Sand is vanishing where life’s a beach : The land that defines Hawaii is being washed away due to sea walls. The remedy pits the state against homeowners.

Some of the sandy beaches that made Hawaii famous are gradually washing out to sea, deflected by walls designed to armor beachfront homes against the rising tides.

After years of winking at the problem, and even building sea walls itself, the state is changing its tune.

“Sea walls and revetments built on these coasts have produced an epidemic of beach loss on Oahu and Maui,” said Mike Wilson, director of the state Department of Land and Natural Resources. “We must take action now to stop this trend. . . . We need our beaches not only for our economy, but for our sense of who we are.”

The department recently ordered a homeowner to remove a sea wall built illegally on state land, and has identified 62 other “questionable” structures. The Office of State Planning also has announced plans to discourage sea wall construction in favor of sand replenishment efforts.

Sandy beaches are nature’s way of dissipating wave energy. A sea wall or sloping rock revetment instead focuses wave energy in front of it, scouring away the nearby sand. Without such “armor,” the sandy beach moves back and forth with the seasons and, as sea level rises, gradually migrates upland.

Nearly a quarter of the sandy beaches on the island of Oahu have disappeared or narrowed substantially as a result of sea walls or revetments built since 1928, according to Charles “Chip” Fletcher, associate professor of marine geology at the University of Hawaii. Working with the U.S. Geological Survey, he and graduate student Robert Mullane recently documented the loss of 6.4 miles of sandy beach and the narrowing of nearly 11 miles.

Beaches are Hawaii’s main claim to fame and a crucial component of its tourism-dependent economy. From fishermen casting on the shore to toddlers building sandcastles, residents also treasure these sandy shores. The state constitution guarantees public access to the shoreline.

With beachfront real estate here among the most valuable in the world, homeowners are passionate about their rights to protect their property. Sea walls may degrade the beaches in front of them, but they protect the land and homes behind them. As one homeowner put it, without such walls, “we are caught between the devil and the deep blue sea.”

“What about private property rights?” asked a landowner who didn’t want to be identified because he has a sea wall application pending.

Another homeowner, Benjamin Baker, who bought his beachfront home in Kihei, Maui, in 1955, has witnessed the erosion of the entire beach in front of his home. More than 40 feet of his front lawn is gone. The erosion began during the first big storm after the U.S. Army Corps of Engineers built a sea wall at a nearby beach in 1970. Other neighbors then built their own sea walls, passing the problem along the coast. Baker, 77, feels he has to build one now but hasn’t been able to get a permit.

“I’d far prefer not to build one, and have all the sea walls removed,” he sighs. “But I have to put one in to protect my property. . . . It’s reached the point where it is so bad, you almost have to laugh about it, because otherwise you’ll go crazy.”

The draft policy issued by the Office of State Planning discourages new sea walls. It urges “soft” alternatives, such as dune-scaping and sand replenishment, using sand deposits from offshore. It also recommends placing structures farther from the beach where feasible. While the policy does not have the force of law, and most sea wall decisions are made by the counties, it signals a new direction for the state administration.

Other coastal states have gone further. North Carolina and Maine prohibit construction of sea walls. Other jurisdictions severely limit them and enforce strict setbacks to block building near the ocean. In Florida, a huge sand replenishment project in the late 1970s widened Miami Beach by 300 feet.

In Hawaii, officials hope to try a pilot project of beach replenishment and may reconsider the state’s standard 40-foot setback from the ocean for building, Uchida said. In the long run, given sea-level rise, a gradual retreat from the shoreline may be necessary in erosion hot spots, Fletcher added. But relocation promises to be an explosive issue, given Hawaii’s limited land.

“You’re dealing with the nation’s most expensive real estate,” Fletcher noted. “To free that up from private hands is going to be really politically unpalatable.”

In the meantime, Mother Nature isn’t waiting. Winter storms ripped the front porches from homes on Oahu’s North Shore. In Lanikai, a fine white sand beach has surrendered to an advancing column of walls. Where the last wall meets the diminishing beach, a desperate homeowner has piled up huge sandbags to save his home from the waves.