In Northeastern Colorado, farmers growing food like corn and potatoes depend for water on a giant, underground reservoir. Called the Ogallala, or High Plains aquifer, this water source spreads across eight high plains states like a giant, underground lake.
In times of drought, farmers who use the aquifer for water take more of it. A report from the U.S. Geological Survey, published December 16, shows the 2012 drought significantly diminished the Ogallala's water.
"The bottom line was, there was with the drought, increased pumping and you have decline of the water levels," said Virginia McGuire, the U.S. Geological Survey scientist who authored the report.
Over the last six decades, Colorado has exceeded the aquifer's resupply by 18.8 million acre-feet of water. An acre-foot is the amount of water needed to cover an acre of land one foot deep.
Between 2011 and 2013, the state used up 3 million acre-feet more than was recharged. Across most of the aquifer, other areas also used a whole lot of water during that period. Kansas and Texas, both hard hit by drought, caused the largest declines in Ogallala water levels.
McGuire, who has been tracking the aquifer's water level for years, said she knew the drought would make an impact. She was a little surprised at how significant an effect it was, though.
"The story is drought was widespread and there were declines in most of the aquifer for the 2011 to 2013 time frame."
2014 has been wetter across much of the aquifer's area, but McGuire said it takes sustained rainfall, at the right time, to refill the aquifer's depths. In two more years, her next report will show if the aquifer's water levels are improving, or continuing to drop.
