Hawaii study identifies coastal roads vulnerable to erosion

WAILUKU, Hawaii – A study of the 20 coastal highways in Hawaii most susceptible to erosion and structural degradation has found 10 of the roads are in Maui County, officials said.

Researchers at the University of Hawaii at Manoa determined Maui and Molokai each had five of the roads considered most at risk, The Maui News reported Tuesday.

The report prepared for the state Department of Transportation ranks the susceptibility of state coastal roads to ocean hazards such as waves, currents, tides, and sea-level rise.

The study is intended to prioritize areas in need of protection from coastal erosion. The modeling and analysis assist the transportation department with a strategy to maintain connectivity of current roadways, said Deputy Director for Highways Ed Sniffen.

The university report recommends actions such as relocating, elevating or hardening that will be analyzed by the department and presented to community members. Transportation officials anticipate a timeline for analysis of about two years, Sniffen said.

A stretch of highway in Hauula on Oahu has the highest erosion risk, while a portion of Honoapiilani Highway on Maui ranked second in vulnerability. The Maui site at Mopua had the highest erosion susceptibility index rating among the 20 ranked highways statewide, the report said.

The cost to protect the areas on the list could reach $15 billion, Sniffen said.

Sea levels in Hawaii have risen 0.6 inches (1.5 centimetres) per decade over the past century, according to the University of Hawaii School of Ocean and Earth Science and Technology. Sea levels are expected to rise more than 3 feet (0.9 metres) by the next century.

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Information from: The Maui News, http://www.mauinews.com