TY - JOUR ID - TI - HYDROGEOLOGY OF THE MESOPOTAMIA PLAIN AU - Hatem K. Al-Jiburi AU - Naseer H. Al-Basrawi PY - 2011 VL - SPECIAL ISSUE - Issue IS - 4 SP - 1 EP - 21 JO - Iraqi Bulletin of Geology and Mining مجلة الجيولوجيا والتعدين العراقية SN - 18114539 AB - The Mesopotamia Plain is characterized, topographically as a flat plain that slopes gentlybetween Baghdad and Basrah, but it is gently undulated in its northern parts. It is totallycovered by Quaternary sediments. These sediments are composed of alternation of clay, siltyclay, clayey silt, silt, sand and gravel. Fine sediments represent the aquitards, while sand andgravel form the aquifers. These sediments have abrupt lithologic changes, both laterally andvertically, therefore, are considered regionally as a lithologically complex aquifer system.There is a hydraulic continuity within the entire Quaternary aquifer system, but the degree ofthe continuity differs from place to another, depending on the lithological characteristics ofwater bearing sediments. It is assumed that, a hydraulic continuity is present between surfacewater and groundwater aquifers, to some extent. Therefore, effluent and influent riverphenomena exist throughout the plain. Moreover, there is a hydraulic continuity betweenQuaternary aquifer system, in the plain and the underlying pre-Quaternary formations.The groundwater level fluctuations throughout the Mesopotamia Plain depend, mainly onthe natural conditions and to some extent on artificial conditions. Generally, water bearingQuaternary sediments, of the plain are considered quantitatively promising, but the problem isconcerned with the quality of the groundwater. High salinity of the groundwater prevailsthroughout the plain, but the groundwater, which is close to rivers and main irrigationchannels may be in better condition for exploitation, particularly where phenomenon ofinduced seepage of fresh water exists, also in areas along Low Folded Zone, where rechargewater zones exist.The direction of the groundwater flow is towards the center of the Mesopotamia Plain,from all neighboring regions, because the plain represents a regional discharge zone for thewhole Mesopotamian Aquifer Mega System of Iraq. The piezometric level of the groundwateris generally inclined from north and northwest (it is < 200 m, a.s.l., near Makhoul Mountain)towards south and southeast (2 m, a.s.l., near Basrah city). The salinity of the groundwaterincreases generally from the recharge areas towards discharges areas, within the plain. Thechemical quality of the groundwater changes from sulphatic to chloridic type from recharge todischarge areas, respectively, being in accordance with the groundwater movement.

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