How Vulnerable is Cambridge to Climate Change?

How Vulnerable is Cambridge to Climate Change?

A study in progress aims to answer that question and help Cambridge become more resilient.

If you’ve lived in Cambridge for more than three weeks, then you experienced the blinding heat wave that just struck, with seven consecutive days in the 90s, culminating with one suffocating day at 100. And if you’ve lived in Cambridge longer than that, you’ve probably also experienced flooding of your basement, neighborhood, or commute.

These extremes we’re beginning to see are likely to become the new normal. While heat waves and flooding are the most prominent early signs of climate change, there are a host of public health issues created by these changes. Excessive heat itself is a threat, particularly for older people. Insect and rodent-borne diseases are likely to rise, as more of these disease carriers survive through warmer winters. Higher temperatures can increase air pollution and aggravate allergies by extending the season for pollinating plants. Our infrastructure is also facing new challenges. When air conditioners are running 24/7, the power system is stressed, and heavy rains can flood subway stations and low lying roads, leaving limited options for us to get around.

These are just some of the challenges Cambridge is grappling with in its ongoing Climate Change Vulnerability Assessment. Back in October 2012, the city assembled a team of consultants, engineers, scientists, and other advisors to better understand what the climate will look like in 2030 and 2070, where we as a city are most vulnerable, and how we can make ourselves more resilient in the face of these changes.

Since the project started, the team has looked at how well we responded to past weather extremes and reviewed methods for making climate projections and assessing public health and economic impacts. Because climate impacts cross city lines, the team is also looking at relevant work being done by the city of Boston, Boston Water and Sewer Commission, and the Metropolitan Area Planning Council, among others.

Through this process, the team discovered that the Massachusetts Department of Transportation is currently evaluating the vulnerability of Central Artery Tunnels to flooding from sea level rise and storm surges by adapting an advanced circulation model to Boston Harbor. As a result, the Cambridge team is coordinating with MassDOT and its consultants to understand their approach and create a more refined assessment of future flooding in Cambridge.

To keep the public informed, the city has set up a project website, and city staff have met with dozens of neighborhood and business associations, environmental groups, advisory committees and boards, youth and senior groups, individual businesses, and other community organizations to discuss the project and understand public concerns. Any organization that would like to arrange a presentation can schedule a meeting by contacting Jennifer Lawrence in Community Development.

The city’s lead contractor on the project is Kleinfelder, an engineering consulting firm that has been working with the city for several years to improve its storm water system. Kleinfelder’s consulting team notably includes Paul Kirshen, whose mapping of potential flood impacts in Boston and Cambridge helped spur action in both cities.

Together with Kleinfelder, a steering committee comprising six city staff from Community Development, Public Works, and Public Health is directing the study. This core team is collecting input from a 16-person technical advisory committee and seven climate change experts from Harvard, MIT, Boston University, and the Union of Concerned Scientists.

The climate change vulnerability assessment will be completed June 2014, and the next public meeting will take place this fall. Once the city’s vulnerabilities are understood, a second 18-month phase will lead to a climate change preparedness plan to help Cambridge become resilient in the new normal.

Flood Map Source: The Boston Harbor Association

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PDF icon Vulnerability assessment project update284.51 KB

Comments

The map and summary description is very useful. When Hurricane Sandy hit New York City, the timing was at its worst : high tide with winds off the water. The result was a flood surge of 14 feet. Boston got lucky because -- when the edge of the hurricane hit our area -- it was low tide. A 5 1/2 hour difference in the timing could have resulted in major flooding for Boston and Cambridge.

It appears from the flood map that the flood surge would go over the new Charles River Dam and spread over the Charles River basin. Rising water would then spread over into East Cambridge and Cambridgeport.

In New York's Rockaway area, the water came over the transit rail tracks with a depth of five feet.

The flood map is very useful to show the vulnerable areas and appears to reflect a flood surge of 7.5 feet. The Turnpike in downtown Boston is shown flooded to a depth of more than 6 feet, so keeping the water out of the Central Artery tunnel will be a big challenge. Mass Water Resources Authority is also studying the vulnerability of its coastal facilities to storm surges.

The track of Hurricane Sandy was predicted with remarkable accuracy. Almost all the models got the strange turn inland through New Jersey. The spin of the storm meant that New York City received much stronger on-shore winds that Philadelphia to the south. Somehow the models did not predict the storm surge very well. We need to know why and how to make sure that any storm surge modeling for Boston is as accurate as we can make it.

Historially, hurricanes would "blow out to sea" and track to the east. The 1938 hurricane was a freak that went straight north inland up the Connecticut River valley. The August 1955 hurricane was more typical in that it hugged the south coast of Massachusetts. It dropped almost 12 inches of rain on Boston in two days, and the Storrow Drive tunnel on the Esplanade was flooded completely. Hurricanes bring both storm surges and heavy rain, so the combination needs to be considered in the planning.

Historically, fllooding in areas such as Alewife in Cambridge is not normally related to storm surges, The floods of 1996, 1998, 2001, 2004, 2005, and 2010 were all created by too much rainwater runoff that could not make its way down the Mystic River fast enough. The storm inundation of the Green Line at Kemore Square in October 1962 and October 1996 was caused by overland water flow, and steps to reduce this problem have been taken. Unlike the New York subway tunnels which were pumped out in a matter of days, the Green Line was closed for several months.

The best country in the world for dealing with flood problems is Holland -- the "Netherlands." Much of the country is below sea level, so they must plan for the possibility of 1000-year storms. They take the threat of flooding much more seriously than we do.

Let us know when the next public meeting is this fall.

Steve Kaiser

Thanks for your comments Steve. Just a word of caution to readers, the creators of the map shown above indicate that it is intended for discussion purposes and is not accurate to the street level. As you point out Steve, this map is for a 7.5 ft storm surge at high tide; a worst case scenario. If you follow the last link I provided in the article, you will have access to the entire range of flood scenarios analyzed.