Steady-state effect of freshwater injection on seawater intrusion

Steady-state solutions for the motion of the freshwater-seawater interface due to series of injection wells were obtained using a sharp interface finite element model. The performance of the numerical model was tested with the existing analytical solution. The model was then used to perform the parametric studies on the effects of the location of the series of injection wells, spacing of the wells, and the freshwater injection rate on the seawater intrusion into coastal confined aquifers. The performances of the injection wells in single and double series along the coast were studied and compared. The key variables were grouped into nondimensional parameters, and the relationship between them was presented as a set of characteristic curves. Results indicate that the reduction of seawater intrusion (up to 60-90%) can be achieved through proper selection of the injection rate and spacing between the wells.