In Antrim, old pipes cause for concern

ANTRIM — Old waterworks in town are a cause for concern, and Capital Improvements Program Chair Ben Pratt recommended an engineering project be funded to determine how they might best be improved and what it might cost the town.

In discussing the five-year CIP at last week’s Planning Board meeting, Pratt noted three Water Department projects that aren’t critical to address right away, but that could create major problems in the town’s water supply at any time. If the projects were to be engineered, the order of importance of the upgrades would become clearer, and workers would have a plan in place to correct a catastrophic failure, Pratt said.

The primary issue in need of attention, Pratt said, is the water line from the Gregg Lake Dam pump house in north Bennington, crossing the Contoocook River and coming across Tenney Field to Depot Street.

“If that should fail, the town would be without water, and it would obviously be something major that would have to be dealt with immediately,” Pratt said at a Planning Board meeting on Dec. 6. The proposed upgrade would be to a high-quality plastic pipe that would theoretically be good for 50 years, according to Pratt.

Second is the state of the gate valve at Gregg Lake, which Pratt said is 102 years old and hasn’t been repaired since 1970.

“If that were to fail in the closed position, the only way of regulating the level of the lake would be with [flashboards], which wouldn’t be satisfactory. If it were to fail in the open position, that would be much more serious. It would draw the lake way down until it was corrected.”

Pratt said Lisa Martin, president of Quantum Construction Consultants, which has been doing work in Antrim for a number of years according to Pratt, looked at the problem and recommended to close off the old valve under the gatehouse and replace the new dam’s valve — which currently can only be on or off — with a control valve that can be adjusted.

“It’s a good plan, but it’s very expensive,” Pratt said. “There’s state permitting that would be required for that kind of undertaking, and Martin estimates that the total cost for that kind of project would be about $350,000. In view of the other needs the town has, that’s something that I think, if it can be avoided or postponed, it’s worth doing so.”

Pratt recommended that the town see if it’s possible to de-water the valve under the gatehouse so it could be inspected, which he said would need to be done anyway if the town decided to pursue Martin’s plan.

“If that was possible, I don’t see how you would probably spend more than $10,000 to do that — and if you got a new gate valve in there, that could realistically serve for probably at least 20 years, maybe more. We don’t know if this would work or not, but if it does it would save the town a great deal of money. It just seems it’s something that we ought to look at and see if it’s feasible,” Pratt said.

Pratt said when that valve is used, there’s typically several rotations before anything happens.

“Sooner or later you’re going to stand there and it’ll go round and round and round,” he said.

The final issue is the need for replacement of water lines on Highland Avenue and Lower Pleasant Street.

“The water lines on both of those streets are 6-inch cast iron and it appears they were installed in 1938,” Pratt said. “This is a pretty complex project. The first thing is the water line on both of these streets is too small. If it was a 6-inch line when it was installed in 1938, the hole in that pipe now is much, much smaller because it’s badly tuberculated.”

Pratt also noted that from the water storage tank on Pleasant Street down to Highland Avenue is new, 12-inch ductile iron pipe that comes down and meets the south end of Highland Avenue. From the north end of Highland Avenue there is also 12-inch pipe, which “represents tremendous investment,” he said. “The town is not getting very much good out of that because you’ve got this old 6-inch line going down Highland Avenue, so you can’t take advantage of the flow capability of that 12-inch ductile iron pipe. The Highland Avenue replacement would be 12-inch.”

Proposed next year is $10,000 for the engineering of the water line replacement, and also $40,000 for the engineering of the highway work that would need to be done in connection with that project. Pratt said he doesn’t know exactly whether that amount will be adequate. Additionally, $10,000 each is proposed for engineering studies regarding the valve and the water line from the pump house. Such engineering projects, Pratt said, are good for a long time and would need to be done anyway if any failure were to occur.

“If the engineering had been done, a job like this probably would have qualified under the stimulus,” Pratt said, referring to the American Recovery and Reinvestment Act of 2009.

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