A Systematic Analysis of the Interaction between Rain-on-Grid-Simulations and Spatial Resolution in 2D Hydrodynamic Modeling

A large number of 2D models were originally developed as 1D for the calculation water levels along main course a river. Due to their development distributed models, majority have added precipitation source term. The can now be used quasi-2D hydrodynamic rainfall–runoff (‘HDRRM’). Within direct rainfall method (‘DRM’), there is an approach, referred ‘rain-on-grid’, in which input applied entire catchment area. study contains systematic analysis model behavior HEC-RAS (‘Hydrologic Engineering Center—River Analysis System’) with special focus on spatial resolution. rain-on-grid approach small, ungauged, low-mountain-range area (Messbach catchment, 2.13 km2) Central Germany. Suitable settings and recommendations discretization parametrization are derived therefrom. sensitivity focuses influence mesh resolution’s interaction resolution underlying terrain (‘subgrid’). Furthermore, parameters interplaying resolution, like height laminar depth, surface roughness, specific filter-settings input-data temporal distribution, analyzed. results evaluated against high-resolution benchmark run, further criteria, such 1. Nash–Sutcliffe efficiency, 2. water-surface elevation, 3. flooded area, 4. volume deficit, 5. balance 6. computational time. investigation showed that, based chosen criteria this size type between 3 m 5 m, combination DEM from 0.25 1 recommendable. we show considerable scale effects areas coarser meshing, due low relation topographic height.