By Leia Green
Boston University News Service
A draft plan to tackle the decades-long issue of combined sewer overflows, which regularly spill raw sewage into Greater Boston waterways like Alewife Brook, has sparked outrage among advocacy groups and local legislators.
Concerns surrounding the plan — drawn up by the Massachusetts Water Resources Authority and the cities of Somerville and Cambridge, known collectively as the Partners — run the gamut.
Some claim the proposal, unveiled late last month, would greenlight the continued flow of sewage into waterways, burden municipalities with massive costs and roll back years of progress to clean the region’s rivers.
“The latest draft plan from the MWRA still leaves people very much concerned that problems are not going to be sufficiently addressed,” said state Rep. Dave Rogers, D-Cambridge, whose district covers all of Belmont and parts of Arlington.
The Massachusetts Department of Environmental Protection urged the MWRA to reconsider the recommendations in a Nov. 17 letter.
“MassDEP is concerned that Recommended Alternatives identified may be insufficient to address CSO discharges and associated impacts,” wrote Kathleen Baskin, commissioner of the Bureau of Water Resources at MassDEP.
Baskin added that “an approach that would result in a greater number of [CSO] activations” than currently occur would violate the federal Clean Water Act and the Massachusetts Surface Water Quality Standards.
Dumping raw sewage into the rivers is illegal under the Clean Water Act, however the MassDEP grants temporary variances to allow for limited discharges, under the condition that work is being done to curb overflows.
“The variance is not a ‘Get Out of Jail Free Forever’ card,” said Emily Norton, executive director of the Charles River Watershed Association, during a meeting addressing the draft plan last week.
“You have to show that you are making progress, real progress, toward eliminating the sewage discharges.”
Alewife Brook — which receives higher volumes of “completely untreated” sewage than any other river in Greater Boston — saw an estimated 19 million gallons inflow of combined sewage in 2024, according to the Mystic River Watershed Association.
When heavy rain overwhelms drainage systems, the six active CSOs lining the Alewife Brook capture excess stormwater and sanitary sewage in one pipe, before releasing both into the waterway.
When the brook’s banks overflow, raw sewage creeps into nearby parks, yards and basements. Around 5,000 people live in the brook’s floodplain, according to Kristin Anderson, co-founder of Save the Alewife Brook.
Anderson’s previous home was located near the brook’s bank. After a downpour, sewage would seep through her back door, ushering in a small flood of used tampons, condoms and tattered toilet paper.
A 2024 study by Boston University’s School of Public Health found that residents in CSO-impacted communities are at significant risk of contracting acute gastrointestinal illnesses within four days of a sewage overflow event.
“I got really sick. My neighbors got really sick,” said Anderson. “It’s terrible. I don’t want that to happen to anybody else.”
Climate change, expected to intensify future downpours, will exacerbate overflows, said Paul Kirshen, a professor of climate adaptation at the University of Massachusetts Boston.
The CSO networks, many of which date back to the late 1800s, were designed to handle a lot less rainfall than what’s falling now, he said.
“It’s designed to discharge untreated sewage into the brook,” said Anderson. “It’s not just what you flush down the toilet, it’s also industrial waste.”
The draft plan includes a proposal to declassify the water quality standards of the Charles River, Mystic River and Alewife Brook from Class B waterways to Class B (CSO), which, advocates argue, would permit the continued flow of sewage into the rivers.
While raw sewage cannot be discharged into Class B rivers, occasional sewage discharges are allowed in Class B (CSO) water bodies.
Advocates say a change in classification could jeapordize the possibility of eliminating combined sewer overflows altogether.
In response to the plan, the Charles River Watershed Association and the Mystic River Watershed Association filed a motion Tuesday to intervene in the 1985 federal lawsuit — U.S. v. Metropolitan District Commission — that kickstarted the cleanup of Boston Harbor and the long-term plan to control CSOs.
“The Boston Harbor cleanup case brought the promise of swimmable, fishable waters in Greater Boston,” wrote Patrick Herron, executive director of the MyRWA, in a press release Wednesday. “This promise has yet to be fulfilled.”
The press release claims the MWRA are looking to close out the case, despite not yet achieving required levels of CSO control.
“MWRA has laid its cards on the table with its recent proposal,” wrote Norton in the press release. “Officials have made it abundantly clear that they have no intention of ridding the Charles River of sewage, as they are legally required to do.”
The MWRA Board of Directors was slated to vote to approve the draft plan this week. However, following the backlash, the vote has been tabled.
“In order to address questions and comments that have been received from MWRA Board Members and the public, this item has not been included on the Nov. 19 Board Agenda,” the MWRA wrote in a statement. “Instead, it will be considered at a future Board Meeting after further information is gathered.”
As the draft hangs in limbo, some advocates and local leaders are preaching a similar message.
“The MWRA needs to pay more,” said Anderson.
‘An impossible situation’
CSOs lining the Charles River, Mystic River and Alewife Brook are either owned by Cambridge, Somerville or MWRA. The draft plan states the owner of each outfall would pay for the solution.
