Groundwater Flow Modeling for Qushtapa Plain Unconfined Aquifer in Southern Erbil Basin, Kurdistan Region, Iraq

Shwan Seeyan

doi:10.4236/gep.2020.83009

Abstract

Increasing population growth and water demand for various purposes such as irrigation, domestic and industrial production in many parts of the Kurdistan Region is causing deficit in fresh water and rising groundwater dependence. Drilling many deep wells in the area unsystematically and continuously increased pumping water from groundwater reservoirs results in lowering of water table. Therefore, it is essential to assess the management of water resources. The study focuses on the groundwater modeling for the Qushtapa District plain area in particular under steady state flow conditions. The aquifer was simulated under unconfined condition and is represented by a single layer of 100 m thickness. MODPATH was used to measure contamination track lines and travel times. This approach involved the introduction of particles at sources of contaminants in the wells and the recharge area, then the identification of the path lines and the determination of the special distribution of contaminants through steady state flow conditions. The simulation of the groundwater head shows that the groundwater head starts from the northeastern part of the plain and decreases towards Lesser Zab River in the south of the plain from 420 m to 140 m above sea level. The modeled layer was calibrated under steady state conditions using hydraulic parameters obtained from observation and pumping wells. The calibrated model is effective in producing steady-state groundwater head distribution and good compliance with observed data. The standard error was estimated as 4.88 m, the normalized root mean square error is 8.3% and the residual mean is 15.79 m. The results of the forward tracking show the source of potential pollutants from the recharge area after different travel time, the particles released at the northern boundary travels to the center and the western part toward the pollution sources. The results of the backward tracking show that the particles located in the extraction wells moved toward the recharge area in the north and northeastern part of the study area.

Highlights

IntroductionGroundwater models contribute additional insight into the complex system practice and can assist in advance special management strategies
The continuous exploitation of groundwater from aquifers for all purposes leads to the depletion of groundwater in many parts of the world (Ramesh & Fritz, 2016).Groundwater models contribute additional insight into the complex system practice and can assist in advance special management strategies.Groundwater modeling is a crucial tool to estimate and evaluate the groundwater flow and quantifying it’s potential
The aquifer was simulated under unconfined condition and is represented by a single layer of 100 m thickness

Summary

Introduction

Groundwater models contribute additional insight into the complex system practice and can assist in advance special management strategies. Groundwater modeling is a crucial tool to estimate and evaluate the groundwater flow and quantifying it’s potential. The same simulation applies to groundwater flow and contaminant transport modeling (Shwani, 2008) indicate that there is groundwater pollution in northwestern part of the study area as consequence of the human contamination, Agricultural crops and using insecticide in the soils to prevent the bacterial effect in the area of investigation. MODFLOW-2000 is the most widely used ground-water flow simulation program which is the only ground-water flow model capable of calculating accurate sensitivities for simple and complex flow systems (McDonald & Harbaugh, 1988; Harbaugh & McDonald, 1996; Harbaugh et al, 2000)

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Discussion

Conclusion