HUB HURRICANE BARRIER EYED
Harbor project would cost $10B
With Tropical Storm Harvey inundating Houston, experts say Boston could face its own extreme flooding crisis in the next century — threatening massive damage and justifying a $10 billion hurricane barrier outside the harbor.
“An event like this is a call to pay attention to the risk,” said Kerry Emanuel, a professor of atmospheric science at MIT and a leading climate change expert. “We’ve ac- tually gotten reasonably good at quantifying how that risk will change over the next century, and unfortunately, that does not look good for Boston. It looks like both the intensity of hurricanes and the amount of rain they produce will go up over the century.”
In a report commissioned by the city last year, the Boston Research Advisory Group concluded that the rate of rising sea levels in Boston will likely exceed the global average through 2100, with the most likely estimates pegging the rise between 2.5 and 7.4 feet. By 2050, modeling indicates a likely sea level rise of 7.5 to 18 inches in Boston, with as much as 30 inches considered possible.
This comes after Boston sea levels rose about 0.11 inches per year between 1921 and 2015, according to the report.
The Boston Green Ribbon Commission predicts a 100-year storm could flood 2,000 buildings and impact 18,000 people by 2030, threatening property valued at $20 billion. By 2070, those predictions jump to 12,000 buildings and $85 billion worth of property.
Austin Blackmon, Boston’s chief of environment and open space, said much of that damage could be done by more common storms — those expected once in a decade instead of once in a century.
“What you’ll ultimately start seeing is a lot of damage from storms that you can expect much more frequently,” Blackmon said.
A team at the University of Massachusetts Boston’s Sustainable Solutions Lab has been studying the feasibility of building a hurricane barrier to wall off Boston Harbor from storm surges, similar to systems in Rotterdam in the Netherlands and one under development in Venice.
Three different scales are contemplated — a barrier that would run from the tip of Logan International Airport to South Boston, one that would encompass the Harbor Islands, and one stretching as far out as the coast of Hull. Rough cost estimates are pegged at more than $10 billion.
Blackmon said studies of the ecological effects of the barriers and economic impact to the booming Conley Shipping Terminal in Southie are being studied.
“When you put up a barrier like that, you basically stop the tidal flow, and it makes it more difficult to get access to the harbor,” he said.
For now, the city is creating “shovel-ready” project ideas to protect the East Boston Greenway, the area of the city deemed most vulnerable to storm surges in the short term. The city plans to release a report in October outlining ways to install green space and berm in the area to protect it, Blackmon said. The section of Charlestown near Ryan Playground also has pressing needs, he said.
Emanuel said he worries about a disaster scenario he calls “the double whammy” — where a fastmoving hurricane pushes a surge of fresh water down the Charles River, causing it to spill over.
“At the moment the Charles River is only 1.8 feet over the level of high tide in Boston Harbor,” he said. “If you had a three-foot surge, and you had a day of very heavy rain preceding the hurricane, which is what happened in 1938, you could have a lot of fresh water trying to come down the Charles River. And it has no place to go, and it floods Back Bay and MIT and East Cambridge pretty badly.”