Three-dimensional modeling of density-dependent salt water intrusion in multilayered coastal aquifers in Jahe River Basin, Shandong Province, China

A three-dimensional variable density flow and transport model has been developed to study salt water intrusion in the Jahe River Basin, Shandong Province, China. A coupled Eulerian-Lagrangian method is applied to solve the transport equation, in which the advection part is calculated by a hybrid method of characteristics. In using the density-dependent tidal effect model, the seaward boundary in the confined aquifer is determined according to tidal-effect information, The aquifer parameters in the Jahe River Basin are estimated by converging long-term observational data of the hydraulic head and chloride concentration. Through numerical analysis and prediction, it can be concluded that the main reasons for salt water intrusion are excessive ground water exploitation and an improper arrangement of pumping wells in the lower reaches of the Jahe River Basin as well as the tidal-affected river, After predicting the effect of several remedial schemes, two measures are suggested to prevent salt water intrusion.