ORIGINAL PAPER Evaluation of aquifers vulnerability to contamination in the Yarmouk River basin, Jordan, based on DRASTIC method Muheeb M. Awawdeh & Rasheed A. Jaradat Received: 18 April 2009 / Accepted: 19 June 2009 / Published online: 13 August 2009 # Saudi Society for Geosciences 2009 Abstract The existing different human activities and planned land uses put the groundwater resources in Jordan at considerable risk. There are evidences suggesting that the quality of groundwater supplies in north Jordan is under threat from a wide variety of point and non-point sources including agricultural, domestic, and industrial. Vulnerabil- ity maps are designed to show areas of greatest potential for groundwater contamination on the basis of hydrogeological conditions and human impacts. DRASTIC method incor- porates the major geological and hydrogeological factors that affect and control groundwater movement: depth to groundwater (D), net recharge (R), lithology of the aquifer (A), soil texture (S), topography (T), lithology of vadose zone (I), and hydraulic conductivity (C). The main goal of this study is to produce vulnerability maps of groundwater resources in the Yarmouk River basin by applying the DRASTIC method to determine areas where groundwater protection or monitoring is critical. ArcGIS 9.2 was used to create the groundwater vulnerability maps by overlaying the available hydrogeological data. The resulting vulnera- bility maps were then integrated with lineament and land use maps as additional parameters in the DRASTIC model to assess more accurately the potential risk of groundwater to pollution. The general DRASTIC index indicates that the potential for polluting groundwater is low in the whole basin, whereas the resulting pesticide DRASTIC vulnera- bility map indicates that about 31% of the basin is classified as having moderate vulnerability, which may be attributed to agricultural activities in the area. Although high nitrate concentrations were found in areas of moderate vulnerabil- ity, DRASTIC method did not depict accurately the nitrate distribution in the area. Keywords Groundwater . GIS . DRASTIC . Yarmouk River . Jordan . Land use Introduction Jordan is overusing its annual renewable freshwater resources. Groundwater is a major source of water for domestic, industrial, and agricultural uses in Jordan. Excessive ground- water withdrawal has caused a severe lowering of the water table of more than 2 m/year in some well fields in central and northern Jordan (Margane 1995). Nitrate concentrations exceeding the Jordanian Standards for Drinking Water in some of the intensively cultivated areas indicate groundwater pollution (Margane et al. 1999; Nawafleh 2007; Obeidat et al. 2008). Groundwater vulnerability maps have become a widely accepted tool in the land use planning process that takes into consideration aspects of groundwater protection from pollution. With the help of vulnerability maps, activities that are possibly hazardous to groundwater resources, such as waste disposal sites, sewage treatment plants, industrial plants, and commercial sites can be appropriately located in areas of low contamination risk. At the same time, these maps help in delineating groundwater protection zones for wells and springs and help in putting into place groundwater monitoring, emergency, or rehabilitation measures. The concept of groundwater vulnerability is based on the assumption that the physical environment may provide some degree of protection to groundwater against natural impacts, especially with regard to contaminants entering the subsur- face environment (Napolitano 1995). Consequently, some land areas are more vulnerable to groundwater contami- nation than others. Vulnerability maps show the distribu- tion of highly vulnerable areas, in which pollution is very common because contaminants can reach the groundwater within a relatively short time. However, groundwater vulnerability maps do not replace more detailed studies M. M. Awawdeh (*) : R. A. Jaradat Department of Earth and Environmental Sciences, Yarmouk University, Irbid 21163, Jordan e-mail: awawdeh@yu.edu.jo Arab J Geosci (2010) 3:273–282 DOI 10.1007/s12517-009-0074-9