Twenty miles from Honolulu, on Oʻahu’s cool central plain, the former plantation town of Wahiawā – best known for its fertile agricultural land – recently gained the dubious distinction as the site selected by the City & County of Honolulu for a new landfill.
Since the proposed site was announced last December, concerns have been raised about the location by residents, legislators and the Board of Water Supply.
In 2019, the State of Hawaiʻi Land Use Commission ordered the closure of Waimānalo Gulch Sanitary Landfill (WGSL) in West Oʻahu by March 2, 2028, due to concerns about its environmental impact and the need to reduce waste diversion in the area – for decades, West Oʻahu and the Waiʻanae Coast have unfairly borne the brunt of Oʻahu’s waste management “strategy.”
The selected 150-acre Wahiawā site is 800 feet above an aquifer. Those opposed to the site are concerned about the potential contamination of Oʻahu’s drinking water.
“We are 100% dependent on groundwater or underground sources of fresh water to serve our need for drinking water,” said Honolulu Board of Water Supply Manager and Chief Engineer Ernie Lau. “Groundwater and underground aquifers are vital to our survival.”
Lau explained that leachate (contaminated water), generated by rain falling through waste in a landfill, is a huge concern.
“Leachate can leak out of the [landfill] containment systems,” Lau said. “Landfills are permanent features, so once you put it there, fill it up, and cap it, it’s there forever. [But a] containment system may not last forever. At some point, it may start to leak leachate. And as it leaks, gravity will pull it down and rainfall will help drive it further down, deeper underground, until it hits the underground aquifer.”
Sharing this concern, some state lawmakers have introduced bills during this current legislative session to prevent landfills from being built over aquifers.
Councilmember Andria Tupola was shocked to hear the announcement and to have been excluded from discussions that led to the decision. “I think everybody was shocked that it was in Wahiawā and the second shock was when they specifically said they were going to put it on ag land,” she said. “Third, it was a shock because we don’t own the property. How in the world are you going to announce a site that we don’t have jurisdiction over, and the landowner had not even been engaged yet?”
Contamination of Oʻahu’s precious fresh water reserves resulting from the Red Hill fuel spill in 2021 is still fresh in our collective memories so the location of the selected landfill site above the aquifer is especially concerning. The Hālawa Shaft, which provided 20% of Oʻahu’s drinking water, was shut down in 2023 due to contamination concerns and remains closed.
“Out of everything that needed to be considered for this landfill site, I thought that the first would be the aquifer,” Tupola commented. “The whole thing about public hearings is that we would have been able to weigh out this decision, and to see the priority order and how the decision was made. We have a finite amount of land on this island, so it would have been cool to announce that there’s an interim site but our push is going to be towards not landfilling anymore.”
Lau said when making decisions like this we must look ahead 100 years or more.
“There’s a saying about ‘looking seven generations ahead’ and that is what we need to consider because our decisions today can affect the lives of the people that haven’t been born – and then they will have to deal with the problems,” he said.
“This landfill is projected to have capacity for the next 20 or 30 years. So, then the question becomes, where do you place the next landfill? And the next?
“We can’t keep putting landfills above our only source of fresh water. That’s not sustainable,” Lau reiterated. “The solution to how we manage our ‘ōpala is not an easy problem [to solve]. And it’s not just the city, the mayor, or the department of environmental services. We, as an entire community, have to be part of the solution.”
Oʻahu has a resident population of about one million and about 115,000 tourists roaming around on any given day. Already, 26% of the island’s land is considered “urban” with only 33% zoned for agriculture and 41% for conservation. Thus, the appropriation of agricultural land located above an aquifer for a landfill that may or may not leak in 30 years is both reckless and short-sighted.
Given Hawaiʻi’s finite land resources, 21st century solutions to waste management need to be adopted.
Solutions could include more aggressive recycling programs, organic waste composting on an industrial scale, or waste to energy incineration. How we manage our waste today needs to take future generations into consideration.
As a stop-gap solution, residents of Wahiawā and state officials have also proposed revisiting conversations with the U.S military to offer land currently under their jurisdiction instead of moving forward with the current proposal.
The next public meeting on this issue will be before the North Shore Neighborhood Board on March 25.
