Water-Level Changes in the High Plains Aquifer, Predevelopment to 2013 and 2011-2013

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 (about 1950). The U.S. Geological Survey, in response to a request from Congress, has monitored water levels in the aquifer since 1987 using water-level data from local, state, and federal entities.

In 2005, estimated irrigated acreage in the aquifer area was 15.5 million acres, or about 14 percent of the aquifer area. In 2005, estimated groundwater withdrawals from the High Plains aquifer for irrigation were 19 million acre-feet, or about 95 percent of total groundwater withdrawals.

Water-level changes from predevelopment to 2013 were assessed using measurements from 3,349 wells. Water-level changes from predevelopment to 2013, by well, ranged from a rise of 85 feet to a decline of 256 feet. Area-weighted, average water-level change from predevelopment to 2013 by state ranged from a rise of 1.8 feet in South Dakota to a decline of 41.2 feet in Texas and was an overall decline of 15.4 feet.

Water-level changes from 2011 to 2013 were assessed using measurements from 7,460 wells. Water-level changes from 2011 to 2013, by well, ranged from a rise of 19 feet to a decline of 44 feet. Area-weighted, average water-level change from 2011 to 2013 by state ranged from 0 feet in South Dakota and Wyoming to a decline of 3.5 feet in Texas and was an overall decline of 2.1 feet.

Total water in storage in the aquifer was about 2.92 billion acre-feet in 2013. This was a decline of about 266.7 million acre-feet since predevelopment and a decline of 36.0 million acre-feet from 2011 to 2013.