Effects of sea-water intrusion interface on the flux of contaminant from coastal aquifers into the coastal water: Results of seven years of continuous work on modeling of ground water discharge into the coastal zone

Recently, a regional-scale numerical model for simulation of groundwater flow and contaminant transport in coastal aquifers has been developed by Ataie-Ashtiani (2004). In this paper, this numerical model is employed to study the influence of Sea Water Intrusion Interface (SWII) on the temporal and spatial variations of contaminant flux from coastal aquifer into the sea. For this study a large number of simulations for different scenarios are performed. For the cases that the land-ward boundary condition are constant head, it is shown that simplification and neglecting the effects of SWII causes an erroneous estimate of the speed of the contaminant plume movement toward sea. The value of hydraulic conductivity has a significant effect on the amount of discharged contaminant. It is concluded that the over-simplification of sea-ward boundary condition in numerical simulations causes an incorrect estimate of temporal and special variations of the discharged contaminant into coastal water.