Water rushes down the narrow embankments where it reaches an historic low arch stone bridge. From there it spills over the Balmoral Dam, creating a small waterfall that collects trash.
For 25 miles through northeastern Massachusetts, water flows down the Shawsheen River from its headwaters in Concord and Lexington to the city of Lawrence, where it enters the Merrimack River.
The goal of the Andover Conservation Commission and the National Oceanic and Atmospheric Administration Restoration Center is to re-establish the free-flowing river to create an ecosystem that can support recreational and economic value to the communities of the watershed.
There are plans to take down both the Balmoral and Marland Place Dam, also known as Steven’s Street Dam, within the next two years. The Andover Conservation Commission still does not have the approval to take down the Ballardvale Dam, which is located upstream from the other two dams.
“All of them were mill dams, and what’s important is hundreds and hundreds and thousands of them are around the state but very, very few of them are used for mill purposed anymore,” said Bob Douglas, the director of conservation in Andover. “They are kind of relics of an industrial age that has long since past. Now it’s time for nature to run its course.”
For a river to be healthy it must be able to transport water, sediment, nutrients and organic material, support fish and maintain good water quality. Dams fragment the river, which can cause low dissolved oxygen, high temperatures, high nutrition accumulation and sinks for toxics.
According to Alison Bowden, the Freshwater Program Director at The Nature Conservancy in Massachusetts, there are about 1,400 recorded dams in the state but about 2,800 dams don’t reach the threshold of height to be recorded.
Bowden said that the controversy behind getting the dams removed is that residents have a sense of loss when the environment changes when they lose a pond or a particular setting. Bowden also said the biggest misconception people have is that dams control floods, but they will only mitigate floods if they are designed to do it.
“As the water level comes up, it gets higher and higher and it will get flooded,” said Bowden. “It is sort of like a bathtub. Once you get to the top of the bathtub it can’t hold anymore water.”
In Massachusetts there are only 43 dams that are designed for flood control. The Balmoral and Marland Place dams in Andover are not designed to mitigate flooding. This is one of the reasons why conservationists want to take down the dams.
Bob Decelle, the special projects manager for Andover Conservation Commission, said that the construction of the Balmoral Dam by William Wood over a hundred years ago for ornamental purposes ended up costing the environment.
“The environmental disaster that he created, other then filling in those wetlands, was that he built these bridges on the other side,” said Decelle pointing towards the Balmoral Dam. “When the water rises above the arch it can’t go through the bridge so it goes around the bridge.”
The last time Andover got struck with a flood was on Mother’s Day in 2007. Decelle said that it caused millions of dollars of damage and a tremendous displacement of people.
The water is channelized, which causes it to rise quickly and then have nowhere to go but out. The removal of the dam will lower the level of the river that will help a little with flooding.
“This will be nice, but it’s not going to improve the flooding issues,” said Decelle. “The bridges do the holding back.”
There is currently nothing that the conservationists can do about the bridges because they are historic.
The Andover Conservation Commission wants to take the lower dams down first in order for the animals and fish to get used to it. The cost of removing the smaller of the two dams, the Balmoral, will cost about $2,000 and the process will include diverting the water through a pipe in order to get an extravator in to take out the stones that make up the dam.
Suzanne Robert, a resident of Andover with a background in technical hydrology and environmentalism, claims that she is the sole person fighting the removal of the Marland Place Dam.
“The whole reasoning if you take down the dams the fish will come back is erroneous,” said Robert. “Because I don’t think the water quality as it stands now will sustain this. This is an urban river.”
Robert’s doesn’t want the Marland Place Dam to be removed because it will flush out the millpond that it is supporting. That ecosystem supports animals including beavers, muskrats, herrings, and snapping turtles. Robert said that when they remove the dam the millpond would turn into a mudflat allowing invasive plants to migrate into where the millpond once was.
Although Roberts is against removing the Marland Place Dam she is still in support of removing the Balmoral Dam because it poses a safety issue.
The Balmoral is a low-head dam that is extremely dangerous because it serves as a vortex. Once you’re in it, it will keep you there until you drown according to Decelle.
Another safety issue concerning the removal of the dams is toxic material that is left behind from industrial times that could be stored in the river’s sediment. Douglas says that the sediment needs to be cleaned before they release the sludge of mercury or some other chemicals down the river.
“You can imagine a dry material doesn’t weigh anything, but you hydrate that with lots and lots of water and it becomes really heavy and hard to move and when its toxic it can only be disposed of in very specific places,” said Douglas.
The cost of removing chemicals can be really expensive. Testing at the Marland Place Dam showed small amounts of cambium that will continue to be tested for.
In Vermont, dams are being revitalized. William Scully, a mechanical worker, restaurant and storeowner recently bought a hydropower dam that will be running by October or November of this year. He hopes the dam will offset Vermont’s energy dependency from other states.
Scully also worked with the community to clean up the surrounding area including trash from a park and conducting a Brownfield remediation of an old paper mill. In order to clean up the PCPs and dioxin chemicals from the site Scully had to borrow $50,000 from the federal government.
When it comes to deciding whether or not a dam should be removed, Scully believes that it is a really complicated question to answer. For him, it’s not just saving the fish but also what the dam has to offer.
“The overarching thing is I think about all of this, great worry about the fish, but you know what, in 50 years that’s the stupidest thing in the world you can worry about because there won’t be an environment,” said Scully. “We actually have to attack the greenhouse gas pollution and green energy problem as much as we attack anything else.”
This article is being published under an arrangement between the Boston Globe and Emerson College.