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Numerical simulation of saltwater intrusion in a groundwater basin

1996-07-01
EMEKLI, NUSRET
Karahanoğlu, Nurkan
Yazıcıgil, Hasan
DOYURAN, VEDAT
The spatial and transient behavior of the coupled mechanism of saltwater and freshwater how throughout the Erzin, Turkey, groundwater basin was analyzed to forecast the position of the interface under a particular set of recharge and discharge conditions. The density-driven saltwater intrusion process was simulated with the use of a finite-element model. Physical parameters, initial heads, and boundary conditions of the basin were defined on the basis of available field data, and an areal, steady-state groundwater model was constructed to calibrate the observed head values corresponding to the initial development phase of the aquifer. Initial and boundary conditions determined from the areal calibration were used to evaluate the aquifer's dispersivities and the porosity in a steady-state, cross-sectional analysis. Consequently, the initial position of the salt concentration distribution was calibrated under steady-state conditions. The initial concentration distribution was then marched through time under discharge and recharge conditions, and the present-day position of the interface was predicted. In the cross-sectional simulation, the saltwater front was predicted to move inland during the discharge period, whereas in the recharge period the heads were pre dieted to recover to their initial positions with no significant movement of saltwater. The present-day distribution of salt concentrations was estimated via a 25-year simulation. Results indicate that the width of the dispersion zone has increased during this period and the saltwater encroachment has gradually been slowed down, tending toward a new steady-state position.