In response to the growing risks of pluvial flooding due to climate change, this thesis presents a framework to assess the resilience of urban drainage systems and guide adaptation strategies using coupled 1D-2D modelling and economic flood risk assessments. The research begins by exploring methods in InfoWorks ICM to simulate interactions between surface and subsurface flows in urban environments, focusing on a simplified approach to model gully flow that reduces data requirements and computational load. Building on this, flood hazards from the simplified model are used to identify buildings at risk of internal flooding, estimate potential financial losses, and calculate expected annual damages under current and future climate conditions, accounting for climate change impacts. Subsequently, this research evaluates blue, green, and grey infrastructure measures, through cost-benefit analysis where benefits are quantified as reductions in expected damages.

A detailed case study from Spangen, a densely populated residential area in Rotterdam, applies the proposed framework, demonstrating that a simplified 1D-2D modelling approach without individual gully data can realistically estimate pluvial flood hazards and support economic flood risk assessments. The findings of the risk assessment suggest that existing infrastructure investments in the neighborhood have effectively reduced current pluvial flood risks. Looking ahead, for future climate conditions, a combination of green, blue, and grey infrastructure proves to be the most effective adaptation strategy as these measures synergistically enhance the resilience. Despite this, the cost-benefit analysis revealed a negative net present value when considering only flood damage reduction due to low flood risks under current climate conditions. Nonetheless, comprehensive decision-making should account for the additional benefits of green infrastructure, such as urban cooling and associated energy savings, improved air quality, and enhanced biodiversity.