Global flood inundation in future climate with current flood mitigation management

Supported by increasing atmospheric moisture associated with warmer temperatures, extreme precipitation has been increasing in the past and is projected to continue to increase in the future in many regions worldwide. Despite the observational evidence of increasing frequency and intensity of extreme precipitation, increasing trends in flooding have not been found in many river basins, partly because of human intervention through dams and river regulations. While previous studies have improved our understanding of the mechanisms of flood inundation using data analysis and modeling, it remains unclear whether the flood control capacity designed based on historical climate is able to maintain its function for flood protection in the future under changing conditions of precipitation and land surface hydrology. To address this knowledge gap, we coupled a flood inundation model with a water management model in the Energy Exascale Earth System Model (E3SM) for modeling flood inundation at global scale. Simulations will be performed under historical and future climate conditions with and without water management. We will identify basins with increasing flood area and intensity in the future under natural conditions and evaluate how water management with the same operating rules influence flood hazard under the historical and future climates. Besides changes in the frequency and intensity of extreme precipitation, changes in the seasonality of mean and extreme precipitation, the phase of the precipitation, and surface hydrology such as snow accumulation and melt will all have important effects on flood inundation. Basin scale analysis will focus on changes in flood mechanisms due to the changing climate and water management to provide insights to guide future dam operations in flood-prone areas.