FOLLY BEACH -- Five years after a $12 million project moved millions upon millions of tons of sand onto the beach here, the city is getting in line for federal money to do it again.

Nearly one-third of the 5-mile beach has lost enough sand to meet the federal requirement for needing renourishment, which is that 60 feet or less of beach remains at high tide. Storm erosion last summer tore up the Charleston County park on the west end, where a portion of the dunes has been taken out along with a portion of the parking lot behind it.

Worse still, nobody really can say why it's happening so fast. The rule of thumb is for beach renourishment projects to last eight to 10 years, depending on storms and other factors.

A dozen years went by between the 1993 and 2005 to 2006 renourishments on Folly Beach. The second time around, no sooner was the sand in place than Hurricane Ophelia whirled past offshore, and the U.S. Army Corps of Engineers came back in 2007 to do an $8 million patch job on the east end toward the Morris Island Lighthouse.

But other than that, there hasn't been what one oceanographer characterized as significant tropical storm damage.

"The renourishment hasn't held up like last time," Folly Beach Mayor Tim Goodwin said. "Why is a good question."

"I don't have a good answer for that," said Bill

Eiser, S.C. Ocean and Coastal Resources Management oceanographer. Particularly puzzling is the accelerated erosion at the county park, which had been fairly stable for a number of years, he said. Eiser suspects a variety of factors are causing it.

The town isn't alone. Wild Dunes Resort on Isle of Palms already has shored up its beachfront golf holes and the city is asking for a state permit to move sand to shore up two "hot spots" of erosion along its controversial $10 million beach renourishment in 2008. The town of Edisto Beach is doing a feasibility study to see if it qualifies for federal beach renourishment funds, after an $8 million project in 2006, even though Town Administrator Iris Hill said the beach isn't seeing any more than a few hot spots of erosion.

At least part of the motivation for both Edisto and Folly is to compete for a shrinking pot of public money being made available for the expensive projects. Isle of Palms financed its project mostly with resort money and a local tax, and is financing the ongoing work the same way.

The state hasn't set aside any money for beach renourishment since 2008 and has only about $3 million remaining in a fund that must be matched dollar-to-dollar by the local community. In 2011, the federal budget set aside $29.8 million for nine renourishment and first-time nourishment projects, after paying less than half of that in 2010, and only for first-time projects.

But something else is happening. The ocean just isn't behaving. Despite the relatively few tropical storms making landfall or passing very near the Southeast coast, beaches are eroding harder.

"I know of a number of places that are moving forward their plan (schedule) to renourish," said Rob Young, a coastal geology professor at Western Carolina University.

The East Coast has been plagued by an unusually high surge of sea level. And the sea level is rising. A federal Environmental Protection Agency study in 1998 indicated that the sea level was rising about a foot per century on the East Coast. Conservationists warn the climate warming is exacerbating that. Young pointed to both those occurrences as factors.

When it comes to erosion and renourishment, Folly Beach is unique. The city won a 50-year commitment from the federal government to help with renourishment projects because its erosion is exacerbated by the Charleston jetties, an Army Corps of Engineers project.

The Army Corps is blunt about why it does beach renourishment.

"The whole point is to protect people and property from storm damage," said Glenn Jeffries of the Charleston District office.

Renourishments are pricey, but there's big money at stake. Beach tourism is said to be a $600 million per year industry in the state, and recession or not, beach development continues.

Folly Beach collects about $1.2 million per year in taxes directly related to tourism, city Administrator Toni Connor-Rooks said. The city has $64 million in assessed beach property value, according to its website.

"Basically, all of our tourism money is that sand out there," Goodwin said.

"I don't have a philosophical problem with beach renourishment," Young said. "But its primary benefits are to property owners and beach communities, and it should be funded by those communities. The projects are designed to protect oceanfront property. That's all they do."

An eroding beach is just a beach whose sand is relocating, he said. If the beach is such a valuable commodity to beach communities, they ought to be able to find financial resources to pay for it, he said, pointing to Isle of Palms as an example.

"If we removed beachfront homes -- and I'm not saying we should do this -- you wouldn't need beach renourishment. You'd still have a beach. If I were a South Carolinian, I'd be very hesitant to finance these projects. In today's fiscal climate, it's pretty hard to justify paying for them," he said.

"Sea level rise in the coming years will make beaches disappear faster. Whether that's happening already is difficult to say. But whatever is causing an early search for beach renourishment money right now, this is going to become the norm," he said. "Get used to it."