3D Groundwater Modeling for Optimal Management of the Complex Alluvial Aquifer in the Cagne Catchment, France

Efficient water resource management is vital for many coastal Mediterranean catchments, particularly in the face of climate change. The changing spatial and temporal patterns of rainfall, along with the competing demands from urban development and tourism, necessitate precise adjustments in resource allocation and management strategies. Effective and secure water supply management requires a comprehensive knowledge of aquifer behavior and possible interactions with surface water flows in adjacent rivers. The optimal approach to comprehend the behavior of the aquifer involves developing a 3D physically based hydrodynamic model that encapsulates all relevant physical processes. The hydrogeological tool was used to model the groundwater system in the Cagne catchment and assess its response to different hydrological scenarios. The model was set up with a resolution of 5 m in the river area and 100 m in the other areas to provide a detailed representation of the hydrological processes involved, and 5 layers were created in the underground part based on geological data. The model was validated using data from the 2015–2017 two-year event, which covered a full annual cycle of recharge and discharge. The results showed that the model was able to accurately predict the behaviour of the groundwater system in the Cagne catchment, both in terms of the distribution of water resources and the impact of changing hydrological conditions. Overall, this study provides a valuable contribution to the understanding of groundwater management in the Cagne catchment. By providing a comprehensive and accurate representation of the groundwater system, this study can inform future management decisions and help to ensure the long-term sustainability of the region's water resources.