UC groundwater project goes international

The University of Cincinnati’s groundwater observatory, the only one of its kind east of the Mississippi River, is helping scientists understand how to protect drinking water around the world

New sensors along the Great Miami River are giving University of Cincinnati researchers more information than ever about how agricultural practices, river flooding and contaminants affect sources of drinking water in Cincinnati and around the world.

UC’s C.V. Theis Groundwater Observatory, built in 2017, provides real-time information about water flowing into and out of the ground along the Great Miami River in suburban Crosby Township.

In particular, researchers are trying to understand the mixing zone in the riverbed where a lot of the geochemistry takes place, said Reza Soltanian, assistant professor of geology in UC’s McMicken College of Arts and Sciences.

“There is increasing demand on subsurface resources for energy, water and agriculture,” Soltanian said. “So a better understanding of coupled hydrological, chemical and biological processes related to water, energy and contaminants is of vital importance.”

Reza Soltanian stands in front of a communications pylon at the observatory.

UC geology professor Reza Soltanian is studying how rivers influence underground sources of drinking water at UC's C.V. Theis Groundwater Observatory. Behind him is a communications pylon that relays real-time information from six wells drilled along the Great Miami River. Photo/Joseph Fuqua II/UC Creative Services

By studying one area in detail, we can learn a lot about all the different complex physical, mechanical and chemical processes that go on.

Mike Ekberg, Miami Conservancy District

UC’s observatory is now part of an international consortium of researchers who are trying to understand how rivers and aquifers interact and how this mixing affects water quality. UC’s data is studied along with sampling sites on every continent in the world.

The project and its community partnerships demonstrate UC's commitment to making a difference in its urban community as outlined in UC's strategic plan called Next Lives Here

A communications pylon is powered by solar panels.

UC's groundwater observatory transmits real-time information about the changing geochemistry of the groundwater along the Great Miami River. Photo/Joseph Fuqua II/UC Creative Services

About half of the people in the United States get their drinking water from underground sources called aquifers, according to the U.S. Geological Survey. And more than 2.3 million people in southwest Ohio get their drinking water from the Great Miami Buried Valley Aquifer.

UC’s observatory consists of three pairs of wells drilled at two different depths to track the water’s movement and geochemistry through the ground. Sensors in each well transmit data to a communications pylon that was built high enough to operate even during the deepest Ohio flood and powered by solar panels.

Geologists call this meeting of surface water and the riverbed the “hyporheic zone.” Soltanian said to truly understand what’s happening unseen beneath the surface, geologists have to be creative and resourceful.

“We use a combination of geology, hydrology, geochemistry, biology, fluid dynamics, math, physics, computer science, satellite imagery and high-performance computing to better understand hyporheic zone processes,” he said. “You combine everything to see what’s happening in the subsurface.”

Reza Soltanian gestures while making a point at the wooded observatory.

UC geology professor Reza Soltanian is studying the groundwater along the Great Miami River. He is trained as a water structure engineer. Photo/Joseph Fuqua II/UC Creative Services

The entire watershed is a single complex and interconnected system, said Mike Ekberg, manager of water resources monitoring and analysis at the Miami Conservancy District. The district oversees drinking water for millions of people in southwest Ohio.

“There is a natural filtration process as river water moves through the biologically active zone in the riverbed into the underlying aquifer,” Ekberg said.

“It’s part of what makes groundwater such an attractive source of drinking water,” Ekberg said. “A lot of the bacteria and microbes we don’t want in drinking water get filtered out.”

By studying the changing chemical composition of water at the observatory, geologists can better understand how this mixing zone influences contaminants such as nitrates from agricultural runoff.

Reza Soltanian stands next to a tree with his hands folded in front of him with the muddy river behind him.

UC geology professor Reza Soltanian stands on the banks of the Great Miami River near UC's C.V. Theis Groundwater Observatory. The observatory measures how the rising and falling river water affects the geology and geochemistry of groundwater. Photo/Joseph Fuqua II/UC Creative Services

The lessons learned at UC’s observatory translate to groundwater systems worldwide, Soltanian said.

“By studying one area in detail, we can learn a lot about all the different complex physical, mechanical and chemical processes that go on,” Ekberg said.

A hand scrolls over a phone screen with data points.

UC's observatory provides real-time data through a phone app. Photo/Jay Yocis/UC Creative Services

UC geology professor emeritus David Nash continues to follow the progress of the observatory that he spent so long getting off the ground, figuratively speaking.

“We now have a continuous two-year record of hourly changes in groundwater chemistry, flow direction and velocity that can be used by regional water treatment plant operators, planners and hydrologists to determine the paths by which groundwater travels to wells providing most of the water used by Southwest Ohio farmers, manufacturers and residents,” Nash said in an email.

UC leases the property from the Great Parks of Hamilton County in partnership similar to the one UC has at its Center for Field Studies a short drive from the observatory. UC conducts classes on everything from biology and botany to geology and anthropology at the sprawling and wooded field center owned by the park district.

At the center, UC stores the geologic cores that were removed from the observatory’s six wells. The cores provide a geologic record of Ohio down to the bedrock. The center also records weather data captured daily at the observatory, center director David Lentz said.

“If anyone wants to study historic chemical composition or ancient pollen, we have it,” Lentz said. “It’s the only observatory of its kind east of the Mississippi River. It’s a valuable resource.”

Featured image at top: A child drinks a glass of water. UC's C.V. Theis Groundwater Observatory is helping scientists understand how rivers affect underground sources of drinking water. Photo/Jay Yocis/UC Creative Services

Two professors stand in the background in front of two large concrete pads that make up wellheads.

UC geology professors Amy Townsend-Small, left, and David Nash, now emeritus, stand in front of two wells at the C.V. Theis Groundwater Observatory in this 2017 file photo. Photo/Jay Yocis/UC Creative Services

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