As the floodwaters receded in Kristin Anderson’s basement in Arlington, she was confronted with a disturbing scene: toilet paper, condoms, and tampon applicators scattered across the floor, remnants of the dirty water that had invaded her home.
What followed were days filled with debilitating gastrointestinal issues, a grim reminder of the raw sewage that had seeped into her living space, all thanks to the overflow of Alewife Brook.
“It came right in through the back door after the brook overflowed its banks,” Anderson recalled. “It was pretty traumatic.”
Originating in Cambridge, Alewife Brook is plagued by a persistent sewage issue, primarily due to a single outfall pipe located behind the Alewife MBTA parking garage. During heavy rainfall events, this outfall becomes a significant source of sewage being discharged into the brook, a problem compounded by increasingly intense storms driven by climate change.
This ongoing situation can be traced back decades to the Boston Harbor Cleanup case, where the U.S. Environmental Protection Agency (EPA) initiated a sweeping cleanup effort to address one of America’s dirtiest harbors.
The federally mandated projects cost over $4 billion, ignited by two lawsuits from the 1980s that compelled a federal judge to mandate the construction of the Deer Island Wastewater Treatment Plant, among other significant steps.
Today, Boston Harbor is often celebrated as an enforcement success for the EPA. However, problems like the sewage discharge into Alewife Brook remain unresolved.
Data indicates that in 2023, 26 million gallons of untreated sewage were released into Alewife Brook, marking it as the area with the highest concentration of sewage outfall in the Boston region, as per the Mystic River Watershed Association.
Around two-thirds of this sewage originated from a specific outfall identified as CAM 401A, which is noncompliant with current cleanup plans and is located near the Alewife Brook Reservation.
Approximately 5,000 residents inhabit the 100-year floodplain of Alewife Brook spanning Cambridge, Arlington, and Belmont. This area is further complicated by nearby MBTA stations and new developments featuring luxury apartments and biotech companies, leading thousands to a daily encounter with the river—and specifically with the problematic 401A outfall.
There have even been disturbing instances where families are seen pushing strollers through what are actually raw sewage puddles.
“We aren’t supposed to be coming into contact with untreated, raw sewage,” emphasized Marja Copeland, stormwater project manager for the Mystic River Watershed Association.
According to the water quality standards established by the federal Clean Water Act, discharging sewage into Alewife Brook is prohibited. Yet the state has issued temporary variances permitting such actions while involved parties formulate solutions.
During combined sewer overflow (CSO) events, debris such as toilet paper and other “floatables”—anything that is flushed—can be observed pooling in Alewife Brook. The current conditions have forced several homeless encampments in the area to relocate multiple times, often with occupants unaware of the health hazards posed during heavy rainfall.
This serves as a public health concern and raises significant ecological alarm, as Alewife Brook is frequently reported to possess some of the poorest water quality in the Boston area. Such contamination inhibits wildlife from thriving and compromises human recreational activities.
“The amount of sewage pollution in that brook is unfathomable considering its size,” stated Anderson, who subsequently founded Save the Alewife Brook, a grassroots organization dedicated to stopping sewer discharge into the brook.
So, what are combined sewer overflows?
During a wet morning in May, Copeland and Andy Hrycyna, the water quality program manager for the Mystic River Watershed Association, guided a MassLive reporter around Alewife Brook Reservation.
The landscape surrounding the brook has rapidly urbanized as development proliferates near the Alewife MBTA station. The creation of more impervious surfaces in the area generates increased stormwater runoff, exacerbating the situation. Additionally, the frequency of intense storms has also surged.
For example, on May 22, a substantial rainfall swept across parts of Massachusetts, characterized as a late-season nor’easter. Sewage overflow from the 401A outfall behind the MBTA parking garage discharged into Alewife Brook during a critical time window.
The city of Cambridge utilized its combined sewer overflow alert system to warn the public against contact for 48 hours, citing increased health risks stemming from contaminants that stormwater might carry, such as bacteria or pesticides.
According to Hrycyna, during these discharge events, “the capacity of that pipe of combined sewage and stormwater is exceeded”.
To prevent local streets from flooding or discharging sewage into homes, the infrastructure design channels this overflow directly into a river.
Nonetheless, flooding can still lead to sewage intrusion into residences, as highlighted by Anderson’s experiences in Arlington.
In the mid-to-late 1800s, combined sewer outfalls were viewed as best practices for handling wastewater and stormwater, allowing both to be discharged through one pipe into local waterways.
