The Pearl Harbor aquifer is the most important aquifer on the island of Oahu and currently supplies about 100 million gallons per day of fresh groundwater mainly for public supply. Decisions related to future infrastructure development and alternate sources of fresh water, including desalinization, will depend on the long-term sustainability of the groundwater resources in the Pearl Harbor aquifer. The current estimate of sustainable yield used by the Hawaii State Commission on Water Resource Management (CWRM) is based on a simple equation that does not account for aquifer heterogeneities and the spatial distribution of withdrawals. Salinity of water pumped by some wells in the eastern part of the Pearl Harbor aquifer have risen in recent years, although recent pumpage from the area is near the CWRM-estimated sustainable yield. It is critically important, from both economic and resource standpoints, to have an accurate understanding of how much fresh groundwater in the Pearl Harbor aquifer can be developed for future needs.
The overall objective of the study is to provide the BWS with a tool that can be used to (1) effectively manage groundwater pumping from the Pearl Harbor aquifer and (2) develop long-range plans for future development of resources in the Pearl Harbor aquifer as well as alternate sources of fresh water. The tool will be in the form of a three-dimensional numerical groundwater model capable of simulating the distribution of salinity in the aquifer and the response of the freshwater lens to user-specified pumping conditions.
See the results to date here…