Recent extreme floods in northern Europe, such as the July 2021 event that claimed over 220 lives and caused €46 billion in infrastructure losses, underscore the urgent need for advanced flood mitigation strategies. Our hydraulic engineering team develops multi-scale and multi-physics frameworks to simulate extreme water hazards across rivers, floodplains, urban corridors and hydropower systems, capturing flow physics, sediment transport, dam-break bores and intense rainfall-driven flooding. We integrate advanced hydrologic–hydraulic models with nature-based measures, digital twins, and real-time monitoring tools that jointly optimize flood mitigation, energy production and climate adaptation. For flood resilience, we couple high-fidelity 2D/3D hydraulic and CFD models with GIS exposure data and UAV/satellite observations to assess vulnerability, fragility and flood risk for buildings, transport networks, hydropower assets and cultural heritage. We also develop AI/ML-based early warning systems and decision-support platforms that fuse physics-based simulations with structural and socio-economic indicators for authorities and civil protection services.