A New One-Dimensional Numerical Model for the Hydraulics of Sediments in Rivers

«Un modèle numérique unidimensionnel est développé pour simuler l'évolution morphodynamique des rivières. Ce modèle, UMHYSER-1D (Unsteady Model for the HYdraulics of SEdiments in Rivers 1D), est un modèle hydromorphodynamique unidimensionnel capable de représenter les profils de la surface d'eau dans une rivière ou un réseau de chenaux, avec différents régimes d'écoulement en prenant compte du transport de sédiments, cohésifs ou non cohésifs. UMHYSER-1D simule des écoulement permanent ou non, avec ou sans transport de sédiments. Il a été développé en plusieurs étapes.» et

Abstract

A one-dimensional numerical model is developed to simulate the evolution of rivers. This model, UMHYSER-1D (Unsteady Model for the HYdraulics of SEdiments in Rivers 1D), is a one-dimensional hydro-morpho-dynamic model capable of representing the surface profiles of water in single river or a multiriver network, with different flow regimes taking into account cohesive or non-cohesive sediment transport. UMHYSER-1D simulates steady and unsteady flows, with or without sediment transport. It was developed in several steps. In the first step, a good part of the code for the quasi-permanent model MHYSER (Model of Hydraulics of SEdiments in Rivers) was adopted. These are the reading of the input data, such as the cross sections and their hydraulic characteristics, and the module solving the equations of mass and energy conservation, for the water surface, and Exner, for the sediment transport, adopted for long-term simulations. Indeed, in this case, the non-permanent terms of the sediment transport continuity equation are ignored. In addition, a non-equilibrium sediment transport method is used. This first step, although easy, is very important since it mainly validates the permanent flow phase and the pre-treatment of UMHYSER-1D. Its validation was made by comparing the solutions with cases from the literature.