Making room for the river

Projected late century flooding in East Boston and Chelsea Creek Credit: Stoss

Today’s news is full of stories of extreme weather events.

California wildfires. Hurricanes. Heat waves.

Mystic River communities are also beginning to experience the effects of climate change: too much water (flooding), too little water (drought), summer heat waves and unpredictable winter weather.  What do these trends mean for our watershed? See the Mystic climate projections:

Near-flanking of the Amelia Earhart Dam during March 2018 Nor’easter Riley. (Photo credit: David Burson)

The Dam that changed everything

The Mystic’s name comes from an Anglicized version of the Pequot word missi-tuk, meaning “a great river whose waters are driven into waves by tides or wind.”  Its original tidal influence was extensive, reaching up, for example, to what is now the Alewife MBTA station in Cambridge and far into Malden.

In the 1960s, the Amelia Earhart Dam was built between what is now Somerville’s Assembly Square and Everett’s Gateway Mall, dividing the river into an upstream freshwater impoundment and a downstream tidal estuary.

Over the subsequent half-century, construction of Interstate 93 filled in many wetlands and many former industrial sites have been cleaned up and redeveloped.  These filled coastal marshes, however, now coincide with areas of increasing flood risk.

Island End River “self-daylighting” through Boston Market Terminal parking lot, Everett. (Photo credit: Greg St. Louis)

Island End River “self-daylighting” through Boston Market Terminal parking lot, Everett. (Photo credit: Greg St. Louis)

Downstream of the Dam

The Lower Mystic has already seen over a foot of sea level rise since the late 1800s.  

In the downstream communities of Somerville, Everett, Chelsea, Boston, Winthrop, and Revere, low-lying areas already flood during astronomical high tides (“King Tides”) and extreme storms.  During the March 2018 Nor’easter Riley, for example, the culverted Island End River broke through the middle of Everett’s Boston Market Terminal parking lot.

The Lower Mystic is home to multiple environmental justice communities along with the highest concentration of regionally important transportation, food, energy and wastewater infrastructure in New England.  Some of these businesses—including fuel storage and scrap metal recycling—have the potential to contaminate surrounding neighborhoods and the river during severe flood events.

Mystic River flooding, March 2010 (Photo credit: David Mussina)

Mystic River flooding, March 2010 (Photo credit: David Mussina)

Upstream of the Dam

Nearly half of the land in the Upper Mystic has been built on or paved over.  This prevents heavy rain or rapid snowmelt from soaking into the ground, putting Mystic communities at risk of stormwater flooding.

In addition, the Cambridge Climate Vulnerability Assessment estimates that the Amelia Earhart Dam could be flanked as early as 2045 by a “100-year” (1% annual probability) coastal storm surge.  Once coastal flooding becomes more chronic and extensive, it will put people and places—including downtown Medford and Malden, the Red and Orange MBTA lines, and Cambridge’s Fresh Pond reservoir—at risk.

Municipal CEOs and state legislators from all 21 Mystic communities have signed on to letters requesting state support to make the Amelia Earhart Dam more flood resilient. 

South Station Commuters, February 2015 (Photo Credit: Jessica Rinaldi, Boston Globe)

South Station Commuters, February 2015 (Photo Credit: Jessica Rinaldi, Boston Globe)

vulnerable residents

Extreme weather—whether winter storms or summer heat waves—falls hardest on our most vulnerable neighbors.  For example, in early 2015, six weeks of heavy snowfall repeatedly shut down Boston-area public transit and public schools.  

For people who could work from home, the blizzards were a nuisance. For single parents making minimum wage who could neither afford taxis nor day care, they meant economic catastrophe.

Similarly, heat waves become life threatening to people with fragile health who lack access to health care.  Flooding can lead to indoor mold and respiratory illnesses for people unable to move or repair their homes.

New or undocumented Americans may be unable to access public health resources due to language barriers or fear of immigration authorities.

Climate preparedness involves identifying and implementing ways of increasing people’s economic and social safety nets so that extreme weather events don’t lead to cascading health and economic losses.