Flood Responses to Climate Warming on Tribal Lands Using High‐Resolution Hydrodynamic Modeling

Abstract Tribal nations across the United States face disproportionate flood impacts yet remain significantly underrepresented in national‐scale assessments, creating a critical equity gap in climate adaptation. We address this deficiency through a climate‐to‐local‐inundation framework for the Santee Sioux Nation, Nebraska, by forcing 10‐m hydrodynamic simulations with a 42‐year paired historical and pseudo‐global‐warming CONUS404 runoff event set. Results show that projected changes in inundation frequency and flood depth are limited, with no evidence of widespread intensification of flood extremes. Instead, changes manifest as localized adjustments in floodplain activation and tributary connectivity. Pixel‐wise return‐period analysis shows small changes in flood depth and only minor deviations in the statistical structure of extremes. These findings demonstrate a transferable pathway for translating climate‐driven hydrologic forcing into locally resolved inundation information for under‐mapped Tribal lands.