Disappearing highway in Hauula a stark example sea level rise perils

Colllapse of portion of highway in Hauula latest example of sea level rise impacting infrastructure.

HONOLULU, Hawaii (HawaiiNewsNow) - The part of Kamehameha Highway that collapsed in Haaula late Friday was considered the no. 1 hot spot for erosion that affects a roadway.

Honoapiilani Highway on Maui, where high tides and surf have become a growing threat, is the no. 2 two spot.

That’s according to the 2019 statewide coastal highway report, which examines roads under threat of seeing impacts from sea level rise and erosion.

For Hauula, there’s $600,000 of emergency repairs to 1,500 feet of the highway.

Proposed solutions include elevating the highway by 9 feet, or moving the road inland — which could cost up to a $1.5 billion for just a 12-mile stretch.

“So it’s a huge but complex situation that we have to consider. Not only are we affecting who can drive through that area in the future, but access to that area in the future,” said Ed Sniffen, DOT Highways Division deputy director.

Josh Stanbro, the city’s chief resilience officer, said from rising seas to fires and hurricanes, climate change is happening at a faster rate.

“By 2100, which is only 80 years away, we are going to have at least 3 feet of sea level rise,” he said.

"The scientists are saying that it's moving faster than we ever though it would and we should be planning for maybe 6," he added.

That’s 6 feet of sea level rise, which could inundate Hawaii coastlines.

State and city experts say the planning is happening, but one solution has generally fallen out of favor.

"In the past, we put up sea walls to harden those areas. We found when we put up those areas. We generally see erosion on the outside. We don't want to do that anymore," said Sniffen.

Added Stanbro, “I think the community has to understand if you put up a sea wall, you lose a beach."

Copyright 2020 Hawaii News Now. All rights reserved.