A new Oʻahu landfill will be placed northwest of Wahiawā on a pineapple field currently owned by Dole Food Company. It will replace Waimanalo Gulch on the leeward coast.
The city had until the end of the year to select the new location as the state Land Use Commission ordered Waimanalo Gulch to close by 2028.
Waimanalo Gulch landfill has been in operation since 1989. West Oʻahu also hosts the private construction and demolition landfill PVT, which is slated to close in the next five to 10 years. The new Oʻahu landfill will then need to absorb that trash as well.
Currently, most of the waste that goes into Waimanalo Gulch is ash from H-POWER, Oʻahuʻs waste-to-energy incinerator, and is then covered by dirt daily.
The city was considering several sites that complied with the state law known as Act 73, which prohibits landfills from being located on conservation land and requires them to maintain a half-mile boundary from any school, residence and hospital.
Opposition to the Wahiawā site
However, the Landfill Advisory Committee in 2022 urged the city not to select the Wahiawā location because it sits above Oʻahu’s aquifer system — the source of the island’s drinking water.
The Honolulu Board of Water Supply has previously come out against the location. BWS Chief Engineer Ernie Lau said he looks forward to receiving more information from the Department of Environmental Services but warned against any actions that could threaten Oʻahu’s drinking water.
“ We did make comments two years ago actually not approving the location of landfills above our drinking water aquifer in accordance to our rules and regulations,” he said. "My focus is very narrow. We need water for life. Ola i ka wai, ka wai ola. Potential threats to our water resources – of course, you know where I'll be coming from.”
Environmental Services Director Roger Babcock explained that there will be safeguards in place to protect the aquifer.
"Based on all this, we’re 100% confident that we can design and operate the next landfill on this site and ensure protection of the underground aquifer from contamination, as well as protect the communities and businesses in central Oʻahu," he said.
The new landfill will have two, two-liner systems to prevent the passage of water, which is called leachate. Those systems consist of one liner of plastic, impermeable to water and then another clay liner.
There will be a chamber where the leachate is continuously collected and pumped to the surface to the wastewater plant. Babcock explained there will be a second system underneath it as a safeguard if the first system fails.
“ We'll be installing a system that will allow us to continuously monitor the integrity of the liner system and if a problem is ever detected, we would be able to take corrective actions,” Babcock said.
Honolulu Councilmember Matt Weyer, who represents the Wahiawā area, was concerned about the mayor’s location choice.
“ I'm disappointed and concerned and the decision again, this isn't a district-specific issue. This is an island-wide issue and protecting our drinking water should be our top priority," Weyer said. " I do have concerns when we throw out numbers like 100% sure. Because when we look at just the potential impacts, we want to be transparent and honest with the community."
Next steps for building the landfill
State Sen. Brenton Awa, who also represents the area, said the new landfill could be an opportunity to get more green waste disposal for people who live near there.
“ We don't look at this as a negative,” Awa said. “We look at this as like, what’s possible and how can we use this piece of land to solve some community problems.”
At a press conference Tuesday, Mayor Rick Blangiardi acknowledged that there were no universally accepted sites to place the landfill.
"If there was a path that the whole island supported, then that is the path that we would have chosen," Blangiardi said. "But it wasn’t that simple because the path simply does not exist."
For the past few months, the city has considered several sites that violated Act 73 and was exploring trying to get the state law amended to use one of those locations instead of those that are above Oʻahu’s aquifer system.
City Managing Director Mike Formby said they have been talking with state legislators about the topic, but did not make a firm decision on whether they would continue pursuing an amendment to the state law.
In the past, the city said it would take at least seven years to close Waimanalo Gulch and open a new landfill, but Babcock said it may be possible to meet the 2028 closure deadline.
“ Nothing has changed, so we're on record with the Land Use Commission for those numbers… that on average it takes quite a few years in order to open, construct and open and permit a new landfill,” Babcock said.
“ But those, those are just numbers. Assuming everything goes smoothly with purchase and with construction. It is a very easy site and has good access. It's theoretically possible that it could happen, but at this point, we really don't know. There's too many unknowns to figure out what a better timeline is at this point.”
Previously, the city estimated that it would cost about $200 million to construct a new landfill. There were no estimates available for the cost of closing Waimanalo Gulch. Babcock said the city just awarded a contract to a consultant to evaluate all closed landfills on Oʻahu and what they could be used for in the future.
The city will next have to work on acquiring the parcel from landowner Dole Foods. Blangiardi said he has made initial contact with the company’s "top guy".
William Goldfield, a spokesperson from Dole Food Company, wrote in an email Wednesday that the location was selected without Dole’s involvement or prior consultation.
“The planned location near Wahiawā directly impacts Dole’s primary pineapple farming operations, posing significant challenges to both state agricultural priorities and our business,” he said. “Dole is committed to collaborating with city officials to explore more suitable options.”
Babcock said the city will begin in-depth discussions with Dole on the site and other portions of their properties that are suitable.
"If the discussions do not result in a willing sale, the city will determine whether or not to pursue an eminent domain purchase," he wrote in an emailed response.
