City selects area northwest of Wahiawā as proposed site for new landfill on O‘ahu

News release from City and County of Honolulu, December 10, 2024

HONOLULU – With all potential landfill sites on Oʻahu subject to challenge, and after carefully and exhaustively evaluating the relevant laws, regulations, rules, restrictions and equities for each potential site, the City and County of Honolulu announced Tuesday that it has selected an area northwest of Wahiawā as the proposed location for O‘ahu’s next landfill.

The landfill siting decision was required before December 31, 2024 and is an important step toward closing the Waimānalo Gulch Sanitary Landfill (WGSL) in accordance with a 2019 decision and order by the state Land Use Commission.

The proposed landfill location, identified as “Area 3, Site 2” in the City’s Landfill Advisory Committee’s (LAC) Recommendation Report (2022), is on agricultural land to the west of Kamehameha Highway, north of Paʻalaʻa Uka Pūpūkea Road.

Map showing the approximate location, northwest of Wahiawā, of the Cityʻs proposed landfill location.

“The siting of Oʻahu’s next landfill is an absolutely critical decision that impacts each and every person on our island,” said Mayor Rick Blangiardi. “For the good of our residents, we cannot and will not kick the can further down the road, because our residents deserve clarity.”

The proposed landfill site selected by the City — along with the five other potential sites included in the LAC’s 2022 Recommendation Report — is located over an aquifer. The City is proposing to design, construct and operate the facility in accordance with state and federal requirements, which prioritize public health and safety, including the protection of Oʻahu’s aquifer system. 

To date, after roughly 35 years of operation, the WGSL has not leaked through its liner into subsurface soil and rocks, and the City’s proposed landfill northwest of Wahiawā will be designed and constructed to include even greater protective measures than are in place at WGSL, incorporating the latest technological advances in waste management.

“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 Dr. Roger Babcock, Ph.D., P.E., 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.”

In working to ensure the safety of the facility, the City will implement a multiple-barrier subsurface monitoring and protection system designed to prevent the escape of any pollutants from the landfill, protecting the aquifer and ensuring its availability for use now and into the future.

The design and operations of municipal solid waste landfills in the United States are highly regulated by the Environmental Protection Agency via the federal Resource Conservation and Recovery Act, which is implemented locally by the State of Hawaii Department of Health (DOH). To protect Oʻahu residents as well as the environment, the design of the City’s next landfill — including the groundwater protection system — is required to be approved by the DOH as part of its mandatory comprehensive landfill permitting process.

“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 Mayor Rick Blangiardi.

If the Wahiawā site is rejected — and with Mayor Blangiardi having eliminated locations along the Waiʻanae Coast as potential landfill sites for equitable and operational reasons — the City will not be able to safely operate a landfill over the aquifer and will be forced to seek legislative changes that would enable siting a landfill closer to residences, schools and/or hospitals than is currently allowed by law (Act 73).

Should the proposed Wahiawā site be rejected, and the Hawaiʻi State Legislature decline to amend Act 73, the City will have no choice but to seek an extension of current landfill operations at Waimānalo Gulch, something the City administration opposes.

(TRANSLATION: BINGO!)

Photo showing operations at the City’s existing Waimānalo Gulch Sanitary Landfill.

Following Tuesday’s announcement of a proposed landfill location, the City will immediately begin discussions with BWS and the property owner of the proposed site. The City will also initiate the required Environmental Impact Statement (EIS) process, which would assess the impact on the physical, cultural, and human environments affected.

As part of the EIS process, the City will undertake a comprehensive public engagement campaign, including community meetings, and outreach to area City Council representatives, legislators and neighborhood boards. The City and the Department of Environmental Services are committed to public engagement throughout the design and permitting process, and area stakeholders will have opportunities to provide input on elements of the potential site design.

Details of the City’s comprehensive and exhaustive evaluation of potential landfill sites were presented during a meeting of the Honolulu City Council’s Public Infrastructure and Technology Committee on October 24, 2024, as well as in an informational sheet that was made available to the public earlier this month.

─ PAU ─

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