Engineering for extremes

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July 8, 2015

Water: The oil of the 22nd century – and maybe the 21st

The use of groundwater is the drought we can't see, said Yadu Pokhrel, who has spent his career studying how humans are affecting the global water cycle.

Story by Matt Roush, courtesy of Technology Century magazine, Summer 2015 

Yadu Pokhrel has spent his career studying rainfall patterns and how humans are affecting the global water cycle. 

The message: With seven billion plus of us on the planet, we’ve got to start rethinking how we use fresh water.

“Extremes are getting worse,” Pokhrel said of global climate. “Rainfall patterns are changing. We are getting historical droughts. We are also getting historical floods. These are affecting water supply systems, not only surface water, but people are getting water from increasingly deep water systems, and those are depleting at a very rapid rate. Water levels in California are going down so fast that if we keep using water at this rate, it won’t last long.”

Pokhrel is a native of Kathmandu, Nepal, where he studied civil engineering. He got a PhD at the University of Toyko. He spent several years as a post-doctoral researcher and research faculty member at Rutgers before becoming an assistant professor of civil and environmental engineering at Michigan State University. 

Pokhrel called the use of groundwater “the drought we can’t see. People don’t realize how fast the groundwater is depleting. Solving these problems requires hard measures. Constructing more dams and storing more water is not feasible in all areas due to environmental impact. But there are softer measures. Better ways of irrigating crops, asking citizens to save water however they can.” 

The clock is ticking on the world's fresh water supply, said Yadu Pokhrel, assistant professor of civil and environmental engineering at Michigan State University. "We are using up our aquifers at 22 times the replenishment rate."

 Pokhrel said water shortages may even force changes in diet. He said raising beef cattle requires much more water than growing vegetables. Chicken requires less water per pound of meat, he said. 

Pokhrel, who recently published a research paper on the depletion of the Ogallala Aquifer under the Great Plains, and the aquifer under California’s Central Valley, said the clock is ticking on the world’s freshwater supply. “We are using up our aquifers at 22 times the replenishment rate.” 

Pumping that much water from that deep under the ground means it never returns to the aquifer. His research shows that humans are now pumping enough water out of deep layers that it’s contributing to sea level rise. 

As for the Great Lakes, he said climate change may balance itself out – warmer winters mean more evaporation from the lakes, but a warmer, more moist atmosphere also means more heavy precipitation events.