Assessment of High Resolution Topography Impacts on Deterministic Distributed Hydrological Model in Extreme Rainfall-runoff Simulation

To represent the extreme rainfall-runoff events, the deterministic distributed hydrological modeling is gaining interest both with the increase of the computation facilities and the availability of data especially the topography inputs. The experience has demonstrated the key role of the topographic resolution within the development of the deterministic distributed hydrological models by achieving the impacts on the characteristics of the basin especially the slope distribution and the representation of the stream network. To define the suitable topography resolution applied in the deterministic distribution hydrological models is one of the key pre-processes before the modelling analysis. Thus, in this paper, the simulation results of four deterministic hydrological models with different topography resolution - 300m, 150m, 75m - for the Var basin, France (2800 km2) are analyzed in order to evaluate the influences on the simulation accuracy. The results of sensitivity analysis indicate the threshold value of the topography resolution on the model simulation with the consideration of both the sufficient accuracy and the reasonable simulation time to cover the extreme rainfall-runoff event in 1994.