LITCHFIELD — Officials and engineers are working as quickly as possible to determine a permanent fix for the Woodbury Pond Dam, which recently began to show signs of seepage.
Workers placed 12 large sandbags along the east wall of the dam as part of a temporary fix; however, dam keeper Terry Averill noted during an emergency workshop Wednesday that some seepage is still occurring, with signs spotted along the right side upstream training wall.
If continued deterioration occurs, it would cause the roadway across the dam to become impassable and significantly lower the water level in the Tacoma Lakes. This would result in negative impacts on animals and plant life, as well as surrounding property values, officials say.
Town Manager Kelly Weissenfels said there has been some debate as to whether or not the sandbags have been effective, or if the lower water level has resulted in a decreased flow. He said he can not definitively say how effective they are, but that he does believe they have helped with the leak.
While no actions were taken during Wednesday’s workshop, Averill and the Select Board discussed conducting an additional dye test to determine the rate of seepage at the dam.
Jason Gallant, senior project manager with Topsham-based engineering firm Wright-Pierce, also discussed plans and cost estimates for a permanent fix during the meeting.
Preliminary estimates for installing a steel sheet pile cutoff wall on the upstream face of the dam are about $633,900 and estimates for installing a concrete secant pile wall on the upstream face of the dam are around $767,000.
“Those will be revised to be more accurate within the next few weeks,” Weissenfels said, “but that’s what we’d been told initially.”
The board will meet for their regular meeting Monday, but Weissenfels said it is unlikely that a final decision on a permanent fix will be made. He said the town’s immediate next steps are to seek out details on how to obtain a loan to fund the repairs, and then choosing between either the steel sheet pile cutoff wall or concrete secant pile wall.
“We will need a special town meeting,” said Weissenfels, “since our regular town meeting does not occur until June, and we are moving forward as rapidly as possible.”
The town will need to get engineering and permitting finished before the bid process can start.
“I’m still holding out hope that we can get this done in the fall, but a conservative estimate is that we might have to wait until next spring to get the project completed.”
The town began working with Wright-Pierce shortly after the issues were discovered in the spring. The firm surveyed the dam with geotechnical consultants from Haley & Aldrich. Engineers discovered a loss of materials within a 10-foot area of the embankment and an item was added to the June Litchfield Town Meeting warrant to add $55,000 to the municipal budget to assist with repairs.
The permanent fixes are designed to last around 75 years, and Weissenfels said engineers have seen instances in which the concrete fix, in particular, can last up to 100 years.
For now, he said Averill continues to monitor the dam closely and will alert the town immediately of any changes or degradation taking place.
“We want to move as quickly as possible to make sure we have everything in motion to meet a fall deadline,” he said. “We may be past that point already; we’ll just have to see.”
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