Author(s): Jerome Dubois; Jean-Louis Boillat; Anton Schleiss
Linked Author(s): Anton J. Schleiss
Keywords: Fluvial system; Flood routing; Head loss equation; Macro-roughness; Flood; Network; Hydrology; Watershed; Numerical simulation
Abstract: The actual possibilities of numerical simulation allow a deterministic and physically based approach of natural phenomena. Hydrology is also concerned and develops models based on hydraulic equations to compute the flood generation and routing on watersheds. The equation of movement imposes the knowledge of a head loss coefficient in order to be solved. This coefficient is the only unknown physical parameter for the flood routing on watersheds, and the quality of its estimation directly influences the quality of the model. The classical head loss formulations, empirically developed for turbulent and rough flows in rivers, are not applicable to surface runoff. In order to find a more appropriate friction law, laboratory experiments were conducted in order to define the relationship between the mean velocity and the surface roughness. The numerical model "Faitou", was developed for the simulation of the generation and routing of floods on steep river basins. With the new head loss equation, it solves the 2D kinematic wave equation over the catchment topography with the finite volume method. This computation of surface runoff is coupled with a hydrodynamic modeling of the river network. The determination of the watershed limits, the mesh of finite volumes and the river network are automatically generated from a digital elevation model. This software, associated with the new head loss equation, demonstrates its potential and qualities by application on an alpine watershed.
Year: 2001