Modelling of Groundwater Flow of Baquba District Area, Diyala Governorate, North-East, Iraq

Abstract

Groundwater is one of the important water resources in the countries that have a scarcity in water resources such as surface water. Modeling of the Baquba shallow unconfined aquifer (Quaternary sediments) has been an attempt by transfer the conceptual model to GMS 10.0-MODFLOW2000 for solving the groundwater equations by the technique of finite-difference. Two types of boundary conditions have been applied (Neumann and Dirichlet conditions). The calibration of the model has been attempt based on adjusting two parameters hydraulic conductivity and recharge rate. The best matching between computed and observed head has been done. The results reflect that the sensitivity analysis shows that hydraulic conductivity and recharge rate are a more sensitive parameter, after calibration, six different scenarios have investigated to study the impact of the discharging rate on the groundwater state. In the five scenarios, the applying discharge rates in the current state and increased by (25%, 50%, 75% and 100%) successively above the current rate, while in the sixth scenario proposed agricultural land with drilling new wells. The stress period that has been applied in transit state extended from (2018-2027) with ten-time steps. The unsteady-state model simulation results for these scenarios clarify that the annual maximum drawdown values have been observed for the next ten years according to the five scenarios are equal to (11.426, 11.938, 12.246, 13.631, and 14.05) m respectively, while the annual maximum drawdown value recorded in the proposed scenario (current rate with the rates of the new wells) equal to 11.87m. As well as this increases in discharging rates indicated that the possibility of drilling new wells within the study area without any mining of aquifer. The results of the model reflect that the maximum values of the drawdown for the two regions of (Kanan and Buhriz) are very large, and according to this reason the management program is very important for dealing and manage the groundwater extraction in these regions