A Parsimonious Model for Simulation of Flow and Transport in a Karst Aquifer
Abstract
A new type of lumped parameter model was developed to predict the impacts of urban development of water quality and quantity in the Barton Springs portion of the Edwards aquifer. The model differs from other lumped parameter models by allowing vertical variation in model parameters within cells. The aquifer was divided in five cells corresponding to the watersheds of the creeks supplying recharge. Each cell was treated as a completely mixed tank with a single well selected to represent conditions in that portion of the aquifer. Simulations using historical data from the period 1979 through 1995 showed that the model could accurately reproduce measured water levels and average nitrogen concentrations in the aquifer and at Barton Springs. The impact of urbanization was simulated by estimating the changes in the hydrology of the creeks supplying recharge. The modeling results suggest that an intense level of development will reduce the average spring flow and significantly increase the average nitrogen concentration in the aquifer.
