Revisiting the Role of Floodplains in Flood Management: A Comparative Case Study of Carlisle, UK and New Orleans, USA

Climate change has intensified the frequency and severity of extreme flooding events, challenging the effectiveness of conventional urban flood management strategies. Floodplains are increasingly promoted as nature-based solutions for flood risk reduction; however, their performance under extreme and compound flooding conditions remains context-dependent and insufficiently understood. This study examines the role and limitations of floodplain-based flood management through a qualitative comparative case study of two flood-prone cities: New Orleans (USA) and Carlisle (UK). Despite substantial differences in geomorphology, governance systems, and socioeconomic contexts, both cities experienced severe flood events that exposed the failure of floodplains and engineered defences to provide adequate protection under extreme climatic stress. Drawing on document analysis and secondary data, the comparison identifies four interacting factors shaping floodplain performance: environmental constraints, urban development patterns, governance capacity, and civic participation. The findings show that floodplains alone cannot function as reliable flood risk reduction measures when ecological degradation, land-use pressures, and institutional fragmentation undermine their buffering capacity. Rather than serving as substitutes for structural defences, floodplains operate most effectively as complementary components within integrated flood risk management frameworks that combine ecological restoration, spatial planning, and inclusive governance. This study contributes empirical insights into the context-specific applicability of floodplain strategies and highlights the importance of adaptive, place-based governance for urban disaster risk reduction under climate change.