Model test and simulation on saltwater up-coning process caused by pumping of horizontal well

In coastal areas, fresh water is stored in the upper aquifer, and saltwater is in the lower aquifer caused by seawater intrusion. The phenomenon of saltwater up-coning is easy to occur when exploiting fresh groundwater, making the extracted groundwater salinized. Horizontal well can effectively postpone the time of up-coning, thereby avoiding the pollution of the upper freshwater. A test for simulating the process of saltwater up-coning caused by pumping of horizontal well is performed in this research, and the saltwater up-coning process caused by pumping of horizontal well with a constant flow rate is obtained. Then based on the analytical solutions of Dagan & Bear, the analytical solution of the saltwater up-coning process caused by pumping of horizontal well with infinite lateral boundaries is derived. The analytical solution shows that the interface is horizontal initially, protruding subsequently, and tapering around the well, which is consistent with the middle stage of the model tests. TOUGH2/T2DM is then used to simulate the test process of saltwater up-coning caused by pumping of horizontal well. The up-coning processes of saltwater-freshwater interface obtained by numerical simulation fit well with the model test results. Based on the proposed numerical model, the effects of boundary conditions and heterogeneity of media on saltwater up-coning process are analyzed. The saltwater up-coning process in laboratory scale studied by model tests, DB analytical solutions and numerical simulation model in this research can provide technical supports for further researches on saltwater up-coning in coastal aquifer.