Long-Term Care & Monitoring
Updated over a week ago

Below are some key questions regarding long term care and monitoring in regards to debris removal.

How long will the temporary debris storage (TDS) area site be allowed?

It is likely the TDS will be in operation for 1-2 years, one to transfer Lahaina ash/debris to the TDS, and at least another 6 months for all ash/debris and cover soil to be transferred safely to a permanent disposal site at the Central Maui Landfill.

Will the TDS site be cleaned up once the ash and debris are removed and transported to the permanent disposal site?

Yes, the permanent disposal site will be located at the Central Maui Landfill, which is already a permitted solid waste landfill which was designed and constructed to meet federal and state landfill regulations. The disposal cell will feature an engineered liner, environmental monitoring, and other controls to protect long-term community and environmental health.

Will the permanent disposal site at the Central Maui Landfill meet the requirements of federal or state landfill regulations?

Yes, the permanent disposal facility will be designed and constructed to meet federal and state landfill regulations. While the permanent disposal site design has not yet been finalized, it will feature an engineered liner, environmental monitoring, and other controls to protect long-term community and environmental health, wherever it is located. Maui County is coordinating closely and working together with Hawai’i DOH and EPA Region 9 in the planning for the safe management of the ash and debris.

How will the permanent disposal site be built to be protective of human health, wildlife, agricultural lands, marine life, and the environment?

Disposal cells within the Central Maui Landfill are already built to stringent design standards intended to completely encapsulate the ash and debris between heavy plastic and clay composite liners (base and final cover) specifically designed for this purpose. Debris (plastic, dust) will be contained within the site and prevented from blowing onto adjacent lands or the ocean. In addition, regular supervision and maintenance to remove leachate to mitigate any potential leaking of contaminants, will be performed. Finally, groundwater monitoring wells are installed around the Central Maui Landfill to detect any changes to groundwater conditions.

How will the permanent disposal site be monitored over the long term to ensure they protect human health and the environment? By whom?

A long-term monitoring and maintenance plan for the permanent disposal site will be developed by Maui County in coordination with Hawai’i DOH. As with other areas of the Central Maui Landfill, it will involve the final cover and stormwater drainage/diversion structures, monitoring for methane gas, air quality monitoring (while in operation), removal of any leachate (liquid from the ash/debris), monitoring for leakage, and perimeter groundwater monitoring. Together with methane gas and groundwater monitoring, these systems will monitor potential impacts to the environment.

Who will maintain and monitor the TDS and permanent disposal site during construction, operation and closure? Will monitoring information be made available on-line for the public to view?

USACE and the County of Maui will maintain and monitor both the Central Maui Landfill and permanent disposal site to ensure compliance with best construction practices and environmental compliance.The County of Maui passed an ordinance (#5596, or Bill 120, 1/21/2024) requiring environmental monitoring and safety measures at the TDS site, with which US ACE and County of Maui Division of Environmental Management will ensure compliance with. Information and data relating to air quality, water quality, and overall progress can be found at https://www.mauirecovers.org/debriscontainment.

How long will the permanent disposal site last?

These type of disposal units are designed to last in perpetuity when maintained and monitored, which is planned to be conducted by Maui County.

Will leachate continue to be collected?

Yes. Any leachate that accumulates on the uppermost liner at a depth of greater than 30 cm will be removed using pumps and proper treatment/disposal at a wastewater treatment plant if necessary until it is no longer being generated.

How does groundwater monitoring work? Can it be cleaned up if it becomes contaminated?

Monitoring wells are already installed around the perimeter of the Central Maui Landfill. Samples are taken using special pumps either quarterly or semi-annually for a list of heavy metals (including arsenic, cobalt and lead) and volatile organic compounds (VOCs) following very specific guidance provided in state regulations, for a period of 30 years. This period can be extended if warranted.

If these compounds are detected, the groundwater monitoring goes into assessment monitoring, which increases the frequency and list to be sampled. In some cases, additional wells are installed so that the extent of groundwater contamination can be understood. If the contamination is found to be a threat to drinking water, systems (i.e., pump & treat, bioremediation) can be used to clean up the groundwater or at least stop it from spreading.

How long will the HDPE liners and PVC leachate collection pipes last? Will the liners rip or tear as waste is being placed into the TDS or permanent disposal site?

After installation, it is standard practice to protect the HDPE liner with a geotextile (a thick fabric) and 2-3’ thick layer of sand, soil or gravel on top prior to waste placement to prevent any waste items from piercing or ripping the liner during placement. When properly maintained and protected, the plastic liner and leachate collection components of engineered landfills can last a very long time, as they have been demonstrated to be resistant to subsurface conditions and are considered state of the art in landfill construction. Regardless, the permanent disposal site will continue to be monitored by Maui County for as long as possible along with the other closed landfills on the island.

Will groundwater monitoring data be available to the public?

Yes. A summary of groundwater data will be produced after monitoring events (every few months) and posted on the https://mauirecovers.org website throughout the cleanup and recovery efforts.

What can be done if groundwater should become contaminated in the future?

Groundwater remediation technologies and processes (i.e., bioremediation, pump and treat) are widely available in the environmental cleanup industry. Construction and implementation, in the unlikely event it is needed, are part of the post-closure care requirements at the Central Maui Landfill.

Will there be monitoring of water quality along the shoreline and the Olowalu Reef Complex?

Officials are currently discussing the need and feasibility of water quality monitoring options along the shoreline near Olowalu with the Hawai’i Department of Land and Natural Resources, Division of Aquatic Resources. There are existing monitoring efforts by Hawai’i DOH nearby, which focus primarily on water quality for safe aquatic recreation. Both the TDS and permanent disposal area are effectively going to quarantine the waste between impermeable liners which will be extensively monitored for leakage. These controls will prevent any ash/debris from making it into the watershed and the ocean.

Will Lahaina, the temporary debris storage area, or permanent disposal site be considered ‘Superfund’ sites?

No. Though USEPA used resources (personnel, equipment, contractors, etc.) from its Superfund program with funding through a mission assignment from FEMA to conduct Phase 1 cleanup operations, this isn't considered a Superfund site. A Superfund site is typically a cleanup project where no other regulatory authority can conduct the work and is meant to address former industrial activities. The permanent disposal site will be built and operated under state and Federal laws other than the Superfund law.

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