The U.S. Geological Survey reviewed groundwater data from 1900 to 2008 and said the annual rate of depletion was accelerating. The Ogallala Aquifer, which covers more than 170,000 square miles in the middle of the United States, declined rapidly because of the high rate of water use for agricultural, industrial and municipal water needs.
"The depletion during the last eight years of record [2001-2008] is about 32 percent of the cumulative depletion in this aquifer during the entire 20th century," the USGS said in a statement.
The USGS said groundwater depletion has increased steadily since the 1950s but has accelerated more quickly in the last eight years.
"Because groundwater systems typically respond slowly to human actions, a long-term perspective is vital to manage this valuable resource in sustainable ways," acting USGS Director Suzette Kimball said in a statement.
The World Meteorological Organization said there was a global level of sustained drought last year. Groundwater sources are replenished in part by rainfall and other forms of precipitation.