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By Ken Ige, Star-Bulletin
The new section of highway at Waimea Bay includes
this buffer zone, between the cliff at right and the road
at left, to protect against falling rocks.

Geologists to rank
danger of rockslides
along Oahu roads

By Steve Murray
Star-Bulletin

The cliffs near Waimea and Makapuu are two of many potential rockslide areas on Oahu to be studied under a contract likely to go into effect this week.

The state Department of Transportation hired Earth Tech Inc. to identify all locations on the island where a possible rockslide could hit a highway or road.

Ardalan Nikou, lead engineer for the $290,000 project, said work will begin when the contracts are completed.

"Once we get the contracts we can start immediately," he said.

A rockslide at Waimea Bay on March 6 forced the closing of a stretch of Kamehameha Highway and divided the North Shore for two weeks until a temporary beach road was built.

A permanent replacement road, including fencing to block future rockslides, opened June 10.

Nikou said his company will group areas along Oahu's roadways into four categories based on the potential of slide debris coming into contact with the road:

Those sites graded "A" will be areas where almost all debris from a slide would land on the pavement. He said these areas are "definitely life-threatening."
Areas graded "B" will be those where a portion of rockfall debris would land on the pavement. Grade "B" areas are considered to be moderate slide threats.
Grade "C" areas would leave little or no rockfall debris on the pavement.
"No slope areas" is the final category and is used for flat areas with no slide potential.

The project will have four stages. The first will be to get background information about slide history and conditions from the state. The second part will be to identify the four categories for all highways and roads. During the third phase of the study, the staff will look in greater detail at the higher-risk areas. The final stage will be submitting the full report to the state.

Nikou will lead the project and will be helped by four Hawaii-based staff geologists. He said the entire study should take eight months.