Abstract

The High Plains aquifer underlies 111.8 million acres (175,000 square miles) in parts of eight States—Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. Water-level declines began in parts of the High Plains aquifer soon after the beginning of substantial irrigation with groundwater in the aquifer area. This report presents water-level changes in the High Plains aquifer from the time before substantial groundwater irrigation development had occurred (about 1950 and termed "predevelopment" in this report) to 2009, from 2007–08, and from 2008–09. The report also presents change in water in storage in the aquifer, from predevelopment to 2009.

Ninety-nine percent of the water-level changes from predevelopment to 2009 ranged from a rise of 41 feet to a decline of 178 feet. The area-weighted, average water-level changes in the aquifer were a decline of 14.0 feet from predevelopment to 2009, a decline of 0.1 foot from 2007–08, and a decline of 0.3 foot from 2008–09. Total water in storage in the aquifer in 2009 was about 2.9 billion acre-feet, which was a decline of about 274 million acre-feet since predevelopment.

Revised December 19, 2011

First posted July 22, 2011