Evaluating the impact of urbanization on groundwater resources, a case study in Karaj Plain, Alborz Province, Iran

Urbanization has profound impact on the hydrogeologic systems. Urbanization may lead to the groundwater contamination, especially where the sanitary sewer systems are absent and/or are not well-designed. This paper aims to provide a hydrogeochemical characterization of the groundwater in the Karaj metropolitan area, Alborz Province, one of the most densely populated areas in Iran. The moving of population from rural areas (because of long drought periods) to megacities in Iran, promoted the semi-urbanization in this area. However, the urban infra-structures are not well-developed in the area. This plain has experienced extensive population growth during last decade. Although, the groundwater withdrawals have increased for water resources and human induced sewage is increased dramatically, there is no sanitary sewer system. To evaluate the impact of urbanization, we analyzed the long term groundwater qualitative and quantitative characteristics. In addition, we considered the study area urbanization rate. The results show that the groundwater system in the study area is seriously at risk and vulnerable to human induced sewage