Global climate change has precipitated a surge in urban flooding challenges, prompting the imperative role of green infrastructure (GI) as the linchpin of sponge city construction to enhance urban sustainability and resilience. But the evaluation of urban stormwater resilience faces challenges due to the lack of a comprehensive evaluation framework taking the intrinsic features of the resilience system into account and the insufficient coverage of alternative scenarios’ performance under multiple rainfall return periods. This study, focusing on Fengxi New City, China, evaluates the suitability of GI (i.e., green roofs, rain gardens, and permeable pavements) and constructs a stormwater management model (SWMM) for urban stormwater hydrological simulation. This study also establishes a comprehensive urban stormwater resilience evaluation system and uses quantitative methods to unify the performances of scenarios under different rainfall return periods. Our analytical findings elucidate that the suitability of GI is predominantly concentrated in the northern and western areas of the study area, with the smallest suitable area observed for permeable pavements. Divergent GIs exhibit disparate performances, with rain gardens emerging as particularly efficacious. Importantly, the combination of multiple GIs yields a synergistic enhancement in resilience, underscoring the strategic advantage of adopting a diverse and integrated approach to GI implementation. This study facilitates a deeper understanding of urban stormwater resilience and assists in informed planning decisions for GI and sponge cities.

The campus is an important place for recreational activities among surrounding residents, which can alleviate the shortage of urban public green space (PGS). However, evidence is lacking on how much campus green space is complementary to the supply and demand of PGS. For this purpose, we chose Yangling, a university town in western China, as the study area. We compared perceived accessibility and the coupling coordination degree (CCD) of the supply and demand of PGSs for residents with different purposes before and after the COVID-19 pandemic, when the campuses were closed or reopened. After the campus reopened, the number of blocks that were able to reach their most frequently visited green spaces within 5 min had increased from zero to one (walking) and two to four (by bicycle). The proportion of blocks with a high level of CCD had increased from 28.6% to 42.9%. The reopening of campuses can significantly increase the perceived accessibility of PGSs within 5 min and 15 min by walking and bicycle, respectively, in central urban communities, but it was not significant in suburban communities. It also effectively improved the PGS supply of the block where it is located. For residents who aim to exercise, walk, go sightseeing, and communicate, its role was similar overall. For residents who aim to play with children, the campus green spaces could not bring significant improvements. In order to enhance the complementary role of green space on campus, it is important to improve its accessibility for adjacent blocks, increase inside footpath density, and add child-friendly facilities.

Accelerating urbanization and the intensifying pace of climate change have heightened the occurrence of urban pluvial flooding, threatening urban sustainability. As the preferred approach to urban stormwater management, coupled gray and green infrastructure (GI–GREI) integrates GREI’s rapid runoff conveyance with GI’s infiltration and storage capacities, and their siting and scale can affect life-cycle cost (LCC) and urban drainage system (UDS) resilience. Focusing on Fengxi New City, China, this study develops a multi-objective optimization framework for the GI–GREI system that integrates GI suitability and pipe-network importance assessments and evaluates the Pareto set through entropy-weighted TOPSIS. Across multiple rainfall return periods, the study explores optimal trade-offs between UDS resilience and LCC. Compared with the scenario where all suitable areas are implemented with GI (maximum), the TOPSIS-optimal schemes reduce total life-cycle cost (LCC) by CNY 3.762–4.298 billion (53.36% on average), rebalance cost shares between GI (42.8–47.2%) and GREI (52.8–57.2%), and enhance UDS resilience during periods of higher rainfall return (P = 20 and 50). This study provides an integrated optimization framework and practical guidance for designing cost-effective and resilient GI–GREI systems, supporting infrastructure investment decisions and climate-adaptive urban development.