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$26M project would reduce Lahaina injection well use

County proposes upgrades to W. Maui recycled water system

An injection well at the Lahaina Wastewater Reclamation Treatment Facility pumps treated water from the sewage system into the ground in September 2019. Maui County is proposing upgrades to the West Maui Recycled Water System that it says will reduce the use of the controversial injection wells. The Maui News / MATTHEW THAYER photo

Saying it will minimize the use of controversial injection wells at the Lahaina Wastewater Reclamation Facility, the County of Maui is proposing $26 million in upgrades to the recycled water system.

The West Maui Recycled Water Expansion Project calls for renovating the existing Honokowai Reservoir; replacing an aging 20-inch recycled waterline with a 24-inch pipe; and constructing a new reuse pump station and recycled water storage basin at the Lahaina facility.

Although the purpose of the project is to continue the county’s commitment to increasing recycled water use, it will also reduce the use of injection wells for effluent disposal, according to a draft environmental assessment.

“Overall, the proposed improvements will help to decrease demand on potable water resources and decrease the use of injection wells for effluent disposal from the Lahaina WWRF,” said the report, which was published Feb. 23 in the state Office of Environmental Quality Control’s “The Environmental Notice.”

Maui County injects 3 to 5 million gallons a day of treated wastewater into wells beneath the facility, which is about a half-mile from the shoreline. Studies using dyes to trace the flow showed more than half the discharge from two wells entered the ocean in a narrow area.

A draft environmental assessment report shows the current pump site where waterlines will lead to the makai reservoir at Lahaina Wastewater Reclamation Facility. West Maui Recycled Water Expansion Project photo

The injection wells were the focal point of a Supreme Court ruling in April that said the discharge of polluted water into the ground, rather than directly into nearby waterways, does not relieve an industry of complying with the Clean Water Act.

Environmentalists said after the ruling that they hope Maui County will work on a solution to end the use of injection wells to discharge large amounts of treated wastewater.

Operated by the county’s Department of Environmental Management Wastewater Reclamation Division, the Lahaina facility produces R-1 recycled water, the highest grade of recycled water for nonpotable use, and distributes it through the West Maui Recycled Water System. R-1 quality recycled water is suitable for many uses, including irrigation, the report said.

The West Maui Recycled Water System comprises two separate recycled water distribution systems: the Mauka System and the South System.

The Mauka System comprises two pumps at the Lahaina facility reuse pump station and a 20-inch recycled waterline that connects to two reservoirs: the Honokowai Reservoir at 300-foot elevation and a county reservoir at 725-foot elevation. With the cessation of Maui Land and Pineapple Co. operations, there is no longer demand for irrigation water from the Mauka System, and the county reservoir is no longer in regular operation.

The makai view over the project area toward the Lahaina Wastewater Reclamation Facility is shown. Saying it will minimize the use of controversial injection wells at the facility, the County of Maui is proposing a project that would add $26 million in upgrades. West Maui Recycled Water Expansion Project photo

The South System comprises two pumps at the Lahaina facility reuse pump station and a 16-inch recycled waterline that ends at a Kaanapali Golf Course reservoir and delivers up to about 1.8 million gallons per day to Honua Kai Resort, Kaanapali Golf Course, Hyatt Regency and Hyatt Residence Club. The system is pressurized only while the Lahaina facility reuse pumps are operating and users along the existing distribution system are restricted to taking recycled water only while the Lahaina facility reuse pumps are running, the report said.

Improvements will connect the Mauka and South systems and will provide a more reliable recycled water supply.

“Upon completion of improvements to the Honokowai Reservoir, the system will be capable of providing a stable recycled water supply and distribution pressure, allowing the recycled water system to function similarly to a potable water distribution system,” the report said.

The upgraded Honokowai Reservoir will provide necessary storage volume such that recycled water, which is predominately generated during the day when wastewater flows into the Lahaina facility are high, can be stored until higher user demand occurs, which is typically at night, it added.

If approved, the project would be bid in phases, with the initial phase bid late this year.

To view the full draft environmental assessment, visit http://oeqc2.doh.hawaii.gov/Doc_Library/2021-02-23-MA-DEA-West-Maui-Recycled-Water-System.pdf.

Comments are due by March 25 and should be sent to the proposing/determining agency, the county Department of Environmental Management, Albert Hahn, by mail at 2200 Main St., Suite 610, Wailuku, HI 96793; by phone at (808) 270-7421; or by email at albert.hahn@co.maui.hi.us.

The consultant should also be copied. Amanda Tanaka of consultant Fukunaga and Associates Inc. can be reached by mail at 1357 Kapiolani Blvd., Suite 1530, Honolulu, HI 96814; by phone at (808) 944-1821; or by email at atanaka@fukunagaengineers.com.

* Kehaulani Cerizo can be reached at kcerizo@mauinews.com.

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