عنوان مقاله [English]
Clean water is an essential requirement for human beings. In areas having limited source of water, it is possible to dig wells to reach and supply groundwater. As water consumption is increasing by the population growth,it is essential to study and investigate the groundwater contamination. As it is somehow impossible to have many boreholes in an area it is required to use contamination dispersion modeling to predict and estimate the groundwater contamination at various points and time. Applying modeling will lead to a great deal of savings both in time and investment. Mathematical modeling of dissolved contamination un-steady dispersion in groundwater for the case in which the contaminant source leaks (5000 ppm) only for 6 months and then the leakage has been ceased. The base equation includes contamination transfer via both dispersion and advection; it has also been solved using the finite difference method. In case of having continuous leakage, the maximum contamination concentration occurs beneath the leakage point. After 2 months of leakage cessation, maximum leakage concentration and distance from the source are respectively 3200 ppm and 50 m while after 7 months of leakage cessation, the contamination concentration will be 370 ppm at a distance of 50 m from the point source. Contamination concentration will be 50 ppm at a half of kilometer distance from the point source after 7 months of leakage cessation.