The crumbling Royal Hawaiian groin, between the Waikiki Sheraton and Royal Hawaiian hotels, is all that is keeping a prime section of Hawaii’s most visited beach from being swept away.

The concrete groin was erected around 1927 to protect structures along the coastline and to create the sandy beach that has made Waikiki so famous. It’s supposed to be replaced with a 180-foot T-head rock-wall groin, which engineers say would provide better protection from the summer swells and high sea levels that imperil Waikiki’s coast.

But the state Department of Land and Natural Resources, which is already two years behind on the project, is headed for more delays since groin funding will lapse this June and didn’t get reappropriated during this legislative session. DLNR must wait another year to ask state lawmakers to restore funding and add another $1 million to cover construction costs, which have mounted to $2.5 million from the delays.

“It’s fair to say that we would have anticipated this project would have been completed by now,” said Dolan Eversole, Waikiki Beach management coordinator for the University of Hawaii’s Sea Grant program. “Fall of 2020 is probably the earliest that this project could start.”

State Sen. Brickwood Galuteria (D, Waikiki-Ala Moana­-Kakaako-McCully-Moiliili) expressed disappointment that DLNR had let the money lapse for a project that is sorely needed in his district.

“I would have hoped that they would have made this a quicker priority. Three years is a long time to get stuff done,” Galuteria said. “The Senate reappropriated the funds, but they weren’t reappropriated in the House. A lot of money this year was diverted: Big money went into housing and disaster relief, and that tightened everything up. I’ll have to work with my colleagues to see what happens next year.”

DLNR’s Office of Conservation and Coastal Lands said the project was delayed because the Board of Land and Natural Resources requested a second design review, which is still in progress. BLNR member Keone Dow­ning, who originally opposed the design along with fellow Save Our Surf members, pushed for the additional review to satisfy concerns that might change wave quality or attract predatory eels.

DLNR said it didn’t know why the Legislature did not act on its request for new funds given that the Waikiki Beach Special Improvement District has pledged to fund half the cost of replacing the groin.

“We are concerned about the possibility of collapse, and further delay,” DLNR said, adding that in the interim it would proceed with project planning and design.

Waikiki Improvement Association President Rick Egged said the related Waikiki Beach Special Improvement District Association is concerned that the wall could collapse during the wait. Given the situation’s urgency, members agreed to cover half the rising costs, Egged said.

Failure of the groin, which experts say could occur any day, could send 1,730 feet of sandy shoreline east of the structure into the ocean. That would make Waikiki and its coastal structures more vulnerable to high waves, storms or tsunamis.

It’s also a liability issue since the nearly century-old groin is made up of stacked blocks of concrete, and some of the grout has washed away, creating hand- and arm-size openings. There’s also some risk that it could topple since the sandbags buttressing the Ewa side of the structure have deteriorated.

Eversole said further deterioration of Waikiki Beach could trigger losses of more than $2 billion in annual visitor spending. The state Department of Business, Economic Development and Tourism estimates that Waikiki tourism contributed $5.5 billion to the gross domestic product, a nearly 7 percent share, in 2016, the most current data available.

Not all visitors to Waikiki are “beach people,” and the destination’s attributes go beyond its sandy shores. But there’s no denying that Waikiki beaches are a top visitor consideration.

“The beach is what we came for — its importance is 100 percent,” said Fran Wallace, a visitor from Australia’s Gold Coast who was soaking up the sun Thursday near the sea wall. “If you didn’t have Waikiki Beach, it would wreck tourism for you guys.”