A NATIONAL ASSESSMENT OF BRACKISH GROUNDWATER

Large-scale development of groundwater with accompanying declines in groundwater levels has led to concerns about the future availability of fresh water to meet drinking-water, agricultural, industrial, and environmental needs. Industry and public drinking-water suppliers are increasingly turning to brackish groundwater to supplement or replace the use of fresh water. Data from the USGS Water Use Program show that brackish or saline groundwater use in the United States has increased from about1 billion gallons per day in 1995 to 3 billion gallons per day in 2005. Although early investigations estimated that two-thirds of the conterminous United States is underlain by mineralized aquifers, relatively little is known about brackish groundwater. The objective of the USGS National Brackish Groundwater Assessment is to develop a better understanding of the distribution and character of brackish groundwater to support develop­ment of the resource and to provide a scientific basis for associated regulatory and policy issues.