OXFORD — Oxford officials held a workshop on the Welchville dam Thursday afternoon, ahead of their regularly scheduled selectmen’s meeting to hear about alternatives to replacing or repairing the dam.
Last November selectmen authorized VHB, Inc. of South Portland to conduct a study of the use of grade controls on the outlet of Hogan and Whitney Ponds, which feeds into the Little Androscoggin River. The environmental consulting company had already done a study in 2019 on water levels and erosion from the ponds.
The study was in response to a survey of property owners with water frontage on both ponds. The options for the dam’s future include the grade controls at a cost of about $100,000, repairing the dam for an estimated $1.6 million or replacing it, which would cost an estimated $1 million. The preferred options of the 135 or so returned surveys was to consider engineered grade controls and then replacement.
Dave Cloutier, a hydraulic engineer with VHB of South Portland presents alternatives to repairing or replacing the Welchville dam in Oxford last Thursday. Nicole Carter / Advertiser Democrat
Last week, Dave Cloutier, a hydraulic engineer with VHB, presented the results of the second study to selectmen with close to 50 residents in attendance. He explained that grade controls are a series of steps in the outlet waterway comprised of boulders to slow the flow of water from the ponds. One big benefit of the controls would be that flooding, which occasionally happens when the Little Androscoggin gets backed up by heavy rainfall, would no longer occur. Grade controls would also slow the erosion on the silty channel bottom.
In addition of saving the town between $900,000 and $1.5 million to repair or replace, grade controls would require zero maintenance in the future.
“Boulders are not likely to move more than a few inches” once installed, Cloutier replied to one question about the control’s expected longevity.
Others questioned how trees falling across the channel, or other natural and weather events, might alter the flow of the water and affect the controls.
To proceed, Oxford would need to obtain access permission from a private landowner between the channel worksite and Route 26, which one audience member said was not a guarantee if future engineering work becomes necessary.
Cloutier also cautioned that permitting from Maine Department of Environmental Protection and the U.S. Army Corps of Engineers would likely be contingent on eventually removing the dam, which would improve access for spawning fish. He estimated the cost to take out the dam to be in the neighborhood of $150,000. Cloutier noted that a similar project of Pierce and White Ponds in Penobscot County required dam removal that allowed alewives migration to return.
The prospect of no dam at all alarmed some residents who feared that if the control system was not adequate and the dam removed, the water levels in the ponds would permanently drop.
One resident asked if dam removal was necessary or conditional to governmental approval. Cloutier said he would he could not comment on that or the timing to start the project until after he met with US ACE and they did their own assessment, a process that would likely take a month or so. Acquiring the required permits would add more time.
Another resident noted that there has been access in the past from the north side, on property that is currently owned by Oxford. He also referenced studies done on the waterway mid-twentieth century, years before the town took ownership of the dam from International Paper.
Cloutier will provide a report with feedback from MDEP and the US ACE for the town to review. Selectmen will then review the options, as well as the wishes expressed in property owners’ surveys before determining final plans for the aging dam.
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