Coastal Erosion Due to Seawater Intrusion into Groundwater Aquifers

Problem Statement: In general, the drinking water systems sourced from ground water (GW) contains chemi- cals at double the current maximum contaminant levels (MCL) of colloids. However, due to increasing demand of water, groundwater may be subjected to over-exploitation and the natural equilibrium is thus disturbed. A steady-state condition is established between seawater and freshwater in a coastal aquifer. This results in aggressive groundwater-surface water interaction, which may even reach the inland aquifer. Approach: The objectives of this research are to determine the level of contamination of groundwater by seawater intrusion and to identify its hazard. A flow model is created using the study area, Kanchong Darat in state of Selangor in West Malaysia in Visual MODFLOW environment. By a transient-state analysis the environmental impact due to groundwater pumping has been studied and the results of are obtained. Conclusion: The simulation results revealed that GW would get lower, and finally the interface between fresh and saltwa- ter could gradually move inland if the abstraction of GW is continued and become over-exploited. In the model the draw- down (DD) at the top most aquifer (depth of 55 m) has been found with a depression cone of radii around 3650 m after 1 day of pumping; the radii reached 7500 m with depth of DD 55.5 m after 10 days, while after 30 days of pumping; it reached about 10 km with DD 56.8m. These models are useful for better water resource management and to understand the coastal hazards into inland resources wherein 75% of the water resource is based on groundwater system.