top of page

CT DEEP, consultants hold informational session on possible removal of lower Collinsville dam

By John Fitts

Staff Writer

The area below the lower Collinsville dam in July of 2023. Visible are the spillway, the abutment on the Burlington side, and the Gate House and retaining wall for the spillway on the Avon side of the River.

AVON – Removal of the Collins Company lower dam would improve the ecology of the Farmington River while opening up miles of watershed to migratory fish, an important step in the recovery of spawning populations of American Shad, Alewife and Blueback Herring, according to officials at the state’s Department of Energy and Environmental Protection and their partners in the potential project.


“The main goal here is to eliminate a passage barrier to migratory fish. … by removing the obsolete dam and reconnecting a free-flowing ecologically productive and natural river,” Jake Dittes, water Resources Engineer for Princeton Hydro, said during a public presentation held at Avon Public Library on Sept. 28. “You have a gem here with the Farmington River. It’s gorgeous and I’m sure most of you are here because of that reason and this is looking to expand that free flowing nature, developing additional spawning habitat for American Shad, river herring, sea lamprey and American eel.”


Princeton Hydro, which has an office in South Glastonbury was hired for the initial assessment and Phase 1 Design for the project and potential dam removal could happen as early as next year. Dittes joined representatives from CT DEEP, the National Oceanic and Atmospheric Administration and others at the presentation. During the evening, attendees asked several questions and a few challenged the assertions presented and/or felt removal could actually harm the environment. At least one area resident objected to the plan to also remove the gatehouse and powerhouse at the site without at least first consulting the town of Avon to see if they could be reused in some way.

This construction photo of the lower dam, courtesy of Burlington Public Library, was part of the presentation.

The lower Collinsville dam spans the river between Avon and Burlington and was built by the Collins Company, a world famous manufacturer of edge tools, in 1912, according to the presentation. The company generated power at both it and the upper Collinsville dam – built circa 1867 - one mile upstream.


In the mid 1960s, both dams were given to the state upon the closing of the factory.

With the installation of fish and eel passage infrastructure at the upper dam – required by the Canton Hydro, LLC dam re-energizing project – removal of the lower dam would open up 18 miles of habitat on the main river and 40 miles of tributary habitat, according to the presentation. Additionally, studies showed it was not economically feasible to include the lower dam in power generation efforts, according to DEEP officials.

Approximately 61.7 miles of river below the dams has been designated wild and scenic while 15.1 miles above them also has that status.


At the information session, presenters gave a brief history – including some photos - of the structure, facts about the current conditions at the dam and in the river, the hydraulics and hydrology related to the dam and the purported benefits of fish passage and fisheries.

The dam, which is tied into bedrock, includes the 300 foot-wide concrete spillway. On the Burlington side along the Farmington River Trail are the sluice gates dam abutments while the gatehouse and power house are on the Avon side as is the raceway (behind the concrete retaining wall) that brought the impounded water from below the gatehouse down through the power house.


Dittes also talked about tests related to the sediment quality and quantity trapped behind by the dam. Testing from seven samples was used to test for contaminants and the majority were either not detected or detected at below “corresponding ecological and human health criteria,” according to the presentation.

The few “exceedances” are associated with “urban runoff” according to the presentation.

“Overall the results indicate that the impounded sediment does not pose an elevated risk to humans or water resources,” he said.


Estimated sediment impounded behind the dam to be about 18,000 cubic yards, which he said could be passively released – i.e. allowed to naturally flow downriver “without any impacts to mussels or other ecology downstream,” Dittes said.

When it comes to the spillway, Dittes said that main dam structure would involve removing over the entire width but it still needs to be determined to what depth that would entail.

Also proposed are the removal of the gatehouse and powerhouse.

Contamination is present in the buildings, officials noted. That includes asbestos in the roof and floor of the power house, lead in debris and wood framing the both buildings he said.

The proposal is to remove hazardous materials from the site, dispose of any painted brick as solid waste and bury concrete and unpainted bricks on site, in the raceway area. Sediment that is evacuated as part of the project could end up in that raceway area and potentially to build up the bank. Responding to an audience question DEEP officials did acknowledge that the project needed coordination with other agencies and companies that own or control property along the river.


James Turek, a restoration with the National Oceanic and Atmospheric Administration, talked about the process of complying with federal statutes, including the National Environmental Policy Act and the National Historic Preservation Act. Both include public engagement and a variety of factors to make sure the process moves forward, he said, noting that he was at the meeting to hear any concerns people may have.

He also that NOAA awarded funds to DEEP in 2021 to assist with the assessment and design phase and the process involved in that.


According to the NOAA web site, the agency has committed up to $1 million over three years for plans, permitting and removal of the dam, which it stated is 15 feet tall.


At the meeting, Turek also said there are several funding sources for this kind of work, such as the Bipartisan Infrastructure law and Inflation Reduction Act.

