GIS-Based Numerical Modeling of Aquifer Recharge and Saltwater Intrusion in Arid Southeastern Tunisia

Water resources globally face unprecedented challenges, but these are at their greatest in the world's arid and semiarid regions. Groundwater plays an important role in the economic development and ecological balance of the arid area of southeast Tunisia. This paper presents the potential to use saline water in sustainable agricultural production in arid southeast Tunisia and the development of a numerical model of groundwater flows for the aquifer system of the El Hicha aquifer. It presents the quantity and quality of saline water resources data and the integration of poverty indicator information with saline water resources. The numerical model constitutes the main method used to solve the groundwater quantity management problems and to evaluate the groundwater flow mixing between different aquifer levels. A groundwater numerical model for El Hicha Basin, an arid area of southeast Tunisia, was developed using MODFLOW software, a Geographic Information System (GIS)-based package, to simulate regional groundwater changes under steady-state and transient conditions. The results from calibration of the model show reasonable agreement between observed and calculated water for the observation wells. The reliability of the model is tested by a long series of historical groundwater monitoring data, and the model is then used to predict the impact of groundwater exploitation until 2020 and 2050. It is shown a significant drawdown and an enhanced seawater intrusion in the El Hicha aquifer. Under current water resources management conditions, groundwater levels in the El Hicha aquifer are in a continuous drawdown trend. It is necessary to take measures to reduce groundwater exploitation to protect the ecological environment.