KAILUA BEACH ERODING AT 'EXTREMELY HIGH RATE'
Sand erosion threatens ramp, parking lot at Kailua Beach
By Eloise Aguiar
Advertiser Windward O'ahu Writer
| |||
|
|||
|
|||
|
|||
| |||
| |||
|
|||
| |||
| |||
Melvin Kwiatkowski knew that the erosion at Kailua Beach Park had reached alarming proportions when he began finding coins like the 1944 "walking Liberty" half-dollar he uncovered last year.
"About a year ago we knew that the old sand was coming out because we were getting coins from the '20s," Kwiatkowski, 70, said last week while looking for metal at Kailua Beach Park. "The erosion was bringing out things that hadn't seen the light of day in 60, 70 years."
Kwiatkowski said another person found a silver dollar from the 1920s. "It's just coming out of these trees," he said, while exploring with a metal detector under an ironwood tree whose roots had been exposed.
Experts confirm that what's happening at Kailua Beach is extreme.
"The beach park (erosion) in the last couple of years has been as high as eight feet per year," said Chip Fletcher, a University of Hawai'i coastal geology professor who has studied erosion in the Islands extensively. "That makes it one of the highest rates in the state. It's an extremely high rate."
What's more, new areas are beginning to erode and areas that have been eroding are doing so at a higher rate.
At some spots entire chunks of land have disappeared, leaving sheer sand cliffs and precious little beach at all but the lowest tides. Dozens of trees and bushes have been claimed by the ocean. Irrigation water lines have been exposed and the beach's lifeguard stand may have to be moved for the second time in as many years due to erosion.
At the rate the erosion is taking place, it's not difficult to imagine that the Kailua boat ramp and its parking lot may soon fall to the encroaching sea.
Waves are undermining the boat ramp, collapsing asphalt on the side exposed to water, and the parking lot wall is now barely 50 feet from a dropoff that the ocean created on its inland sand grab.
Nearly 40 yards of shoreline at the boat ramp is gone.
Naupaka plants are falling into the ocean at high tide and the roots of ironwood trees are being exposed. When they become a safety issue, city crews chop the trees down and grind them up.
Two studies are under way that could help experts understand what's happening at Kailua Beach and how to handle the problem.
For the past couple of years, officials have been taking a wait-and-see approach, said Dolan Eversole, principal investigator for a project being conducted by the UH Sea Grant Program and the state Department of Land and Natural Resources.
The goal of the project is to produce a beach and dune management plan that will include recommendations and implementation strategies. An initial report is expected in about one year.
Fletcher has been collecting coastal erosion data for every beach on Maui, Kaua'i and O'ahu and expects to complete a study within two years. The goal is to be in a position to make better management decisions about Kailua Beach as well as other areas, he said.
Eversole downplayed the severity of the erosion at Kailua Beach for now, saying no major infrastructures are threatened.
"As it is now, there's no need to respond with emergency erosion control by dumping rocks or anything like that," he said.
However, he said, "We were hoping this cycle would recover naturally, but it doesn't appear that it's going to do that any time soon."
POSSIBLE CAUSES
Kailua Beach is a little more than two miles long, and the beach park is at the south end of the crescent-shaped bay. For decades the beaches on this bay were accreting sand, building wide beaches, Fletcher said. But that changed about three years ago when the sand started to erode at the boat ramp.
Locals who have lived in Kailua all their lives were not concerned at first, because in their experience the sand always came back.
But Bryan Amona, 55, who has fished at Kailua Beach Park all of his life, said the sand is not coming back as usual and more and more trees are being lost.
"That's the worse I've ever seen it," Amona said. "The beach came halfway out along the boat ramp. That boat ramp was never looking so long because there was a big beach. Now there's no beach there. You want to go to the beach, you have to go to Waimanalo."
Generally, the cause of beach erosion falls into one of three categories: manmade structures; waves and currents; and rising sea level, Fletcher said.
Seawalls, groins or anything that impedes sand movement could lead to erosion or accelerate it, he said.
Unusual storms can take away sand permanently, and then there are the seasonal changes in wind, waves and currents.
"All of these will change sand availability, take it away or deliver it," Fletcher said.
Sea level change will drive a beach landward or drown it, he said. But Kailua Beach hadn't been affected for two centuries because it has an excess of sand.
"It's even had so much excess sand that it has accreted seaward in the face of sea level rise," he said.
However, something has changed.
But figuring out what that is takes detective work, Fletcher said.
"Beach erosion doesn't come with a set of instructions," he said, but a unique contributing factor at Kailua Beach Park is the practice of clearing sand from the mouth of Ka'elepulu Stream that empties into the ocean at the park.
Sand collects at the mouth of the stream, blocking its flow and filling its bed inward for hundreds of feet.
City crews periodically open the mouth of the stream to prevent flooding. Fletcher said he's not sure what happens to the sand, but the federal Clean Water Act prohibits placing the sand back onto the beaches because it may be contaminated.
RECOVERY STRATEGIES
Eversole, with Sea Grant, said he's working to develop a memorandum of agreement to reuse the sand and allow the city to place "clean" sand on the beach at the boat ramp.
He said the city is placing the sand from the stream mouth onto the banks, making the dunes there higher, which in turn could be contributing to the erosion problem.
"We are working on various long- and short-term strategies and the short-term strategy is let's change the practice of stream clearing so the sand goes back on the beach," Eversole said.
Meanwhile, State Rep. Cynthia Thielen, R-50th (Kailua, Mokapu) has responded to the issue by introducing a bill that would place a temporary moratorium on building closer to the shoreline.
House Bill 593 was introduced and referred to the committees on Finance and Water, Land & Ocean Resources.
Thielen said she was motivated to propose the two-year moratorium by the erosion at the boat ramp and the building of a new home that was closer to the shoreline than the old dwelling it was replacing.
Experts have learned a lesson in Lanikai where people built too close to the shoreline, she said, thereby not allowing for the natural migration of sand on and off the beaches. When the water threatened property, people built seawalls and the seawalls have since been blamed for the major loss of beaches in Lanikai, she said.
Thielen predicted the same thing can happen on Kailua Beach.
"Then what happens?" she asked. "They get to put up a seawall."
Reach Eloise Aguiar at eaguiar@honoluluadvertiser.com.