Today was a milestone for Alewife Brook. Congresswoman Katherine Clark met at the Brook with Save the Alewife Brook and our state and local delegation to see the sewage, sediment, and flooding crisis for herself. We talked with her about engaging the Army Corps of Engineers for a project to dredge, dechannelize, and restore Alewife Brook.
“Protecting our environment means protecting our neighbors. I’m grateful for the incredible advocates at Save the Alewife Brook for their continued work to eliminate sewage pollution, safeguard our local ecosystem, and build the cleaner future our kids deserve. I’m looking forward to partnering with them and with leaders at every level of government to keep moving the ball forward.”
Democratic Whip Katherine Clark (MA‑5)
Joining the Congresswoman at the Brook were State Senator Pat Jehlen and State Representatives Christine Barber, Dave Rogers, Sean Garballey, and Steve Owens. From the Town of Arlington, we were joined by Town Manager Jim Feeney and Select Board members Diane Mahon and Steve DeCourcey. Save the Alewife Brook was represented by steering committee members Kristin Anderson, Gene Benson, Ann McDonald, George Laite, and Mike Lonetto.
Why this visit matters
A portion of the Alewife Brook is confined to a 27-foot-wide concrete channel that receives untreated sewage from six active Combined Sewer Overflow (CSO) outfalls. In 2021, MWRA, Cambridge, and Somerville dumped 51 million gallons of untreated sewage into the Brook.
The Brook has accumulated 2 1/2 to 3 1/2 feet of contaminated sediment and, according to the 2024 Inter-Fluve Sediment Study[1], will lose its remaining capacity as sediment continues to fill in.
The public health toll is already severe. During CSO discharges, E. coli levels in Alewife Brook reach roughly 950 times the EPA safe standard.[2] A Boston University School of Public Health study found that even living near CSOs can increase the risk of illness serious enough to require an ER visit.[3]
Roughly 5,000 residents of Arlington, Cambridge, and Belmont, many in Environmental Justice neighborhoods, live in the Alewife Brook 100‑year floodplain.
Our two asks of Congresswoman Clark
- Request the U.S. Army Corps of Engineers to lead sediment dredging, dechannelization, and river restoration of the Alewife Brook. This work should run in parallel with, not instead of, the regional CSO‑elimination effort. In 2022, EPA recommended that MWRA dredge the Brook as part of the Long Term CSO Control Plan and work with DCR to remove sediment.[4] River restoration is also supported by DCR's Alewife Masterplan.
- Secure a water gage in the Brook near where the Little River meets Alewife Brook. A gage would improve accuracy of the water quality model. Real‑time flow data at that location is essential for calibrating CSO‑control performance, storm response, and future restoration design.
Two tracks, one clean Brook
Track 1: Eliminate Sewage
MWRA, Cambridge, and Somerville, pushed by EPA and MassDEP through the Updated Long Term CSO Control Plan, must end CSO discharges. This is a state and regional fight, not the Congresswoman's ask.
Track 2: Restore the Brook
A parallel federal effort: a water gage at Little River / Alewife plus Army Corps dredging, dechannelization, and river restoration. This addresses the sediment and flooding crisis the LTCP does not.
This is what we ask Congresswoman Clark to lead.
Thank you to our state delegation and Arlington's local leaders
Reps. Dave Rogers, Sean Garballey, and Steve Owens have led the charge on this issue for years. Together with Rep. Christine Barber, Chair of the Joint Committee on Environment and Natural Resources, and Rep. Marjorie Decker, Chair of the Joint Committee on Public Health, they secured the state earmark that funded the sediment study now driving this federal ask.
State Senator Pat Jehlen has been a consistent champion of the infrastructure improvements needed to end sewage discharges into the Brook.
Thank you as well to Town Manager Jim Feeney and Select Board members Diane Mahon and Steve DeCourcey for standing with the community at the Brook today. Arlington's continued leadership matters.
The cost of CSO elimination? Less than an annual MWRA rate increase.
At the 07/27/2026 Arlington Select Board meeting, MWRA Interim Executive Director Stephen Estes‑Smargiassi explained how eliminating CSOs[5] across all three rivers (Alewife, Charles, and Mystic) costs households in the MWRA's system an average of $45 per household per year, less than $4 per month. That is less than the average annual MWRA rate increase.
What you can do today
Tell MassDEP, EPA, and Governor Healey to end CSO sewage in Alewife Brook.
Footnotes
- Inter‑Fluve, Alewife Brook Sediment Study Report (2024): Read the study (PDF). The Inter‑Fluve and Stantec Alewife sediment and flooding studies were supported by a grant from DCR and managed by the Mystic River Watershed Association.
- E. coli data from the MWRA Board of Directors meeting presentation (page 18): mwra.com/media/file/2025-10-29-mwra-board-directors-meeting-presentations
- Haley et al. 2024 in Environmental Health Perspectives (open‑access on NIH PMC). Plain‑language summary from BU: "Sewage Overflows Linked to Increase in Gastrointestinal Illnesses" (BU SPH, May 23, 2024). Key finding: 62% higher ER‑visit risk for AGI in the four days after the largest CSO events.
- EPA's Scope of Work Comment to MWRA: "The channelized nature of Alewife Brook, as well as the amount of sediment in the Alewife constructed channel that takes up flood storage capacity (this sediment volume was estimated by USGS in 2005 to take up approximately 0.5 million cubic feet), exacerbates the flooding issue." Read the full EPA comment (PDF).
- Elimination of CSOs means control up to a 25‑year storm event in the year 2050. That is the highest level of control.