“More jargon,” he said, alluding to the multiple acronyms used for laws and regulations, “but basically there’s a lot of money available right now the state may apply as a proposal to try and secure additional money to implement the project.”


Later, residents asked about cost and Ramona Goode, sanitary engineer, Water Planning and Management Division, CT DEEP, said the construction – i.e. removal of the dam – is currently estimated at $5 million. She added that she didn’t have an immediate estimate of the total project cost.

Dam infrastructure as presented during the session.

While Turek said the historical information is not his specialty, he noted a

representative from the state Historic Preservation Office in attendance had also been to the site and said a historic consultant will be further involved with Princeton Hydro’s work. However, he briefly touched on the state office’s request for “Historic American Engineering Record” documentation with descriptions, photos, graphics, measurements and more.

“If a structure is going to be removed, you want to have good documentation that well defines what had had been there, so it’s all part of the package that goes to the record,” he said.


Turek also noted the process could reveal unknown historical artifacts.

“If you take the dam out and the impoundment drops down, what hypothetically could happen is you might find historical resources within the river bed that no one’s aware of because you can’t see them and it’s hard to find them,” he said.


He also noted that the project could include signs or other ways to educate the public on the past history of the site and said that would be included in a memorandum of understanding for the project, which would also involve plans for any potential impacts of removal.

“If there are impact, adverse affects, there are different ways that mitigation is carried out,” he said.


Matthew Goclowski, supervising fisheries biologist, Fisheries Division, CT DEEP, spoke further about the river and its habitat.

“So, the Farmington River is widely known as one of the best cold-water fisheries resources in the Northeast region. The big reason for that is that the river receives a steady release of cold, high-quality water from the base of the Goodwin Dam and this essentially creates optimal conditions for growth and survival of trout in the river.”


The section of river below the dam is a popular fishing spot in spring and fall, he said. It's not as good above the impoundment, according to Goclowski.

“In the area immediately upstream of the dam we generally consider that relatively low quality habitat for trout and some of our stream fish,” he said. “One of the big reasons for that is when you have water behind the dam. … it sits there and it warms up in the sun.” He added that water downstream of the dam often gets too warm for trout, causing them to move and seek other areas.


Dam removal would be much better for “resident” and migratory fish, encourage aquatic life and improve habitat quality and lower the water temperature somewhat, he said.

“If the dam is removed the impounded section, the ponding section is going to be converted to a naturally free flowing stream,” Goclowski said. “That’s going to restore full aquatic passage through this area and it’s really going to improve habitat quality for all life stages of trout and many of our other resident species in the river.”


Goclowski also asserted that the biggest benefit of dam removal would be the “improved upstream passage for the migratory species that we’re looking to restore in the river.”


Those target species are “diadromous” – ones that move between fresh and saltwater – including Alewife, Blueback Herring, American Shad, Sea Lamprey and American Eel. The later species is catadromous, meaning they live mostly in fresh water but spawn in the ocean. The others in that list are anadromous, meaning they spawn in freshwater but live mostly in saltwater.


The American eel can ascend the lower dam in some conditions but removal would enhance their movement, according to Goclowski. The others cannot navigate over the dam, he said.

“The Farmington River watershed is really the top priority watershed for anadromous fish restoration in the state of Connecticut,” he said, adding that The Farmington is the largest tributary if the Connecticut River.


Goclowski also spoke to the Wild and Scenic portions of the river, its quality water and habitat and popular recreation such as fishing and kayaking.

“There’s a lot of interest and support for ecological restoration within the watershed,” he said.


The Connecticut River, from the confluence of the Farmington, has zero dams and "some of the best anadromous fish runs on the East Coast," according to the presentation.


Goclowski also noted the current and former dams on the Farmington River and how they impede – to varying degrees – migration between it and the Connecticut River and beyond.


The Rainbow Dam in Windsor is located 9 miles from confluence of the Farmington River with the Connecticut River. While privately owned, the state owns an upstream fishway and downstream bypass on it, he said. He said those structures were designed for Atlantic salmon and are not as effective for the other migratory species he discussed. However DEEP officials are working with the dam owners to hopefully “enhance fish passage at this location.”


He also noted how the Spoonville dam upstream of Rainbow in the Tariffville Gorge section of the Farmington River was removed in 2012. The Winchell-Smith Dam in Farmington is partially breached and also could be fully removed as early as next year, he said.


The lower Collinsville dam doesn’t have any form of fish passage, he said, calling it the “end of the line" for migration.


The upper Collinsville Dam, recently re-energized by Canton Hydro, now has “state of the art fish passage,” involving several systems, Goclowski added.


“The long-term outlook for fish passage in the Farmington River Watershed is actually very bright,” he said. “So, with the existing conditions and infrastructure present on the river, anadromous fish species have access to up to about 52 miles of riverine habitat. With the removal of the lower Collinsville dam that would open up an additional roughly18 miles main steam riverine habitat and up to 40 miles of tributary habitat for these species.”

One slide from the presentation showing target fish for restoration.

