By Northern Plains News
The report presents water-level change data in the aquifer for two separate periods: from 1950 — the time before significant groundwater irrigation development — to 2013, and 2011 to 2013. Find state-by-state information for each year back to 1980 online through the USGS
“The measurements made from 2011 to 2013 represent a large decline,” said Virginia McGuire, USGS scientist and lead author of the study. “This amount of aquifer depletion over a 2-year period is substantial and likely related to increased groundwater pumping.”
In 2011, the total water stored in the aquifer was about 2.92 billion acre-feet, an overall decline of about 267 million acre-feet — or 8 percent — since predevelopment. Change in water stored from 2011 to 2013 was an overall decline of 36.0 million acre-feet. The overall average water-level decline in the aquifer was 15.4 feet from predevelopment to 2013, and 2.1 feet from 2011 to 2013.
The USGS study used water-level measurements from 3,349 wells for predevelopment to 2013 and 7,460 wells for the 2011 to 2013 study period.
The High Plains Aquifer, also known as the Ogallala Aquifer, underlies about 112 million acres (175,000 square miles) in parts of eight states, including: Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. In South Dakota, it underlies all of Bennett County, most of Todd County, part of Shannon, Mellette, Gregory and Tripp counties.
The USGS, at the request of the U.S. Congress, has published reports on water-level changes in the High Plains Aquifer since 1988. Congress requested these reports in response to substantial water-level declines in large areas of the aquifer.
Read more about water on the Black Hills Knowledge Network.