Seagrass and Shellfish: Building Resilience to Storms Along NYC’s Coastline

by Susan Price

Susan Price is a student in the EICES Executive Education Program. This blog post describes her experience on a recent field trip for the course Hurricanes, Nor’easters,
and Sea Level Rise: Implications for Coastal Systems taught by Dr. James Cervino.

On September 22, 2018, Dr. James Cervino brought the students in the Hurricanes, Nor’easters, and Sea Level Rise course to MacNeil Park in Queens. It was this field component that originally drew me to the course, and I was not disappointed. I gained a first-hand look at the impact of storms on New York City’s intensely-developed coastline.

Prior to the field trip, Dr. Cervino gave background information about the carbon cycle, climate change, atmospheric dynamics, and ocean circulation. The lectures focused on marine systems, particularly those that occur along what has become a highly urbanized coastline. Dr. Cervino showed numerous aerial images of New York City’s coastline before and after development and discussed the Federal Emergency Management Agency’s (FEMA) recommendations for coastal construction.

Dr. Cervino’s lectures came to life during the field trip. In fact, the trip served as a stark reminder of New York City’s vulnerability to climate change. What made MacNeil Park such a great field site was the visible difference between the park’s newly constructed foundation and the nearby residential areas. We climbed a fence to explore the New York City Parks and Recreation Department’s current project to reconstruct the esplanade and were reminded of FEMA’s recommendations:

A building’s foundation is arguably its most important structural element…a foundation must support the building above it and all the loads that are exerted on it…while being exposed to the damaging effects and conditions present in a coastal environment. These effects include erosion and scour, breaking waves and moving floodwaters…Coastal foundations must, therefore, be stronger, better planned and designed, and more solidly constructed than inland foundations.^[1]

The condominiums on either side of the park had foundations with visible erosion. The development to the east of the park had iron fencing that collapsed into the bay over a foundation of granite gravestones, which were oddly out of place. In contrast, MacNeil Park was benefiting from Dr. Cervino’s restoration project, which enhances the human-built environment with biological structure. Seagrasses provide a gradual slope, while also serving as a sponge and extra layer of protection for the man-made foundation.  Dr. Cervino pointed out the complexity of the seagrass community. Not only do the roots act as a net to hold the sandy soil in place, but they are home to shellfish. These shellfish in turn create a biological “concrete” with their hard calcareous shells, further holding the coastal soils in place while also sequestering carbon. We observed many oyster shells, which were evidence of another break for waves–a final layer of biological protection from storm surges.

Ironically, that very day the aftermath of Hurricane Florence was wreaking havoc in North Carolina, and it was not hard to imagine what such a storm could do to New York City as we watched planes land at La Guardia Airport. It made us fully aware of New York City’s coastal development and question how developers could build so close to the water’s edge and on such precarious foundations. The field trip convinced me that true resilience to sea level rise requires not just good human engineers, but biological engineers such as shellfish and seagrasses as well. Given the increased strength of storms, along with the inevitable rise in sea level, restoring wetlands and oyster beds may be a viable solution to protecting New York City’s coastline long into the future.

^[1] https://www.fema.gov/media-library-data/20130726-1707-25045-4311/chapter6.pdf