He said DEEP anticipates the watershed would produce significant spawning populations of the American Shad, Alewife and Blueback Herring.


Presenters acknowledged several steps are left in the process before potential dam removal including “additional site investigations, historic assessment, landscape rendering, additional public outreach and input, determine demolition sequence, engineering and design and permitting.

“In a perfect world and everybody says this is a great idea and nobody has any questions and the permits go through and there’s no delays it would be some time in 2024 but once again, nothing is set in stone,” Goode said. “We are flexible with the movement of when this is going to happen.”


Responding to an audience questions, she said it is not yet known if explosives would be needed for removal efforts. The Farmington River Trail would likely be closed for a short time, but likely not during peak times, she added in response to another question.


Presenters acknowledged the river channel would change and water levels in the impoundment drop several feet. The water level varies with flows and terrain but Dittes said the deepest portion there is about 12 feet. With dam removal that would drop to approximately 6 feet.

Several residents in attendance had questions and a few spoke against the project as a whole or to aspects of it.


“First I’ll sat I’m totally against this,” said Brian Demski of Canton. “To take and invest $5 million dollars to gain 2,000 feet of river, disrupt 18,000 yards of sediment that’s going to go downstream – an enormous amount of silt. Now you’re going to disrupt possible contaminants from the Collins Company because you’re going to drop, from what I’m hearing, 12 feet of water when you probably could put a fish ladder alongside the raceway, as he’s calling it, for a million and a half. That’s just input.”


Burlington resident Jennifer Davis said she swims in the impoundment area and has seen a host of wildlife there. She acknowledged she might not have liked the change had she been around when the lower dam was constructed but said the area now has an important ecosystem today.


“I live where it is now and it is a unique ecosystem it is embedded between two dams and I spend every day looking at the birds and the animals that live in that impoundment that we have created and you know I hear about blasting and I think about the nesting pair of eagles that lives right there and I’m wondering what we’re doing for them?” she said. “I hear about reducing the level of water and I think about the nesting pairs of ospreys and what are we going to do for them? I know that there are at least two active beaver lodges that need that depth that need that need that water there and what are we going to do for them? And so I love hearing about it’s going to grow, it’s going to be beautiful, its going to get a gorgeous array of beautiful flowers and plants there but we have a gorgeous array there now. We have created an ecosystem. The animals didn’t ask for us to dam all of this but we did and we created this area for them and when I walk, I’ve documented over 55 species of birds in this area, and so I worry about what we’re going to do ….. I understand the fish have to move but I also wonder what we’re doing ecologically to this space that we’ve created that animals are now populating, are now living in and what’s going to happen to them when we say in 2024 or 2025 so sorry you don’t have a lake anymore; you have a river and where are they going to go and where are they going to fish? I spent a lovely night until dusk listening to all the Eagles – mom and dad – training this year’s fledge – how to fish in this impoundment – not down below the dam and not up above – in this space – and it is a beautiful space that we have created and I think we need to be thoughtful.”


Steve Gephard, retired fisheries biologist for the CT DEEP, spoke to that changing environment, as well as the aspect of safety as a speaker prior to him referenced tragic drownings of Plainville resident Lucas Brewer, 15, and his friend Anthony Nagore in July of 2021 – when water levels were particularly high.


“I’d like to make a couple of points,” he said. “One is about the uniqueness of the impoundment. I think what makes it special are the people who live there and are sentimentally attached to it and that’s totally understandable but the state of Connecticut has over 4,000 dams which makes us probably the most densely damned state in the nation and there’s nothing ecologically unique about that impoundment. In fact, impounded waters are more common in the state of Connecticut that free flowing waters are… We’ve done a lot of dam removals in the state of Connecticut. We’ve had a lot of experiences before and after and there’s always concern that were going to destroy nature and we’re going to do this horrible thing for fish and wildlife, especially wildlife but in fact we don’t destroy nature, we convert it. Yeah, there may be fewer mallards but there’s going to be more great blue herons. There’s going to be less sunfish but there’s going to be more brook trout. The eagles and the ospreys are not going to care; they’re going to do their business because they have huge home ranges. So, I think it’s important to recognize that there will be changes but there will not be wholesale destruction."


"Until just now, nobody’s mentioned the public safety aspect of it," Gephard added. "Those drownings, those tragic drownings likely were not the first there. There have been drowning at that dam throughout and as long as that dam with ogee shaped spillway, which creates that sweeper hydraulic. You go by there at certain flows and there’s basketballs, beach balls and rubber rafts right up against the dam and you’re saying why don’t they flow downstream? It’s because the hydraulics keep them there and they keep swimmers there too as long as that spillway is there, we’re going to have more drownings and it’s one if the considerations when we removed the Spoonville dam… I think that’s another thing to keep in mind on this. Just for the record I think this is a great project and I support it.”

Benefits of dam removal - according to DEEP staff and consultants on the project.




Comments


bottom of page