A few months behind schedule, the $20.9 million project to restore Town Brook near Jenney Pond and the Plimoth Grist Mill to something closer to a pristine state – where the river herring can run much as they did hundreds of years ago – is expected to finish by the Spring.
As for now, the area remains a massive construction zone as workers complete the transformation.
“I’m really excited,” said David Gould, the town’s director of energy and environment. “This is much, much nicer habitat than was ever here before. This is really a nice section of stream now.”
He said he realizes folks are impatient to see the end of a project, now in its second full year of construction.
“I know people really want to get here and be able to walk,” he said. “The amount of work that’s going in here, there’s a lot to do: the dam repairs, the utility work, the pathways, the river work. It’s a big project.”
Gould said work will continue through the summer, fall, and winter, with plantings and landscaping in spring of 2027. He said the work is “a little bit” behind schedule because of the harsh winter. He had hoped to open the paths for the coming New Year but now predicts the walkways will be open to the public by spring, while the landscaping and planting continues.
The project is the last in a decades-long effort to restore Town Brook and the herring run to allow the fish an unobstructed migration from the Atlantic Ocean to Billington Sea to spawn, much as they have done every year since before the English first arrived in 1620.
Since 2002, five dams have been removed. The last one, which holds back Jenney Pond, will remain but has to be repaired in part because its current spillway would not withstand a 100-year storm.
The stream work and the building of the nature-like fish path to replace the current fish ladder is being funded with a $10 million grant from the National Oceanic and Atmospheric Administration, which reimbursed the town for the first $1.1 million for dredging Jenney Pond last fall. Since then, the town has been reimbursed another $6 million for the project.
The NOAA grant funds the stream work and the nature-like fishway.
Town Meeting approved another $2.7 million in community preservation funds for the footbridge over Jenney Pond and walkways leading up to it and an additional $1.5 million for the trails from the dam to Brewster Gardens.
The dam across Town Brook has largely been repaired thanks to Town Meeting approval last year to borrow $6.7 million. The work includes removal and regrading of Spring Lane, the road that goes over the dam, and improvements to curbing, sidewalks, signage, light poles, erosion controls, and water control systems, as well as tree work.
A new water main now runs within Spring Lane. About half the sewer line has been repaired. The storm water runoff catch basins are finished. A new gas line runs under the street, as does the power line that used to hang over Spring Lane.
A rock armor now covers the dam on its upstream side. Within the dam, a four-foot-deep reinforced concrete wall now comes up on the upstream side that during flooding will force water up and over the dam. The wall is designed to relieve pressure on the dam by preventing storm flows from scouring away the earthen material in the dam.
Three culverts under the roadway are in place. When the project is completed, they will connect Town Brook to a new nature-like fishway around the back of the mill. The new fishway will replace the fish ladder the herring use now.
Fish will then be able to go up the fishway, under the road, and exit into Jenney Pond.
Concrete sidewalks are in place. They will eventually be finished with bricks.
On the downstream side of the dam, where there was a failing stone wall, there are now steel beams and concrete panels to support the dam and the roadway over it.
The garden at the mill has been ripped out. When it is landscaped and planted again, it will include wheelchair accessible walkways compliant with the Americans with Disabilities Act.
The fishway will be lined with concrete and stone as it goes past the mill, with a path alongside made of colored concrete embedded with aggregate into which animal prints will be impressed.
Downstream from the mill, the fishway will lose its concrete and stone cladding and will be more like a natural stream. Instead of going up the ladder, the herring will enter the natural fishway, which will snake its way up the slope and around the mill – give the fish a gentler upstream swim.
All the old pathways downstream from the mill will be replaced by ADA-compliant paths. Drainage will be put in so ground water will no longer flow across the walkways, where it used to freeze in winter, making the paths slippery.
Where Town Brook flows under Market Street, the water was very shallow, which made it challenging for the fish to swim upstream. The channel has now been narrowed, which makes it deeper.
“So now, it’s much easier for fish,” Gould said.
The water rushes around newly placed random clusters of boulders and rocks that fish can rest behind, sheltered from the current as they make their way upstream.
This time of year, the run of the adult fish upstream to Billington Sea is over. The juvenile fish hatched there will head out to the ocean through summer and fall.
“So, we’re making sure that when we do work, we don’t impede the ability for the juveniles to get to the ocean,” Gould said.
Below Market Street, there will be a concrete boardwalk precast to look like wood. Groundwater seeps will be able to flow under the boardwalk down to the stream, so it will be safe to walk the boardwalk even in winter. There will be new landscaping and lighting.
“These little falls are one of the best spots in the whole world,” said Gould as he watched the sun dance off the rippling water.
Under Main Street Extension, the old broken asphalt walkway has been removed. The new walkway will be elevated by 6 to 8 inches and thus less likely to be submerged during king tides. There will be a railing where there was not one before. In the center, a low-flow channel has been dug to make it easier for fish to pass through.
The last section of path will tie into Brewster Gardens, where the project ends.
Fred Thys can be reached at fred@plymouthindependent.org