HYDROGEOLOGY OF AL-JAZIRA AREA

Abstract

The Iraqi Jazira Area is generally a flat terrain of less rugged topography with scattered hills. It is dissected by shallow wadis with presence of numerous salt marshes. The drainage is either internal into the marshes, swamps and sabkhas, or originating at the slope of the main structures. The recharge sources of the groundwater in the Jazira Area are mainly direct infiltration and/ or run off, from the intermittent wadis in form of percolation in shallow aquifers. The main water bearing formations in the area are Fat'ha and Injana formations in addition to Quaternary sediments. The groundwater discharge areas occur along Tharthar Lake and Sabkhas.The regional trend of the groundwater movement in the Jazira Area is generally from north towards south, southeast and southwest. However, locally, the flow of the groundwater takes different directions depending on geological setting, topographic and structural features. The depth of the groundwater reaches some tens of meters in the northern parts, while it is near the surface or as seepage within the discharge areas, along Tharthar Valley and Tharthar Lake and at low lands of salt marshes.Salinity of the groundwater in the Jazira Area increases, generally from the recharge areas, in the northern parts towards the discharge areas. The quality of the groundwater is mainly sulphatic with chloride and bicarbonate water types in some areas. According to the hydrogeological interpretations, the promising zones of good water qualities and quantities are fixed in Injana Formation, within the northern parts of the Jazira Area near the recharge areas.