEET: The Value of Coastal Wetlands for Reducing Property Damage


Media Coverage

More information about SNAPP Coastal Defenses Working Group and other research publications


Photo Credit: Kristine Hartvigsen, The Nature Conservancy

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Posted on October 25, 2016