Future Water Supplies from Ogallala Aquifer Could be in Jeopardy

A new report from the U.S Geological Survey says that future water supplies from the High Plains or Ogallala aquifer could be in jeopardy if large amounts of water are pumped out of it and if farmers continue using chemicals on the land above it.

The aquifer is the most heavily used groundwater resource in the United States, supplying water to Kansas, Colorado, Nebraska, New Mexico, Oklahoma, South Dakota, Texas and Wyoming. Most of the water is used for irrigation, but about 2 million people also depend on it for drinking water. 

Of particular concern to researchers is nitrate, which was found in high concentrations in about six percent of drinking water wells tested. Although nitrate is naturally occurring, it's also a byproduct of fertilizer and manure.

The vulnerability of the Ogallala aquifer is that its recharge rate is limited by a number of factors. The plains region is semi-arid with steady winds that quicken evaporation of surface water and rain. In some locations, the aquifer is overlain with a shallow layer of sedimentary rock that is almost impermeable. And, while recharge does occur through the high plains playa lakes, their destruction, caused by farmers and development, decreases the available recharge area.  All of these factors limit the amount of water able to recharge the aquifer from the land surface. 

While the water quality from the aquifer is currently very good, Jason Gurdak, lead author of the study, says that changes in how the water is used will need to be made if supplies are to last into the future.

Photo: USGS