Authors: Tasfia Mahjarin and Dan Ames – Brigham Young University
Title: Basin-Scale Flood Inundation Mapping Web Application Using a FIMserve, HAND-Based Inundation and NWM Retrospective Discharge
Presentation Type: Poster Presentation
Abstract: This poster presents a web application that connects hydrologic modeling outputs to an interactive map, enabling users to explore potential inundation at the scale of an eight-digit hydrologic unit (HUC8)—a standard watershed unit in U.S. water resources work. It uses FIMserve flood inundation mapping driven by National Water Model (NWM)–based forcing and retrospective discharge, producing basin-scale inundation GeoTIFFs from high-resolution terrain and routing concepts consistent with Height-Above-Nearest-Drainage (HAND)–style mapping. Watershed boundaries come from the National Hydrography Datasets, served as GeoJSON; the basemap is OpenStreetMap. A Python backend exposes REST-style services to generate or locate flood maps, reclassify inundation for simple flooded or not-flooded display, stream preview images to the browser, download processed raster, and attach discharge values to mapped stream reaches. Mapped discharge labels visually link streamflow magnitudes to the inundation footprint. For the public, planners, and students, the tool lowers the barrier to seeing how modeled high water might relate to familiar geography, supporting awareness, outreach, and discussion of flood risk and preparedness without installing desktop GIS, while still providing downloadable data for technical follow-on analysis. This web application is being deployed within the Tethys Platform and the CIROH Hub, providing free, open-access, and scalable web-based delivery of basin-scale flood inundation products.