In March 2013, researchers from the University of Hawaiʻi at Mānoa and UH Hilo began drilling at 64-hundred feet above sea level, between the mountains of Mauna Loa and Mauna Kea in the saddle region of the Big Island of Hawaiʻi.

UH Mānoa professor Donald Thomas is leading the effort, called the Humuʻula Saddle Hydrologic Study Project.

What they discovered seven months later may radically change conventional wisdom regarding the state’s most valuable resource: fresh water.

“The conventional model that we worked with for years and years is that we have a relatively thin basal fresh water lens, is what we call it,” said UH Professor Donald Thomas, the director of the Center for the Study of Active Volcanoes. “A layer of fresh water saturated rock that rises very slowly as we move inland.”


Humuʻula Saddle Hydrologic Study Project drill site.

According to that conventional model developed decades ago, the research team should have had to drill for 5,900 feet to 500 feet above sea level, before reaching the Big Island’s fresh water supply.

“We found something just completely different,” said Thomas. “The stable water table in the saddle is not 500 feet above sea level. It’s more like 4,500 feet above sea level. So we are almost ten times higher than we could have expected when we started out on the project.”

Geologists have long thought that only a small fraction of rainwater is stored in the islands because the geological makeup of Hawaiʻi is volcanic and porous.

“With our findings here, it looks as though the islands really act as huge containers,” said Thomas.

The impact could be far-reaching for residents, ranchers and farmers in drought stricken areas across the island chain and on Oʻahu, where fresh water may be scarce one day after supporting the majority of the state’s population for decades.

Right now, only one thing is certain.

“What we really need to do is go back and look again, using modern geophysical methods, to really define the ground water systems within all of the islands,” said Thomas.

The next step for the Humuʻula Saddle Hydrologic Study Project is a second drill site six miles from the first, to measure the extent of the groundwater discovered. If that test well proves successful, it will also provide strong support for high level water beneath a large tract of Department of Hawaiian Home Lands property on the eastern side of the Humu’ula Saddle where their lessees have long needed a reliable source of water for ranching operations.

The United States Army is funding the project in hopes of finding water for its Pōhakuloa Training Area, where the first drill site is located. Currently, the Army spends $1.5 million each year trucking fresh water to the training camp for use by troops and support staff.

“It’s been, as far as I am concerned, an outstanding partnership,” said Thomas. “We are able to develop scientific information that I think is really of fundamental importance to Hawaiʻi and at the same time, we have a practical outcome.”

As UH-led work continues in the area, ripples of excitement are spreading through the community. This unprecedented find on the Big Island could change the way we understand the geology of the Hawaiian islands and the state’s fresh water supply.

“I really believe the university should really try to become involved in to try and really improve the quality of life and preserve the quality of life that we have here in Hawaiʻi,” said Thomas.

This Post Has 7 Comments
  1. But to whom does this water belong? Not UH, Not ranching lease-holders, Not the Federal Armed Forces of the U.S. but to the indigenous Hawaiian People, and the life of the land itself.

    “I really believe that the University should try to preserve the quality of life”

    Whose life? Not for pure abstract research, not for cattle, and not for soldiers, but to perpetuate the life of the land in righteousness.

  2. I remember what happens when kanaka maoli give our resources to foreign governments. . .the Army will control the wai that comes from their drilling…let us all be witnesses and tell the truth about what is seen. This smells like fish…

  3. Water as know about and discovered Hundreds of years before the university was even here. Learn from our Kumu before you go digging. Hawaiians didnʻt have to dig to know this stuff.

    Go to 9:50 sec of the video to learn the truth.

  4. The fresh water that UH are digging up should be left alone… Because it don’t belong to UH or the MILITARY or even RANCHERS who are not NATIVE… IT BELONGS TO THE NATIVES OF HAWAI’I… SO WHAT MAKE IT YOURS TO SAY WHAT IT SHOULD BE USED FOR… LEAVE THE LAND ALONE!!! Native Hawaiians knows it’s there… QUIT MESSING WITH THE WATERSHED!!!

  5. I know this is 1 year late, but has anyone considered the possibility of dangerous water contamination from decades of military bombing and testing (which includes uranium and who-knows-what-else)? Does the lava filter *everything*?
    Not to mention, all water flows makai…and Pohakuloa is mauka of everyone on the island. Has anyone considered this and done testing to assure that all people of Hawaii are safe?

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