Series of coastal engineering projects underway amid race to save Waikiki Beach

Series of coastal engineering projects underway amid race to save Waikiki Beach
Three months after a sandbag groin was installed, the DLNR said the project is performing well so far. (Source: State Department of Land and Natural Resources)

HONOLULU, Hawaii (HawaiiNewsNow) - A series of coastal engineering projects aimed at saving Waikiki Beach is underway, and one of the projects that kicked off three months ago is performing well so far.

The state Department of Land and Natural Resources said it is “very, very happy” with its 95-foot-long sand bag groin — made of 83, 10,000-pound bags of sand — installed in November to restore the coastline and slow erosion at Kuhio Beach.

“We developed a project in which we developed a small sandbag groin and then we took some sand and backfilled to stabilize that section of the beach where we were having an erosion hotspot,” said Sam Lemmo, of the DLNR Office of Conservation and Coastal Lands. “That project was completed several months and it’s been quite successful.”

But the $700,000 project comes ahead of an even bigger project to fix an erosion hotspot that will launch next month.

The more than $2 million project — proposed by the DLNR — will involve replacing the Royal Hawaiian groin with a stable, sloping rock groin, as well as pumping dredged sand in.

The existing groin — between the Sheraton Waikiki and Royal Hawaiian hotels — holds sand in place from the Kuhio Beach basins to the groin. But it is nearly 90 years old and teetering on the brink of deterioration.

Without the groin, the sand would erode very rapidly, experts say.

Dolan Eversole, Waikiki Beach management coordinator, said the Royal Hawaiian groin replacement project is an important first step in saving Waikiki’s crowning jewel: its beach.

Work on a major groin replacement project is set to kick off in March.
Work on a major groin replacement project is set to kick off in March. (Source: Hawaii News Now/file)

He’s among a team of scientists working to save the beach.

"One of the overarching goals with a lot of the work that's happening in Waikiki is one, to maintain a viable beach, a sand beach resource in Waikiki," Eversole said.

Many don’t realize that Waikiki is an extensively developed beach with a history of coastal engineering projects that began in the 1930s to the 1950s.

The 2-mile-long shoreline, separated by several smaller beaches, is dotted with man-made structures ― from seawalls and groins to piers and storm drains.

Much of the sand, too, is imported from various sources. But structures built to widen Waikiki Beach are now part of the problem.

The hardened shoreline structures, sand hauling, and dredging and mining of the reef have significantly altered the dynamics of the coastline — and in turn have accelerated coastal erosion and actually contributed to beach narrowing.

What that means is that without consistent maintenance and management, erosion would ultimately swallow up Waikiki's beach.

[Read more: Major project begins to tackle erosion hotspot on Oahu’s most famous shoreline]

Another looming challenge remains: Sea level rise due to climate change.

As coastal erosion is already a problem for this highly engineered beach, Eversole worries that sea level rise will not only expedite erosion, but it could flood Waikiki's streets and infrastructure.

“In that 20-plus year timeframe, we’re going to need to look carefully at our infrastructure throughout Waikiki — not just along the shoreline, but along the Ala Wai Canal and everything in between,” Eversole said.

“And what is underground now may need to be re-engineered so that it’s watertight or elevated so it’s not underground anymore because that will continually be wet.”

Lemmo said sea levels have risen 9 to 10 inches over the past century — and have posed a major problem for Hawaii’s beaches, especially Waikiki Beach.

“It has a profound impact on the viability of our beaches and you gotta bring sand into these areas, especially here because this is not a natural beach — we created it and really need to maintain it in the same way you would maintain a road for instance,” Lemmo said. “You gotta keep investing money in maintaining and upkeeping amenities if you want them to perform satisfactory.”

Eversole said without these maintenance projects, we run the risk of losing Waikiki’s beloved beach.

“I think there’s pretty much a universal agreement that having a sand beach in Waikiki is not only desirable but it’s crucial for the future of Waikiki as a resort destination.”

A 2016 study funded by the Waikiki Beach Special Improvement District Association and produced by several University of Hawaii programs found that more than half of mainland and Canadian visitor and about 14% of Japanese visitors wouldn’t flock to a Waikiki without a beach.

Rick Egged, president of the Waikiki Beach Special Improvement District Association, said there’s also an economic incentive to preserve the beach. Hawaii could lose $2 billion worth of annual sales due to severe beach erosion.

But Egged recognizes that Waikiki Beach is not your typical beach. It takes manpower to keep it going.

“If you just look at it from a standpoint of … because it’s man-made, it requires more maintenance than if it were not,” he said.

Lemmo said all this work that’s underway is vital to ensuring Waikiki — and Hawaii — remains a major tourist destination.

“People come to Hawaii to visit our beaches and to enjoy our water, our coral reefs, our mountains,” he said. “This is just one component of an overall strategy to make sure we can give people what they pay for in terms of visiting us, enjoying our resources, enjoying our aloha.”

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