Abstract's details
SWOT Derived River Bathymetry for Global Flood Model Applications
Event: 2025 SWOT Science Team Meeting
Session: Hydrology: Global Hydrology Modeling Working Group
Presentation type: Oral
Accurately parameterising river channel geometry, in particular river bathymetry, remains a key uncertainty and bottleneck for improved accuracy in flood inundation models. Whilst channel bathymetry cannot be directly observed using Earth Observation (except for limited cases of clear and shallow water), we can infer it based on observations of river water surface elevation (w.s.e) and discharge. Historically, these data have been spatiotemporally sparse globally (and declining), preventing bathymetry from being estimated beyond a few localised test cases. SWOT, since its launch in 2022, has provided direct w.s.e measurements for all major global rivers (>50m width) every 21-days; presenting an opportunity to address this current major model limitation. Our recent proof-of-concept for the River Severn, UK, demonstrated that a flood inundation model built with SWOT-conditioned bathymetry had comparable accuracy to a local scale engineering model conditioned on observed field observations (Neal et al, 2025), demonstrating the potential of the approach on a test-case deemed to be at the limit of SWOT detection capability (40-70m river width).
Here, we advance on this proof-of-concept to show how SWOT can be used to develop a consistent global channel bathymetry data set for large rivers, using the SWOT HR Level 2 RiverSP Node product. We present an overview of the methodological approach required to utilise SWOT data for bathymetry inversion for large complex river hydrographies. This will include a focus on the further development of the quality filtering approach developed for the River Severn proof-of-concept, in order for it to be generally applicable for global scale applications. Additionally, we will present an analysis of how the SWOT-based approach for determining bathymetry compares to the current bank height based approaches used in the current generation of flood inundation models. Finally, we will discuss how future planned SWOT processing developments can enhance this work further, such as future evolution of the SWORD hydrography, the changes upcoming in the Version D product and possibility of using SWOT-derived discharges.
References
Neal J.C, Chuter S.J., Archer L., et al. Flood Inundation Modelling using the Surface Water Ocean Topography Mission. ESS Open Archive . March 28, 2025. DOI: 10.22541/essoar.174319735.54049202/v1
Back to the list of abstractHere, we advance on this proof-of-concept to show how SWOT can be used to develop a consistent global channel bathymetry data set for large rivers, using the SWOT HR Level 2 RiverSP Node product. We present an overview of the methodological approach required to utilise SWOT data for bathymetry inversion for large complex river hydrographies. This will include a focus on the further development of the quality filtering approach developed for the River Severn proof-of-concept, in order for it to be generally applicable for global scale applications. Additionally, we will present an analysis of how the SWOT-based approach for determining bathymetry compares to the current bank height based approaches used in the current generation of flood inundation models. Finally, we will discuss how future planned SWOT processing developments can enhance this work further, such as future evolution of the SWORD hydrography, the changes upcoming in the Version D product and possibility of using SWOT-derived discharges.
References
Neal J.C, Chuter S.J., Archer L., et al. Flood Inundation Modelling using the Surface Water Ocean Topography Mission. ESS Open Archive . March 28, 2025. DOI: 10.22541/essoar.174319735.54049202/v1