Mapping groundwater’s influence on the world’s oceans

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June 4, 2019

Written by Laura Arenschield / Ohio State News / arenschield.2@osu.edu

Researchers at The Ohio State University have created high-resolution maps of points around the globe where groundwater meets the oceans-the first such analysis of its kind, giving important data points to communities and conservationists to help protect both drinking water and the seas.

In a study published June 3 in the journal Geophysical Research Letters, the team showed that nearly half of fresh submarine groundwater discharge flows into the ocean near the tropics. They also found that regions near active fault lines-the area around the San Andreas Fault in California, for example-send greater volumes of groundwater into the ocean than regions that are tectonically stable. And, they found that dry, arid regions have very little groundwater discharge, opening the limited groundwater supplies in those parts of the world to saltwater intrusion.

The Ohio State team worked with researchers at NASA’s Jet Propulsion Laboratory and the University of Saskatchewan to combine topographical data from satellites and climate models to show the flow of groundwater around the world’s coasts.

The findings could help coastal communities better protect and manage their drinking water.

"Freshwater-groundwater discharge is a natural line of defense against saltwater intrusion," said Audrey Sawyer, assistant professor of earth sciences at Ohio State and a co-author of the study. "And saltwater intrusion is a concern in places like Miami, Georgia, Cape Cod-it’s up and down the coast. It’s a problem that dry regions have as little groundwater discharge as they do because these are also the places where people are going to tend to look for groundwater to meet their freshwater needs."

Get a visual of the high-resolution map where the groundwater meets oceans and about the study here.