Availability of groundwater from the volcanic aquifers of the Hawaiian Islands

Abstract

The islands of Hawaiʻi were built by basaltic shield volcanoes in the Pacific Ocean. These volcanoes formed aquifers that supply hundreds of millions of gallons of fresh water per day to the islands’ residents and diverse industries. Groundwater discharge from the volcanic aquifers to streams and the coast also supports traditional practices and ecosystems. The aquifers' capacity to yield fresh groundwater is limited, however, by limitations placed on the consequences of groundwater withdrawal, such as water-table depression, rise of saltwater, and reduction of groundwater to streams, springs, and the ocean. The magnitude of these consequences will change if groundwater recharge changes as a result of climate and land-use changes. This fact sheet summarizes groundwater availability and its relation to the consequences of groundwater withdrawals in the volcanic aquifers of Hawaiʻi. This topic was addressed in detail in the Hawaiʻi Volcanic Aquifer Study ( https://doi.org/10.3133/pp1876 ).