Could a sea wall protect Boston from coastal flooding?

Oceans are rising and storms are intensifying and it wouldn't take much to flood a coastal city like Boston.

Hurricane Sandy was eye opening in 2012, killing 43 people and causing billions of dollars in damage in New York City alone with a surge of sea water that flooded many neighborhoods.

If Sandy hadn't just missed Boston, there could have been a similar storm surge in the low areas of the city.

Now, Boston is looking for new ways to adapt to climate change and keep Boston dry.

The idea is to spend billions of dollars to build a wall that could run from Winthrop to Hull. The price tag could be similar to the $24 billion Big Dig project!

"The western part of East Boston, right near where the greenway is, that right now would be flooded pretty severely if we had a, so called, 100-year storm," said Dr. Paul Kirshen, academic director of the Sustainable Solutions Lab at UMass Boston.

The chance of a 100-year storm happening is one percent each year, but those chances increase over time. And with warming waters and rising seas, managing future coastal flooding due to climate change is a mission Boston is ready to take on.

"So one of the options of dealing with this is think about building a barrier. Let's say it would extend from Winthrop all the way around to Hull and this barrier would be designed so that it had very large gates in it, openings in it, they would be closed when we would get a major storm. And if it was closed, it obviously would prevent the storm surge and the waves from going in and impacting the Boston Harbor coastal area," said Kirshen.

Kirshen showed Boston StormTracker Meteorologist Sarah Wroblewski one type of a sea wall that the city is proposing to protect the area from major storms.

While big storms can result in the highest flooding potential, scientists predict flooding in 2100 could be a normal occurrence on a sunny day during high tide in Boston Harbor.

"By the end of the century, 3-7 feet of sea level rise. Just because of climate change," said Kirshen.

The team at UMass Boston is currently studying if this sea wall in Boston Harbor even makes sense. What potential impacts to the harbor eco system could it bring? What impact would it have to the multi-billion dollar commercial and recreational shipping industry.

"All the fuel. Comes into Boston Harbor for essentially all of New England so it's really important that we maintain these shipping activities," said Kirshen.

While trying to reduce impacts and changes to the shipping industry, changes in the view will be apparent.

"One of the gate openings would be 1500-feet. That would be the largest gate of its kind in the world," said Kirshen.

The City of Boston knows all too well about engineering challenges in recent years.

"It's going to be comparable to the Big Dig type of expenses. We haven't done the cost analysis yet, but it's billions," said Kirshen.

But it would be protecting billions of dollars of real estate along the Boston waterfront, with places like South Boston the most vulnerable to coastal flooding.

"One of the ways we evaluate this project economically is we look at the damages avoided," said Kirshen.

If the sea wall was accepted and put into place, it would take years to build.

"Right now, we're experiencing some coastal flooding with major storms and that's obviously going to increase in the future. So between now and 2050, Boston Harbor is going to have to take some activity to protect it from coastal flooding," said Kirshen.

The City of Boston is already taking immediate steps to create coastal resilience. The mayor recently announced one project for East Boston where a $100,000 deployable floodwall across East Greenway will be installed, and another in Charlestown that would raise the elevation of Main Street as part of the Sullivan Square redesign project.

As for the feasibility study of the sea wall barrier, UMass Boston is expected to wrap up early next year with results by February or March.

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