Oct 14, 2020

Hurricanes & Heavy Rains Impact Hawaii's Groundwater Supply

Research in Hawaii found that rain impacts groundwater supply.


hawaii groundwater

New research led by University of Hawai'i at Manoa scientists shows that rain brought to the islands by hurricanes and Kona storms can be the most important precipitation for resupplying groundwater in many regions of the island of O'ahu.

Hawai'i is critically dependent on an ample supply of fresh water, reported Science Daily.

"The majority of Hawai'i's freshwater comes from groundwater," said Daniel Dores, lead author and groundwater and geothermal research in the UH Manoa School of Ocean and Earth Science and Technology. "In this study, we investigated the relationship between trade wind showers, major rainfall events like Kona storms and groundwater."

Dores and a team of scientists from SOEST and the Hawai'i Department of Health collected rainfall around the island of Oahu, reported Science Daily. The team analyzed the stable isotopes of rainwater, chemical signatures in the water molecules and then compared the chemical signatures in rainwater to those of groundwater to determine the source of water in the aquifers. 

According to Science Daily, Hawai'i is experiencing significant changes in trade wind weather patterns, meaning precipitation events could become more extreme. 

"Because windward and mauka showers are so common, it is easy to assume that is the main source of our drinking water," said Dores. "Also, large rainfall events such as Kona storms result in significant runoff into the oceans. However, our research found that a lot of the rain from Kona storms makes it into our groundwater aquifers and is an important source of our drinking water."

Dores hopes that by better understanding how our groundwater is impacted by these extreme precipitation events that we can better protect the resource.

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