Maui County Council Chair Alice Lee (clockwise from upper left) and Council Member Tamara Paltin ask questions Monday of Eva Blumenstein, the Department of Water Supply’s Planning Program administrator, about proposed deep monitoring and exploratory water wells in West Maui. PC: YouTube
The Maui County Council’s Water and Infrastructure Committee received a briefing Monday afternoon on a bill that would authorize the mayor to enter into an intergovernmental agreement with the US Geological Survey for water resource exploration in West Maui.
Bill 108 passed first reading on Aug. 12. It was referred to committee for further discussion before returning to the full Council for second-and-final reading. According to the bill, the Maui County Department of Water Supply and US Geological Survey of the US Department of the Interior would jointly fund a water-resource monitoring program from Oct. 1, 2025, to Sept. 30, 2026.
The program’s total cost is $321,217, with Maui County paying $270,558 and USGS providing the balance of $50,659. Cooperation between the county and USGS dates back to the 1980s to monitor rainfall, stream flow and groundwater resources in Maui County. Data collected is used to evaluate the status and trends of water resources on Maui and Molokaʻi.
The county’s funding is already included in the Water Department’s fiscal year 2026 budget. More funding is being provided for a new rain gauge at Honomanu in East Maui and to assess groundwater availability in the Launiupoko aquifer system in West Maui.
The Water Department has completed a draft environmental assessment for a project to sink and test four exploratory wells in Launiupoko. Public comments are due Sept. 8. The draft environmental study can be viewed by clicking here.
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Public comments can be submitted via email to consultant Munekiyo and Hiraga at planning@munekiyohiraga.com.
On Monday afternoon, the committee heard from Eva Blumenstein, the Water Department’s Planning Program administrator. She detailed two primary projects: a deep monitoring well and two exploratory wells.
Chair Alice Lee asked about the capacity of the two exploratory wells in the Launiupoko aquifer.
Blumenstein said the capacity of those wells, for which an environmental assessment was published recently, would be different in terms of capacity versus yield, the later being what the county could actually add to the fresh water drinking supply.
A map shows the location of proposed exploratory water wells in West Maui. PC: Munekiyo and Hiraga
One well could have a production capacity of about 0.7 million gallons per day, but most of that would really be needed to offset what needs to be staying in the Kanaha Stream that the county is currently diverting to the Lahaina water treatment facility.
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“So there’s really not much net yield for one of the wells,” she said. “It’s really just to comply with the in-stream flow standards for Kanaha Stream. The second well that comes out, we hope, could produce at a yield that could be 0.7 million or more gallons a day to meet demand both for the reconstruction of Lahaina town and new housing demand.”
Lee asked whether Lahaina town doesn’t already have existing water capacity for reconstruction.
Blumenstein said that, at the time of the wildfires in August 2023, the county was already in a “capacity deficiency” in Lahaina where “we were just catching up.” New water resources are needed to beef up capacity and have a backup supply of water, just to serve existing demand and the reconstruction of Lahaina town, she said.
The state Commission on Water Resource Management has designated West Maui as a designated groundwater resource. That means the state has taken over water use permits in that designated area. The commission is collaborating with Maui County on the West Maui water resource study.
Council Member Tamara Paltin asked Blumenstein to clarify that the deep monitoring wells and exploratory wells are two sets of different wells.
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“Yes, that’s correct,” she said. “What we’re asking for in the joint funding agreement here is a well that would not become a production well . . . just for monitoring purposes.”
Paltin asked whether a monitoring well could become a water production well, and Blumenstein said that, “theoretically, it could . . But the intention here is that we need the monitoring well to have a better understanding of the hydraulic conditions of the aquifer. It’s not really proposed to ever be transformed into production.”
The exact site for the monitoring well has not yet been determined. According to Blumenstein, a Phase 1 study will involve stakeholder input and a hydrogeological assessment to select the best location.
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The project would also include the installation of a new rain gauge at the Honomanu Stream in East Maui, with the USGS funding the equipment and installation and the county taking over operations and maintenance.
The environmental assessment for the two exploratory wells has been published, clearing the way for the department to apply for a new-use permit from the Commission on Water Resource Management. However, Blumenstein said it is unclear when the commission will begin to address new-use permit applications because it is still processing existing-use permits.
“We do not have a timeframe of when they will address them,” she said.
Paltin expressed concern about the potential for high chloride levels and aquifer recharge. Blumenstein explained that high chlorides can be a sign of over-pumping or could be related to a well’s proximity to the shoreline. (Salty water, as measured in chloride levels, shows when too much fresh water, which floats atop lower brackish water, is being pumped from an underground water well.) Blumenstein also noted that the department is working on projects related to watershed protection and stream restoration to help improve aquifer recharge.
Committee Chair Tom Cook deferred action on the intergovernmental agreement, which is expected to return to the full Council for second-and-final reading.