Professor develops ’emerald tutu’ to protect Boston from flooding

People have heard of Boston’s famous “Emerald Necklace” with its network of parks and green spaces.

Assistant Professor at Northeastern University Julia Hopkins hopes Boston will soon be known for the “Emerald Tutu” a system of interconnected circular mats of floating vegetation that can be arranged in rings and semi-circles to protect urban coastlines from rising sea levels and intensifying storms.

Like land parks, the Emerald Tutu is designed to feature walkways that allow people to get out into nature, in this case to the shallow waters of coastal shorelines.

Julia Hopkins, assistant professor of civil and environmental engineering from the Northeast, poses for a portrait in front of Snell Engineering. Photo by Alyssa Stone/Northeastern University

But in addition to being aesthetically pleasing and recreational, the Emerald Tutu is said to absorb wave energy and help mitigate flooding that increasingly threatens to inundate Boston and other coastal cities.

“It works like a swamp without being a swamp,” says Hopkins, a civil and environmental engineer and lead scientist at startup Emerald Tutu.

The circular mats that make up the components of the tutu measure approximately seven feet in diameter and are designed to have marsh grasses growing on top and seaweed below.

“They are like a sponge. They absorb wave energy,” says Hopkins.

“The basic idea takes some of the theory we have about how nature is supposed to protect the shoreline and applies it to something we can use in urban environments,” Hopkins says in a Northeastern article. University College of Engineering.

The Emerald Tutu project was developed by Hopkins and other collaborators, including Tutu CEO Gabriel Cira, a landscape architect; and former Northeast student Louiza Wise. He received a Small Business Innovation Research Grant from the National Science Foundation in 2020 to develop floating wetlands.

Hopkins, who has been testing mats in Oregon State University’s massive wave energy pond, rolled out Emerald Tutu’s first mat on a pier in East Boston in the spring of 2021.

Made of biodegradable materials such as coir, wood chip by-products, hessian and marine grade rope, the mats will not pollute the environment if they come loose and get lost at sea, explains Hopkins.

Moira Zellner, Northeastern Professor of Public Policy and Urban Affairs and Director of Participatory Modeling, poses for a portrait. Photo by Alyssa Stone/Northeastern University

She says she was thrilled when researchers pulled the East Boston rug out of the water in late summer 2021 to see what was growing on it and discovered it was laden with sea plants.

“There was so much vegetation. We didn’t expect so much grass or seaweed to grow. We didn’t know it would colonize so easily and so much.

The more vegetation there is, the greater the wave absorption, Hopkins says. “Density has improved network performance.”

Currently, the Emerald Tutu Project has two mats in the water, one near Salem and the other off Cape Cod.

A third should be launched in Boston Harbor in cooperation with the stone living lab at any time. “We’re just waiting for the boat,” Hopkins said.

Plans are underway for a massive pilot project off Cape Cod next summer employing around 100 mats. The exact location is yet to be determined, Hopkins says.

Although Cape Cod is not an urban area, the variety of its waters – salt, brackish, and estuarine – should provide much insight into how carpets behave in ocean waves and which plants grow in different environments. says Hopkins.

The ultimate goal would be to surround parts of east Boston, which are particularly susceptible to flooding, with concentric rings of the Emerald Tutu, Hopkins says.

Tutu’s developers simply cannot install the floating mats without the cooperation of numerous officials and agencies, including Harbor Masters and other transportation authorities such as Logan and the Massachusetts Port Authority.

It is important not only to work with these agencies, but also to involve residents and community leaders in efforts to transform the landscape and seascape to reduce the impact of environmental change, says Moira ZellnerNortheast public policy and urban affairs professor.

Laura Kuhl, assistant professor of public policy and urban and international affairs in the Northeast, poses for a portrait. Photo by Alyssa Stone/Northeastern University

Her and Laura KuhlNortheast Assistant Professor at School of Public Policy and Urban Affairswith Hopkins, are the new recipients of a Tier 1 grant northeast to work with communities on the Emerald Tutu project.

The focus is on examining coastal adaptation through a climate justice lens.

“We need to invest in building relationships” and including the voices of people from minorities and low-income neighborhoods before researchers can try things, Zellner says.

“It’s a co-design process,” says Zellner.

Coping with rising sea levels and intensified storms due to climate change is a huge challenge for the Boston area, much of which is built on reclaimed wetlands.

“It will not be a one-size-fits-all solution. It will be a question of building a portfolio. The Emerald Tutu expands the options,” says Kuhl.

“It’s really about the vision communities have of what they want their future to look like,” Kuhl says.

“There is no right answer here,” only a range of options, which could include possible relocation of communities, Kuhl says.

For now, Hopkins, who spent three years studying in the Netherlands, hopes projects like the Emerald Tutu will give the Boston area more time to find solutions to the challenges posed by climate change.

The Emerald Tutu Project is the first to deploy floating wetlands in the ocean, Hopkins says. She says the modular system could be duplicated in coastal cities around the world.

The project is buzzing – in December, Hopkins spoke about the Emerald Tutu as the first presenter at MIT Water Summit.

Nature-based solutions have some advantages over traditional breakwaters and breakwaters in that they encourage interaction with the environment and can adapt to changes in water levels and wave intensity, explains Hopkins.

“Hardscapes are not adaptable. We need an adaptable infrastructure,” says Hopkins.

“The emerald tutu is just one example of what might work,” she says.

“We just have to prove it works.”

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