‘ALIOMANU — Erosion along ‘Aliomanu Road has been a longstanding issue as the street that runs along the bay loses more and more of its beach.
In 2007, the county began shoreline-erosion control, with sandbags placed strategically to save the one-lane road.
Wednesday, county Department of Public Works Acting County Engineer Troy Tanigawa spoke to the County Council on other temporary measures and a possible permanent solution.
“The temporary repair is coming up again because the erosion has been expanding,” Tanigawa said. “It’s been moving farther east from the prior erosion area that has been fortified with sandbags.”
Tanigawa said there’s an additional 75 to 100 feet of erosion area the county wants to protect by these temporary measures before a permanent solution can be implemented. The sandbags are filled with material from previously-completed, rivermouth-opening projects.
In May 2020, the state Board of Land and Natural Resources approved a Conservation District Use Application for a proposed sloped revetment, which DPW Chief of Engineering Michael Moule said is not a seawall. This would be the permanent solution.
“The idea behind that is to provide the best balance between protecting the road and not creating erosion down the shoreline, that we’re all aware I think vertical sea walls are very problematic with respect to that,” Moule said.
“A sloped revetment acts somewhat more like a natural beach although it’s obviously not a natural beach and is intended to reduce erosion.”
It’ll be made out of a 390-foot-long boulder sourced from the beach. After this, the road will be rebuilt.
“What you’ll see on the surface of the slope will be natural stone boulders,” Moule said.
Councilmember Felicia Cowden walked the area Tuesday, prior to the meeting, and noted fresh signs of erosion and torn-up sandbags.
Sandbags can cause nearby erosion, but Moule said he was unaware if the ones in this area were the cause for more erosion.
Both Cowden and Councilmember Luke Evslin expressed concern about the county justifying prolonging the lifespan of the road against erosion, and the issues that can come with it.
“My big ongoing concern here is that, inch by inch, you end up protecting, protecting more and causing greater issues on the flank,” Evslin said, offering a hypothetical situation where this solution could cause erosion elsewhere.
“We’re going to end up tumbling into all of these tremendous problems over time with sea-level rise that is an inevitable and obviously-overwhelming problem. I support this as a potential — not terrible — solution.”
The project is subject to 32 conditions, including to not create more erosion near the project area.
A previous, emergency, temporary-shoreline protection was approved in October 2015, with amended work approved in March 2017, according to a letter from the state Department of Land and Natural Resources to the county.
In 2015, the BLNR approved the placement of four sandbags along the erosion bank. The county requested, in 2017, an additional 10 more sandbags along 3 feet of the shoreline. A condition of the project is that a temporary measure is only used for three years from the date of issuance.
The county has proposed a repair timeline that sets the completion date for August 2022.
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Sabrina Bodon, public safety and government reporter, can be reached at 245-0441 or sbodon@thegardenisland.com.
Source: The Garden Island
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