PRESERVING LIGHT FOR FUTURE GENERATIONS

LIGHTHOUSES are one of man's most positive structures.

They are built to save lives, guide seamen, and light up the darkness. No wonder they inspire a kind of awe. Everybody loves a lighthouse.

But here, along the United States' eastern seaboard, several lighthouses are perched perilously close to the advancing waves. If something is not done, they will likely fall into the ocean. The US government and many private groups are trying to save them. But figuring out how to do that is not easy. It means coming to terms with the forces of nature.

The most dramatic activity this year is taking place on Block Island, 20 miles off the coast of Rhode Island. There, man has decided to retreat. Engineers are digging up the island's historic lighthouse, jacking up all 2,000 tons of it, and moving it 250 feet away from the shoreline. The project is expected to last through September.

Other lighthouses are also threatened by the sea. A group has formed to try to save the Cape Cod lighthouse near North Truro, Mass. To the south, the tide is slowly moving in on the Nauset Lighthouse and on Nantucket Island's Sankaty Lighthouse.

But it is here, on the sandy Outer Banks of North Carolina, that man and nature have fought the longest and most interesting battle to save the Cape Hatteras Lighthouse.

"It's quite a saga," says Orrin Pilkey, director of the Program for the Study of Developed Shoreline at Duke University. "People think they're too great to be beaten by the sea.... [But] you're not going to stop the shoreline eroding. We're going to lose."

If anything, the mood here at the Cape Hatteras National Seashore is upbeat. On May 28, the National Park Service reopened the lighthouse to the public. For the first time in nine years, tourists can again climb to the top of the newly refurbished structure.

"The public interest in that is just astounding," says Chris Eckard, park historian for the Cape Hatteras National Seashore. "Tell people that they can climb the Cape Hatteras lighthouse and their faces just light up."

Perhaps it is the size of the thing. Hatteras is the tallest lighthouse in the US, stretching 208 feet high - the equivalent of a 20-story building. Its big black candy stripe has made it a famous landmark. Feelings run strong

"To some people, it's religious," says Wayne Wheeler, president of the United States Lighthouse Society. "It's the light against the darkness. The sea is dangerous and the darkness - allegorical evil. And there's that light pointing the way. [To others] it's that picket fence, that last vestige of civilization before people went off" to sea.

"There's a certain aura about that Grand Lady that strikes a sense of romance," agrees Mary Collier, management assistant for the Cape Hatteras National Seashore. "The very fact that it's imperiled by the sea, I think, draws a certain sentiment from the visitors."

Every day since the lighthouse reopened, tourists have clambered up Hatteras's 268 steps to take in the view and, maybe, to see how far the sea has encroached.

"We planned this trip 30 years ago," says Sandra Oates, a Tennessean whose first venture to the Outer Banks was postponed by an illness in the family. "How many feet did we lose?"

"We have been reading all that stuff" about the erosion, adds her sister, Laurie Swenson. "It doesn't look too imminent to me."

Indeed, the Cape Hatteras lighthouse looks safe behind its large protective dune and 50 feet of beach. To some old-timers, the threat to Hatteras is hype and old hat.

"It's nothing new," says Rany Jennette, a park ranger and the son of the last lighthouse keeper at Hatteras, Unaka Jennette. As a boy, Mr. Jennette remembers 300 feet of beach.

But in the mid-1930s, a huge storm pushed waves to the base of the lighthouse. The structure's demise seemed so imminent that the Coast Guard abandoned it in 1936 and put a light on a skeleton steel structure one mile northwest. Then the unexpected happened. The erosion stopped.

By 1950, the shoreline seemed so stable that the Coast Guard returned to the structure. Jennette is convinced the lighthouse is safe. "It's not going anywhere soon," he says, "not in my lifetime, anyway."

Oceanographers disagree. "The lighthouse is in imminent danger," Mr. Pilkey says. "No question that the right storm will take it, even if there's a giant wall there."

Two threats loom over Hatteras. One is storms. Although hurricanes draw the most attention, it is the region's northeasters that do the most damage. Cape Hatteras has an average 34 such storms a year.

The second threat is the relative sea level. For reasons oceanographers do not fully understand, the world's oceans are rising while, on the East Coast at least, the shoreline is sinking.

