The last place most people would expect to find fresh groundwater is tens or hundreds of kilometers offshore in the ocean. Yet not only is that where freshwater can be found, in the ground of the continental shelf beneath the ocean, but simulations have shown that it could be a common occurrence across a range of geologic systems. These offshore groundwater resources could be exploited for uses such as drinking, agriculture and oil recovery, but new research from the University of Delaware’s Holly Michael and Xuan Yu, who worked as a postdoctoral researcher at UD, suggests that tapping into those resources could lead to adverse onshore impacts.
The research was published in Geophysical Research Letters and is part of Michael’s National Science Foundation CAREER Award. Through simulations and computer modeling, the research explores how using offshore freshwater resources could threaten onshore aquifer systems, lead to diminished onshore groundwater availability and cause widespread land subsidence. Coastal communities may consider using these offshore groundwater resources as populations increase and the limited freshwater resources are degraded by overuse and pollution, but a more immediate use of the offshore fresh and brackish groundwater is to enhance oil recovery.