The City and County of Honolulu says it’s out of options and is considering expanding the Waimanalo Gulch Sanitary Landfill by 3.7 acres.
The state Land Use Commission ordered the city to close the west side landfill by 2028. Last year, a new landfill location in Wahiawā was selected. But it was over a freshwater aquifer.
So the state Legislature passed a law banning landfills from being sited over sources of drinking water, invalidating the Wahiawā location. Another state law also puts restrictions on landfills from being located in conservation-zoned land or within half a mile of any residence, school or hospital.
“After good faith efforts in 2023, 2024 and 2025 to locate a landfill in areas outside West O’ahu were unsuccessful, the City has no operational choice but to extend the operational life of Waimanalo Gulch Sanitary Landfill while proceeding with the acquisition of lands, planning and permitting of a replacement landfill to WGSL,” wrote city Communications Director Scott Humber in an email to HPR.
“The expansion of WGSL should not impact West O’ahu residents more than they are already impacted by the presence and operation of WGSL as expansion is in the mauka portions of the existing property.”
Area elected officials want other options considered
State Rep. Darius Kila represents the Nānākuli area, which has housed Oʻahu's landfill since 1989. He emphasized that the city needs to continue to explore other options.
“The easiest path to pursue is expanding the timeline or the expansion of Waimanalo Gulch to buy them more time. The harder and maybe right thing to do is to look at all your other options that are on the table, but having the hard discussion,” he said.
“I would hate for Mayor Blangiardi and this administration to pass this off to the incoming or next mayor, because of course, they only have two more years in office. So I would hope that they would want to champion this so that they no longer have to pass it off to the next administration and they can make headway on the things that they promised.”
Despite its mandated closure date, Waimanalo Gulch has about six years of capacity left. Adding more acres would extend its capacity by another two to three years.
West side state Sen. Samantha DeCorte called an expansion of the landfill an “injustice.”
“For decades, Waiʻanae has been the host for landfills,” she said.
“There should never be another landfill in Waiʻanae … Nobody wants it in their backyard, right, but everybody should be carrying the burden at some point. To be honest, there should be equal responsibility throughout the entire state. Every community, at some point, should be hosting a landfill so that it's evenly spread out.”
Both Kila and DeCorte pointed to the federal government and military to collaborate with the state and city to find a location for a new landfill so that the city can meet the 2028 closure date of Waimanalo Gulch.
However, a city spokesperson wrote in an email to HPR that the city has already exhausted federal land opportunities.
In 2024, the city was negotiating with the U.S. Navy to use the Wapiʻo Soccer Complex land as a new landfill site. But the Navy ultimately did not give the city permission to use the land.
“With the exception of Lualualei Naval Magazine on the Waianae Coast, which Mayor Blangiardi ruled out as a matter of equity and policy, there are no remaining federal military lands available that are not located over the aquifer, inconsistent with state law restrictions on the siting of landfills or lands required for essential military operations,” wrote Humber.
The city has not yet started the expansion process and has only started to evaluate available additional space and the permitting requirements.
Expanding Waimanalo Gulch Sanitary Landfill would require approval from the Honolulu Planning Commission, the state Land Use Commission, and other agencies such as the Department of Health.
There is a public meeting scheduled on Jan. 13 at 10 a.m. at Kalanianaʻole Beach Park Multipurpose Room — in the Nānākuli area — to report on the status of the Waimanalo Gulch Sanitary Landfill. It is a general meeting required each year, and it is not about a new expansion to the landfill.
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