FL MORRIS / FMORRIS@STARBULLETIN.COM Erosion seen yesterday at Kailua Beach Park is undermining some of the ironwoods, and the lifeguard stand foundation has fallen onto the beach.

Trees at risk

At least half a dozen large ironwood trees could topple from erosion at Kailua Beach Park, experts warn.

Erosion at arguably one of the most beautiful beaches in the world has caused major root exposure from the ironwood trees near the dunes. It also forced lifeguards to relocate their tower inland.

"If the erosion continues, at some point, those trees will fall over," said University of Hawaii coastal geologist Charles "Chip" Fletcher.

A combination of a big-wave event that occurred several years ago and the ongoing sand dredging of the adjacent Kaelepulu Stream by the city might be catalysts for the erosion, Fletcher said. The average erosion rate for Kailua Beach is now 3 to 4 feet per year, he said, noting that strong winds could make the situation worse.

He recommended the trees be removed so the sand underneath can replenish the coastline.

City spokesman Bill Brennan said the city is regularly checking the condition of the trees.

"If any present a potential safety hazard, we would likely cut the top off," he said. "Leaving the roots helps prevent further erosion."

That was done with one of the ironwoods near the shore within the past year.

Meanwhile, a toppled concrete slab that served as the lifeguard tower's foundation remains embedded in the sand at its original site. Last spring, lifeguards relocated the tower farther inland because of the receding shoreline.

It hasn't stopped there.

Just a few weeks ago, lifeguard Keith Halemano said they were forced to remove the tower's ramp because only three feet of sand remained in front of the ramp to the edge of the sand cliff.

Now, lifeguards use a ladder to gain entry into the tower.

Longtime resident Joe Gilman, who lives next to Kailua Beach Park, said major erosion has occurred in the area just in the past year. As a child, Gilman said, he could see the ocean from the street level. Now, the view is obscured by dunes.

"It's 10 to 12 feet high," he said as he pointed at the sand dune at the beach park from his property. "Exponentially, it just gets worse and worse."

Winds easily blow the white, powdery sand, Gilman added.

Sam Lemmo, administrator of the Department of Land and Natural Resources' Office of Conservation and Coastal Lands, said Kailua Beach Park is going through a serious erosional phase. "As a result of that, it's going to take some trees with it."

Will Ho, parks superintendent for the Windward District, said there was an effort to move sand to eroded parts of the beach, but concerns raised by some residents caused the city to put a halt to the sand replenishment work. "More sand is leaving than coming back after the winter season," Ho said.

The Department of Health had some concerns about the sand from the mouth of Kaelepulu Stream going back into the ocean, said Brennan.

A member from the Kailua Neighborhood Board complained in September about "turbidity and bubbling" at the boat ramp from the sand replenishment job, said Janice Okubo, spokeswoman of the Department of Health.

The city did not get the proper permits to meet standards of the Water Quality Act, she said. The city can continue with the sand replenishment work as long as they apply for the permit, Okubo said.