Assessing the impact of hydrodynamics on large-scale flood wave propagation – a case study for the Amazon Basin

摘要: Abstract. Large-scale flood events often show spatial correlation in neighbouring basins, and thus can affect adjacent basins simultaneously, as well result superposition of different peaks. Such therefore need to be addressed with large-scale modelling approaches capture these processes. Many currently place are based on either a hydrologic or hydrodynamic model. However, the resulting lack interaction between hydrology hydrodynamics, for instance, by implementing groundwater infiltration inundated floodplains, hamper modelled inundation discharge results where such interactions important. In this study, global model PCR-GLOBWB at 30 arcmin resolution was one-directionally spatially coupled Delft 3D Flexible Mesh (FM) Amazon River basin grid-by-grid basis daily time step. The use flexible unstructured mesh allows fine-scale representation channels while preserving coarser less flood-prone areas, not unnecessarily increasing computational costs. addition, we assessed difference 1-D channel/2-D floodplain 2-D schematization 3D FM. Validating shows that coupling routing scheme generally increases performance compared using only all validation parameters applied. Closer examination 1-D/2-D outperforms r2 root mean square error (RMSE) whilst having lower Kling–Gupta efficiency (KGE). We also found has significant advantage better smaller streams throughout domain. A simulated extent revealed those set-ups incorporating capable representing inundations reaches below mesh. Implementing is particularly models, they built upon remotely sensed surface elevation data which enclose strong vertical bias, hampering downstream connectivity. Since one-directional approach tested, important feedback processes incorporated, both overpredicted. Hence, it will subsequent step extend two-directional obtain closed loop current findings demonstrating potential models improved estimates form an towards full dynamic hydrodynamics.