Jesper Bjergsted Pedersen

During the last century, many large irrigation projects were carried out in arid lands worldwide. Despite a tremendous increase in food production, a common problem characterizing these zones is land degradation in the form of waterlogging. A clear example of this phenomenon is in the Nubariya depression, Western Desert, Egypt. Following the reclamation of desert lands for agricultural production, an artificial brackish and contaminated lake started to develop in the late 1990s. Available data provide evidence of a simultaneous general deterioration of the groundwater system. With the main objectives of understanding the hydrological evolution of the area, characterizing the hydrogeological setting and developing scenarios of artificial aquifer remediation and recharge, an extensive hydrogeophysical investigation was carried out in this challenging environment using Magnetic Resonance Sounding and ground-based Time-domain EM techniques. The integrated interpretation of the geophysical surveys provided a clear hydrogeological picture of the upper 100-m sedimentary setting, in terms of both lithological distribution and groundwater quality. The information is then used to setup a regional groundwater flow and a local density-dependent flow and transport numerical model to reproduce the evolution of the aquifer system and develop a few scenarios of artificial aquifer recharge using the treated waters provided by a nearby waste-water treatment plant. The research outcomes point to the hydrological challenges that emerge for an effective management of water resources in reclaimed desert areas and they highlight the effectiveness of using advanced geophysical and modeling methodologies.