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Two years ago a sewer main collapsed in Hamden causing over 2 million gallons of raw sewage to pour into the town’s Mill River — it was accidental, but ultimately cleared quickly. Even before the collapse, this ecosystem, which provides drinking water, as well as fishing and other recreational activities, was already struggling, and old sewer systems were just one part of it.
Despite being one of Connecticut’s smaller rivers, the Mill River is a vital resource to the Hamden-New Haven area. Yet over 70% of the river is not suited for aquatic life, recreation or both.
Of the 17 miles that the Mill River runs from Cheshire through the Hamden-New Haven area, about 12.5 miles are considered impaired, according to Save the Sound, a nonprofit environmental action group.
“There are segments of the Mill River that are known to have impairments on them,” said Kimberly DiGiovanni, an associate teaching professor of civil engineering at Quinnipiac University. “It’s not rated for the uses that we think of using the river for, which means it’s not considered safe to swim and fish and do recreation.”
Water testing has revealed increases in residential and industrial activities along the river as the cause of many of these impairments. Experts and local residents are working together to curb these effects by spreading awareness about the importance of the river.
The Mill’s ebbs and flows through history
The Mill River is embedded in Hamden’s identity and was transformed by inventor Eli Whitney Jr. in the 1860s when he increased the size of a dam, installed by his father, and created Lake Whitney, the first public water supply in the area.
“It (the Mill River) is part of the history of how the town of Hamden grew,” said Paul Saubestre, a volunteer researcher for the Hamden Historical Society and longtime resident. “Hamden grew as a series of separate little villages concentrated around … a source of water supply on the Mill River.”
Although the river isn’t used for industrial activities anymore, Saubestre said the industrial centers that flourished with the help of the Mill River helped Hamden grow into the town it is today.
In the early 1900s, a water purification system was installed along Lake Whitney to ensure better water quality. However, the facility, which utilized sand filters to treat water, shut down in 1991 after becoming outdated and obsolete.
“That system started to be inadequate, but the Regional Water Authority had many other sources of water, so they stopped using Lake Whitney as one of their reservoirs,” said Gaboury Benoit, director of the Hixon Center for Urban Ecology at Yale University.
Due to the rapid expansion of Hamden’s urban spaces around the river, the quality of the water flowing into Lake Whitney worsened, and it was left unfiltered for 15 years until the RWA installed a new water treatment plant.
Lake Whitney was reinstated for reservoir use after the opening of the plant in 2005.
Benoit, who routinely performs research on the river, ensures the water quality that flows out of the lake and the plant is safe, but it’s the water flowing into it that remains an issue.
“Not just the university [Quinnipiac], but lots of streets have been put in, lots of residences and businesses. So the water quality as it flows into Lake Whitney is not as good as it used to be.”
— Gaboury Benoit
A study of the Mill River conducted by the Connecticut Department of Energy and Environmental Protection concluded that “the majority of the watershed surrounding the impaired segments is dominated by urban land use.”
With testing data in the impaired areas from 2001 to 2012, DEEP found high levels of E.coli and other bacteria, which were associated with illicit discharge, failing septic systems, farming activity, stormwater runoff and pet feces.
As of 2022, with routine testing from River Advocates of South Central Connecticut, a nonprofit promoting river advocacy, the quality of the river has improved, but the toxins still remain.
DiGiovanni said the testing shows that bacteria, from many of the associated sources, are still present. The river’s close proximity to Quinnipiac, DiGiovanni said, makes it a convenient “classroom” for her students.
“I take students out there annually, to do measurements, and learn different techniques. We’ve gone out with the US Geological Survey, which has a data monitoring station right there on the river,” she said. “It’s a fabulous resource from that perspective.”
Benoit’s involvement with the Mill stems not just from the proximity but also the scale of the river itself.
The smaller size of the Mill provides him and his students with a better understanding of river mechanics and trends, whereas in larger rivers “you can lose the detail,” he said.
Both DiGiovanni and Benoit serve as directors for The Mill River Watershed Association, a nonprofit focused on the Mill’s long-term health, community involvement and sustainable use of the river.
Advocacy through film
Curiosity led one local filmmaker to a fact-finding expedition, following the experts and exploring the very impairments plaguing the river.
For freelance writer and filmmaker, Steve Hamm, creating a documentary about the Mill River stemmed from the unknown.
Living in Cheshire for a brief stint in the ’80s and now living in New Haven for the past six years, Hamm was frequently near the river but “didn’t really understand it very deeply,” he said.
Hamm’s curiosity about that unknown led him to walk nearly the entire river length one day.
Letting the river speak for itself, he originally created a 13-minute silent documentary, until this sparked a conversation.
“I put that version up on Facebook and people loved it and they said, ‘You know, I really want to know more, let’s have some interviews and information,’” Hamm said.
Hamm reimagined the film, this time interviewing experts like Benoit, historians and more to further his understanding of the river.
In early 2021, Hamm put in his final edits and released: “A River Speaks,” a 30-minute-long documentary exploring the river’s history.
“We love our rivers, but we treat them terribly,” he said.
— Steve Hamm
The opportunity to bring awareness statewide came to fruition as dozens of educational spaces, including the New Haven Museum, held documentary screenings for public viewing.
Hamm said he hopes this project is able to shed light on an ongoing issue with local waterways.
“I got a really unique and valuable window into the world, not just the river, but everything else and I do it so I can share it with other people,” Hamm said. “My appreciation of the river was strong, and now it’s monumental.”
Protecting the river at home
For Ryan Paxton, director of the Eli Whitney Museum, river advocacy can and should start at a young age.
“A big part of our (the museum’s) educational philosophy is teaching kids materials, their impacts on the environment,” Paxton said.
With the Eli Whitney Museum’s proximity to the Mill River, educating on the river’s history with Eli Whitney or just the anatomy of the river is as simple as throwing a stick.
“We can learn about the flow of water,” Paxton said. “We can throw a stick in the water and watch it go under the bridge and see how the water is flowing.”
Education can also be as simple as not leaving the parking lot, either. Paxton unveiled an ongoing collaboration with The Greater New Haven Water Pollution Control Authority to convert the museum’s main parking lot into a bioswale, an often curvy vegetated path that slows the flow of stormwater.
“Really managing that stormwater effectively is a big step to protecting the river and the water quality in the river,” DiGiovanni said.
DiGiovanni recommended homeowners avoid using fertilizers and pesticides on their lawns and gardens as the chemicals can run off into the river. She also recommended furthering an understanding of your home’s septic system and plumbing, which can help determine and prevent accidental spills.
Picking up waste, while walking along the river, or even in your neighborhood could be the first step.
“If you walk your dog along the Mill River and don’t clean up the poop, you are essentially drinking your dog’s poop,” Hamm said.
In the winter, Benoit recommends finding salt substitutes for deicing or looking at the chemical makeup of the salt you’re buying.
“If you do have to salt, it’s usually somewhat better to not use sodium chloride,” Benoit said. “One common alternative is calcium chloride.”
Planting native plants and rain gardens are also effective methods for mitigating runoff at home or even at work.
Knowing where to start in this ongoing conservation effort can be difficult, but all it takes is a simple walk and conversation to begin helping.
“We should look at our rivers next door and talk to people about them. If you explore the river next door, you can really understand the complex relationship between humans and nature.”
— Steve Hamm