CHESTERVILLE — Residents at Tuesday evening’s Planning Board hearing raised concerns about a proposal to excavate gravel 27 feet below the water table on land between Dutch Gap and Besson Pit roads.

In 2012, Adam and Susan Castonguay, owners of Castonguay Sand and Gravel of Chesterville, applied to the Department of Environmental Protection for a permit to excavate gravel below the groundwater table. 

In November 2013, voters approved the Chesterville Water Quality Ordinance, which includes a section on mineral extraction that prohibits excavation within 5 feet of the high-water table without a waiver or variance. 

In January 2015, the DEP approved the Castonguays’ permit, and the Castonguays submitted a waiver application in July 15.

If the waiver is granted, the Castonguays plan to excavate up to 27 feet below the water table. In the process, a pond, up to 8.1 acres, will be created where the gravel once was.

At the hearing, Code Enforcement Officer Brenda Medcoff said an applicant for a waiver has to explain why the case is different from any other. 

Albert E. Hodsdon III, consulting engineer for the Castonguays, said public health, safety and welfare would not be compromised should the waiver be granted. If not approved, the applicant would suffer undue economic hardship, he said.

Certified geologist Ricky S. Pershken said groundwater flows in toward the pit and a nearby stream flows north. The esker acts like a drainage tile and sucks water into it. When water and gravel are taken out, a hole forms, he said.

As part of the DEP permitting process, several test wells were dug and the water analyzed. A trace amount of benzene was found in one sample, thought to be from reclaimed asphalt stored in the pit.

Pershken couldn’t say with certainty that the asphalt caused the contamination. Storing the asphalt on an impermeable pad and covering it could alleviate residents’ concerns, he said.

“If it is already contaminated, is that a reason to add to it?” Board of Selectmen Chairman Guy Iverson asked.

Pershken said, if needed, food-grade hydraulic fluid could be used in the excavators, even though it is not required by the DEP.

Some said the large pond that would be created could be a good thing for the town, because it would be a water source and invite wildlife to the area. Others said it would be a breeding ground for mosquitoes. 

Concern was also expressed about the amount of land that has been forever changed because of gravel mining. Several hills have been eliminated and large areas are unusable.

Others voiced fears that approving this waiver would result in more requests being made. Contamination of nearby wells was another concern.

A few residents were worried that there would be no provisions in place for monitoring the area once the work was completed.

Another resident said he preferred a family-owned business to a large corporation, because it would be willing to abide by any conditions set.

“We’re duty-bound, whether we agree or not, if it meets all the requirements to approve the application,” Planning Board member Greg Soule said. 

Planning board members agreed that all information requested has been provided.

A workshop on the matter will be held Sept. 22., following a 7 p.m. public hearing on a road name change.

The board is expected to make a decision at the Oct. 11 meeting.

Medcoff said abutters may appeal that decision within 30 days.

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