As someone who has been helping monitor the Charles River’s water quality for the past 17 years, I know very well that a spike in bacteria follows a heavy rain. A rainstorm that overwhelms some antiquated sections of Boston and Cambridge’s sewer systems can raise E. coli counts by a factor of 100 or more. But you don’t need to gather samples for the lab to know that — the smell is proof enough.
So my heart sank when I read that the Massachusetts Water Resources Authority (MWRA) has proposed abandoning its long-term goals of eliminating sewage outfalls and making the Charles a truly clean river.
During the nearly 50 years I’ve lived in the Boston area, the Charles has seen a remarkable transformation from a notoriously foul embarrassment to a sparkling venue for sailboats, rowing shells and kayaks. Decades of persistent efforts by municipalities and the MWRA have separated storm sewers that carry off rainwater from sanitary sewers that carry — uh — sewage to the treatment plant on Deer Island.
But there remain sewers yet to be separated, so when storm water combined with sanitary wastewater exceeds the system’s capacity, the flow is diverted to the river rather than allowing it to back up into your basement. This is called a “combined sewer overflow” (CSO). In 2024, 48 million gallons of minimally treated fecal matter combined with stormwater went into the Charles. The Mystic River, primarily via Alewife Brook, faces a similar problem with CSOs.
It’s not only a question of smell, but also of health. The MWRA’s own website notes that it’s unsafe for humans or pets to come into contact with the water for 48 hours after a CSO.
Workmen experiment with a method of removing thick oil spilled on shore line of a lagoon in the Charles River in Boston on April 6, 1965. (Walter Green/AP)
Although disposing of sewage in a “Class B” river (meaning a river that’s usually suitable for boating and swimming) like the Charles is technically illegal under the Clean Water Act, the Massachusetts Department of Environmental Protection has granted variances since 1998. The variances were supposed to buy time to fix the problem, not become a perpetual permission slip for pollution. Now the MWRA wants to downgrade the Charles to “Class B (CSO),” which would formalize the acceptance of dumping human waste into the river.
The MWRA’s analysis concludes that it’s not worth trying to make the Charles conform to its current classification, so the best course is to simply reclassify the river so that CSOs are deemed permissible.
Rather than remedy the violations, the authority seeks to legitimize them.
Despite the impressive progress made to date in CSO reductions, the MWRA proposal revises the expected volume of sewage overflow into the Charles in a typical year around 2050 up to 38.4 million gallons. That’s almost three times what the MWRA’s original 1997 Long-Term Control Plan modeled.
Why the backpedaling? The MWRA points to cost. The proposal notes the significant cost increase that would result from the effort to prevent CSOs in all but the most severe storms. The MWRA report claims the cost of achieving near-zero CSOs is hundreds of millions to billions of dollars more than the cost of making incremental improvements. The question of where that money would come from is one that river advocates need to work with political leaders, municipalities, and the MWRA to answer.
When weighing the benefits of remediating CSOs, it’s also legitimate to consider the disruption to communities that protracted construction projects entail. And to be fair, the MWRA has to allocate limited funds across a number of communities exposed to CSOs, many of which are lower income than Boston and Cambridge and lack vocal advocates.
Massachusetts Gov. William Weld takes an unannounced dive into the Charles River in Boston on August 7, 1996, just moments after he signed the Rivers Protection Bill. Gov. Weld is followed into the river by State Sen. Robert Durand, D-Marlborough. (Gail Oskin/AP)
But none of that hides the lack of environmental ambition in the MWRA’s conclusions. In the 1980s, consultants told the MWRA that the Charles was beyond saving, that it was just a filthy river and not worth the effort to try to clean it up. If that view had prevailed, Boston would not be the city it is today.
Tomorrow’s Charles faces the added threat of climate change, which is increasing the frequency of extreme downpours that result in CSOs. To its credit, the MWRA’s analysis acknowledges that intense rainfall will be more frequent in the 2050 timeframe. Still, despite the heightened risks posed by a warming climate, the MWRA supports lowering the bar rather than raising it.
Who determined what an acceptable cost for a clean river is? Both the Charles River Watershed Association and the Mystic River Watershed Association have advocated for the highest level of control, and there is strong public support for that stance. Advocacy groups are raising awareness and creating outlets to protest against the MWRA’s proposal. Lowering standards for any river sets a dangerous precedent for all.
My own contributions as a volunteer water quality monitor are predicated on the assumption that the data collected will inform policies that protect and sustain the river’s health. The decision to reclassify the Charles, to resign to having millions of gallons of human waste dumped into the waters we love, calls that assumption into question.
Like the stench coming off the river after a CSO, a scent of surrender rises from the MWRA’s proposal — the odor of a city settling for permanent pollution.