Improving the performance of Aquifer Storage and Recovery schemes using Multiple Partially Penetrating Wells

Aquifer Storage and Recovery (ASR) is one of the most effective ways of artificial groundwater recharge to assure freshwater availability during droughts in arid and semi-arid areas. However, this method of managed aquifer recharge is less prevalent in saline groundwater regions due to low recovery efficiency (RE). The injected freshwater of an ASR scheme in saline regions is decreased due to mixing between fresh-saline water and the upward movement of stored freshwater due to gravity effects. The losses due to mixing, however, can be reduced by managing the operational parameters. This study proposes a solution for reducing losses of injected freshwater due to gravitational within the saline aquifer by introducing multiple partially penetrating well-system (MPPW) in place of a single fully penetrating well-system (SFPW). A variable-density flow (SEAWAT) model is used to simulate and compare the ASR system performance for specific hydrogeological conditions and variable operational parameters for SFPW and MPPW well systems. The results indicate that by using MPPW in place of the SFPW ASR well system, 8 to 15% extra injected freshwater can be recovered. The difference in recovery efficiency due to the use of MPPW in place of SFPW tends to increase with the increasing values of injected freshwater storage duration and the number of successive ASR cycles and decreases with increasing the injection/recovery rates and injection volumes. This research provides the basis for understanding the suitable ASR well type for any specific site for different operational factors.