Beneath the U.S. High Plains, a substantial underground reservoir stretches from the Texas Panhandle to South Dakota, providing drinking water for more than 2 million people and supplying irrigation for dozens of valued crops across eight states, which account for at least one-fifth of the nation’s total agricultural harvest.
But as population growth in the region slowly trends up — and the climate warms at a quicker-than-anticipated pace — uncertainty over the future of Texas’ water infrastructure has culminated among both state leaders and residents as the Ogallala Aquifer diminishes and inches its way toward insufficient supply.
Researchers from Kansas State University in Manhattan, Kan., conducted a four-year study of a portion of the Hig Plains Aquifer, called the Ogallala Aquifer, which provides the most agriculturally important irrigation in the state of Kansas, and is a key source of drinking water for the region.
If current irrigation trends continue unabated, 69 percent of the available groundwater will be drained in the next five decades, the researchers said in a study published online Monday in the journal Proceedings of the National Academy of Sciences.
“I think it’s generally understood that the groundwater levels are going down and that at some point in the future groundwater pumping rates are going to have to decrease,” study lead author David Steward, a professor of civil engineering at Kansas State University, said in a statement. “However, there are lots of questions about how long the water will last, how long the aquifer will take to refill, and what society can do.”
Taking water measurements
Steward and his colleagues collected data on past and present groundwater levels in the Ogallala Aquifer and developed statistical models to project various scenarios of water depletion over the next 100 years.
Using current trends in water usage as a guide, the researchers estimate that 3 percent of the aquifer’s water was used up by 1960; 30 percent of the aquifer’s water was drained by 2010, and a whopping 69 percent of the reservoir will likely be tapped by 2060. It would take an average of 500 to 1,300 years to completely refill the High Plains Aquifer, Steward added.
But, if reducing water use becomes an immediate priority, it may be possible to make use of the aquifer’s resources and increase net agricultural production through the year 2110, the researchers said.
“The main idea is that if we’re able to save water today, it will result in a substantial increase in the number of years that we will have irrigated agriculture in Kansas,” Steward said.
A lot of variables
Yet, making projections about water security is challenging, because there are a number of factors to consider, and even though the High Plains Aquifer touches eight different states, the effects can be highly localized, said Bridget Scanlon, a senior research scientist and leader of the Sustainable Water Resources Program at the University of Texas at Austin, who was not involved with the new study.
“We know the aquifer is being depleted, but trying to project long-term is very difficult because there are climate issues and social aspects that have to be included,” Scanlon told LiveScience. “Projections are so difficult because I think we’re clueless about a lot of things, like extreme weather events.”
