Below the ocean surface, there's a small mountain of sand waiting to be dredged.
That sand — 130,000 to 150,000 cubic yards — would come from the navigation channel at the mouth of the Merrimack River that the Army Corps of Engineers has been digging out every few years.
If you were to dump it all in downtown Newburyport, it would bury State Street from Market Square to High Street in a 35-foot-tall pile of sand.
No one owns that sand, but both Salisbury and Plum Island want it.
Next year, or perhaps the year after that, the dredgers will come and dig it out. The battle over who gets that sand has become contentious, and a corps spokesman says if the fight over it continues, it will delay the salvation that both communities are asking for — the delivery of a massive pile of sand to replenish the beach.
The mouth of the Merrimack River is a natural chokepoint for sand. Enormous sandbars form there, making it difficult for large boats to get through.
Since at least 1937, the corps has followed a routine of dredging a channel about every three years and depositing the sand far off shore, according to Ed O'Donnell, Chief of the Navagation Section in the corps' New England District Office.
But beginning around 1983, dredgers began to dump nearer and nearer to Plum Island's shore. The action nourished the beaches, undoing some of the damage caused by storms and natural erosion.
In 1996, dredged sand was deposited off Salisbury's beaches after the state — which owns Salisbury Beach — asked the corps to place the sand north of the river. In 1999, the Merrimack River's dredged sand cycled back for use at Plum Island, with a written agreement Salisbury would get sand again after the next dredging. That dredging was expected to take place around 2002.