This paper describes the characteristics of the aquifer systems in Wadi ElLajjun Catchment Area, Jordan.The investigated area lies between coordinates 218-255E and 105-107.7N(according to Palestine grids) and covers an area of about 643.3 square kilometers.The Mesozoic system, especially the Upper Cretaceous sedimentary rocks are the most dominant formations in the study area.The Upper Cretaceous ...