Hidden Hydrology: Subterranean Groundwater Transfer

Aug. 10, 2016

I’m continually amazed by the way data allows us to “see” things that are otherwise invisible to the human eye—the exploration of cosmic landscapes that no human has ever traveled to, the molecular wonder of microscopic worlds, and recently the unseen places along the US coast where freshwater and seawater intermingle underground.

Using data collected by NASA’s Jet Propulsion Laboratory, Audrey Sawyer, assistant professor of earth sciences at Ohio State University, and a team of researchers, recently created a map of these invisible water exchanges. Pinpointing these sites of submarine groundwater discharge is of critical importance. For, as Sawyer explains, each one represents a point of vulnerability for water contamination.

The Metropolitan Water Reclamation District of Greater Chicago is seeking a visionary Executive Director. The District is an award-winning wastewater agency which has been a leader in protecting the Chicago area water environment for over a 120 years. For information and to apply, click here or contact [email protected]The District is an Equal Opportunity Employer.

“We’re all pretty familiar with the idea that rain falls on land and flows out to the ocean in rivers, but there’s another, hidden component of rainfall that infiltrates the ground near the coast and spills into the ocean below sea level,” Sawyer told The Ohio State University. “If you’ve ever been swimming in the ocean and felt a cold spot, there’s a good chance that the cold spot is due to groundwater seeping out from underfoot.”

She explains that there are two directions of potential contamination: sea to land and land to sea. “Freshwater flows out to sea, and vice versa. Urbanization, agricultural development, climate, and topography all affect how much water flows in either direction, and the exchange has a big impact on both onshore groundwater that we drink and offshore seawater where we swim and fish.”

Sawyer and the Jet Propulsion Laboratory’s Cedric David and James Famiglietti, examined rainfall, evaporation rates, and the amount of known surface runoff to calculate the amount of water flowing below ground. The study found that more than 15 billion tons of freshwater flow through these underground networks every year.

The team’s research determined that 12 percent of the continental US coastline is highly susceptible to freshwater contamination from septic tanks and fertilizer runoff. It also discovered that 9 percent of the US coastline is especially susceptible to contamination from sea to land.

Awareness of these hidden confluences means that we can now take more enlightened steps to protect our water resources from coastal contamination. The research team is currently collecting global data with the hope of creating a similar worldwide coastline study. What steps do you suggest that industry leaders and policy makers take once the areas of vulnerability are identified?
About the Author

Laura Sanchez

Laura Sanchez is the editor of Distributed Energy and Water Efficiency magazines.

Sponsored Recommendations

ArmorBlock 5000: Boost Automation Efficiency

April 25, 2024
Discover the transformative benefits of leveraging a scalable On-Machine I/O to improve flexibility, enhance reliability and streamline operations.

Rising Cyber Threats and the Impact on Risk and Resiliency Operations

April 25, 2024
The world of manufacturing is changing, and Generative AI is one of the many change agents. The 2024 State of Smart Manufacturing Report takes a deep dive into how Generative ...

State of Smart Manufacturing Report Series

April 25, 2024
The world of manufacturing is changing, and Generative AI is one of the many change agents. The 2024 State of Smart Manufacturing Report takes a deep dive into how Generative ...

SmartSights WIN-911 Alarm Notification Software Enables Faster Response

March 15, 2024
Alarm notification software enables faster response for customers, keeping production on track