Hydrogeological site investigation and economic evaluation to assess the potential of managed aquifer recharge in the Lower Jordan Valley

Improving water availability and distribution is key to combatting water stress in semi-arid regions. This study presents an approach that integrates hydrogeological surveys and economic analysis at a pilot site in the eastern Lower Jordan Valley to assess the potential for managed aquifer recharge (MAR). Based on exploratory drillings, hydraulic tests, water-quality analyses and previous studies, an appropriate storage space in the alluvial fans along the eastern margin of the valley was found. Average measured infiltration rates of 9.8 × 10−5 m/s in a gravel pit and average hydraulic conductivity values of 6.8 × 10−5 m/s in the aquifer indicate that up to 1 Mm3/year can be infiltrated and stored underground. It is assumed that water is trapped towards the center of the valley where the alluvial sediments inter-finger with fine-grained layers. An increase in electrical conductivity values in the same direction probably indicates irrigation return flow and the presence of evaporitic layers and suggests a water recovery before reaching these saline zones. Depending on whether the water provided by MAR is used for irrigation or domestic water purpose, an average incremental profit of 0.81 and 2.44 US$/m3 can be achieved, respectively. These calculations result in a net present value of the MAR plant of 10.6 or 31.9 million US$, respectively, over a lifetime of 30 years. The presented study serves as a basis for further investigations and planning of a MAR plant, and can be transferred and upscaled to other sites in the Jordan Valley.