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Growing up in New Bedford, Dan Goulart spent many summer days down by Buttonwood Brook. He would dip his hands in its crystal-clear waters, which flowed from New Bedford into Dartmouth and to healthy shellfish beds in Apponagansett Bay. 

Nowadays, the water in the brook is murky. Signs around Buttonwood Park tell people not to touch it. Those shellfish beds are degraded, and often closed. 

This has become the new normal for Buttonwood Brook, as the surrounding area has developed. Yet in Goulart’s eyes, “people are ready for change.” 

The Buzzards Bay Coalition has been working to spark this change and restore the polluted waters of Buttonwood Brook and Apponagansett Bay.

This initiative, known as Buttonwood-to-Bay, started in 2021. Goulart, who managed the project for the coalition for three years, showed a Light reporter around the project area this fall, just before he left the job to become the Nature Conservancy’s coastal program manager. Buttonwood-to-Bay is now being managed by Korrin Petersen, vice president of clean water advocacy at the Buzzards Bay Coalition.

The project’s goal is to reduce bacteria and nutrient pollution in those waters and Buzzards Bay. It also aims to improve access to natural space in New Bedford — home to many environmental justice communities.  

Buttonwood Brook flows from the area around Hidden Brook Apartment Homes down Route 140, and into Buttonwood Park. It meanders through the Buttonwood Park Zoo and then Dartmouth before emptying into Apponagansett Bay.

Significant development came to this corridor after World War II, and before state lawmakers developed robust wetlands regulations. New Bedford, Dartmouth and their residents filled wetlands and forests. They put in homes and businesses and septic systems and roads and sidewalks.

Now, during rains, the brook receives storm runoff from impervious surfaces in the Kempton Street area north of Buttonwood Park, which contributes large loads of bacteria and phosphorus. More bacteria loads enter the brook further downstream, when manure-laden stormwater flows out of Buttonwood Park Zoo animal enclosures. Bacterial contamination can close shellfish beds and limit recreational opportunities, as it presents a public health risk.

Buttonwood Brook also experiences pollution problems in dry weather. In Dartmouth, septic systems contribute nitrogen loads. Excess nitrogen and phosphorus loads cause algae to bloom, which makes the water murky and degrades fish and shellfish habitat.  

This pollution ends up in Apponagansett Bay. Its water quality consistently ranks in the bottom 10% of all major harbors and coves in Buzzards Bay.

Also, old dams and culverts on Dartmouth Natural Resources Trust property limit fish passage and present safety risks.

In 2022 and 2023, the coalition tested the brook’s waters and identified these problems in New Bedford and Dartmouth as priority targets for restoration projects. Now, the nonprofits are working with New Bedford and Dartmouth to lighten those pollution loads.

Getting zoo manure out of the brook

One fall afternoon, walking through the Buttonwood Park Zoo with a Light reporter, Goulart pointed toward the back of the domed bison enclosure. 

“You can see there’s an outfall tucked in behind the corner,” he said. Murky, still water filled a pond around it. “That brings water all the way from the elephant pen — where it collects in catch basins — and dumps them into this pond.”

About 30 years ago, New Bedford and the state’s Olmsted Historic Landscape Preservation Program developed domed enclosures for the zoo animals. They graded the enclosures towards Buttonwood Brook. They installed catch basins and pipes to direct stormwater runoff to the stream. 

The goal was to keep the animals safe from flooding during rains. Yet the zoo did this before passage of Massachusetts stormwater regulations, and without knowledge of what the runoff would do to Buttonwood Brook. During storms, the rainwater gets loaded with animal manure from the enclosures before discharging into the brook.

Goulart and the coalition worked with zoo leadership over the last couple years to map out the zoo’s stormwater system. They studied the major wet-weather sources of pollution in the zoo. 

They are now designing green infrastructure projects that the zoo can install to filter and absorb runoff during storms, like restoring wetlands. The partners want to put these projects in the enclosures of major manure producers, like the horses, bison, and elephants. That should slow stormwater flows off the enclosures, and reduce bacteria loads within the brook.

Zoo officials did not make themselves available for an interview with the Light to talk about the green infrastructure projects. Instead, the city released a statement from Zoo Director Gary Lunsford, which said the zoo is “deeply committed to protecting the environment.”

Goulart estimates it should take roughly $2 million to design and install these projects, which will be done with an eye to the zoo’s visitor experience. The partners have secured roughly $750,000 for their work thus far. They hope to move into construction by 2026.

