The aquifer has long been drained for irrigation and for industrial uses such as ethanol plants, which turn corn into motor fuel. From the time humans began extracting water from the aquifer through 2000, the volume of water in the aquifer fell by about 6 percent. Since then irrigation and industrial usage has accelerated.
The decline in the aquifer isn’t uniform. From 2007 to 2009, for example, there was an increase in water stored in the aquifer in Nebraska overall, according to Goecke, but in southwest Nebraska water levels are falling; by 2007, there were 41/2 times as many irrigation wells in the state as there had been in 1960. In north Texas and west Kansas, the Ogallala water levels are falling precipitously, more than 100 feet in 60 years, according to a University of Texas at Austin study.
And the use of pesticides on cropland has polluted parts of the formerly pristine aquifer.