Arlington residents, watershed groups urge elimination of raw sewage in Alewife Brook

Several Arlington residents and regional watershed advocates told the Select Board the MWRA draft CSO plan does not go far enough to prevent raw sewage from reaching Alewife Brook. Kristen Anderson, a founding member of Save the Alewife Brook, said sewage‑laden floodwater entered her home and caused illness in her household. "Alewife Brook sewage floodwater came into my home through the back door," Anderson told the board, describing gastrointestinal illness and high E. coli counts in the brook.

Representatives from the Mystic River Watershed Association and other advocates said the plan relies heavily on storage tanks and conveyance to Deer Island and that the Alewife will continue to receive untreated CSO inputs at times. The witness representing the watershed association said modeling showed the plan would have reduced but not eliminated combined sewage volume in recent years and argued that more sewer separation and green stormwater infrastructure would create more resilient, long‑term benefits for communities and parkland.

Board members and MWRA staff discussed tradeoffs: MWRA said its alternatives evaluation considered water‑quality benefits, construction impacts and loss of open space, and encouraged advocates to use the public comment period to press regulators for different outcomes. Advocates asked the Select Board to oppose any final plan that leaves untreated sewage inputs in the Alewife and to press for design options that prioritize sewer separation where it is cost‑effective.

Why it matters: Residents described acute public‑health impacts from flooding that carries untreated sewage into yards, paths and parkland used by families and children. Advocates requested that Arlington use its voice with regulators and MWRA to seek alternatives that reduce or eliminate untreated discharges in the brook.