In most large and fast growing urban areas, finding suitable lands for construction of landfill is one of the serious problems in environmental management. Land fill site selection process depends on different factors, regulations and constraints. Ignoring each of these parameters may cause miscalculations and lead to selection of an inappropriate landfill site which could have negative environmental, economical, and ecological impacts. Therefore, this process must be accomplished by taking into account all of the related criterions and variables. In this study, landfill site selection is performed by combining geographic information system (GIS) and analytical hierarchy process (AHP) in Hamedan province, west of Iran. In relation to landfill site selection, ten different criteria including Geology, surface water, aquifer, land use, elevation, slope, and distance to main roads, residential areas, faults and sinkholes were investigated. Using AHP each criterion was weighted, then geographic information system (Arc GIS 9.3 software) was used to manipulate and present spatial data. Finally, suitability map was prepared by overlay analyses and most suitable and suitable areas were identified and checked in field. The results indicate that 60.4 % of the area in the Hamedan province (11,631 km2) is unsuitable, 33 % (6,257.7 km2) moderately suitable and 6.6 % (1,344 km2) most suitable for construction of landfill.
