Sponge city theory utilizes policy-driven design to mitigate urban flooding and shape urban development. However, existing approaches primarily focus on micro-scale landscape facilities and performance assessments, overlooking the integration of macro-scale urban design strategies. This study develops a parametric design framework linking the quantitative control requirements of sponge city policies to urban morphological elements, establishing a "form-performance" correlation model. Key design indicators (green space, roof, water body, pavement, and their sub-indicators) were identified, and sensitivity analysis evaluated their responses to varying plot ratios and site scales. Results indicate that policy-guided stormwater runoff reduction strategies differ significantly by development density: high-density projects favor increased green roof ratios, while low-density projects are better suited for permeable pavements. Larger sites necessitate greater emphasis on peak runoff control and rational catchment zoning. The analysis empirically validated the framework and model, revealing that current policies risk over-incentivizing specific high-performance technologies, potentially compromising strategic diversity and resilience to extreme weather events. Consequently, optimizing policy evaluation metrics and refining design guidelines is recommended to achieve more balanced, efficient, and resilient stormwater management during preliminary urban design phases.
Xu et al. (Tue,) studied this question.