Introduction
Combined Sewer Overflows (CSOs) are a big source of pollution in the Mystic River. When a combined stormwater and sewage system gets overwhelmed, usually because of heavy rainfall, CSOs occur to divert flow directly into nearby rivers, like the Mystic River and Alewife Brook, to insure that it doesn’t back up into people’s homes. In 2021, a total volume of approximately 338 million gallons of combined stormwater and sewage was discharged in our watershed during CSO events, a steep increase from years past.
We recently attended a public briefing by the Massachusetts Water Resources Authority (MWRA) about progress made in reducing and eliminating combined sewer overflow discharges and volumes. Patrick Herron, MyRWA’s Executive Director, reports out below:
By Patrick Herron
On February 17th, the Massachusetts Water Resources Authority (MWRA) gave a presentation on the progress they’ve made in reducing and eliminating combined sewer overflow discharges and volumes. The presentation was mandated by the current Mystic and Charles River Variance and aligned with the ongoing Boston Harbor Cleanup court case.
The most striking aspect of the event was the number of people on the call–80 strong. And while the call was about CSO discharges in the Charles, Mystic, Boston Harbor, and Alewife Brook–the majority of the people on the webinar were speaking out for the elimination of CSOs on Alewife Brook. Save the Alewife Brook, a newly formed group spoke forcefully on the need for local, state, and federal investment to eliminate CSOs and replicate the Cambridge stormwater wetlands.
The MWRA was able to communicate on the tremendous progress that has been made to reduce volumes throughout the Boston Metro system (~88% reduction in CSO discharge volumes), and called out the 16 outfalls where they continue to struggle (including SOM001A) on Alewife Brook.
Also of note, this MWRA presentation was in the frame of the Long-Term Control Plan, the series of projects and milestones agreed to in court. The MWRA descriptions of the system performance were about how the system would have performed in a typical year based on updated modeling from 2020-2021.
What is clear is that while the MWRA is navigating the end of the court case, the public is focused on the actual and enormous volumes of discharge in 2021 (nearly 300 million gallons), and wondering what work is being done and what commitments are being made to eliminate CSOs for a potentially wetter future.
