Stephanie Kruel
Not long ago, developers put their faith in historic patterns of flooding to inform decisions about how to keep buildings and vital infrastructure out of harm’s way. New understanding of rising sea levels has changed that paradigm, however. While the past used to be a good predictor of the future, it isn’t anymore and those charged with keeping structures high and dry must rely on new tools tied to the most sophisticated sea level rise forecasts available.
Later this week, scientists, engineers and policymakers will convene in Boston for a two-day “Rising Seas Summit” (Nov. 4–5), during which we will discuss the latest data on sea level rise and chart the best paths for preventing and mitigating its economic, environmental and social damage. As an environmental planner, I know the solutions we’ll discuss will involve looking forward, not backward, as future modeling of climate change and the sea level impacts it will bring take on increasing importance, whether you’re trying to erect a skyscraper or sink a sewer pipe.
According to the Boston Water and Sewer Commission’s Draft 25-Year Plan, the volume of rain attributed to very heavy precipitation events has been significantly above average for nearly a quarter century and continues to increase; annual rainfall in 2100 is forecast to total four to seven inches more per year compared with 1990. Meanwhile, a recent study on coastal flooding in the Northeast notes that, by 2050, the 100-year storm surge could exceed the elevation of today’s 1,000-year storm surge, and the 100-year surge will likely arrive as frequently as every 15 years – possibly every two.
What does this mean for the building boom that Boston and other coastal communities are experiencing? Most importantly, it signals an urgent need to reset the way we plan for and build structures near the ocean and other large water bodies. Ideally, developers should view the expected lifecycles of their buildings not based on historical or even present conditions, but through the lens of future climate change impacts expected in their particular locations. Locally, one of the soundest sources for this information is the Massachusetts Office of Coastal Zone Management (CZM), which publishes data that models sea level rise scenarios through 2100. Developers need to look beyond what they think is “reasonable” to expect and instead examine closely what reputable sources such as CZM are actually predicting. In that way, they can judge the vulnerability of planned structures and choose resiliency measures wisely.
“The Impacts of Sea Level Rise on Tidal Flooding in Boston, Massachusetts,” a study I authored and which is currently in press with The Journal of Coastal Research, finds that severe tidal flooding due to future sea level rise will likely affect an array of important resources – from housing and public facilities to transportation infrastructure and hazardous waste sites. It notes that Boston will require non-emergency responses to flooding and a new approach to urban floodplain management to address these conditions.
In terms of non-emergency responses, it’s worth noting the Boston Water and Sewer Commission’s foresight in moving to increase the size of storm water infrastructure at each interval of scheduled maintenance over a 10-year period. Through this program, the commission will recalibrate the system’s pipes and other components to meet increased rainfall projections – making it more resilient to the inevitable storms ahead.
Another example of forward thinking in the face of sea level rise is in play at Atlantic Wharf. Located at the intersection of Atlantic Avenue and Congress Street, Atlantic Wharf includes a number of state-of-the-art measures that contributed to making it Boston’s first LEED Platinum high-rise. Among its sustainability features is a temporary flood protection system manufactured by Aquafence. Originated in Norway, it comprises a removable four-foot, L-shaped fence that can be deployed around the building before major storms. The system creates what amounts to an empty bathtub around the building – keeping floods at bay until water abates.
As the first property in Boston to use this system, Atlantic Wharf had to clear hurdles with the Boston Redevelopment Authority before it could place anchors for fence panels in the sidewalk around the building. If we want buildings constructed to withstand climate change impacts going forward, it’s important for innovations such Atlantic Wharf’s flood protection system to be allowed “by right,” rather than through an involved permitting process. Similarly, the city should consider changing its zoning to allow existing buildings to take lower, flood-prone floors out of commission and add higher floors without obtaining a variance if capacity allows.
It’s clear that climate change isn’t going away and the sea will continue to rise. The more developers plan their buildings for these impacts, and the fewer hoops regulatory agencies make them jump through to do it, the more resilient our cities will become. n
Stephanie Kruel, a senior environmental planner with VHB in Boston, will present a study on “The Impacts of Sea Level Rise on Tidal Flooding in Boston” at the 2015 Rising Seas Summit in Boston Nov. 4 – 5.
