Coastal infrastructureBuilding a network of canals to save Boston from sea level rise

By the end of the century, sea-level rise on the U.S. east coast is predicted to reach six feet, so city planners in Boston recently met to discuss how to live with rising waters along the city’s historic streets. One suggestion is to turn Boston’s Back Bay district into a network of canals. “Much of the model has been how do we keep the water out? Everybody’s afraid of the water,” says Dennis Carlberg, sustainability director at Boston University and co-chair of Boston’s sea-level rise committee. “So we wanted to turn that conversation on its head and say, well what if we let water in? How can we make life better in Boston by bringing water in?”

According to BBC News, the idea for turning streets into canals came about in May when national real estate association, the Urban Land Institute, held brainstorming sessions involving architects, developers, real estate experts, and business owners to discuss ways of preserving the city’s buildings as sea-levels rise. “It can’t be that we provide a giant dam at the Boston harbor and solve all our problems that way,” says Boston’s Chief of Environment, Energy and Open Space, Brian Swett. “The way we solve this has to be vibrant, liveable, exciting and enhance our quality of life.”

Back Bay, a neighborhood which was actually a tidal bay before it began to be filled in and built on 150 years ago, now houses rows of five story brownstone homes arranged in a grid pattern. “Currently the Back Bay streets are about four feet above high tide, so if the sea level rises as predicted, they would be underwater part time by the end of the century,” says Harvard Business School’s John Macomber, who helped assess the financial implications of the canal concept.

The canals would alleviate sea-level rise by draining water into lower-lying back alleys and some main streets, but the proposed plan would have to contend with freezing temperatures in the winter. “The question is whether in a climate where it can snow for six months of the year you want canals that are always open and partly full of slush, sand and salt,” says Macomber.

Other options for coping with sea-level rise include re-introducing natural wetland habitats that would soak in excess water. “As sea level rises, we are going to be losing this natural sponge globally, so trying to add some of it back is an important thing to be paying attention to,” says Carlberg.

Architect Amy Korte, who is working on building design in Boston’s Innovation District, has proposed increasing the foundation height for vulnerable structures and make sure critical infrastructure, such as electrical and mechanical equipment, are placed above flood levels. “We’ve looked at raising the ground floor elevation as much as possible,” Korte said. “We asked how do we raise critical equipment and create a new vision for what good urban design can be.”

Swett compares the recommendations for coping with sea-level rise to Venice and Amsterdam. “Boston’s been around for 400 years and we’re going to be around for another 400. Amsterdam is already more than 700 years old, and Venice more than 1,500. So canals can work - even if they do make it more difficult to park.”