As officials in Natick, Massachusetts, continue to debate the future of a dam that has stood for nearly 90 years, some in the area are pushing for the structure to remain in place while others want the spillway to be removed.
The area of the Charles River that passes through South Natick Dam Park is beloved for the serenity it provides to visitors. But the aging dam holds It holds 160 million gallons of water, and a breach could be catastrophic.
"That could cause a tidal wave of water coming downstream, impacting homes, residents, businesses downstream," said Robert Kearns, a climate resilience specialist with the Charles River Watershed Association.
He explains the risk lies largely among the trees that have grown on the dam and could be knocked down during severe weather events.
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"Like we're seeing with climate change, the likelihood of this is happening more, and because this dam is rating in poor condition from a dam safety inspection, we would have to see something done here to fix the dam to make sure it's up to snuff, or remove it to reduce that potential hazard of a tidal wave failure," he said.
He is among environmentalists in support of removing the spillway and restoring the river's natural flow.
"Dams are actually not great for the river's health. They slow down the water in the impounded area, or the mill pond behind it, so that water is really warm," said Kearns. "It leads to things like algae blooms or algae outbreaks."
He added the spillway also disrupts the passage of fish.
"We have trout downstream in Dover in a couple of brooks, and currently, they get up to the dam, they can't get through. There is a fish ladder, but it's made for the wrong species, and fish ladders really don't work well for passage of fish," he said. "By removing the spillway, the fish will be able to get right up here, and get up to 26 miles of river upstream and all the tributaries to get more spawning habitat."
The town is also considering repairing the dam, which would mean removing 60 trees along the right embankment.
"Trees do a lot of things for the environment, they help clean the air, they help reduce noise, but also, they help cool the water, but also the air in the surrounding area," Kearns said. "So removing 60 trees in a village center like South Natick would really be a negative impact."
The South Natick Dam was constructed in 1934. According to the Town of Natick, a dam or impoundment structure has been present in the area since the 1700s, and historic documents indicate a timber dam that once served local mills was destroyed by a flood in the early 1930s and replaced in 1934 with the current configuration: an earth fill embankment, stone masonry and concrete structure.
The dam serves no functional purpose and does not provide flood control.
"When Natick was first established, this really was the center of town, because the indigenous people would move along the waters to get from place to place and trade and do many other things," said Dr. Ian Ian Mevorach, founding minister and director of Common Street Spiritual Center.
He is among Natick area faith leaders and environmentalists who support removing the spillway in solidarity with the indigenous communities.
"We have heard indigenous leaders speak and they say that not only is this better for the health of the river, not only does it give a chance for fish to come back, but also for traditional forms of recreation to happen, like possibly canoeing or kayaking," he said. "But also that it's a way to honor their ancestors, who never wanted the river to be dammed, because for them, the river is sacred."
Several current residents along the river told NBC10 Boston they oppose removal of the spillway, in part because it would change the width and depth of the water, making it challenging to kayak in drier seasons. They support an effort to repair the dam.
"This spillway, the dam, is a cornerstone of this environment, and if they remove it, we'll lose our pond and it will become essentially a dry, muddy creek like the rest of the Charles River beneath the spillway," said resident Brad Peterson.
"It is part of my everyday life throughout the winter and summer, and for there not to be a body of water to kayak in during the summer would be devastating," said Steve Dannin. "Not only for me and my family and our neighbors, but the whole town."
Kearns said Tuesday that the notion that the area will become a mud pit is "really not true and unfounded."
"It would not be a big pond area, it would be more of a riverine system, which obviously fluctuates, so in the springtime, you'd have better suitability for passage, but if it's a situation like we have now, with the drought, it could be times where you would not be able to pass in certain areas," he said. "However, you can get out [and] move your boat. I think we are looking at what's the best thing for the river and the river's health."
The town is also considering fixing the dam, which would mean removing sixty trees along the embankment and repairing the aged infrastructure.
The estimated cost of removing the trees and repairing the dam is over $2 million with future maintenance costs. Removing the spillway is expected to cost $1.5 million. Either plan would take at least three years to implement.
"Money, the environment, the indigenous people, to see all these things line up for the removal of the spillway is pretty powerful in my mind," said Mevorach.
The Charles River Advisory Committee has been evaluating the options for over a year. There are two committee meetings scheduled this month before they are expected to present their recommendation to the Natick Select Board in August.