“Emerald Tutu” Floating Biomass May Help Eastie Against Sea Level Rise

Last year, coastal engineer and professor, Julia Hopkins led a team to place a floating biomass mat off the shores of East Boston.

The mat tested were part of a larger National Science Foundation (NSF) funded research project dubbed the “Emerald Tutu” to see if these mats that resemble a ballerina’s tutu can help stave off coastal flooding and sea level rise in the neighborhood.

After a year of testing the mat in Eastie exceeded Hopkins expectations. Hopkins said the mats tested  grew “so much vegetation” and her research team didn’t expect as much grass or seaweed to grow.

“We didn’t realize it would colonize that easily and that much,” she said.

The floating biomass, with marsh grass above the waterline and sinewy seaweed below, dampens incoming wave energy and retards storm surge in order to reduce crisis flooding ashore.

Based on the initial results, the research team is looking to design and implement biomass-based coastal protection infrastructure all around Eastie’s waterfront.

The goal is to have a floating network of interconnected, anchored massive organic growing modules dampens wave energy and reduces flooding, storm damage, and erosion on shore while improving nearshore water quality. These biomass modules are seeded with marsh grass at the surface, and are home to many seaweeds below the waterline, all of which add significant mass and frictional surface area and provide habitat for many types of creatures, human and non-human.

“But it also draws people down to the coastline in fair weather; its green landscapes and floating pathways enable public access to new waterfronts,” said Hopkins.

Eastie and other coastal neighborhoods in the city already see some flooding, including on sunny days, and some new properties are being developed to adapt. Massachusetts had the third highest number of affordable housing units under threat of coastal flooding in the nation, according to a Climate Central analysis released last year.

An alarming report from a UN panel warns that the next two decades will bring more damaging floods, worsening droughts and more dangerous heat waves.

Adaptive infrastructure that absorbs tidal energy from rising seas is considered a crucial way to adjust to life as climate change makes the world hotter and wetter and threatens waterfront communities.

According to the project team’s website they drew influence from landscape architect Frederick Law Olmsted’s 1,100-acre connected park system in Boston known as the Emerald Necklace. Olmsted envisioned the park system in Boston as a collective space where inhabitants of the crowded, chaotic city could find healthy activity and mental solace. A series of pleasant public spaces brought nature back to the city, where it could be enjoyed by all.

A byproduct of the Emerald Necklace is that it solved major drainage challenges of an industrializing city, and it integrated transit while balancing residential development.

According to the team the goal of the Emerald Tutu in Eastie is to provide a climate resilience infrastructure solution that is deployable, flexible, inexpensive, green, non-invasive, and a joy to experience.

“As is abundantly clear in our era, “gray infrastructure” coastal barriers and other traditional coastal engineering approaches are ineffective and even harmful, both ecologically and economically,” said the research team. “Civil infrastructure for climate resilience should be accessible to all people, encouraging everyday use and environmental benefits as well as protection during catastrophic storms. Furthermore, it should economically empower local populations during its implementation and upkeep.”