“If you look on the left hand-side of this graphic, you can see that sewage discharges are in the 10s of millions of gallons. On the left is Alewife Brook and all of that sewage is untreated. That means that proxy indicators like E coli and the parasite and viruses are all live. They’re going down the river and impacting people. The blue is the total treated sewage in the Mystic River.

If you look across all of Boston on the right, this small stream of Alewife Brook actually gets more untreated sewage in every place in the Greater Boston area, except for Fort Point Channel, which is being washed out by the tide twice a day.

Untreated sewage discharges at Alewife Brook are an acute problem that need to be addressed.”

– Patrick Herron, Director of the Mystic River Watershed Association
from the 4/3/2025 CSO Listening Session