It fills your shoes, ruins the kitchen floor in the summer and gets in your food at picnics.

But whoever thought of sand as a commodity?

On the Vineyard sand is emerging as exactly that, right up there with gold futures and pork bellies, as towns and private groups compete to get their hands on the stuff to use as ammunition in their ongoing battle against erosion.

The value of sand has skyrocketed, and given all the predictions that global warming will cause a rise in sea levels, it’s unlikely to come down anytime soon.

This week a joint committee made up of Edgartown and Oak Bluffs officials and charged with improving water quality in Sengekontacket Pond, opened bids for a project to dredge 57,000 cubic yards of sand from a channel in between Big Bridge and Little Bridge at Joseph Sylvia State Beach.

The project is sponsored by the town of Oak Bluffs, but is being managed by the joint committee.

Committee members hope the project will reduce bacteria levels and help lift a ban on summer shellfishing imposed by the state Division of Marine Fisheries four years ago. But the project will also harvest piles of precious sand, just as private groups, among them the Cow Bay Association in Edgartown, a private homeowners group, are looking to scoop it up at a premium.

When the bids were opened at Oak Bluffs town hall on Tuesday, the lowest bid was from Synagro Northeast LLC of Naugatuck, Conn., which offered to dredge the sand at $17 a cubic yard, and charge another $71,000 for storage and transport. Two other companies offered less per cubic yard to harvest the sand, but more for moving and storage.

No bid has been awarded yet, as committee members said they still hope the town of Edgartown will perform the work. Of the six Island towns, Edgartown is the only one with its own dredge.

Edgartown shellfish constable Paul Bagnall, also a member of the joint committee, said yesterday the dredge committee, which decides when and where the machine is used, would probably charge Oak Bluffs $11 a cubic yard to dredge the sand.

“We want to work together, this is for the good of the pond, not individual towns,” Mr. Bagnall said.

But this spirit of collaboration comes as both towns are now vendors of valuable sand, and groups are lining up to buy the stuff.

Over the past two years both towns have pursued dredging projects. Two years ago Edgartown embarked on a private-public partnership with the Cow Bay Association to dredge 40,000 cubic yards of sand from the pond and divide the spoils.

Some 17,000 cubic yards of sand went to the private homeowners, who used it to combat erosion near Eel Pond, while the rest went to the town beach at the Bend in the Road. In return for the sand, the Cow Bay Association paid approximately $150,000 of the $250,000 cost of the project.

Last year Edgartown completed another dredging project, harvesting another 20,000 cubic yards of sand from Sengekontacket, which will again be split between the town and the Cow Bay Association. Those spoils can be seen in huge piles near the Bend in the Road, waiting to be spread out along the beaches sometime this fall. The final amount is not set yet, but Cow Bay is expected to pay the town in the neighborhood of $100,000 for the sand.

Meanwhile, Oak Bluffs, which has struggled with its own dredge project, recently won final approval from the Army Corps of Engineers to dredge 57,000 cubic yards of sand from the channel from the Big Bridge to Little Bridge.

At the annual town meeting in April 2009, voters agreed to spend $500,000 on the project. The town had hoped to begin the project last fall, but it was delayed when an artifact believed to be part of an old Wampanoag fishing weir was found.

Ironically, the artifact that delayed the Oak Bluffs project was found during the Edgartown dredging project.

At yesterday’s meeting, committee chairman Duncan Ross, who also is an Oak Bluffs selectman, said he still hopes that Edgartown will do the work on the Oak Bluffs side of the pond.

Mr. Ross said Edgartown did not bid on the project because it doesn’t have to; the two towns can instead enter into an intermunicipal agreement or sign a memorandum of understanding. “Right now they are still very much in the picture, and I would say the favorite. At least I hope they will be the favorite,” Mr. Ross said.

He also shed more light on the town’s plans for the valuable byproduct of the dredging work: the sand. He said the town will keep 17,000 cubic yards, using it to renourish several town beaches, including the Inkwell and old Pay Beach, and give another 10,000 cubic yards to Dukes County to use on the Joseph Sylvia State Beach — at no charge.

Mr. Ross said the town plans to sell the remaining 30,000 cubic yards to the Cow Bay Association, most likely at a cost of more than $1 million. He said the money from the sale of the sand will help defray the cost of the dredging project, now pegged at closer to $750,000 instead of the $500,000 projected last year.

“We are now sure the $500,000 approved at town meeting last April is not enough. The costs keep going up,” Mr. Ross said.

Lynn Fraker, a consultant for the joint pond committee who helped secure the permits for the dredge project, predicted the demand for sand will continue to increase in the coming years, as private homeowners scramble to protect their beaches and beachfront homes from erosion.

“I think you will see the value [of sand] increase dramatically. The ocean will keep washing it away, and people will be looking for more,” she said.

Mr. Ross admitted that his town is still new at the business of selling sand. But he denied that the two towns are competing against each other.

“I think both sides agree the priority is improving the water quality of the pond, and getting it back open for shellfishing. That pond plays such a valuable role to both towns, in terms of shellfishing, recreation, tourism, that I think we have no other choice but to work together,” he said.

He concluded: “Right now selling the sand only pays for the dredge. We don’t want to borrow money to dredge the sand, and we don’t want to put more of a burden on taxpayers. I can finally say that it appears this dredge will take place [this fall] and we have a plan in place to pay for it.”