One phase of work on the Waipi‘o Valley Road is over, but the rest is still a long way off.
The county Public Works Engineering Division announced last week that the first phase of rockfall mitigation measures on the Waipi‘o Valley Road is complete after about a month of work, but the next two phases are still in such early development that a timeframe for when they might start is still unknown.
The three-phase plan was announced last year after the county closed the road to all non-local traffic following a geotechnical evaluation that determined that the risk of rockfall was too great to allow public access. Although the county pulled back on that restriction after a lawsuit and now allows Big Island residents and some commercial tour operators to drive on the road, much of the cliff face above the 1.4-mile road is still unsafe.
Public Works Public Information Officer Sherise Kana‘e-Kane said the second phase of the project could take several different shapes, each of which would require different schedules and costs.
“If we just do the hazard mitigation, that’s one thing and it’ll be done in a certain amount of time,” Kana‘e-Kane said. “But if we add drainage work to Phase 2, or if we extend the road, then that’s going to extend the timeframe too.”
But regardless of which option the county chooses, Phases 2 and 3 are anticipated to be much more elaborate than the first phase.
The first phase of the project began May 22 and primarily focused on removing hazards along the uppermost 750 feet of the cliff face over the road, such as trees, vegetation, and “scallops” — parts of the cliff face that have been undermined to the point that rocks distinctly protrude. Daily road closures were implemented between 8:30 a.m. and 4:30 p.m. to protect users from falling material.
According to plans drafted by Honolulu geotechnical firm Haley and Aldrich last year, Phase 2 would do the same work for the next 1,300 feet of cliff face, but would be divided into four subphases, each focusing on different sections of the cliff. It will also install metal meshes along the cliff in order to contain rockfalls.
Phase 3 will install further rockfall fencing higher up the slope. Both Phase 2 and 3 will require daily closures of the road as well.
Whether the road will be reopened to non-Big Islanders upon the completion of the final phase will be a decision for the mayor, Kana‘e-Kane said.
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.