Multi-Model Flood Mapping for Continental-Scale Forecasting Frameworks
Follum Hydrologic Solutions (FHS) is leading a multi-year research and development effort to advance operational flood inundation mapping by integrating multiple flood modeling approaches into continental-scale forecasting frameworks. Sponsored by the U.S. Army Engineer Research and Development Center (ERDC), the project develops an open, modular methodology that converts large-scale streamflow forecasts into flood inundation maps using multiple models—including FloodSpreader, FIST, and Curve2Flood—rather than relying on a single deterministic approach. Central to the work is the development and refinement of the Automated Rating Curve (ARC) framework, which generates spatially distributed depth and water surface elevation estimates that serve as common inputs across flood mapping models.
During the first two years of the project, FHS completed extensive tool development, documentation, and testing across river-scale and basin-scale applications. This included building and validating workflows that connect ensemble streamflow forecasts to multiple flood inundation models, comparing model accuracy and computational performance against observed flood events, and producing basin-wide flood maps for the Yellowstone River Basin using both historical and forecast conditions. The project demonstrates how multi-model flood mapping can quantify uncertainty, improve situational awareness, and support both military and civil decision-making for flood response, mobility analysis, and hazard assessment. Ongoing work extends these methods to additional large basins and international test cases, with results documented through open-source code, technical reports, and peer-reviewed publications.