Modeling aquifer storage and recovery potential for seasonal water storage in the Flemish alluvial plains of Belgium using MODFLOW

The necessity to preserve, reuse, and recycle water is becoming increasingly significant for both environmental and economic sustainability. Conservation of groundwater resources in Belgium is coming under increasing threat due to the variability of climate, rapid urbanization, and population growth. Environmental challenges, as well as rising costs associated with surface water reservoirs, have encouraged water professionals to explore an adequate and sustainable adaptation strategy. Nowadays, aquifer storage and recovery (ASR) is an effective technique and widely applied for seasonal or emergency water storage in an environmentally acceptable, sustainable manner. The work described in this paper explores the potential of ASR to enhance the buffer capacity of water supply systems in pilot sites (Herent Bijlok and Winksele Kastanjebos in Belgium). A conceptual groundwater flow model was developed using the finite-difference code, MODFLOW, for these representative sites. After calibration, the steady-state model was utilized initially for transient simulation, prediction simulation, and later on scenario analysis. The scenario analysis was performed primarily on individual wells and afterward on two multiple wells. The water balance components of the winter and summer stress period showed an increase in groundwater heads during winter months while decreasing throughout the drier periods. Furthermore, among individual ASR wells, one achieved 97% recovery efficiency (RE) while multiple ASR wells attained above 100% RE. Overall, the study indicates that the ASR tool provides an attractive alternative to increasing storage capacity and ensures a sustainable long-term supply of fresh water in the study site of Belgium.