Wellhead zoning changes detailed


MEXICO – A proposed wellhead protection ordinance that would create zoning changes along the Swift River and Thompson Hill Brook was discussed in depth at Wednesday night’s selectmen meeting.

Afterward, the Water District’s consulting hydrology geologist, Ricky S. Pershken of A. E. Hodsdon Consulting Engineers in Waterville, agreed to revise the second draft before a public hearing on the ordinance is held starting at 5:30 p.m. on Wednesday, May 24, in the town hall.

Selectmen and Town Manager John Madigan were mainly concerned about the Public Works garage, which Pershken said was built atop the aquifer that charges the town’s three wells.

The wells went on line in 1994, and there’s never been a problem associated with the garage.

Still, selectmen and Madigan asked Pershken to change a definition in the ordinance draft about the garage.

At issue are three zones that are designed to protect the water supply’s watershed into the future.

“We don’t want to be too restrictive,” Pershken said.

The first, Pershken described as a 200-day zone, meaning an area where it would theoretically take 200 days for a drop of water falling at the zone’s outer edge to travel to the well.

“Zone 1 requires the greatest degree of protection,” he said.

Because state law prohibits placement of a septic system within 300 feet of a well, the district is proposing to make it a 300-foot protection zone.

“The primary idea of Zone 1 is that it will give you protection against bacteria, because any kind of bacteria in groundwater will die off in 200 days,” Pershken said.

In this zone, “we’d like to see just about nothing, except open space, outdoor recreation, things like that,” he added.

An existing all-terrain vehicle/snowmobile club trail in the zone wouldn’t be closed, but off-road vehicle use would be prohibited in Zone 1 except on the designated trails.

Single-family homes would be permitted, but accessory uses would only be allowed with Planning Board review.

Zone 2 – the contamination protection zone – is considered less restrictive, Pershken said. It has a 2,500-day travel time for that theoretical drop of water, but was modified to require a 250-foot setback along Thompson Hill Brook.

That means single-family homes would be allowed, and home occupations would go before Planning Board review, but multifamily homes would be prohibited, Pershken said.

“Anything over a duplex is not permitted. Existing uses are grandfathered, but expansions of non-conforming uses are limited, unless an owner can show hardship,” he said.

Zone 3 would be the watershed area, but, “there’s so much land there and it’s so far away that existing state and federal regulations will take care of anything going on there,” Pershken said.

Still, the Water District plans to keep an eye on it.

Selectmen raised several questions about Zone 2, to which, Pershken replied, “We’re not saying you can’t do anything. We’re saying there are certain things you can’t do in there.”

He said the town has the area zoned as limited residential, but the proposed wellhead protection ordinance isn’t as restrictive.

“Single-family homes would be permitted in there, but it’s the things that might cause a spill into that brook that we wouldn’t want to see up there, like a gasoline station or a bulk oil facility,” the geologist said.

The Water District, though, would be exempted in Zone 1, because of its buildings there, and another well may have to be added.

When asked why the exempt status, Pershken said the district “must do things in that zone just to deliver water to the town.”

The Planning Board will continue discussion on the ordinance at its 6:30 p.m. meeting on Thursday, May 18, in the town office conference room.