In the Brunswick, Georgia, area (fig. 1), saltwater has been contaminating the Upper Floridan aquifer for about 50 years. As of 2008, within a 2-square-mile (mi2) area in downtown Brunswick, the aquifer yielded water with a chloride concentration greater than 2,000 milligrams per liter (mg/L), which exceeds the State and Federal secondary drinking-water standard of 250 mg/L (Georgia Environmental Protection Division, 1997; U.S. Environmental Protection Agency, 2000).