On Tuesday, the City and County of Honolulu officially announced its selection for the site of Oahu’s next landfill: an area northwest of Wahiawā, which sits above the island’s water supply.
The selected site is on agricultural land owned by Dole Food Company, located to the west of Kamehameha Highway and north of Paʻalaʻa Uka Pūpūkea Road.
This decision comes after the Department of Environmental Services has been considering new landfill locations for over a decade. The site selection is limited by Act 73, a law passed in 2020 by the Hawaii State Legislature, which excludes using conservation lands for a landfill and requires a half-mile buffer between a landfill and residential properties, schools or hospitals. Other laws stipulate the site can’t be in tsunami inundation areas, in an airport flight path, on land zoned for development, or on federal lands, which are mostly owned by the military and would require approval to be used. And, in 2023, Honolulu Mayor Rick Blangiardi promised that the new landfill would not be located on the Waianae Coast, citing equity and operational impact.
In Sept. 2021, Blangiardi put together a committee to once again evaluate and select potential landfill sites. The location northwest of Wahiawā was one of six sites selected in the City’s Landfill Advisory Committee’s 2022 report, which are all above the aquifer. However, the Honolulu Board of Water Supply testified in 2021 that they did not support any site in the interior of Oahu, where the underlying groundwater aquifer is not protected from landfill contaminants by caprock.
During a news conference on Tuesday, Blangiardi noted that the Waimanalo Gulch Sanitary Landfill in Nanakuli — in operation since 1989 — is also above the aquifer, but has never leaked through its liner into subsurface soil and rocks.
“The City understands and acknowledges the public’s concerns and the absolute necessity to safeguard our island’s underground water supply aquifers against contamination,” said Roger Babcock, the director of the City’s Department of Environmental Services. “We will ensure aquifer protection by exceeding federal and state design standards for safe operations and regulations for monitoring solid waste landfills, building instead to a higher level of protection that would typically only be required for the creation of a hazardous waste facility.”
The City plans to use a multiple-barrier subsurface monitoring system to prevent the escape of pollutants from the landfill. The design of the landfill will need approval from the state Department of Health.
“We are extremely confident that we can operate a landfill safely over the aquifer, and by doing so, we are able to site our next landfill further away from where our residents live, where they take their kids to school, and where they receive medical care,” said Blangiardi.
Shortly after the press conference, House Representative Sean Quinlan, D-47 (Waialua, Haleiwa, Pupukea, Kahuku, Laie, Hauula, Waiahole, Sunset Beach, Punaluu, Kaaawa), sent a statement saying he was concerned about the selected site because it is above the island’s water supply.
“The City Administration's proposal to establish a landfill near Wahiawā presents a significant threat to the North Shore of Oahu's precious water supply,” said Quinlan. “Landfills are known for leaking hazardous substances like PFAs, which could permanently contaminate nearby wells and aquifers just minutes away in Waialua.”
If the selected site is rejected, the mayor said he will have limited options for a new landfill site. He said the City would be forced to ask the state legislature to amend Act 73, so that they could consider other sites that aren’t above the aquifer, but may be closer to schools, residences or hospitals.
If the state legislature doesn’t amend the law, then Blangiardi’s administration said it would be required to seek an extension of current landfill operations at Waimanalo Gulch. A 2019 state Land Use Commission order requires the closure of the current landfill by March 2028, but the landfill could potentially be used until 2035, according to the City. Blangiardi’s administration emphasized their opposition to extending operations at the current landfill.
State Rep. Darius Kila D-44 (Honokai Hale, Nānākuli, Mā‘ili), released a statement Tuesday afternoon thanking the administration for selecting a new location, signaling the upcoming closure of the Waimanalo Gulch Sanitary Landfill that is located in his community.
"I understand that this announcement may not be welcomed by everyone. However, let me be clear: the Leeward Coast has endured the burden of hosting this landfill for decades — a landfill named after another community but placed in our backyard. For far too long, we have carried more than our fair share of this responsibility," he said.
"No matter where the new location is designated, the Administration has an obligation to follow through and shut down the Waimānalo Gulch Sanitary Landfill. Today's announcement reflects an overdue acknowledgment of that responsibility."
Every year, Oahu generates about 1.2 million tons of recyclables and residential and commercial waste. Of that, 650,000 tons is sent to H-POWER, where metals are recovered and the remainder is burned for electricity. About 225,000 tons of municipal solid waste, ash from H-POWER, and other special waste materials are disposed of at the landfill annually.
The City plans to use the new landfill for 20 years, accepting the above along with the disposal of all construction and demolition waste, which currently goes to the PVT landfill.
Now that a site has been identified, the City will begin discussions with the Honolulu Board of Water Supply and Dole. The City will also start the process to get an Environmental Impact Statement, followed by acquisition, landfill design, obtaining permits, and construction.
Michelle Broder Van Dyke covers the Hawaiian Islands for Spectrum News Hawaii. Email her at michelle.brodervandyke@charter.com.