St. Simons Island, Ga. — Tall, slender-stalked sea oats along the edge of the beach danced to an increasing tempo as a northeastern breeze turned into a forceful wind. With an unusually high tide, waves began smashing against expensive sea walls of boulders, pouring over onto the yards of apartments and homes.
But the recent two-day pounding of this and other barrier islands along the southeastern coast passed without major damage - certainly not enough to dim prospects of further development of the coastal island necklace that extends from Maine to Texas.
St. Simons Island, about the size of Manhattan Island and about half undeveloped, is one of some 300 ''gems'' in the necklace. One out of four Americans live within 100 miles of one of these islands. As a result, federal and local officials see tremendous pressure mounting that could turn hundreds of miles of island beachfronts into a ''wall of condominiums.''
Environmental leaders and US Interior Secretary James Watt are backing legislation to curtail federal flood insurance and federal development projects on barrier islands. But some experts say the legislation would only slow, not stop, private development.
''What we're finding is a wealthier resident coming to this area,'' says Craig Mahlman, director of the local planning commission here. Some newcomers have enough money to buy homes with cash, he says. They are not likely to be deterred by lack of federally subsidized flood insurance or lack of federal projects such as sewage and road construction on the island, Mr. Mahlman and others predict.
So what lies ahead for the approximately 700,000 acres of undeveloped and federally unprotected land on the nearly 300 barrier islands identified by the Interior Department in 1979?
According to developers, residents seeking limits on development, and local officials, the answer seems to be more condominium and other development. But how much, how tall, how many? This island's recent efforts to prevent runaway development may offer some clues.
''We will not have Ft. Lauderdale (Fla.),'' says John Holbrook, who retired here from Illinois 10 years ago and is a leader of the island's Citizens Coalition for Planned Growth.
The coalition backed a recently adopted growth plan for the island, but the plan is much less strict than an earlier proposal. The earlier version and tougher amendments to the zoning ordinance were withdrawn in the face of stiff opposition from beachfront homeowners and developers.
The majority of island residents might have favored the tougher measures. But , says planner Mahlman, the island's representation on the county commission is outnumbered by mainland representatives. On the island, ''The silent majority is just that - they're silent. They'll wake up,'' he adds.
The zoning amendments the planning commission has recommended to the county commission would expand the space required between buildings from the current 14 to 24 feet. Building height would remain limited to 45 feet and the requirement to not build within 40 feet feet of the most stable oceanfront dunes would be retained.
Sea Island Company, which owns The Cloister hotel, owns about one-third of the island but has been slow to sell. The company foresees developing more golf courses and tennis courts but has no specific development plans, says Sigmund Kauffman, a company spokesman.
State protection of marshlands is ''fragile'' and subject to legislative change, as are local controls on development, says Mr. Kauffman. Meanwhile, other developers are going ahead, slowed only by high interest rates, which are discouraging land sales. The county anticipates more than 300 condominium units will be built on the island in the next two years, according to Mahlman.