The City of Savannah owns and operates an industrial and domestic (I&D) water treatment plant. The raw water intake for this facility is on Abercorn Creek, a tributary of the Savannah River (fig. 1). The conventional water treatment plant was constructed in 1947 to treat 35 million gallons of water per day (Mgal/d). The plant originally served many industries in the area that required water with a chloride concentration of less than 12 milligrams per liter (mg/L). Historically, the water plant withdrew groundwater and surface water to meet its quantity and quality water demands. As the population of Savannah increased, the treatment plant and its associated processes have been upgraded to its current 75-Mgal/d maximum capacity. Because of groundwater salinity intrusion in the Savannah area, a capacity-use restric-tion has been imposed on groundwater withdrawals, and the plant has expanded its use of surface-water supplies (Georgia Environmental Protection Division, 2001).