Kempton Street stormwater project underway

Upstream from the zoo, city crews will install rain gardens and vegetative barriers around the Buttonwood Senior Center parking lot over the next few years. They will build wetlands and vegetated ditches on the north side of Buttonwood Park. They will reconstruct the parking area near Brownell Avenue with porous pavers. 

All of this is to allow stormwater to better infiltrate into the ground around Kempton Street, where a roughly 2 million square-foot stretch of impervious surface generates huge “peak flows” of bacteria-laden stormwater that run off into the brook. That scours the stream bed and degrades the ecosystem.

When these efforts are complete, more stormwater should trickle through the soil, instead of running off of it. That water will enter Buttonwood Brook in a slow “base flow” through the groundwater. That will preserve stream bed habitat and reduce pollutant loads. 

The roughly $10 million Kempton Street project will also reduce the urban heat island effect and improve air quality. It is being funded through grants, American Rescue Plan Act dollars, and low-interest wastewater infrastructure loans. 

Work started this summer, New Bedford Department of Public Infrastructure Commissioner Jamie Ponte said. It should be complete in 2026.

Sewering homes in Dartmouth 

Downstream in Dartmouth, the Buzzards Bay Coalition is working with town officials to launch the Connect to Protect Apponagansett Bay program, which will connect homes on septic in the bay’s watershed to existing sewer lines. The goal is to reduce nitrogen pollution in Buttonwood Brook and Apponagansett Bay. 

The idea started when the coalition overlaid a map of Dartmouth’s sewer system onto a parcel analysis of Dartmouth homes on septic. It revealed that 130-plus properties on septic systems in the Apponagansett Bay watershed could hook up to a sewer line.

But connecting a home to the sewer system can be expensive. So the coalition went to the town for help. Now they’re finalizing an agreement for a voluntary program to subsidize sewer connections. 

With Connect to Protect, the coalition would contribute $900 to homeowners’ new connections to the sewer system. Dartmouth — which increased its sewer connection fee earlier this year to $2,500 — would offer its older connection fee of $1,500 to participants. That means they would pay a discounted fee of $600 to connect to the sewer. 

A pilot program will launch in coming months, with homeowner engagement efforts and mailers. The aim is to hook 20 homes up to sewer per year. 

Dartmouth leaders view centralized sewage treatment as a more efficient option for handling human waste than septic systems, said Rob Almy, chairman of Dartmouth’s Board of Public Works. Connect to Protect funds will go to homes that have already paid into the sewer system through betterments. Dartmouth’s sewer system has capacity for these homes.

“They have a place in line,” he said. “It seems to make sense to everybody that they be encouraged to connect to the sewer.” 

Goulart said the homes contribute roughly 2,600 pounds of nitrogen to Apponagansett Bay per year. If they can get all of these homes to connect, they can reduce the nitrogen flowing into Apponagansett Bay. The coalition has set aside about $100,000 in grant money for incentives. 

Combined with the New Bedford projects, Goulart said, the corridor will start to see water quality improvements within a couple of years. 

A future of fish passage

Dartmouth Natural Resources Trust is also working with the coalition to bring back fish passage and floodplain connectivity in lower Buttonwood Brook. The parties are looking at modifying a few of the trust’s dams and culverts. 

An aging culvert near Elm Street and an 18th-century dam, both on trust property, block fish passage on Buttonwood Brook. The culvert is in a state of disrepair. 

The coalition and the trust are studying possible modifications, and the coalition has acquired roughly $500,000 in grant funding for the project. 

Nick Wildman, the executive director of DNRT, said modifying the structures would make the trust’s properties safer. But he notes that the trust hasn’t committed to modifying the structures, and that the trust and the coalition haven’t yet agreed on a design. 

The projects must get done with an eye toward DNRT’s visitor experience, and account for potential changes to stream hydraulics, he said.

“We need to make sure we’re going to do this in a way that is all benefit and has no downside,” Wildman said. 

Goulart said that once these projects are completed, it shouldn’t be long before they bring benefits to Buttonwood Brook, Apponagansett Bay, and local residents. 

The waters should get cleaner, and wildlife should return. Flood risk in the area should be reduced. 

“I think their takeaway will be ‘this was a really good use of money, and it made my community a better place,’” Goulart said. 

Editor’s note: This story was updated on Dec. 11, 2024, to add that Korrin Petersen is now managing the Buttonwood-to-Bay project.

Email environmental reporter Adam Goldstein at agoldstein@newbedfordlight.org.