Study of Saltwater Intrusion in the Coastal Aquifers under Transient Condition using Image Processing and Numerical Modelling

Understanding the problem of saltwater intrusion under transient condition has an effective role in the management of coastal groundwater resources. In this study, the transient dynamics of the saltwater wedge and mixing zone was investigated in an aquifer with head-controlled system both numerically and experimentally. The experimental data were acquired using image processing and numerical simulations were conducted by SUTRA code. In order to study the saltwater wedge behavior in transient condition, in addition to examining the changes of the indicator of wedge toe length (that was used in most of the previous experimental and numerical studies), changes in indicator of the saltwater wedge height on the sea boundary were measured too. The results demonstrated that in the case of the advancing wedge, the wedge height reaches the steady state condition sooner than the wedge toe length, while in the case of the receding wedge, both indicators are stabilized simultaneously. Furthermore, the results for mixing zone showed that due to flushing and mixing process, the mixing zone expanded at early stages of the receding period. As the wedge approaches the steady state condition, the flushing and mixing process were stopped and mixing zone condensed gradually.