When it comes to reducing sewage in the Alewife specifically — which receives the highest volume of untreated sewage from a Cambridge-owned CSO and a Somerville-owned CSO — the MWRA said it expects to contribute around a third of the estimated $340 million project cost.
“A huge percentage of that cost comes on to [Somerville], and the costs are astronomical,” said Somerville City Councilor Ben Ewen-Campen, during a council meeting last week.
The infrastructure projects proposed in the draft plan would subject the city’s water bills to annual increases of up to 20% for a minimum of five years, he said.
Instead of burdening individual municipalities with these costs, advocates and policymakers say MWRA could hike water bills for the approximately one million households under their jurisdiction to raise funds for sewage infrastructure projects.
“Storms don’t care about the municipalities,” said Ewen-Campen. “Sharing the burden among all these communities needs to be controlled by some kind of regional authority.”
Implementing widespread rate increases to reduce sewage overflows has been done before.
Throughout the 1980s and 1990s, the MWRA raised approximately $5 billion by upping regional water bills in order to fund the court-ordered clean-up of Boston Habor and sewage infrastructure projects.
MWRA’s investments slashed combined sewer discharges by nearly 88%.
“There’s a precedent,” said Somerville City Councilor Wilfred Mbah, during the meeting. “A billion dollars isn’t so much money when you can split it up among a million customers.”
Kirshen, who worked as a contractor with the MWRA for two years, said the agency should inform ratepayers — who would fund a sizable chunk of a potential project to end CSOs — how much the construction would cost.
“[The MWRA] live in a budget-constrained world, and it’s really up to the public if they want to bear the cost of total CSO elimination,” Kirshen said.
“The public should see what it would cost to eliminate [CSOs] and understand how that would change rates,” he added. “Then the public can make an informed decision.”
MWRA claims the most stringent CSO control option — complete elimination — would cost roughly $7 billion, $3 billion of which would be paid by its ratepayers, according to the MWRA website.
Citing cost and regulatory concerns, the Partners did not recommend the complete elimination of CSOs in the updated draft plan.
“We’re being asked to spend basically an impossible amount of money to burden ratepayers, to do a project that’s not even good enough,” said Ewen-Campen.
The ‘least ambitious’ alternative
The draft plan for the Alewife — involving eight acres of sewage separation, a micro tunnel and two underground storage tanks — aims to reduce sewage discharges into the river but would not eradicate them.
It’s the “least ambitious” alternative for the waterway, according to Save the Alewife Brook.
“Those neighbors in the community who are impacted, what they really want to see is a plan to eliminate [CSOs] completely,” said Rogers, who has filed state legislation aimed at eradicating CSOs.
The sewer separation — the most “common way” of eliminating CSOs — would entail the construction of a second pipe only in the area tributary to CAM001, a Cambridge-owned CSO, said Cambridge City Engineer Jim Wilcox. Sanitary sewage would flow through one pipe to the Deer Island Wastewater Treatment Plant, while rainwater and snow melt would flow through the other into the Alewife Brook.
The underground storage tanks and micro tunnel — more complex infrastructure projects — would store combined sewage during rainfall events, before sending it to Deer Island, said Wilcox.
The projects — estimated to take 13 to 18 years to complete — would cut down the rate of sewage discharges. However, advocates are pushing for a greater level of control.
Save the Alewife Brook is advocating for either complete sewer separation or a 25-year storm control design, which would ensure CSOs only discharge sewage in rare storm events expected to occur every 25 years.
Wilcox said achieving that level of control would involve “much, much bigger projects than what is currently being proposed in the draft plan.”
The Partners have pointed to high costs and feasibility issues as obstacles to infrastructure projects that would achieve the highest levels of CSO control, such as expansive sewer separation and large underground tunnels.
“I’ve been in the Legislature for 12 years now, and for over a decade, like a mantra, they just repeat the difficulty and the expense,” said Rogers. “The difficulty and expense can’t be an excuse not to find a way through.”
A long time coming
The updated draft plan presented by the Partners has been in the works for the past four years. Wilcox said project planners have met at least once a week throughout the yearslong process.
“It’s been a really good collaborative and cooperative process with both MWRA and Somerville,” he said.
In the five public meetings held throughout the plan’s development, advocates have proposed alternatives and shared concerns. The ultimate reveal of the draft was a shock to many.
“We study this stuff, and we try to understand it, and we do our best to help guide the process,” said Anderson. “Then we find out that they haven’t been listening to us at all.”
Wilcox said balancing the demands of advocacy groups with technical, fiscal and regulatory realities is “always a challenge.”
“We seek feedback, we listen to what people have to say, we take that into consideration,” he said. “Then you do need to look at what realistically can be done with the space that’s available, with the logistics of actually doing the construction, and the cost of the work.”
Advocates and council members say they worry the MWRA – created by the state Legislature in 1984 to tackle the region’s environmental threats — is losing sight of its original mission.
“A solution can be had and it’s going to cost money,” said Anderson. “But the plan that they are proposing right now for the Alewife Brook, it will mean an increase in sewage pollution with no end in sight.”
This article originally appeared in Your Arlington.
