D. Farshi - The Laboratory of Hydraulics, Hydrology and Glaciology (VAW), Swiss Federal Institute of Technology Zurich (ETH)
H.-E. Minor - The Laboratory of Hydraulics, Hydrology and Glaciology (VAW), Swiss Federal Institute of Technology Zurich (ETH)

A numerical model based on cell-centred finite-volume method is developed for unsteady, two-dimensional, shallow water flow on triangular meshes for calculating the depth and velocities in a natural river. The model uses special form of Riemann solver as a building block to compute fluxes, and an explicit predictor-corrector time stepping is used to provide a second-order accurate solution in time. Special approach in Riemann solver is used to take into account the presence of variable bottom topography and hydraulic structures such as a weir. The approach has been successfully verified for different examples.