Climate variability

Deep underground aquifers respond rapidly to climate variability

According to hydrologists from Penn State and Columbia University, climate change can quickly impact even the deepest freshwater aquifers.

Researchers have found that responses to climatic variations can be detected in deep groundwater aquifers faster than expected – in many cases in less than a year.

Since rainwater can take years to reach deep aquifers through natural infiltration, the results suggest that another factor is involved, such as the pumping of aquifers by agricultural industries.

“We have seen a rapid response of deep groundwater levels to major climate cycles and local precipitation events,” said Tess Russo, early career RL Slingerland professor of geosciences at Penn State. “These aquifers are so deep that we expect it to take years for rainfall to descend, so if it’s not natural recharge that’s causing groundwater to respond to changes in rainfall, it may be from pumping changes.”

The research, published in nature geoscience, sheds new light on groundwater budgets in the United States and better defines how water in deep aquifers might change with climate. Groundwater used by municipalities and industry almost always comes from deep wells, which provide a more reliable source of water than shallow aquifers, especially in times of drought.

Despite the importance of these deep aquifers, no one really knows how much water they contain or how they might react to climate change.

“Groundwater doesn’t move very quickly, so we generally think deep aquifers have a delayed response to what’s happening on the surface, including our changing climate,” said Russo, who is also associated with Earth and Environment Systems Institute at Penn State. . “But we’re actually seeing a relatively quick response.”

Russo and Upmanu Lall of the Columbia Water Center at Columbia University analyzed the relationships between climate and groundwater data across the United States and used a small set of regional pumping data from wells in Kansas to demonstrate the potential connection.

Russo said evidence suggests pumping represents an intermediate link between rainfall and deep groundwater levels. Changes in temperature and precipitation can affect crop water requirements, for example, leading to changes in the water dependence of deep wells.

“If you look at agricultural areas where crop water demand changes with rainfall, that’s going to control the variability in pumping over time,” Russo said. “Pumping could be an intermediate connection between climate and groundwater – a connection that elicits an immediate response.”

Although evidence suggests that pumping causes the rapid response between deep groundwater and climate, scientists have been unable to link them conclusively due to a lack of pumping data across the states. -United.

“We need more data collection on human activities,” Russo said. “We need pumping records if we really want to make the link between climate and groundwater.”

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Material provided by Penn State. Original written by Matthew Carroll. Note: Content may be edited for style and length.