Saturated unsaturated subsurface flow and salinity transport using method of lines

A new model is presented to solve the coupled flow and salinity transport equations in the continuous saturated and unsaturated flow domain. The numerical model employs the method of lines, a technique that reduces the non-linear partial differential equations to a set of ordinary differential equations. The model is verified with a comparison to a quasi-analytical solution, and used to show the effects of infiltration and recharge on the water table location and salinity distribution in a tidal marsh plain environment.