Author(s): N. Schrage; E. Pasche
Linked Author(s): Nico Schrage
Keywords: No Keywords
Abstract: The EU Floods Directive (EC, 2007) establishes a framework for flood risk management in Europe including the generation of flood risk maps. One of the necessary steps for a flood risk analysis is the determination of inundation areas for flood events of different return periods. As measurements from gauging stations are generally not sufficient, mathematical models need to be applied. Today, a strong trend towards application of 2-dimensional hydrodynamic numerical models can be observed. However, in many river reaches 1-dimensional flow processes are dominating. From a practical point of view the application of the 1-dimensional Saint-Venant equations is appropriate as this requires much less computational effort. A real river system is very complex consisting of alternating regions dominated either by 1-or 2-dimensional flow regime. Especially in flow situations and rivers with strong retention the need for unsteady flood studies arises. To reduce the processing costs a hybrid modelling scheme with an integrative approach should be available for a modeller. In principle numerical schemes allow the integrative application of 1-and 2-dimensional discretization schemes, but there are very few successful implementations and applications in the engineering world and not much is known about the accuracy which can be accomplished in 1D-2D transition zones. It is the objective of this paper to describe different possibilities of 1D-2D discretization schemes in fluvial flood modelling. Its implementation will be presented at the wellknown fluvial flow model RMA, which has become a simulation engine of the open GIS-based modelling suite KALYPSO. General conclusions about the efficiency and reliability of these combined discretization schemes will be given based on an example model.
Year: 2009