“I deal in a science you can’t see, so you have to use converging lines of evidence,” Tim White said.

White, a hydrogeologist with Sanborn, Head & Associates, Inc. working for the Moretown Landfill, attended the Moretown Development Review Board (DRB) hearing that took place on Thursday, October 25, at the request of residents worried that the landfill’s proposed expansion will contaminate their groundwater supplies.

While Moretown Landfill is still working on a state application deemed “technically incomplete” by Ben Gauthier of the Vermont Agency of Natural Resources (ANR) Solid Waste Division, the company continues to pursue its expansion permit at a local level.

Thursday’s hearing was the fourth in a series of DRB hearings that must take place before the board can approve Moretown Landfill’s conditional use permit to construct a fourth trash cell that would extend the landfill’s life by 15 to 18 years. Without the 40-acre addition, the landfill will reach capacity and have to close within the next two years.

White said he’s “confident” that the groundwater that flows beneath the landfill’s Route 2 location is flowing north to the Winooski River—and not northwest, in the direction of people’s homes—but the statement was not strong enough to stop residents’ questions.

“You say you feel confident, but you don’t really know,” one resident said.

In hydrogeology, “you can’t prove anything,” White explained. “But you can disprove things. . . . The Winooski River is by far the lowest spot in the area that groundwater would be able to discharge,” he said.

In addition to considering the layout and makeup of the land, however, White also studies the hydrology of the landfill site through a series of monitoring wells, which collect groundwater samples from as deep as 50 to 110 feet below the surface.

“But why are there no wells set up where the neighbors live?” one resident asked, looking at the map marking monitoring well locations.

The wells were set up “in places where we might expect to find permeable zones,” White said, explaining that the side of the landfill closest to the residential neighborhood was not one such zone.

When John Haney, a professional engineer with Sanborn, Head & Associates, explained the layers of plastic liners and pumps that keep liquid from leaching out of the trash cells and into the groundwater in the first place, he described it as “the best available technology for liner systems.”

It may be the best available technology, but is it 100 percent effective?

While residents left Thursday’s three-hour-long hearing with a greater understanding of the landfill’s layout and construction, they also left the meeting with a greater understanding of the serious consequences that could arise if any part of the 40-acre expansion project does not go exactly according to plans and predictions. Which—to use hydrogeological language—is highly unlikely… but not impossible.

The next public hearing regarding the Moretown Landfill will address air pollution, dust and odors associated with landfill activities. It is scheduled for November 13 at 6:30 p.m. at a location to be determined.