In Ocean City, bulldozers are used to help shore up the coast at an annual cost of $400,000. Virginia Beach rebuilds its beaches by dredging sand from Chesapeake Bay.

In Miami Beach, the Army Corps of Engineers is building a $64 million beach to replace the old one destroyed by high-rise development, bulkheads and jetties.

Everywhere from Cape Cod to the Outer Banks, from Texas to California, the story is the same. Geologists predict that by the year 2000 the rising sea level and land erosion will have resulted in a loss of 20,000 acres of shoreline property.

A 1971 Corps of Engineers study found that 2,700 mile of U.S. shoreline are in critical erosion condition. It proposed $1.8 billion worth of engineering projects to help remedy the situation.

While millions of dollars of shoreline engineering schemes are still in progress, geologists, environmentalists and even the engineers are beginning to question the technological fix.

"Efforts to control erosion are temporary," Orrin Pilkey and Wallace Kaufman argue in a new book, "The Beaches Are Moving." Pilkey, a prominent geologist, and Kaufman, a conservationist and developer, contend that the Corps has "set the stage for the most massive technological defense of coastal development ever attempted in the world.

"Much of the development it will encourage and protect will become part of storm disasters larger than any this nation has ever known," they say. "In other areas, where development survives behind its fortifications, the beaches will disappear."

In Texas, for instance, the Gulf Coast cities of Galveston, Houston and Texas City have barricaded themselves against the sea, while, at the same time, they have pumped 600 gallons of fresh water a day from the coastal plain.

In 50 years, 1,300 square miles of land has subsided. Water flows through the streets of Galveston at high tide and splashes over the 13.5-foot high levee of the Humble Oil refinery near Bay Town.

The engineers, however, may be rethingking past strategies. In May, the Corps of Engineers abandoned a $500 million plan to protect the New Jersey coast with huge jetties and sea walls. Instead, the corps announced it would work with state and local officials on a more modest scheme emphasizing land use controls.

Rudolph Savage, a corps official, said at the time, "when the Indians lived along the shore for centuries, they moved their teepees back when a storm came. We've learned, at great expense to society, that you can't put permanent shelters on the shore. We've got to start moving back, away from the battered beaches."