Beaver Lake is unusually low this spring, but there is a reason – water is spilling out from underneath the Beaver Meadow Dam, slowly emptying the meadow and keeping the lake low. As a result, the Derry Department of Public Works is at work on repairs to the dam. On Wednesday, May 1, Director of Public Works Michael Fowler notified residents of Martha Drive and Sabra Circle, near the dam, that “the dam requires an immediate repair due to significant undermining of the dam structure.” Repair crews were on site the next day to begin work.
Fowler anticipates it will take most of this coming week to complete the repairs unless they prove more extensive than expected. The repair plan, worked out cooperatively with the New Hampshire Department of Environmental Services (DES ) Dam Bureau, is to sandbag an area about 25-feet out from the dam and siphon off the water to expose the dam so it can be inspected and the problem analyzed. Then the engineers will determine what is going on and what constitutes a permissible solution.
Fowler said it is evident that some sort of sink hole or erosion has occurred. Once the exact nature of the problem is determined and a solution decided upon, action can begin to address
it. If it is, as they suspect, a sinkhole or erosion, Fowler said they would anticipate plugging it with cement or pressurized grouting. State Dam Bureau personnel would come up with a more extensive repair plan, should that be required.
As of now, sand bags have been placed at the leak to slow the flow. “We intend to do whatever is necessary to save the dam as it exists,” he said. As of press time, Fowler said a 5-or 6 foot hole has been found on one side of the sluiceway. The water is still being pumped out, and he will be working with DES on a repair plan. Fowler acknowledged that saving the dam is involved with protecting Beaver Lake. The dam is an old structure dating back to the early 1900s, when Benjamin Chase, owner of the Chase Mill, erected it to create water power, and later electric power, for his mill.
There formerly was a second dam at the end of Beaver Lake, between the lake and the meadow, but this had become totally dysfunctional and the town, rather than repair it, removed it last year. The Beaver Meadow dam that is now being worked on controls the lake level and the flow down Beaver Brook. According to Fowler, a resident noticed the flow of water under the dam down the stream and reported it to his office, initiating Fowler’s inspection and prompt ac-
tion to address the situation.
