2007-11-01 / Front Page

No leak at north reservoir

By Sam Bari

When Deputy Public Works Director Michael Gray was asked about an alleged leak in the town's reservoir on North Main Road, he sounded frustrated. "What leak?" he asked. "Why do people keep calling about a leak in the reservoir? Whoever started this rumor was misinformed," he said. "There is no leak in the proverbial dam. It is just not true," he emphasized.

Gray went on to explain that every dam, reservoir, lake or pond that sits above sea level has a certain amount of seepage on the downstream slope or slopes. "Whoever said the town was repairing the reservoir with a bandage when a splint was needed couldn't be more wrong," he said.

"They were probably referring to a 40- to 50- foot strip along North Main Road where we discovered some seepage that was causing the ground to soften and the tractor to sink slightly into the soil when maintenance personnel were cutting the grass," he added.

He said the town contracted Matt Bellisle, of Power Engineering in Lincoln, a professional engineering firm that specializes in dams and reservoirs to examine the situation and make recommendations. The engineer designed a sub-drain to absorb the seepage and return it to the groundwater. It will eventually work its way back into the aquifer, Gray said. He went on to say that a layer of soil was used to cover the sub-drain and firm up the area under the grass. He also said that the amount of seepage was not abnormal, or a cause for concern. The installation of a subdrain is a maintenance procedure, not a repair, Gray said.

Gray explained that a layer of pervious material, called a blanket, is often placed directly over the downstream slope, or in the case of dams, the foundation, to facilitate seepage draining from the embankment. This allows the water to find its way back to the aquifer or to an under drain where it will be redirected. "The small amount of seepage that occurred along North Main Road is not enough to adversely affect the water supply, and it is certainly not a cause for alarm," Gray reiterated. "The reservoir is not leaking and it never was."

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