This American city is building a network of waterfront parks to absorb floods

To protect itself from floods, Boston was considering building a huge sea wall. But a new plan unveiled in October represents a 180-degree turn: instead of fighting to keep the water out, the city is letting it come in.

E very year, sea levels rise by one-eighth of an inch. That might not sound like much, but for the 40% of Americans who live in high-density coastal areas, it poses an existential threat. Within the next 30 years, experts predict that more than 300,000 homes located on US coasts will run the risk of flooding every two weeks.

The typical response to this looming threat is to attempt to keep the water out, usually by building concrete sea walls. So tried and tested is this approach that there are 14,000 miles of concrete coastal barricades across the US, covering 14% of the country’s coastline. 

But now, one American city is opting for a different strategy: instead of using bulky structures to keep the floods out, Boston is letting them come in by building a network of waterfront parks that will work with the rising tide rather than against it.

Beaches and parks instead of barricades

Of all America’s cities, Boston is perhaps one of the most vulnerable to rising sea levels. In the past 40 years, it has experienced more high-tide flooding than any other city on the East Coast.

While the original idea for dealing with this challenge had been to construct a sea wall, a report from the University of Massachusetts-Boston Sustainable Solutions Lab determined it to be too expensive, too slow to build, and too cumbersome to maintain. “According to the analysis, if a wall is built, it likely won’t be operational until 2050, at the earliest, and it could cost up to $11.8 billion,” Boston Magazine reported at the time. “On top of that, because sea levels will continue to rise, wear-and-tear on such a barrier will only increase over time.”

The report’s authors recommended that Boston take a different approach, which Mayor Walsh announced to the city’s business leaders in October 2018. “We’ve identified ways to protect our neighbourhoods that also enhance access and enjoyment of our waterfront,” he told them. “It’s a system not of barricades but of beaches — and parks and trails and open spaces — that are elevated to block floods.” Under the plan, the city will introduce 67 new acres of waterfront green space and restore access to 122 tidal acres, Mayor Walsh pointed out.

“With shore-based systems, we can really improve the quality of life for people living on the shore, with the amenities those systems provide,” said Paul Kirshen, the academic director of the Sustainable Solutions Lab.

Environmental common sense

Waterfront parks might be great news for locals who will benefit from the new green space, but in many circumstances, they also make more environmental sense than sea walls. 

As Erin Blakemore wrote for, “concrete walls can bounce waves back into the ocean, destroy tidal marshes and hurt wildlife, and even make coastal areas more vulnerable to storms.” Indeed, as academics pointed out in a 2016 paper, seawalls support 23% lower biodiversity and 45% fewer organisms than natural shorelines. The approach being adopted by Boston will pose less of a threat to marine life, Mayor Walsh said in his announcement, while being just as, if not more, effective at keeping the city safe from floods.

It’s no surprise, then, that other cities are also embracing this philosophy of “living with rather than fighting water,” a concept Boston borrowed from the Netherlands, one-third of which is below sea level. For example, Bangkok — which experts predict could be partially submerged in just over a decade — has built a park that acts like a sponge, capturing rainwater that can then be used for irrigation during periods of drought. And in Beijing, authorities are planning on building 73 waterfront parks to reduce the risk of flooding.

The plans in Boston won’t come cheap, and Bloomberg reports that city officials are working with investors to secure billions in funding. But as Mayor Walsh reminded locals in his speech, the choice is either to adapt today or suffer the consequences further down the line. “We either invest now, or else we pay a much bigger price later.”

The ideas presented in this article aim to inspire adaptation action – they are the views of the author and do not necessarily reflect those of the Global Center on Adaptation.

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