First Line of Defense

New studies show that coastal wetlands play a crucial role as a first line of defense from storm surge and rising sea levels.


By Bridget Moynihan and Severn Smith on October 02, 2017

October 2017 marks the five-year anniversary of Hurricane Sandy.  The ongoing relief and recovery efforts following Hurricanes Harvey, Irma and Maria provide daily reminders of the growing threats of storms, flooding and sea level rise – and the urgent need to take action to protect threatened coastal habitats and communities.

A new study led by The Nature Conservancy shows that coastal wetlands play a crucial role as a first line of defense from storm surge on the Northeast and Mid-Atlantic coasts of the U.S.

Led by a team from the engineering, insurance, and conservation sectors, the study finds that coastal wetlands in the northeastern U.S. prevented more than $625 million dollars in direct property damages during Hurricane Sandy, reducing damages by an average of 22% in over half the affected areas, and nearly 30% in Maryland.

A second study, conducted by The Nature Conservancy and funded by the U.S. Fish and Wildlife Service, aims to help Maryland coastal communities plan for, and adapt to, growing threats due to sea level rise.

Using science to identify Maryland’s coastal strongholds gives us hope that – if we work to conserve these areas – coastal habitats and communities can overcome the growing threats of sea level rise.


Coastal Strongholds

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Coastal wetland, Maryland.  Photo © Kent Mason

“Coastal strongholds” are areas that, because of their unique topographies, elevations and landforms, give threatened habitats a chance to escape rising sea levels and continue to provide vital services to people and wildlife.

The Conservancy / USFWS study offers land managers a tool to gather comprehensive data – such as water quality, important wildlife areas, sediment and soil nitrogen levels – that can be used to develop targeted conservation plans across Maryland that will have the greatest chance of protecting coasts and communities against rising sea levels.

Among the strongholds identified in Maryland were the wetlands along Chincoteague Bay’s northern edge and along the shoreline of Pocomoke Sound, upstream of which the Conservancy is actively engaged in restoration work along the Pocomoke River’s floodplains to improve water quality.

With sea levels projected to rise as much as six feet by the next century, many coastal habitats – such as tidal marshes, sandy beaches and sea grass beds – could disappear forever under rising waters.

But scientists say these “strongholds” provide escape routes that allow threatened habitats to migrate inland and survive sea-level rise. The authors of the study, however, warn that man-made development and pollution could cut off these escape routes and lead to habitats being drowned out of existence.

If these important habitats are lost, it will have severe impacts on our economy, our environment and the health of our communities. Taking action now will help ensure these coastal habitats remain strong and productive so they can continue to support both people and nature. 


Data Collaboration

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Marsh wren (Cistothorus palustris), Elliott Island Road, Dorchester Co., MD.  Photo © Matt Tillett / flickr CC by 2.0

The Conservancy’s Maryland/DC chapter has also partnered with NASA to apply Earth observation data, such as satellite imagery, to better understand the extent and health of Maryland marshes. The data will help indicate to scientists where there are healthy marshes in need of protection, and degraded marshes in need of restoration, with the ultimate goal of reducing potential damage from storm surges.

Conservancy GIS Project Manager Michelle Canick recently attended the Annual Earth Science Applications Showcase held at NASA Headquarters to discuss the initiative. Michelle is featured in a three-minute video created by NASA interns, which highlights the collaboration.



Additional Resources

Read the full reports:

Categories: Coastal Resilience, Sea level rise, Wetlands





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