Urban pluvial flooding is worsening due to climate change and urbanization, requiring faster forecasts. This study presents RIM2D, a multi-graphics processing unit (GPU) 2D flood model, simulating high-resolution events (2–10 m) across Berlin (891.8 km²) with up to 8 GPUs. Simulations of real and synthetic floods show multi-GPU use is vital for fine-scale, timely forecasts. RIM2D proves operationally viable for urban-scale early warning using modern GPU hardware.

This study examines how extreme rainfall in Berlin, Germany, may intensify due to global warming and how that could worsen flooding in a selected part of the city. We assess the role of the drainage system, infiltration from unsealed surfaces, and a potential adaptation scenario with all roofs as retention roofs in reducing flooding under extreme rainfall. Combining climate and hydrodynamic simulations, we provide insights into future challenges and possible solutions for urban flood management.