How do Urban Interactions Influence Flood Resilience in Cities? A Land Use Simulation Framework for Flood Risk Regions

Cities worldwide face escalating risks from natural hazards, a trend exacerbated by the increasing intensity and frequency of climate extremes. This study investigates the implications of projected urban growth patterns on flood resilience in Colombo, Sri Lanka—a city highly susceptible to flooding. Employing a Cellular Automata-based land use simulation, integrated with the Urban Flood Risk Mitigation Model, we quantify urban flood resilience for the year 2031 under three distinct urbanisation scenarios. The analysis reveals that a scenario emphasising land-use regulation results in the highest expansion of flood-susceptible areas (43.9%), whereas scenarios characterised by unplanned growth yield the most substantial reduction in resilience (20.9%). Furthermore, urban sprawl controls and rapid ecosystem restoration efforts improved the highly resilient (responsive) locations by about 4% and 17% respectively, compared with the baseline scenario in 2021. By advancing an urban simulation-driven framework, this research provides a comprehensive understanding of resilience dynamics and actionable insights for policymakers and urban planners.