Reducing 3D Hydraulic Interferences in Water Tunnels through the Strategic Installation of Artificial Bulkheads in Geological Hydraulic Barriers

Water tunnels play a crucial role in managing groundwater resources on volcanic islands, where freshwater availability is limited and highly sensitive to climate change impacts. However, hydraulic interferences between water tunnels and surrounding aquifers often lead to unintended drawdowns, reduced efficiency in water resource utilization, and ecological disturbances. Addressing these challenges is essential to enhance the resilience of critical water infrastructure, particularly in regions like the Macaronesian islands, which are the focus of the GENESIS project.

This study explores the strategic installation of artificial bulkheads within water tunnels, restoring existing geological hydraulic barriers to mitigate three-dimensional hydraulic interferences. By integrating these engineered solutions with nature-based approaches, it is possible to regulate groundwater flow, minimize hydraulic connectivity, and protect aquifers from saltwater intrusion. Hydrogeological modeling and geotechnical analysis were employed to assess the performance of this approach under various operational and climatic scenarios.

The results demonstrate that the implementation of these devices significantly reduces hydraulic interferences, stabilizes aquifer drawdowns, and improves the efficiency of water capture and storage. Furthermore, these solutions enhance the resilience of groundwater systems to external stressors, including over-extraction, seasonal variability, and the impacts of extreme climatic events such as droughts and floods.

This work aligns with the GENESIS project's mission to develop geologically enhanced nature-based solutions (NbS) for climate-resilient water management in the Macaronesian biogeographical region. By harmonizing engineering and natural systems, this methodology provides a replicable framework for securing freshwater resources on volcanic islands and other vulnerable regions in the EU, ensuring sustainable socio-economic and ecological development in the face of climate change.