Jordan Journal of Civil Engineering

Modeling Groundwater Flow and Solute Transport at Azraq Basin Using ParFlow and Slim - Fast


Shadi Moqbel; Wa’il Abu-El-Sha’r;


Azraq basin, being one of the largest basins in Jordan and a viable drinking water resource, witnessed a dramatic increase in water demand over the past four decades. This led to an over-abstraction from this aquifer, which in turn resulted in deterioration of its water quality. To better manage and sustain this and other aquifers, new elaborate computer codes, called ParFlow and Slim-Fast, have been used to simulate groundwater flow and contaminants’ transport at Azraq basin. ParFlow is a portable and parallel processing simulator, designed for modeling multi-phase fluid flow in 3D heterogeneous porous media. This code possesses a local mesh refinement capability, uses site topography and subterranean formations and offers a variety of numerical methods for various aspects of numerical simulation, while Slim-Fast uses the random walk method to solve sub-surface transport problems of multi-phase, multi-constituent contaminant mixture. Slim-Fast was written specifically to exploit a quasi-analytical formulation to find a rapid solution for the advection transport. These codes provided means to predict the hydraulic head in the upper and middle aquifers, simulate the movement of Total Dissolved Solids (TDSs) in the upper aquifer and estimate the age of groundwater. Results from groundwater model showed that steady state drawdown at points of observation may reach 28 m, which exceeds the 15.3 m drawdown previously predicted by other formal studies. Contaminant transport model results indicated that the concentration of total dissolved solids is expected to increase slowly in the basin due to the movement of high-salinity water toward the pumping wells used for domestic purposes. Estimated values of groundwater age varied between 3000 and more than 50,000 years based on the flow direction.


Groundwater flow, Over-abstraction, Hydrochemical modeling, Numerical modeling, Groundwater age, Azraq basin, ParFlow, Slim-Fast.