Long-term solution for erosion along Kamehameha Highway won't co - Hawaii News Now - KGMB and KHNL

Long-term solution for erosion along Kamehameha Highway won't come cheap

Image: Hawaii News Now Image: Hawaii News Now
Image: Hawaii News Now Image: Hawaii News Now
Image: Hawaii News Now Image: Hawaii News Now
Image Source: State Department of Transportation Image Source: State Department of Transportation
Image Source: State Department of Transportation Image Source: State Department of Transportation
NORTH SHORE, OAHU (HawaiiNewsNow) -

The state finished repairs Wednesday to a portion of Kamehameha Highway in Kaaawa damaged by big waves last week. New concrete was poured to replace a section of the road that fell into the ocean, and a new guardrail was installed.

While the fixes were extensive, they're only stop-gap measures.

And they pale in comparison to the cost and scope of a long-term solution for Kamehameha Highway, which butts up against the ocean along much of the North Shore coastline and faces threats from beach erosion, rising sea levels and severe weather events.

Panos Prevedouros, chairman of the Civil and Environmental Engineering Department at the University of Hawaii at Manoa, estimates fixing the problem will cost a "minimum of a hundred million per mile."

That’s roughly $1 billion for the 10 miles of thoroughfare, which is the only way in and out for North Shore communities.

The state Department of Transportation hasn't made clear what it's long-term fix for Kamehameha Highway will be.

A spokesman told Hawaii News Now on Wednesday that unspecified work scheduled to begin in three years is being expedited to start next year. The state had no specifics on how it will address the situation.

But, as Prevedouros noted, there aren't many choices.

"We have at least three options: Take the road inland, leave the road as is but lift it by 10 feet, or expand the shore as an arrangement like jetties like they have in Ko Olina," he said. 

All of the options have pros and cons. And obstacles abound.

"Challenging topography, distractions of agriculture, distractions of homesteads," Prevedouros said.

Prevedouros favors a series of jetties and lagoons, but it's unclear what the environmental impacts of such a plan would be.

Part of the Transportation Department's process will be soliciting public input.

Until that happens, the state will employ short-term measures to keep the roadway operable. One short-term fix: "Basically, drop boulders," Prevedouros said. "Concrete or other boulders so essentially the ocean hits the boulders and not the road."

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