Between oblivion and promise: a sustainability-oriented spatial design probe for a River Island on the Yangtze

River islands sit at the confluence of hydrological dynamism, ecological sensitivity, and socioeconomic marginalization, rendering them acutely vulnerable to climate change yet critical as sustainability testbeds. However, research on sustainability-oriented spatial design interventions in such contexts remains sparse. Addressing this gap, a design probe on Tianxingzhou, Yangtze River, deploys a multi-pronged framework – structural contradiction diagnosis, strategic development assessment, and design experimentation/translation – to interrogate the island’s trajectory and generate evidence-informed spatial interventions. Findings expose a tension between oblivion and promise—a development impasse driven by hydrological risk, institutional fragmentation, and socioeconomic marginalization, counterbalanced by ecological assets, strategic location, and emerging policy windows. Operationalizing sustainability’s three pillars (environmental, social, economic) as normative criteria and grounding them in site-specific contradictions identified through investigation and formal analysis, strategy responses are derived: climate-responsive building addressing flood risk (environmental), spatial translation of cultural memory countering memory disruption (social), and low-impact ecological services resolving the conservation–development impasse (economic). Based on an evidence-based (traceable) foundation, a heuristic spatial probe further synthesizes an amphibious architecture system, a cultural-memory transposition module, and low-impact ecological service programming into one single high-accessibility public space node, articulated through concrete proposals while acknowledging the limitations inherent in any singular intervention. Positioned as hypothesis-generating design exploration, it contributes a transferable contradiction–pillar–strategy–probe model for alluvial island and deltaic regions, articulating an “adaptive coexistence” pathway and charting trajectories for future research and practices.