Groundwater Flow Modeling - Case Study of the Eocene Aquifer in the West Bank, Palestine

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Journal Title, Volume, Page: 
Engineering - Water and Environmental Engineering, An-Najah National University, Nablus. Palestine
Year of Publication: 
2003
Authors: 
Hamees "Mohammad Sameh" Rawhi Tubeileh
Department of Civil Engineering, Faculty of Engineering and Information Technology, An-Najah National University, Nablus. Palestine
Current Affiliation: 
Department of Civil Engineering, Faculty of Engineering and Information Technology, An-Najah National University, Nablus. Palestine
Preferred Abstract (Original): 

The Eocene aquifer is one of the major groundwater basins in Palestine. It is located at the northeastern part of the West Bank covering areas in both Jenin and Nablus districts. The aquifer is considered one of the main sources for fresh water for the majority of the population in the northern West Bank. Many models have been formulated to develop the groundwater resources within the Eocene aquifer. In this thesis a simulation for the groundwater flow is developed. MODFLOW, as a strong available groundwater modeling tool, has been used to model the Eocene aquifer. The groundwater budget, flow computation and flow path lines were estimated and calibrated. Groundwater balance has been also evaluated. The modeling indicated that the model runs only for certain initial hydraulic groundwater levels of more than 340m. The recharge and hydraulic conductivity were found to be the most sensitive model parameters. The hydraulic conductivity has resulted double of the original value in some areas. This is due to neglecting the faults and fractures effect. The recharge coefficients resulted in high inflow values. Groundwater balance indicated that the water budget of the Eocene aquifer totals about 72MCM/yr. The simulation showed that the groundwater level increases gradually by increasing the recharge rate. The change of groundwater level is nearly linear. Due to the variation in the aquifer geometry, the groundwater levels were mild at the beginning and became steeper as the recharge ratio increase. The groundwater levels showed higher sensitivity to hydraulic conductivity as its value increases from moderate to high or from moderate to low values. There has been a reasonable matching between the observed and calibrated groundwater level and spring flows. The direction of the flow within the aquifer is from the south to north and northeast. The Far’ a spring system located in the south of the aquifer, seems to be the major sink point within the aquifer since it attracts most of the particle tracking lines in the model. This is due to its high discharge rates. Based on the results of this study it is recommended that groundwater wells located or proposed at or near the anticlinorium should be designed and operated carefully. The gradients and the modeling results indicate that a substantial quantity of groundwater flow across the eastern and the northeastern boundaries, materialized as lateral subsurface outflow. It is recommended that this good quality water could be tapped and exploited. Field investigations are recommended to verify the geological conditions. It is recommended to monitor the existing wells and springs permanently and to construct a reasonable additional monitoring network. this package can be applied to model groundwater transport model for the Eocene aquifer. A finer grid is important in order to control the variation in hydraulic properties. In this study the effects of the fractures (due to the faults) are neglected. So it is recommended to assess carefully the effect of the faults on the actual hydraulic conductivity.

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