Preliminary projections of the effects of chloride-control structures on the Quaternary aquifer at Great Salt Plains, Oklahoma

About 1,200 tons of chloride per day are added to the salt load of the Salt Fork Arkansas River at Great Salt Plains Lake.from brine discharge from the rocks of Permian age in the vicinity of the lake. The U.S. Army Corps of Engineers has planned a chloride-control project. The Corps requested that the U.S. Geological Survey use a digital model to project the effects of the chloride-control structures on ground water. Ground-water flow and ground-water transport models were calibrated to represent the Quaternary aquifer (the near-surface part of the flow system). Although ground-water levels are projected to rise as much as 19 feet in areas near three reservoirs, changes in ground-water levels caused by the project will be small throughout most of the area. Chloride concentration of ground water is projected to increase by more than 90,000 milligrams per liter at one location. However, significant increases in chloride concentration during the 50-near period simulated are projected to be limited to areas where the ground water already contains excessive chloride concentrations.