A1.3 River Hydrodynamics and Modelling

To understand the river hydrodynamics, such as varying water levels or flooding, the basic knowledge of the characteristics of the flow and the transport processes of sediment is required; this knowledge is provided in the following order:

1. Basics of one-dimensional uniform channel flow. Gradually varied flow. Solution methods-calculation of water surface profiles: Standard-Step method; Direct-Step method – Introduction to the HEC-RAS model; applications.
2. Unsteady flow. Equations Saint-Venant and their simplifications (kinematic and diffusion wave). Solution of the Saint-Venant equations using the Finite Difference Method. Application to a simplified flood propagation problem.
3. Flash-floods and dam-break waves. Mathematical modelling of floods; use of the HEC-RAS model.
4. Sediment transport:  physical properties of sediment; basics of bedload and suspended load sediment transport. Mathematical modelling of sediment transport. Use of the HEC-RAS model; sediment hydrodynamics (quasi-steady flow); sediment continuity equation; physical constraints to erosion and deposition (sorting and armouring).