Context-sensitive Sponge City strategies: A cross-case and multi-scalar analysis

Sponge Cities are more than technical solutions to urban flooding–they are dynamic spaces where water, land, and society converge in adaptation and resilience. This study bridges theory and practice through a comparative, cross-case framework that analyzes Sponge City strategies across five Dutch lowland landscape types (coastal, riverine, peat, sandy, clay) and selected international contexts. Emphasizing scale as a critical dimension, the study explores how blue, green, and blue-green strategies are shaped by ecological conditions and local practices. Beyond hydrological performance, it highlights the often-overlooked social dimension, including community participation, equity, and social resilience. The research adopts a qualitative, interpretivist methodology, combining within-case and cross-case analysis. It unfolds in two phases: first, a global typology of 38 Sponge City strategies is developed, categorized as green, blue, or green-blue, and analyzed by spatial scale (site, neighborhood, city), sponge basin principles (protect, delay, store, release), and hydrological processes (infiltration, retention, storage, purification, utilization, drainage). The second phase offers an in-depth evaluation of eight Dutch projects across Amsterdam, Rotterdam, Almere, Purmerend, and The Hague, examining ecological, spatial, and social performance through thematic coding and structured comparison. The findings highlight a gap between the coherence of Sponge City theory and its real-world application, particularly regarding social integration. Successful implementation depends on context-sensitive strategies that go beyond water management to include accessibility, inclusivity, and community engagement. This study contributes to a broader understanding of how human-centered, adaptive design can support climate resilience across diverse urban landscapes, grounding its analysis in a landscape-based Sponge City framework that links Sponge Basin principles (protect, delay, store, release) with lowland landscape typologies and cross-scalar design strategies.