High Plains Aquifer System
| As part of the the NAtional Water-Quality Assessment (NAWQA) Program,
the USGS is evaluating ground-water quality in the High Plains aquifer
system. The High Plains aquifer system underlies 175,000 square miles in parts of eight
States (CO, KS, NE, NM, OK, SD, TX, and WY) (figure
1). Approximately 27 percent of the irrigated land in the United States is
in the High Plains and about 30 percent of the groundwater used for irrigation
in the U.S. is pumped from the High Plains aquifer. Irrigation withdrawals in 2000 were 17 billion gallons per day. In 2000, 1.9 million
people were supplied by groundwater from the High Plains aquifer with total
public-supply withdrawals of 315 million gallons per day.
The quality of water in the High Plains aquifer generally is suitable for irrigation use but, in many places, the water does not meet U.S. Environmental Protection Agency drinking-water standards with respect to several dissolved constituents (dissolved solids/salinity, fluoride, chloride, and sulfate). Only sparsely scattered water-quality data are available for pesticides, volatile organic compounds, and trace metals in the High Plains aquifer system. Nutrient data are available, to a varying degree, across the aquifer.
Beginning in 1999 and continuing for a period of 6 years, the High Plains Regional Groundwater Study will intensively investigate the quality of groundwater resources within the study area. Investigations will begin in the Central High Plains and move to the Southern High Plains and Northern High Plains as the project progresses (figure 1). Water quality impairment coupled with water-level declines focus concern on the continued sustainability of this Nationally important groundwater resource.