Combine those two forces and the Atlantic coast's relative sea level is rising about one foot a century.

It does not help that Hatteras has some of the highest wave energy anywhere along the East Coast. The Outer Banks is losing an average three feet of shoreline a year to erosion, Pilkey says. Some places are losing 10 feet a year; some are not losing any. And all this has happened in a geological era of relative stability.

Ever since the peak of the last glacial age, roughly 20,000 years ago, the Outer Banks have migrated toward the coast. About 4,000 years ago, the process slowed down. Now Pilkey sees signs that the erosion is speeding up. The inner as well as the outer shoreline of the islands is eroding.

For years, the US government has tried to protect the Hatteras Island's existing shoreline. It has built groins, pumped new sand onto the beach, put up sandbag barriers, and overseen the installation of artificial seaweed. Some of these measures have slowed the erosion. Nothing has stopped it. Long-term plans

So in the 1980s, the National Park Service asked the National Academy of Sciences to come up with a long-term solution. The academy recommended moving the lighthouse. Last year, the Park Service hired a Washington, D.C., engineering firm to draw up plans to move the lighthouse 2,500 feet southwest of its current location.

The planning will take a few years, Ms. Collier says. And the Park Service has decided not to move the lighthouse until the risk of leaving it in its current location outweighs the risk of moving it.

That plan seems to suit the growing number of lighthouse lovers.

"We like to see things in situ wherever possible," says Mr. Wheeler of the San Francisco-based Lighthouse Society. But "let's not have it destroyed."

Some locals, however, oppose the move.

"You let 'em come in and try to move it," threatens Carol Dillon, who traces her roots here back to a shipwrecked seaman in the late 1600s. "That's part of our heritage and we don't want to see some idiots come in and have a big pile of black and white bricks" on their hands. She also worries about the environmental impact of the move.

If the lighthouse moves, the Park Service will not necessarily keep up its efforts to protect the existing shoreline. Mrs. Dillon, who owns the Outer Banks Motel, has already seen storms destroy six of her cottages and cause more than $1 million in damages - most of it uninsured.

"I would rather have an honorable death than to have man tear it apart," she says of the lighthouse. There is plenty of precedent for that. Until the early '70s, man let the sea take several lighthouses, including the first Hatteras lighthouse - a 90-foot structure built in 1803.

Ever since the 16th century, when Europeans began sailing up and down the American coast, seamen have clamored for a lighthouse on Hatteras. The problem for sailors was that, at Hatteras, the Gulf Stream pinches in on a colder countercurrent, known as the Virginia Coastal Drift. That forced southbound ships into a narrow channel near the treacherous Diamond Shoals - constantly shifting arms of underwater sand. Even with a lighthouse, so many ships sunk off Hatteras that it became known as the "Graveyard of the Atlantic." Wrecks include everything from Spanish gold ships to the Civil War's iron-clad Monitor.

"It's the opposite of what a lighthouse should be," concedes Mr. Eckard, the park historian. But many more ships would have gone down had it not been for the lighthouse. After the Civil War, the original lighthouse was so damaged that Congress agreed to pay for a new one. The ocean has covered the remains of the first.

Ships do not really need lighthouses to navigate anymore. Advances in radar and satellite technology have relegated lighthouses to a secondary role in navigation. But the Coast Guard still lights them, including the Hatteras lighthouse. It sends out a flash every 7.5 seconds, which is visible 20 miles out on a clear night.

Joe Jakubik, who supervised the refurbishing of the Hatteras lighthouse, thinks the structure deserves to be saved anyway. "It should not be allowed to fall in the sea," he says. "By all means, I'd say, move it."

Mr. Jakubik and his company, International Chimney based in Williamsville, N.Y., are also involved in moving the Block Island lighthouse. Moving Hatteras lighthouse, he adds, would be tough but doable.

Up here at the top of the lighthouse, where beach and ocean stretch for miles in every direction, it is hard to disagree with him. The wind blows so hard that Gloria Marshall has a tough time holding onto her hat. She is one of the many new Park Service volunteers working here since the lighthouse opened in May.

"Since we have interfered with nature, I guess it's going to be difficult not to fight the battle," she says philosophically. "People from Ohio and way across the country come here and seem to show the same concern as if it belonged to them. And I guess, in a way, it does."