Landowners around Edgartown Great Pond are looking at buying a half-million-dollar dredge to improve the water quality of their pond, and potentially that of other fresh and salt water ponds on the Island.

As a first step, they will put up between $50,000 and $100,000 to lease the small, easily transported machine to conduct test dredging of the pond this fall. If all goes well, the plan is to buy it and take pressure off the increasingly-overtaxed town dredge.

The proposal was raised at this week’s meeting of the Edgartown selectmen. While it will be further considered next week, it has won strong initial support.

The Edgartown shellfish constable, Paul Bagnall, who is directly responsible for the town’s dredging operations, said the new machine would complement the town dredge. The great ponds advisory committee, which is a town subcommittee managing south shore ponds, has unanimously endorsed the trial. And the Martha’s Vineyard Commission water resource planner Bill Wilcox said he saw the new dredge as a possible solution for problems in other Island ponds as well.

The chairman of the great ponds advisory committee, Tom Wallace, who put the plan before the selectmen this week, said pledges have already been made by landowners around the Edgartown Pond for about two-thirds of the purchase cost of the piece of equipment.

The new dredge would have a couple of advantages over the larger town dredge. It is only as big as a medium-sized boat, and could easily be transported into areas inaccessible to the other dredge. It also is capable not only of moving sand, but of removing water weeds which can choke ponds.

Mr. Wallace also is president of the Great Pond Foundation, the nonprofit group which is putting up the money for the trial and would meet the cost of the purchase.

The proposal was spurred by the fact that the town dredge has been unable to work in the great pond for the past four years because of the pressure of other dredging tasks. As a result, he told the selectmen, water quality in the pond was at an “all-time low”.

The problem is that while cuts are made in the barrier beach several times a year to allow an exchange of water with the ocean, sand deposition inside the pond limited the water flow.

“A backhoe is used to open the barrier beach, the pond level drops about 3.5 feet and there is an exchange of water with the ocean,” he said. “The last time the town dredge was brought in it was wonderfully successful for a couple of years.”

“But the last two openings have essentially been unsuccessful in allowing a major exchange of water.”

The dredge would be used to cut a channel through the deposited sand to improve water flow.

“The foundation is now negotiating a lease which might run to about $50,000 to $100,000 to get it into the pond this fall. It would be an experiment, or proof of concept, to verify if this piece of equipment is adequate for the job.

“If we’re pleased and the town is pleased, then the foundation is proposing getting it as a permanent tool for future openings.”

It would cost the town nothing, he said.

“The foundation is not only proposing to pay for the lease, but to underwrite all the costs. In the future we’re looking at raising funds for its continued use so the selectmen’s concern of increased cost to the town is not an issue.”

If the foundation bought the dredge, it would lease it to a private operator who would clear the channel once or twice a year.

But the dredging program still would be carried out under the town’s direction.

“The permit that exists that allows us to open the pond is held and controlled by the town,” Mr. Wallace said. “It was stated in front of the selectmen that it would be used under the auspices of the shellfish constable.

“We’re not just going to go out willy-nilly. We’re only going to do what is directed by Mr. Bagnall.”

Mr. Bagnall said he understood the concerns which had forced the foundation to look at buying its own dredge.

“We’ve been having a hard time getting back there as frequently as needed,” he said.

“So if this piece of equipment works out I think it would be a valuable addition. It’s a different type of dredge: it’s smaller, it has an articulated arm, so you can put various attachments on it, like underwater vine harvesters and so on.

“It’s trailer-able so it can go into places where we wouldn’t even think of putting ours, like the Mill Pond in West Tisbury or Crystal Lake in Oak Bluffs,” he said.

“It makes it a little more versatile for purposes other than moving sand. That said it’s smaller so you move less per hour.

“I think they’re doing a wise thing taking a look at it.”

The town dredge is likely to be heavily committed into the foreseeable future. The dredge is committed to work at Cape Pogue, answering the demands of shellfishermen concerned about siltation there. There also are plans for significant dredging in Sengekontacket Pond in the hope of improving the flushing and water quality of that pond, which was closed this summer due to high bacterial levels.

Mr. Wallace said: “Let’s face it, the importance of the fisheries of Cape Pogue Bay or Sengekontacket are so much greater to the town than our pond, dear as it may be to our hearts. There are other priorities and this plan recognizes that.”

He said he was optimistic the selectmen would approve the idea next week once the town had examined the associated legalities relating to insurance liability. “I’m sure next Monday should be exciting,” he said.