Sometimes a major storm will scoop unwanted sand out of an inlet, and sometimes the heavy winds and high seas make the natural buildup of underwater sediment worse.
Early reports on the impact of superstorm Sandy are mixed.
The U.S. Army Corps of Engineers, which has responsibility for maintaining the channels through inlets, says its preliminary assessment is that Sandy made the already shallow channels at Jones, Fire Island, Moriches and Shinnecock inlets shallower.
"We always like storms to help us and take away material from the inlets and put it back on the beach," said Randall Hintz, chief of the Operations Support Branch for the Corps' New York District. But he said Sandy doesn't appear to be one of those storms.
"There was a lot of dredging that needed to be done before, but Sandy has clearly made that worse," Hintz said.
But the Coast Guard said Sandy didn't seem to have much of an impact.
"Based on the reports from the stations, for the most part it really hasn't changed that much from the storm," said Lt. Ben Duarte, chief of the Coast Guard Sector Long Island Sound Waterways Management Division. "You have certain areas where there seems to be a little more depth and other areas where it seems to have gotten a little worse."
Duarte said his agency will continue to monitor the channels and shift its buoys to mark the changing depth.
The storm damaged or moved more than 90 buoys along the South Shore and in Long Island Sound, the majority of them along the ocean. So "our crews have been out there daily restoring buoys or replacing them with temporary buoys," Duarte said.
He said about a dozen buoys still need to be repositioned and that should be done before the end of the year.
Hintz said the only firm indication that sand accumulated in the inlets from Sandy was a pre-dredging project survey done in Moriches Inlet by a contractor getting ready for a project there.
"It looks like there's more sand in the inlet than there was before," Hintz said, based on what the contractor found after Sandy had passed through.
"We're still doing the preliminary assessments and we don't have any hard and fast survey data yet for the inlets because we haven't had a chance to go out there and collect that data," Hintz said.
The surveying of the Long Island inlets has had to wait while the Corps focused on the deep-draft channels into New York Harbor to get gasoline and other products moving into the port.
So the Corps has been relying on satellite data and information gleaned from laser aerial surveys to determine where the sand has moved.
Once the data are gathered, the Corps will come up with a volume and dollar estimate for dredging to determine if there is money in the agency's budget that can be transferred for emergency dredging or if funds can be obtained from the Federal Emergency Management Agency.
He said the dredging would cost millions of dollars.
Those on the water are reporting conflicting results from the storm.
Capt. Nick Manzari of the Island Princess and the Bay Princess based at Captree State Park said the boats that use Fire Island Inlet have seen a difference after Sandy.
"It's gotten shallower because there is a lot more sand," he said. But the fishing boats can still get in or out because their captains know the areas of deeper water.
Anthony Joseph, who owns a commercial fishing boat in Point Lookout, said about Jones Inlet that "we can only transit at the very top of the tide and only in fair conditions. There's a sandbar that's closed off the whole south end of the inlet. It was always a tough inlet but Sandy really closed it off."
Dave Lofstad, who owns a 65-foot fishing boat docked by Shinnecock Inlet, said, "it was actually good" in terms of shoaling after Sandy.
The problem was all of the buoys in and on either side of the inlet were displaced by the storm, making navigation "kind of spooky."