The benefits and drawbacks of having Honolulu’s next solid waste landfill located in Central Oahu were highlighted at the state Capitol this week.

Two joint Legislature committees held an informational meeting over the city’s plan to site its dump on Dole Food Co. Hawaii property near Wahiawa.

That site — meant to allow the city to continue to handle the island’s estimated 225,000 tons of solid waste and related materials it puts into its landfill each year — was first announced by Mayor Rick Blangiardi on Dec. 10.

At the Capitol, city Managing Director Mike Formby, city Environmental Services Director Roger Babcock and ENV Deputy Director Michael O’Keefe offered reasons to have the next dump on Dole lands.

In part, the trio said it was due to a state-imposed Dec. 31 deadline to find an alternate site, ahead of the planned closure of the 35-year-old Waimanalo Gulch Sanitary Landfill in Kapolei, in accordance with a 2019 decision and order by the state Land Use Commission.

That West Oahu dump is set to close in 2028, though the landfill will not reach full capacity until 2032, the city said.

Conversely, Board of Water Supply Manager and Chief Engineer Ernie Lau noted a landfill not properly sited on the island posed a significant public health and safety risk, as it could affect the potable water supply of Oahu’s underground aquifer.

BWS must evaluate the proposed landfill site and, based on its proximity to potable water sources, may approve or reject the proposal.

Previously, BWS objected to the city siting a landfill within its so-called “no-pass zone,” an area that covers the interior of the island where Oahu’s potable water aquifer is located.

The city’s proposed landfill location — identified as “Area 3, Site 2” in the city’s 2022 Landfill Advisory Committee’s recommendation report — is on agricultural land to the west of Kamehameha Highway, north of Paalaa Uka Pupukea Road, the city said.

The city hoped to negotiate purchase of about 150 acres — the amount of land needed for a solid waste landfill — out of what it described as an approximately 2,360-acre parcel now owned by Dole, according to Babcock.

“Ninety acres of that is the actual landfill,” he said at the Tuesday meeting. “And the remaining area is for a little bit of a buffer zone as well as storage for equipment, a place for trucks to get off the road, a scale house, etcetera.”

Dole has publicly stated opposition to the city locating a landfill on its actively used agricultural lands.

Still, Babcock explained that the new landfill — planned for about 800 feet above the island’s aquifer — also offered protections against leakage.

He noted the dump site will have “required monitoring wells in the groundwater to detect any unlikely leak” or contamination.

“And most importantly, the liner system,” he said, “and the leachate collection system, which together prevent the escape of contaminants from the landfill and prevent contamination of underlying groundwater.”

He added that U.S. landfills require “a dual-liner system that consists of both a thick plastic geo- membrane … and it also includes a clay liner.”

BUT THE city wants the state Legislature to change a state law, too.

Babcock explained the city’s desire to “relax” restrictions under Act 73, which governs where a landfill can legally and safely be located in order to achieve a new, permanent landfill location on Oahu.

The 2020 law places restrictions on locating waste-disposal facilities, particularly those close to conservation lands or half-mile “buffer zones” near residential areas, schools or hospitals, as well as near airports or tsunami inundation zones.

Babcock said amending Act 73 could do one of two things: reduce buffer zones down to a quarter-mile or eliminate them altogether, thereby opening up more lands for potential city dump sites.

Such a legislative change could take time, however. “If that is unsuccessful, then it would be necessary to extend the operations at the Waimanalo Gulch Landfill,” he added.

But BWS’ leader expressed his strong reservations over the safety of a landfill being sited above the island’s “freshwater resources.”

“Landfills contain contaminants that can enter groundwater if it leaks out of a landfill,” Lau said. “And that leachate is actually pretty contaminated” rainwater.

He said “landfills, once constructed, are permanently there.”

But cap rock — an area of hard, impervious rock — also rings around Oahu’s coastline like a protective barrier, he added.

“The cap rock is a very important geologic feature here because that’s the basis of why the Board of Water Supply over 40 years ago decided to create a ‘no-pass’ area on our island,” Lau said. “Because that cap rock along the coastal areas helps to protect and keep the freshwater inland, and helps to keep large capacities of freshwater inland in these underground, volcanic aquifers.”

“And the cap rock is where we would recommend that landfills be considered if they had to be put in,” he said.

Noting a U.S. Geological Survey study conducted in 2003, Lau added that all landfills eventually leak — often dispersing into the environment harmful chemicals like arsenic as well as PFAS, or so-called “forever chemicals,” linked to illnesses like cancer.

He also noted that USGS’ 1999 “Ground Water Atlas of the United States” showed that groundwater underneath the proposed Wahiawa dump site flows downward, in directions toward Waialua, Mokuleia and Kawailoa.

“If leachate were to leak from this area, it might head toward the Waialua-­Haleiwa area, and might impact the aquifer down there,” Lau said. “So the contaminant plumes would potentially move to the north.”

During the joint meeting of the House Committee on Energy and Environmental Protection and the Senate Committee on Agriculture and Environment, legislators questioned the city’s overall plans for the new landfill site as well as potential changes to Act 73.

Among them, state Sen. Mike Gabbard, chair of the Senate’s committee, asked, “Who has the final say, the Board of Water Supply, City Council, the mayor? Where does it end?”

Formby replied the city has set out a plan “to exhaust as many options as we could, respecting the rule of law.”

The city, he added, has not “formally made a recommendation for this proposed site to (BWS) yet.”

“Right now the mayor firmly believes that the city and county can site a landfill over the aquifer safely,” he said. “Whether or not that gets challenged, and (Chief Engineer Lau) might write us a letter and say, ‘For your specific proposal, I say ‘no,’ in which case, we would appeal that to the (BWS’ board of directors).”

“And the board then has the ability to actually override the chief engineer, which would then give us a green light for this proposed site,” said Formby. “We’re just not there yet.”

Gabbard also asked, “I’ve heard that Dole is not real excited about selling that land. … Is that true? What’s the latest?”

“Our understanding of what Dole has said is that particular, specific location that we have identified would affect their operations,” Babcock replied. “But at the same time they did say that they have other land that they have for sale … so that’s a pretty good indication that they’re interested in talking with us and to find a solution.”

After the meeting, Dole Hawaii General Manager Dan Nellis said his company believes the city’s proposed landfill on its Wahiawa property is “untenable.”

“Particularly because it is right in the middle of our pineapple fields,” he told the Honolulu Star-­Advertiser by phone, “and it would create extreme hardship on us, operating our farm.”

Nellis confirmed Dole does indeed have other parcels for sale. However, he said the city hasn’t approached his company regarding those available lands.

“I just told them initially, ‘Hey, why are you asking to go into our land that we’re farming when we have other land that we’re not farming that is for sale?’” he said, adding the for-sale properties are not far from the proposed landfill site. “They’re pretty close, about a mile away.”