“Combined sewer overflows represent a legacy of pollution, industrialization and historic infrastructure systems that no longer serve the cities we inhabit today,” stated Copeland.
However, tackling and eliminating combined sewer overflows poses a monumental challenge, given the complexity and cost of upgrading outdated underground infrastructure. While advancements have occurred over recent decades, Alewife Brook remains under threat.
According to the Massachusetts Water Resources Authority, 45 out of 86 combined sewer outfalls from the late 1980s in the Boston Harbor area are still operational today. Alarmingly, the estimated annual discharge has decreased from 3.3 billion gallons in the late 1980s to around 401 million gallons currently.
The situation has compelled Cambridge to undertake several major projects, including the successful separation of sewer and stormwater systems across more than 420 acres in 2013. The initiative included constructing the Alewife Stormwater Wetland—a natural solution intended to treat stormwater prior to its entry into the brook.
This project carried a price tag in excess of $150 million. Future sewer projects in Cambridge, such as pipe separation, sewage storage facilities, and tunnels, are expected to exceed this initial investment.
“We’re talking hundreds of millions to billions,” shared Lucica Hiller, a senior project manager for Cambridge’s Department of Public Works.
Funding for these initiatives is typically derived from water and sewer rates along with property taxes, resulting in limited federal financial support for such projects.
Currently, the cities of Cambridge, Somerville, and the Massachusetts Water Resources Authority (MWRA) are actively updating their long-term control plans for sewer overflow—a requirement stemming from the Boston Harbor federal court case. The aim is to lay a foundation for future improvements that will ultimately address and diminish the extent of sewer discharge.
The initial version of the approved plan, completed in 2015, incorporated 35 projects costing over $900 million.
Hrycyna described the sewer overflows into Alewife Brook as a “recalcitrant, last, unfinished chapter of the cleanup of Boston Harbor.”
Updating the long-term control plan is critical since it is part of the variances issued last August by the state Department of Environmental Protection, allowing sewage discharge while the MWRA and its partners develop actionable solutions.
Hiller stated that the updated plan will explore a mix of alternatives focused on reducing combined sewer overflows. The draft is anticipated to be presented to the public and regulatory bodies by December 2023, showcasing what is feasible and cost-effective in terms of construction.
“It’s definitely not sexy to talk about sewer and combined sewer overflows,” Hiller remarked. “At the end of the day, this work is expensive, and I know people are often reluctant to discuss the potential for tax increases. But it is a costly endeavor if we wish to leave a better legacy for future generations.”
Parallel efforts are underway elsewhere, including in Western Massachusetts, where Holyoke is set to commence a $30 million project aimed at separating stormwater and wastewater to improve the health of the Connecticut River.
In a recent ruling, a judge approved a plan between the EPA and Holyoke to rectify violations of the Clean Water Act related to sewer overflows.
“Forced exposure to hazardous sewage” remains a pressing issue, according to concerned members of the community, particularly as the Cambridge City Council has taken steps urging both Governor Maura Healey and the MBTA to ensure redevelopment projects at Alewife Station play a pivotal role in resolving the sewage discharge issue.
Proposed legislation is currently before state lawmakers that would mandate the effective abolition of combined sewer overflows within the service areas operated by the Massachusetts Water Resource Authority, specifically targeting storm events calculated as a 25-year occurrence by 2035.
Members of Save the Alewife Brook have been tirelessly advocating for significant action regarding these matters. They have engaged in discussions at city council meetings, appeared before the state Legislature, and participated in the public commentary process pertaining to the new long-term control plan.
However, skepticism prevails among these residents, particularly considering the prolonged impact of combined sewer overflows in the region.
“These entities could potentially address the situation through a combination of sewer separation, storage tunnels, and enhanced green infrastructure,” expressed Gene Benson, a Save the Alewife Brook member who resides in Arlington. “They hold the technical expertise needed; the issue lies in their lack of incentive to move forward.”
Benson perceives the long-term control planning process as fundamentally flawed.
“Here we are in 2025, and the brook still faces an incredible volume of CSOs every year,” he said. The group has raised concerns over the use of a “typical year” in data measurements, especially as climate change leads to less predictable weather patterns.
As Anderson pointed out, “This is forced exposure to hazardous sewage.”
For information regarding the long-term control planning process and how to get involved, further resources can be found online.
image source from：masslive
