Mathematical modelling of morphological variations in mountain streams

The paper discusses and analyzes the main physical and mathematical aspects taken into account by the mathematical models available for modelling the morphological variations of mountain streams. Specifically, two models are described: one for the short-term and one for the long-term. Although these models deal with the water flow and continuity equations in a simplified manner they allow grain size composition of the river and the mixing between the transported sediment and the bed material to be described in great detail. The results obtained from the application of the two models point to the possibility of their being used to evaluate overaggradation phenomena occuring in the long and short term. Finally, some considerations are presented on the need for further analyses to be made both at a theoretical and an experimental level, especially as far as the physico-mathematical structure of the governing equations is concerned.