As a current resident of West Somerville and former resident of North Cambridge, I use the wooded refuge of the Alewife Brook Reservation frequently to escape from urban life. After a stressful commute home in Boston traffic, a jog across the boardwalk along the brook – past wildflower meadows, mute swans and great blue herons – is often all it takes to soothe nerves frazzled by staring at brake lights surrounded by irate commuters and blaring horns.

My typical route takes me up Broadway, past the Stop & Shop on Alewife Brook Parkway and across the street, with a right turn onto the Alewife Brook Reservation walking path. If I run along the brook after heavy rainfall, however, a pungent smell is likely to rip me out of this escapism and back to reality. With summer 2023 being the second wettest on record across much of New England, this past year saw numerous occurrences of municipal sewage overflowing into the Alewife Brook, turning the idyllic reservation into a smelly, polluted mess.

This slow, shallow brook bordered by a lush, riparian habitat has endured many changes throughout its natural (and unnatural) history. According to Mass.gov, in pre-colonial times, the region surrounding the brook was wetland, all part of the regional Great Swamp. This expansive wetland stored water from storm runoff and served as a massive biogeochemical filter for the local watershed. Urbanization and industrialization saw fit to change that, and the wetland was drained in the late 19th and early 20th centuries, resulting in more than 90 percent of the surface area of the original Great Swamp being lost to development. With the decline of this gargantuan natural water filter, water that would have been stored in the marsh now has nowhere to go, causing it to backflow into homes and businesses unless allowed to overflow into the Alewife Brook – along with municipal sewage.

These discharges of sewage into the brook are known as combined sewer overflows. State law requires local municipalities to alert residents when CSOs “create a risk to public health,” with occurrences being reported on town websites. In Somerville, residents may sign up for an email notification system. It was revised as recently as June, yet many residents still seem unaware of the issue. The current method isn’t efficient or timely enough to reach residents who may be unaware of CSOs and be put in harm’s way by using a public green space.

Torrential rains and subsequent CSOs on Aug. 8 caused the brook to overflow onto public walkways. Many residents kept running, biking and pushing baby carriages through the contaminated water, unaware of the unsavory and unsafe nature of what they walked through. This spurred an outcry, culminating in an online petition and letter to the Environmental Protection Agency that dismissed the existing notification system as a “failure” and said residents “need to know immediately if the discharge has made using the Alewife path unsafe,” then when an elevated level of risk has passed. Effective methods of communicating CSO events have been implemented elsewhere: The Potomac River in Washington, D.C., has four indicator light stations that glow red during CSO events. Similar indicator lights, with interpretive signs, could be an effective method of warning users of the Alewife Brook pathway.

Even though municipalities are complying with the legal obligation to post publicly when CSOs occur, it does not seem effective – and that’s grossly negligent. I wasn’t aware of the incidents except through word of mouth, and took it upon myself to research the issue online. This should not be how someone learns about a serious environmental and public safety issue in their own community. Residents walking through untreated wastewater with infants in carriages shows that the way this information is disseminated to the community needs to be reevaluated.

As a resident with a professional and academic interest in climate change and resiliency, I am particularly concerned with how this issue is going to develop as annual rainfall totals increase. How will this affect the Alewife Brook Reservation’s recreational amenities? My proximity to this green space adds significant value to living in the area. If there is no transparency regarding how CSOs are controlled and mitigated, that value will certainly be diminished.

Local municipalities have profited immensely off the development and urbanization of the Great Swamp, to the detriment of the local ecosystem and those who seek to enjoy it. They now owe it to the citizens they serve to stem the negative consequences of this development and act as responsible stewards for a fragile natural resource. At the very least, they can find a better way to tell people when their local park is flooded with untreated sewage.

Tyler Mourey is a resident of Teele Square in Somerville and a graduate student at the University of Massachusetts at Boston studying environmental science.