Numerical modeling of Managed Aquifer Recharge (MAR) systems

Managed aquifer recharge (MAR) is a process whereby water is intentionally added to an aquifer for storage and later recovery. This technique is used to replenish depleted groundwater reserves, enhance water quality, and mitigate the effects of overdraft or contamination. MAR can involve various methods such as injection wells, infiltration basins, or spreading grounds to introduce water into the subsurface. The goal is to restore or maintain groundwater levels and make the current level of exploitation more sustainable in the long term. In this thesis, numerical flow modeling of MAR was conducted using the finite-difference code MODFLOW. A recharge basin was hypothesized, which injects water out of the irrigation season, whereas a water well downstream extracts water for an irrigation seasion that lasts 155 days per year. The influence of several factors such as the size of the infiltration basin, the distance between the basin and the well, the volumes injected, and the hydraulic conductivity of the aquifer was studied. The result of MAR is the reduction of the drawdown at the end of the irrigation season, compared to the value that would have been reached without the recharge. This results in a reduction of such impact or in the possibility to extract larger quantities of water, thus being able to cope with the increasing irrigation requirements. Not surprisingly, the efficiency of such storage is quite low: however, MAR is also much less expensive and less environmentally impacting than surface water storage. Through numerical modeling, you likely investigated factors such as recharge rates, infiltration patterns, and potential changes in groundwater quality to optimize MAR strategies and understand their implications for aquifer management.