Study on the influence of seawater density variation on sea water intrusion in confined coastal aquifers

The coupled influence of seawater density and groundwater level variation plays an import role in seawater intrusion in confined coastal aquifers. In this study, the effects of seawater density variations along with changing hydraulic gradients were investigated by conducting laboratory experiments and numerical simulations. Parameters of salinty and density in the experiments are based on the references related Bohai sea of China. The results indicate that the higher density of saltwater facilitates the seawater intrusion into the aquifers at the bottom and accelerates the circulation at the changing hydraulic gradient. Even slight variations in saltwater density can change the steady-state conditions in a confined aquifer, which should be considered when attempting to control the intrusion of seawater. Moreover, the influence of seawater density variations on transient salt-wedge dynamics was also examined in these experiments. Numerical modelling was simultaneously performed to mimic the behaviour of SW using the TOUGH2/EOS7 package. The simulated results were generally consistent with those obtained from the experiments. This study is conducive to further understand the mechanism of seawater intrusion, thereby leading to effective management of the problem in coastal areas.