Laboratory and numerical investigation of saltwater intrusion into aquifers

Laboratory methods along with numerical solutions are suitable methods to study the process of seawater intrusion (si) into aquifers. in this study,we successfully visualized the saltwater intrusion process in a laboratory scale model. also the si process was numerically simulated using the seawat model to validate the physical model results. the effects of saltwater concentration variations and freshwater head gradient changes on the interface movement and how they influence the interface behavior in recession and intrusion stages,were key points of this study. results showed that the saltwater with c2 concentration (50g/l) intruded into a greater part of the aquifer than that with the concentration of c1 (35g/l). moreover,intruding rates of the fresh-salt water interface by application of the c2 concentration were faster than those by application of the c1 one in all the experiments. in the both concentrations,raising the freshwater level by 0.5 cm caused the interface to recede about 30 cm and vice versa. comparing the intruding and receding data under an identical experimental condition showed that the recession time of the fresh-salt water interface was less than its intrusion time,which was an important result in si management. we also analyzed the dispersion effect and measured the mixing zone thickness as 2.5 cm. finally the velocity vector analysis was done to investigate the saltwater and freshwater velocities under the steady state conditions. furthermore,comparison of the seawat simulation results with the experimental data showed a good agreement between them. © 2017,university of mohammed premier oujda morocco.