| Volcanic eruption sparks water officials to rethink how to rebuild
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Volcanic eruption sparks water officials to rethink how to rebuild

Kilauea volcano eruptionWhen the Kīlauea volcano on the Big Island of Hawai‘i first started erupting in 2018, water crews scrambled to keep in front of the damage.

Bypass for lava flowLava first flowed underground, creating fissures in the land and gasket-melting subsurface temperatures, and broke the ductile iron pipe buried below Pohoiki Road. 

Crews rigged up a bypass (pictured left), looping a temporary pipe from one hydrant to another to keep water flowing. 

“That success story didn’t last too long though,” said Keith Okamoto, manager-chief engineer of the County of Hawai‘i’s Department of Water Supply. 

“Because the lava kept coming.”

And coming. In 2018, Hawai‘i’s most active volcano, Kīlauea, had a series of eruptions in the east rift that caused lava to flow from May to August, steamrolling 700 homes in the Puna district and melting water infrastructure in its path. 

“You really cannot mitigate against lava. You cannot harden infrastructure against lava like you can with hurricanes or high winds or flooding,” Okamoto said. “With a lava event, it comes, it lasts for a while, and then it re-creates the whole environment.”

Eruption view from helicopterThe eruption destroyed 14.5 miles of pipe and rendered two above-ground reservoirs useless. Officials estimate the eruption caused about $40 million in damages — close to the water department’s operating budget for an entire year.  

“I remember flying in a Blackhawk helicopter at the time to survey the damage, and to see Mother Nature at work, destroying, but also creating, was something unique to our island,” he said. “I’ve been with the department for 25 years, and I’ve never seen anything like that.”

Recovery plans underway

The county’s water department serves roughly half of the Big Island’s 200,000 residents through 23 individual water systems. The remaining residents are supplied by private water service, wells or individual water catchment systems. The Kīlauea eruption cut service to about 200 accounts, which was a portion of one of the department’s water systems.  

Now the utility is sorting through what makes sense to repair and rebuild and what should be left to Mother Nature. The utility will receive $30 million in Federal Emergency Management Agency (FEMA) funds to support water infrastructure improvements and is working with the community to prioritize projects, which will go before FEMA for approval this spring.

Keith OkamotoIt’s a big, fuzzy crystal ball, as Okamoto said, because the department does not know how many residents will return to the area most impacted by the eruption. Many may participate in the county’s voluntary housing buyout program, an effort to relocate people away from high-risk lava zones. If that happens, the water department will have to balance the expense and potential water quality issues with the need to rebuild water infrastructure in an area with a smaller population than before. 

“What makes the most sense when reinvesting in infrastructure in an area that people may not return to?” he said. 

One community priority is the effort to rebuild the Pohoiki Boat Ramp, which many fishermen and women in the area rely on for their livelihoods. That would require a $6 million water line that would cross a high-risk rift zone, still boiling with pipe-damaging subsurface temperatures. 

“There are no standards for installing pipe in hot lava,” Okamoto said. “We’re in uncharted territory. How can we dissipate heat so gaskets won’t melt? It’s highly unlikely that we can do buried line in trench because it retains the heat. It may have to be some open type of installation with boulders to help dissipate the heat.”

Lava impacting water linesOkamoto, a member of the American Water Works Association since 1997, said he’d “welcome any creative thoughts on how to deal with elevated subsurface temperatures.” He can be reached at dws@hawaiidsws.org.

In other proposed repair projects, engineers will have to redesign old plans to account for new topography.

“There are some areas that are buried under 100 feet of lava now,” he said. “Whatever pipe we had there is more than 100 feet from surface. Of course, we can’t repair that. We’ll have to lay new pipe on the ground, and hydraulically, we’ll have to see if that’s going to work.”

Emergency underscores importance of communication 

Okamoto said his department learned plenty during the 2018 eruption, but most important was to stay in close contact with emergency response managers. 

“Communication is key. Things are happening always, continuously, and it’s not just water, it’s roads, it’s infrastructure, electricity, which all work together. If electricity goes out, our wells are impacted. If roads go out, our ability to access our infrastructure is impacted.”

And the chief engineer acknowledged that wherever humans are involved, you’ll be met with surprises. 

“Engineering is straightforward; it deals with physics and standards,” Okamoto said. “One thing you cannot predict is people. Their reactions, their desires, their needs. Some people say, ‘I’m not coming back. That was the last straw.’ Others say, ‘I don’t care if it’s still black lava, I’m determined to return.’ Navigating that is quite interesting, quite challenging. 

“Weighing all those different human components is the tougher challenge.”

(Photos courtesy of County of Hawai‘i’s Department of Water Supply)