A study of the analytical solution for seawater intrusion in a coastal vertical heterogeneous unconfined aquifer

Groundwater in coastal areas is a vital resource for various human activities. However, increasing water consumption and sea level rising pose significant threats to the safety and sustainability of this resource through seawater intrusion, which has become increasingly pronounced. This paper employs analytical methods to derive solutions for the length of steady-state saltwater wedge and the spatial distribution of saltwater-freshwater interface in a coastal vertical heterogeneous unconfined aquifer affected by seawater intrusion. A parameter sensitivity analysis is conducted to determine the influence of key hydrogeological parameters on the extension length of the saltwater wedge. The effectiveness of the analytical solutions obtained is subsequently verified through numerical simulations. The proposed solutions can be utilized to predict both the extension length of the saltwater wedge and the spatial distribution of the saltwater-freshwater interface resulting from seawater intrusion in coastal vertical heterogeneous unconfined aquifers.