Harnessing Community Science to Address Flood Risks and Build Climate Resilience With Nature‐Based Solutions (NbS)—A Case Study From the Quad Cities Region

Abstract Urban regions situated along major river systems are increasingly facing flood risks, driven by the combined effects of rapid urbanization and intensifying climate change. The Quad Cities region, comprising Davenport and Bettendorf in Iowa, and Rock Island, Moline, and East Moline in Illinois, is vulnerable to flood hazards caused by extreme precipitation, fluvial surges, and extensive impervious surfaces. Historical records indicate 10%–20% increase in annual precipitation, with a rise in high‐intensity rainfall. Projections under the SSP5‐8.5 scenario, using statistically downscaled MIROC6 data, predict a continued increase in short‐duration high‐magnitude rainfall events. To quantify flood inundation scenarios, this study developed a coupled hydrologic‐hydraulic (HH) model over a 35.5‐mile Mississippi River corridor. Simulations indicate that, without intervention, flood depths could rise by 20%–45% and the inundation extent of flooding could expand significantly in low‐lying areas of Rock Island and East Moline. To mitigate these risks, the study tested eight nature‐based solutions (NbS), including bioswales, rain gardens, riparian buffers, infiltration trenches, and detention basins. HH modeling showed that the combined implementation of NbS can reduce peak discharge by up to 69.4% and increase water infiltration by over 25%, resulting in an estimated 37% reduction in flooded areas by the end of the century. Through over 30 stakeholder interviews, three public forums, and participatory mapping workshops, residents identified priority flood zones and proposed NbS strategies. This integrated approach helped develop a streamlined framework that combines high‐resolution flood modeling with community‐led planning, creating robust and socially equitable adaptation pathways for riverine urban systems.