Water Balance Assessment of Unconfined Aquifer (Karbala-Iraq)

Abstract

Groundwater is consider as a sole resource for irrigation in the study area. The unconfined Dibdibba aquifer in this area is considered as a producing hydrogeological unit that extend over large areas in the central and southern part of Iraq.In this study, hydrogeological characteristics of the aquifer system as well as aquifer flow direction were investigated. The pumping test results analysis by AQTESOLV Version 4.5 reveals that transmissibility and hydraulic conductivity of Dibdibba Aquifer in the study area ranged from (129–161) m2/day and (3.6–5.3) m/day respectively.The flow net showed that flow direction is from the southwest to the northeast and east, towards the discharge zone along the Euphrates River.Water balance was evaluated using meteorological data of Karbala meteorological stations. The main purpose of a water balance calculation is to predict temporal variations of water content in a closed system and to estimate change in groundwater storage in the study area. Overall calculations of the water balance components shows that the inflow water that reach the study area is (6,317.57 m3/day) while the amount of outflow water is (6931.93 m3/day). Therefore the change in the groundwater storage (ΔS) will be (−6,317.57 m3/day). This result is dangerous sign of increasing of groundwater consumption and overexploitation in the study area.