A Decision Support System to Manage the Groundwater of the Zeuss Koutine Aquifer Using the WEAP-MODFLOW Framework

This paper describes the development of a Decision Support System (DSS) for groundwater management of the ‘Zeuss Koutine’ aquifer in southeastern Tunisia using the WEAP-MODFLOW framework. First, a monthly MODFLOW model was developed to simulate the behaviour of the studied aquifer. A conceptual model of the study area was designed and a WEAP schematic representing the real hydraulic system was developed. In addition to the studied aquifer, other water resources available in the region, such as desalination plants and groundwater, were taken into consideration in this DSS. Inputs to the hydrogeological model include natural recharge and inflow from higher neighbouring aquifers. Outputs are mainly agricultural, touristic and urban water consumption. It was shown that the DSS developed was able to evaluate water management scenarios up to 2030, especially future water consumption, transmission link flow and active cell heads of the MODFLOW model for each time step. Results for the Zeuss Koutine aquifer demonstrated that desalination plants already built in the cities of Jerba and Zarzis have contributed to decreasing the continuous drawdown observed before 1999. The use of a sea water desalination plant to supply Jerba and Zarzis in the future is a solution for reducing the Zeuss Koutine aquifer drawdown. Defining its optimal capacity over time poses a new research question.