Simulations of non-steady flow in a glacial outwash aquifer, southern Franklin County, Ohio

A two-dimensional, finite-difference model is used to simulate transient flow conditions in a glacial outwash aquifer in southern Franklin County, Ohio. The model was calibrated by matching observed and simulated water-level changes for December 1977 through March 1980. Drawdowns for three different hypothetical pumping rates are simulated with the calibrated flow model. An increase in the pumping rate from the steady-state rate of 10 cubic feet per second to 48 cubic feet per second results in water-level declines of 10 to 20 feet near the area of the pumping wells. Declines of 20 to 40 feet result when the pumping rate is increased to 70 cubic feet per second, and a simulated pumping well goes dry when the combined pumping is increased to 94 cubic feet per second. For the first two cases, steady-flow conditions are reached after 12 years of pumping; infiltration through riverbeds accounts for 28 to 33% of the pumpage.