The University of Hawaii was awarded $20 million to combine Native Hawaiian knowledge with modern geological data to figure out exactly how fresh water flows in the islands.

The grant from the National Science Foundation will give the university funding to study water sustainability throughout the state. This comes as Hawaii faces a growing population and climate change, as well as cultural and legal battles surrounding water rights.

“Water is at the core of just about everything,” said Gwen Jacobs, director of the project. “It is the one natural resource that we don’t bring in from the mainland.”

The project, which was named Ike Wai from the Hawaiian words for knowledge and water, will use the money to drill wells and collect data to chart the flow paths and amount of groundwater in Hawaii. It will also fund new research positions at the university.

UH researchers are working with the U.S. Geological Survey and state departments of Land and Natural Resources and Health, which will help steer the university’s research so it can help policymakers craft rules on water use — for example, such as where housing developments or landfills should go.

“To my knowledge, I think this is quite groundbreaking,” said Jacobs.

Researchers are also using Native Hawaiian stories and knowledge to understand where fresh water is, said Greg Chun, who’s on the study’s leadership team. For instance, knowing where ranchers in arid areas used to water cattle and horses could help researchers pinpoint where groundwater surfaces from the aquifer, he said.

“That kind of knowledge is really important to helping us locate where the water might be,” Chun said.

Much of Hawaii’s water comes from aquifers where it’s filtered underground by volcanic rock for years. Health and environmental officials say Hawaii is fortunate to have lots of volcanic soil and rainfall to supply the state’s residents with an ample supply of clean drinking water.

Researchers want to focus on two areas that are critical to the state’s water supply. One is the Keauhou aquifer on Hawaii island, which researchers know relatively little about and could potentially hold lots of fresh water.

Meanwhile, the study will also focus on the security of the Pearl Harbor aquifer on Oahu, which is the most important aquifer on the state’s most populated island, according to the USGS.

Two years ago the Navy detected a 27,000-gallon fuel leak from a tank that sits atop the aquifer. While the Navy says the tank and others there aren’t currently leaking, the study would analyze how fuel from 20 giant storage tanks built into the side of a mountain could potentially permeate into Oahu’s drinking water.

“There are not enough monitoring wells in that area to figure out where these plumes of leaking aviation fuel are,” said Roy Hardy of the state Commission of Water Resource Management. “We don’t know where it’s going.”