Twice as much freshwater is kept offshore of Hawai’i Island than was formerly believed, according to a University of Hawai’i research study with crucial ramifications for volcanic islands all over the world. An substantial tank of freshwater within the submarine southern flank of the Hualālai aquifer has actually been mapped by UH scientists with the Hawai’i EPSCoR ‘Ike Wai task. The groundbreaking findings, released in Science Advances, expose an unique method which significant volumes of freshwater are transferred from onshore to overseas submarine aquifers along the coast of Hawai’i Island.
This system might offer alternative sustainable resources of freshwater to volcanic islands worldwide. “Their evidence for separate freshwater lenses, stacked one above the other, near the Kona coast of Hawai’i, profoundly improves the prospects for sustainable development on volcanic islands,” stated UH Mānoa School of Ocean and Earth Science and Technology (SOEST) Dean Brian Taylor.
Through making use of marine controlled-source electro-magnetic imaging, the research study exposed the onshore-to-offshore motion of freshwater through a multilayer development of basalts ingrained in between layers of ash and soil, diverging from previous groundwater designs of this location. Conducted as a part of the National Science Foundation-supported ‘Ike Wai task, research study affiliate professors Eric Attias led the marine geophysics project.
“Our findings provide a paradigm shift from the conventional hydrologic conceptual models that have been vastly used by multiple studies and water organizations in Hawai’i and other volcanic islands to calculate sustainable yields and aquifer storage for the past 30 years,” stated Attias. “We hope that our discovery will enhance future hydrologic models, and consequently, the availability of clean freshwater in volcanic islands.”
Co-author Steven Constable, a teacher of geophysics at the Scripps Institution of Oceanography, who established the regulated source electro-magnetic system utilized in the task, stated, “I have spent my entire career developing marine electromagnetic methods such as the one used here. It is really gratifying to see the equipment being used for such an impactful and important application. Electrical methods have long been used to study groundwater on land, and so it makes sense to extend the application offshore.”
Kerry Key, an associate teacher at Columbia University who utilizes electro-magnetic techniques to image numerous oceanic Earth structures, who not associated with this research study, stated, “This new electromagnetic technique is a game changing tool for cost-effective reconnaissance surveys to identify regions containing freshwater aquifers, prior to more expensive drilling efforts to directly sample the pore waters. It can also be used to map the lateral extent of any aquifers already identified in isolated boreholes.”
Two-times more water
Donald Thomas, a geochemist with the Hawai’i Institute of Geophysics and Planetology in SOEST who likewise dealt with the research study, stated the findings verify two-times the existence of much bigger amounts of kept groundwater than formerly believed.
“Understanding this new mechanism for groundwater…is important to better manage groundwater resources in Hawai’i,” stated Thomas, who leads the Humu?ula Groundwater Research task, which discovered another big freshwater supply on Hawai’i Island numerous years earlier.
Offshore freshwater systems comparable to those flanking the Hualālai aquifer are recommended to be present for the island of O’ahu, where the electro-magnetic imaging strategy has actually not yet been used, however, if shown, might offer a total brand-new principle to handle freshwater resources.
The research study proposes that this freshly found transportation system might be the governing system in other volcanic islands. With overseas tanks thought about more durable to environment change-driven dry spells, volcanic islands worldwide can possibly think about these resources in their water management methods.
Reference: 25 November 2020, Science Advances.
This task is supported by the National Science Foundation EPSCoR Program Award OIA #1557349.