Swanzey to consider several options for Upper Wilson Pond Dam

Jack Rooney, The Keene Sentinel, N.H.
·4 min read

Apr. 8—SWANZEY — Town officials in the coming months will consider several plans for the future of Upper Wilson Pond Dam, which the state has deemed deficient, before moving ahead with construction on the project no earlier than next summer.

Specifically, Swanzey is looking at rehabilitating the town-owned dam to maintain its current water levels, partially removing it and lowering the level of the pond, or completely removing the dam and draining the pond. Charles Johnston, an engineer at DuBois & King, the Randolph, Vt.-based firm the town has hired to handle the engineering for the project, presented these options during a public information meeting Wednesday evening.

The project is necessary, Johnston said, because the N.H. Department of Environmental Services Dam Bureau has determined the Upper Wilson Pond Dam is a "high hazard."

"Basically, there is a potential for loss of human life downstream," he said during the meeting, which was held in Whitcomb Hall and also broadcast via Zoom. "We imagine the downstream area of that dam, if it was to breach, would flow through the culvert or over the road, and you have several houses in the inundation area that would be impacted by that potential breach wave."

Upper Wilson Pond Dam is a 40-foot long and 16.5-foot high earthen embankment, with two concrete core walls within the embankment, on Swanzey Factory Road, according to Johnston's presentation. It was built in the early 1900s, according to the town.

Swanzey has received several letters of deficiency from the N.H. Department of Environmental Services in the past decade spelling out necessary actions to bring the dam into compliance with state safety standards. The most recent of them, last June, requires the town either to reconstruct the dam to meet those requirements, remove it or modify it so that it would no longer be considered a high-hazard dam by October 2023.

Johnston, whose firm also led the project to repair Lower Wilson Pond Dam in 2018 and 2019, said Wednesday that the town could remove a portion of the upper dam while still maintaining the primary concrete spillway, which creates a waterfall effect at the outlet of the pond.

Elizabeth Richardson, one of only a few residents to speak during the roughly 30-minute meeting, said she lives across the street from the spillway and wants to see it preserved.

"I can see it from all the windows in the front of my house, and hear it when it's time to open the windows," Richardson said. "And I think it's very beautiful, and if we can make the structure safe, I would love to try to see the waterfall remain."

Johnston said DuBois & King still needs to gather more information, including a field survey of the dam area and wetland delineation (a procedure that determines the location and extent of wetlands on a property) before developing specific proposals for the town to consider.

"Once we have that pulled together ... we're going to go and present this back to the town and get some public input and see where the people around the pond are leaning towards, where the town would like to go, and then work through the process of selecting which one the town would like to move forward with."

The next public information meeting on the project will likely take place in late May or early June, when DuBois & King should have more specific plans and costs estimates, Johnston said. The plan is for the Swanzey selectboard to settle on a proposal in June, so the project can move to final design and permitting with the goal of completing construction next summer.

Swanzey has received a Federal Emergency Management Agency grant to cover 65 percent of the cost of the engineering work. Town Administrator Michael Branley told The Sentinel last week that the town plans to apply for another grant to help offset the costs of construction.

The town also has funds remaining in a capital reserve for the dam, which the selectboard can spend unilaterally, Branley said Thursday morning. However, the rehabilitation project will need voter approval if it involves raising taxes or issuing a bond to fund the work, he said.

Sentinel Staff Writer Paul Cuno-Booth contributed to this story.

Jack Rooney can be reached at 352-1234, extension 1404, or jrooney@keenesentinel.com. Follow him on Twitter @RooneyReports.