Synthesis of research findings and general criteria for sustainable groundwater recharge and recovery in saline aquifers

Abstract

Managed Aquifer Recharge (MAR), a reliable technique for groundwater restoration in arid regions, struggles with the limited recovery of stored water in salt-affected areas due to fresh-saline water mixing. Groundwater recharge and recovery project performance in saline aquifers is primarily controlled by operational factors because it influences fresh-saline water mixing significantly. Understanding the impact of operational factors is thus crucial for optimizing MAR performance, particularly in saline groundwater regions. This study conducted a comprehensive literature review of literature studies related to MAR in Salt-affected groundwater regions (MARS), along with statistical analysis to discuss each operational factor’s common positive or negative effects on aquifer recharge and recovery performance. The Recovery Efficiency (RE) values in each MARS study analyzed in this article are influenced by unique hydrogeological and operational settings, resulting in significant variations. However, a similar influencing trend of each operational factor on the observed RE variation is found. To validate the results of this analysis, a variable density groundwater flow model was developed from the data of a MAR field application project given in Reese (2002) and simulated for similar variations in operational factors. The simulation results corroborated the general trends observed in the review analysis. This study provides a comprehensive analysis of how operational factors influence the RE of MARS. The results demonstrate that a higher recharge rate, larger freshwater volume, smaller storage durations, and a minimum of four subsequent recharge-recovery cycles may lead to higher RE. The trends obtained for each operational factor can be utilized to optimize the operation of MARS projects for achieving higher RE in the salt-affected regions of the world.