Landfills are one of the groundwater pollution sources in the world. This study focuses on two landfills; the first has a lining system and the second does not have lining system to assess the generated leachate quantity and percolation to the groundwater aquifer at a specific sites, using the approaches of (i) the Hydrologic Evaluation of Landfill Performance model (HELP) and (ii) the water balance method (WBM). Furthermore, landfill components were analyzed to study their influence on the quantity of percolated leachate to groundwater. The Geographic Information System (GIS) was used as a...