Towards climate resilient cities: An adaptive zoning approach based on flood vulnerability assessment

Coastal megacities face escalating threats from climate-induced hazards such as sea-level rise and extreme precipitation events, which highlight the limitations of static urban planning approaches relying upon historical data, as they struggle to predict and adapt the real scenario of future flood conditions. To overcome the limitations of static urban planning, this study proposes a rule-based adaptive zoning approach based on flood vulnerability assessment. The proposed approach aims to translate multi-dimensional risk data into concrete spatial planning strategies, in order to address the “assessment-to-action” gap that has long persisted in the field of flood resilience and spatial planning. Specifically, this rule-based framework integrates inundation scenarios simulation (generated by a Digital Elevation Model) and flood vulnerability assessment (by incorporating population density, building coverage, and green-space coverage), and consequently delineates three adaptive zones of “Core Protection Zone”, “Retreat Zone”, and “Buffer Zone”. A case study of Huangpu River region in Shanghai has been conducted to exemplify the effectiveness of the proposed framework. The framework has effectively delineated the waterfront into three distinct adaptive management units. The first unit is the “Core Protection Zone”, which concentrates extremely high population and building densities, making structural flood defenses a planning priority. Unlike the “Core Protection Zone”, the “Retreat Zone” captures areas where severe exposure or limited ecological buffering makes long-term risk reduction and ecological restoration more appropriate. The “Buffer Zone” occupies the largest area and provides a transitional space highly suitable for deploying hybrid grey-green infrastructure. By explicitly identifying the “Core Protection Zone”, “Retreat Zone”, and “Buffer Zone”, the findings of this research not only deliver an operational bridge between vulnerability science and actionable spatial planning, directly addressing the long-standing “assessment-to-action” gap, but also provide a replicable and transferable toolkit that enables coastal megacities to move beyond “one-size-fits-all” flood control toward more climate resilient urban development in complex metropolitan areas.