Importance of catchment hydrological processes and calibration of hydrological‐hydrodynamic rainfall‐runoff models in small rural catchments

Abstract

In recent years, many two‐dimensional (2D) hydrodynamic models have been extended to include the direct rainfall method (DRM). This allows their application as a hydrological‐hydrodynamic model for the determination of floodplains in one model system. In previous studies on DRM, the role of catchment hydrological processes (CaHyPro) and its interaction with the calibration process was not investigated in detail. In the present, case‐oriented study, the influence of the spatiotemporal distribution of the processes precipitation and runoff formation in combination with the 2D model HEC‐RAS is investigated. In a further step, a conceptual approach for event‐based interflow is integrated. The study is performed on the basis of a single storm event in a small rural catchment (low mountain range, 38 km2) in Hesse (Germany). The model results are evaluated against six quality criteria and compared to a simplified baseline model. Finally, the calibrated improved model is contrasted with a calibrated baseline model. The results show the enhancement of the model results due to the integration of the CaHyPro and highlight its interplay with the calibrated model parameters.

Preparing for severe flooding: Flood risk management research leading to better flood preparedness

“…Development and optimization of tools and approaches towards understanding flooding potential and evaluating flood risk management approaches are also required to improve flood preparedness. This is exemplified in this issue by several studies into new approaches for numerical modelling tools in flood simulation, including the effect of cross-sectional orientation in a one-dimensional hydrodynamic model on variability in model flood simulations (Jesna et al, 2023), incorporation of spatially distributed precipitation into a two-dimensional hydraulic model for a vulnerable, steepterrain catchment (Godara et al, 2023), integration of local-scale features into a hydraulic modelling framework to improve model representation of local urban flood defence infrastructure (Massam et al, 2023), and the relationship between spatiotemporal catchment hydrological processes and the calibration process in hydrologicalhydrodynamic models (David et al, 2023). A new modelling approach for critical infrastructure networks that can be disrupted by flooding is explored by Schotten and Bachmann (2023).…”