A Waikiki hotel is moving forward with a plan to install three, 160-foot-long rock groins in the water fronting its property to restore a sandy stretch of beach, and has started a lengthy approval process for the work.

Sheraton Waikiki officials said it likely will take 18 to 24 months to get all the necessary approvals to build the structures in the water at Gray's Beach and pump in 15,000 cubic yards of sand from offshore.

If all the permits are awarded, the work to create a beach big enough for 500 people (where there is currently only a small beach at very low tides) would wrap up in 2011, after six to nine months of construction.

If it goes through, the Sheraton project would be the first major shoreline restoration in Waikiki undertaken by a hotel since the early 20th century, and the groins would be the first permanent structures aimed at stopping erosion to be built off Waikiki in 30 years. The last groin was built in 1971 off Fort DeRussy.

The $4 million Sheraton beach restoration work comes as tourism officials are raising concerns about the gradual disappearance of Waikiki Beach to erosion. Some have said the project could spur other hotels to take a more active role in what many call one of the biggest problems facing the state's No. 1 tourist destination.

"Waikiki Beach is starting to go away," said Ernest Nishizaki, executive vice president and chief operating officer of Kyo-ya Hotel and Resorts, which owns the Sheraton Waikiki. "We do hope this is a start of a restoration of the entire beach."

SEEKING FUNDING

The state has no immediate plans to move ahead with any beach restoration projects on its own, though some state agencies have been working behind the scenes to facilitate privately funded work on the Neighbor Islands by helping interested entities, including hotels, navigate the complicated permitting process for pumping sand in.

The state has also long been in on discussions with Sheraton on the Gray's Beach project, though it is not actively supporting the work.

The Hawai'i Tourism Authority also has $2 million set aside for beach restoration work that is intended to be matched by a company. Sheraton plans to seek some of that funding, though it has not been promised it.

Meanwhile, the governor recently released $500,000 to design a beach restoration plan for as-yet undetermined sections of Waikiki.

The most recent state project to tackle erosion in Waikiki was a $475,000 sand-pumping demonstration project at Kuhio Beach, which was completed in January 2007 and brought in about 9,500 cubic yards of sand.

Within five years, the project will have to be repeated.

But securing funding for erosion-abatement projects is not easy. Before the 2007 sand-pumping project, the last time Kuhio Beach had been replenished was in 2000, during a small pilot project in which just 1,400 cubic yards of sand was pumped in. The previous large replenishment project was in 1975.

EARLY DISCUSSIONS

Kyo-ya first started studying the possibilities for restoring the beach in 2005, Nishizaki said, and officials have had discussions on the project with small groups of surfers and other interest groups over the last year. So far, there has not been much vocal opposition to the plan, but that could change now that it's moving ahead.

George Downing, spokesman for the environmental group Save Our Surf, said he expects a groundswell of opponents to come forward in the coming months. Downing fears that the groins, which will be made out of large rocks, will be bad for the environment — including turtles in the area — and a popular surf break.

"They're trying to play God," said Downing, who helped lead opposition to a proposal to build T-groins at Kuhio Beach in 2000. That project, undertaken by the state, was tabled after lawmakers declined to release $2 million for the work because of community protests to the plan.

Sam Lemmo, administrator of the Coastal Lands Division in the state Land and Natural Resources Department, said community input will likely play a vital role in the Sheraton project.

"Opposition can certainly influence the outcome of these matters," he said.

But he added it will ultimately be up to myriad state and federal agencies Sheraton is seeking approvals from whether the project comes to fruition.

Those agencies will weigh the community input along with potential impacts.

APPLYING FOR PERMITS

Though it's hard to say how difficult it will be for the Gray's Beach project to get through the permitting process, Sheraton officials say they have started discussions with the approving agencies to make sure all the necessary documents are in.

Sea Engineering Inc., which designed the three T-shaped groins Sheraton proposes to install, said the structures would fit in well with other possible erosion-abatement additions along the shoreline and would likely not affect the Populars surf break. Sea Engineering vice president Scott Sullivan said yesterday that the only potential environmental impact is to sea turtles, which feed in the area.

And he said those impacts would be minimal.

OTHER RENOVATIONS

The groins would be made out of 2,800- to 4,800-pound rocks, and stick 2 feet out of the water at high tide. They would be spaced some 250 feet apart. Sullivan said the technology behind the structures, designed to deflect waves and reduce rip current formation, has been employed on similar beaches in Mexico and Florida.

He added the sand that would be pumped in would not spur any negative environmental effects. And he said that just pumping in sand, without installing the T-groins, would do more harm than good because it could affect neighboring beaches.

The Gray's Beach plan comes as Kyo-ya is in the midst of massive planned renovations — totaling $750 million — at its four Waikiki properties, including the 1,700-room Sheraton. Nishizaki said though the Gray's Beach plan will certainly benefit the hotel and its guests, it will also benefit other hotels and residents.

"Hopefully, at the end of this, we'll get community support," he said.