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.