Simulation of Various Management Scenarios of the Mississippi River Valley Alluvial Aquifer in Arkansas

The Mississippi River Valley alluvial aquifer is a water-bearing assemblage of gravels and sands that underlies most of eastern Arkansas and several adjacent States. Ground-water withdrawals have caused cones of depression to develop in the aquifer’s water-level surface, some as much as 100 feet deep. Rivers, such as the Arkansas, White, St. Francis, and Mississippi Rivers, are in hydraulic connection with the alluvial aquifer. Recharge to the alluvial aquifer from these rivers becomes induced as ground-water level declines. Long-term water-level measurements in the alluvial aquifer show an average annual decline of 1 foot per year in some areas. The expansion of the cones of depression and the consistent water-level declines indicate that ground-water withdrawals are occurring at a rate that is greater than the sustainable yield of the aquifer.