WRRC 2024 Spring Seminar

February 9, 2:00pm - 3:00pm
Mānoa Campus, Zoom Meeting

The Present and Future State of the Pearl Harbor Aquifer

by Paul Eyre

Since 1879, the Pearl Harbor aquifer (Ewa-Kunia excluded) has shrunk to around 60 percent of its original size; from about 33 feet to about 19 feet currently. Irrigation of sugarcane crops during the plantation era, amounting to about 120 million gallons per day (MGD), accounted for most of the pumpage that resulted in the shrinkage of the Pearl Harbor lens. However, by 2008, the aquifer stopped shrinking and had reached an equilibrium with the new conditions of recharge and pumpage that were established following the end of plantation agriculture in the early 1990s. In the decades to come, the aquifer will shrink again, to about half of its current size, as it comes into a new equilibrium with the increased pumpage allowed by the Commission on Water Resource Management鈥檚 sustainable yield of 150 MGD. The current pumpage, mostly for residential use, is about 90 MGD. This presentation will show the data and the methods that led to these conclusions. This is a vital subject that has been studied, discussed, and debated for many years and will continue to be discussed by all who have an interest in Hawai鈥榠鈥檚 future. Hopefully, this presentation will encourage a lively exchange of ideas on the current and future state of the Pearl Harbor aquifer and the consequences of future water demands.

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