Received: 30 Jan 2017 – Discussion started: 14 Feb 2017
Abstract. At the basin scale, neglecting localized deviations caused by geological constraints like knick-points, alluvial rivers commonly exhibit a concave profile and a progressive sediment fining in the downstream direction. Although this configuration is, perforce, not in equilibrium, yet it usually shows a quasi-stationary behaviour at the very long (historical and geological) time-scale.
A zero-dimensional, two-reach, two-grainsize hydro-morphological model is presented and applied to a schematic river. The description of the processes involved is done assuming several reasonable and verified simplifications, giving reason of the extremely slow evolution of many alluvial rivers and providing a quantitative approach to evaluate their response time. Different from previous analytical formulations, the response time appears here to be affected, among others, by the granulometry of the sediment input.
Applications of the model to different geometries demonstrate that the present riverine morphology at the basin scale will persist practically stationary for extremely long periods of time (centuries and even millennia), if the climatic forcing remain unchanged and no anthropogenic perturbations are introduced in the system.
This preprint has been withdrawn.
How to cite. Franzoia, M., Nones, M., and Di Silvio, G.: Long-term Morphodynamics of a Schematic River Analysed with a Zero-dimensional, Two-reach, Two-grainsize Model, Earth Surf. Dynam. Discuss. [preprint], https://doi.org/10.5194/esurf-2017-7, 2017.
Describing the long-term evolution of rivers can be very challenging, especially because of the computational effort required by a detailed description of the physical processes involved. To address this problem, simplified physically-based models can represent an innovative approach, but a thorough verification of equations and simplifications adopted is strictly required. In this work, a 0D, two-reach, two-grainsize hydro-morphological model is presented and applied to a schematic reach.
Describing the long-term evolution of rivers can be very challenging, especially because of the...