The hunt is on for sand in the sea because beach towns are running out of beach.

The S.C. Department of Natural Resources just won a $200,000 "Hurricane Sandy" grant to look for potential beach renourishment sand in federal waters more than three miles offshore. The federal government wants to inventory the supply off 13 Atlantic coast states.

The inventory could be critical to communities such as Folly Beach, where sands are eroding harder for a number of coastal dynamic reasons, renourishments are expected to be needed more often, and quality sand for them is getting hard to come by. Having an established supply of sand would cut down at least on the permitting survey work and cost.

The inventory is one of the takeaways from the hurricane that racked the East Coast in 2012. Beaches that had renourished sand and dunes stood up better to the storm and needed less restoration work, said Renee Orr, federal Bureau of Ocean Energy Management chief of strategic resources.

"It's very clear that sand restoration projects are very important. Knowing where the sand is is critical to making decisions whether, where and how to provide it (for projects)" she said.

The grants come, incongruously, as federal legislators incrementally are backing away from the renourishment business, not willing to pay the rising costs. But Orr said whether federal money pays for the work, renourishment projects will continue because of the economic value of coastal communities.

In South Carolina, coastal tourism is said to be an $18 billion industry.

The technology is making it more feasible to pull sand from farther out, beyond the federal 3-mile boundary, said S.C. Department of Natural Resources state geologist Scott Howard, who is conducting the inventory work. If enough sand is found there, one option could be to move it in closer to shore and stockpile, he said.

Having sand supplies inventoried would be huge, said David Warren, Army Corps of Engineers project manager for the Charleston district.

The shallow, flat South Carolina nearshore generally is acknowledged to have plenty sand. But not a lot of it can be used to renourish. Nearly 200,000 acres are off limits to dredging renourishment sand, if federal money is used, under the Coastal Barrier Resources Act designed to protect habitats. Most of the acreage is around inlets, including both Lighthouse and Stono inlets on Folly.

Sand washed from the inlets tends to be the richer supplies. In 1993, when Folly first was renourished under a federal settlement contract, sand was taken from Stono Inlet, said Glenn Jeffries, of the Army Corps of Engineers, Charleston district. Then the inlet was put off limits.

The just completed renourishment dredged sand from two offshore spots that hadn't been used before because earlier dredgings had diminished the areas used then. Core samples suggested the quality was fine enough for the beach, but the sand dredged turned out to be strewn with "cemented sand," in Warren's words.

To beachgoers it was just rocks. The poor sand became more debris left from a project that was a mess almost from the start, scraping its way through funding delays, escalating costs, property disputes and storms that washed away some of the sand almost as soon as it had been renourished.

Folly is renourished under a legal settlement that requires the federal government to pay the lion's share of the cost each time because the ocean sand flow to the beach is disrupted by the Charleston shipping channel jetties.

But a set amount of money was set aside for it in 1992. Since then costs have risen steeply. With more than 25 years left to run in that settlement and costs climbing each time, there's not enough money left in the set-aside to pay for another round of renourishment.

With legislators balking, federal renourishment funding has flatlined. Requested projects are backlogged and the Army Corps is parsing out the work.

Folly, like other beach communities, might well find itself paying for future renourishments largely on its own.

The sand inventory work is being overseen by the Bureau of Ocean Energy Management's marine minerals program at the same time the office has approved the use of underwater sonic cannons to find oil and gas deposits off the East Coast, in part to learn more about mineral resources there.

But Orr said that exploration work would take place farther offshore and the two projects are "completely separate."

Reach Bo Petersen at 937-5744, @bopete on twitter or Bo Petersen Reporting on Facebook.