OXFORD — After years of debate and planning, water levels on Hogan and Whitney ponds will no longer solely rely on the aging and unreliable Welchville dam.

A grade control system is being installed in the ponds’ outlet channel above the dam, which feeds into the Little Androscoggin River.

Everett Construction of West Paris is handling the site prep and excavation phases. A temporary access road across private property was completed earlier this month, and coffer dams to divert water around the work area were installed last week.

A grade control system is being installed in the channel that leads from Hogan and Whitney ponds to the Little Androscoggin River. Courtesy VHB, Inc.

The work is set to be completed in the next seven to 10 days. At that time, the dam will be opened and water levels will be measured and studied over the next few years to gauge if the grade controls work properly from season to season and under weather conditions both dry and with above-normal precipitation.

The grade controls should also help mitigate the release of sediment into the Little Androscoggin. If the system handles the water flow, then plans may be made to permanently remove the dam.

Back in 2019, environmental consulting firm VHB began the process by conducting a study on water levels and erosion from the ponds into the channel. Using the data collected, the following year VHB researched grade systems already in use in similar environments.

Welchville Dam, just below Main Street in Oxford. Nicole Carter / Advertiser Democrat

In 2021 Dave Cloutier, a hydraulic engineer with VHB, presented to Oxford selectmen and residents how such a system would be installed in the channel, as a series of steps in the outlet waterway composed of boulders would slow the flow of water from the ponds but also prevent flooding, which occasionally happens when the Little Androscoggin gets backed up by heavy rainfall, and slow silt deposits. It would also facilitate spawning fish and amphibians from the river into natural breeding grounds.

At different times over the last several years some members of the Oxford Select Board have expressed reluctance to the concept of eventually removing the dam, a point that could have made it more difficult to secure environmental grants and permitting to maintain the ponds. But last year officials approved moving ahead with the project.

As the project manager, VHB acted as liaison to oversee federal and state agencies and was responsible for getting permit approvals from the Maine Department of Environmental Protection and the U.S. Army Corps of Engineers and facilitating public hearings.

The cost to repair or replace the Welchville dam would likely exceed $1 million. The two studies, excavation and installation, will cost about a quarter of that. If the dam is eventually removed, VHB has estimated that expense to be around $100,000.