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The University of Hawaii is proposing to deepen two water wells to research unusually high levels of brackish water several hundred feet above sea level on Lanai.
Wells within the Palawai Basin are the only location in the state where salty water exists above sea level and its origin remains a mystery to scientists, according to UH's draft environmental assessment published Oct. 8 by the state Office of Environmental Quality Control.
The study involves drilling a hole less than 4 inches in diameter to improve the overall understanding of the groundwater system within Lanai to conserve the island's water. The university does not believe the project will have any significant effect on the environment.
"The current prevailing model for groundwater in Hawaii is generalized and outdated and commonly provides an inaccurate and oversimplified picture of groundwater dynamics within the ocean islands of the state," the draft assessment reads. "Direct drilling and sampling of the groundwater resource will provide residents and decision-makers with more accurate and specific groundwater information so they can better understand and manage this resource."
UH researchers believe the high-level brackish water might be due to circulatory mixing of warm seawater; a giant tsunami; or an abundance of sea salt aerosols in a basin that is relatively dry, or at least was relatively dry for a period of time.
Lanai's groundwater hydrology has a number of "unique aspects" that have left researchers uncertain on its distribution and transportation within the island, according to the environmental assessment. The island has very limited rainfall, lying in the rain-shadow of Maui, so most of its nearshore areas have very limited basal freshwater aquifers.
The research project is separate from the decadeslong legal battle over water use at Lanai's Manele Golf Course, according to Nicole Lautze, an associate specialist with the Hawaii Institute of Geophysics and Planetology at the University of Hawaii.
In 1996, the state Land Use Commission ruled that Lanai Resorts had violated irrigation rules and ordered it to stop using water from the aquifer. Critics complained the course was squandering potable water on irrigation, argued some brackish water could be used for drinking and worried about high-quality drinking water leaking into the wells.
Legal challenges that reached the Hawaii Supreme Court eventually brought the case back to the commission last year, where the judges ultimately decided Pulama Lana'i did not violate irrigation conditions at the golf course.
Lautze said in an email Friday that the research project is not exploring drinking or potable water from the high-level aquifer and only focusing on the brackish water. She said the project would have no impact to agriculture or drinking water because it is using two existing wells and not pumping water out of the ground.
To view the draft environmental assessment, visit oeqc2.doh.hawaii.gov/EA_EIS_Library/2018-10-08-LA-DEA-Hydrogeological-Assessment-of-Lanai.pdf.
* Chris Sugidono can be reached at csugidono@mauinews.com