Williamstown's Leaky Well Drills Hole in Project Budget
  Kaiser explains what's occurring between the test well, left, and the main well. Left, the drilling rig had to be moved when a sinkhole appeared. |
The problem became apparent about 2 1/2 weeks ago when a sinkhole developed between the two well shafts off Stetson Road endangering a massive drilling rig. The ground sank nearly 14 feet in one corner.
Town Manager Peter Fohlin told the Selectmen on Monday night that the problem was the natural aquifer under the town. "We are always in jeopardy of punching a hole in the aquifer that will allow water to escape under natural pressure."
That appears to be what's happening in the case of the test well that was drilled more than a year ago in preparation of replacing Well No. 1, which had silted up over 50 years. Town meeting last year had appropriated money to drill a new well to ensure a third public water supply in addition to Wells No. 2 and 3.
"The aquifer is a phenomenal water supply. The town is blessed to have it but it's also a nightmare to work with," said Public Works Director Timothy Kaiser. "If you punched a hole in this formation, you could expect the water to push 40 feet above your head."
Extra precautions were taken in drilling the new well, including using nested casings, beginning with a 54-inch pipe, to prevent leaks. But water began to bubble up after the main shaft hit the 30-foot mark.
Kaiser said the theory is the test well leaked into about that level; when the main well hit the pressurized water, it began flowing at about 10 gallons per minute, bringing silt along with it.
"We could lose this well," he said. "In a worst-case scenario we could lose this well field."
Helical Drilling of Braintree was called in to plug the leak, as it had previously on Well No. 1. On Friday, it injected a hydroactive gel (drinking water safe) that showed good results — the water slowed and cleared. But by Saturday, the water had found a way around it, probably because the ground wasn't solid enough.
Kaiser said the next step is to inject "concrete grout" into the area to provide a more solid mass; once that's set, gel will be injected again. "It needs to build pressure against a solid material."
"I am encouraged by what we saw on Friday that we're on the right track. I'm fairly confident we'll get it done," he continued.
Meanwhile, drilling company Layne Christensen Co. of Amherst will continue work on the new well.
The cost for the entire project — drilling, pump station, infrastructure and chlorination — was estimated at $892,000. So far, the project's cost $245,000. The emergency repairs will come out of the budgeted money but, if everything goes right, the project will likely be $88,000 short. Any further expense will have to authorized by town meeting.
The town should know within a couple weeks whether the plug will work — or if it will have to go to Plan C.
In other business, the board approved the Fohlin's recommendation to appoint Robert E. Muir Jr. to the Conservation Commission. Muir will replace Brian Turton, who resigned his post in December because of concerns over possible conflicts of interest because of company, New England Landscape and Aquatic, and the commission's responsibilities in relation to wetlands protection.
