Author(s)

L. Schippa & S. Pavan

Abstract

A numerical model for the simulation of mud flow and debris flow is presented. It is based on an alternative formulation of conservative balance equations, in which source terms are mathematically reorganized in order to guarantee an improved computational stability over complex geometry channels. For numerical implementation, the first order Godunov scheme with Roe’s approximation is used. Source terms are computed with Euler’s method and added by splitting. Such a simple basic scheme has been chosen to underline that the improved numerical stability depends on the proposed mathematical formulation, and not on a sophisticated numerical scheme. The correct wet-dry front velocity and propagation mechanism have been verified with standard dam-break test cases, and particular attention has been directed to the celerity computation inside the Roe’s scheme when dealing with irregularly shaped cross-sections. The numerical model has already been verified with analytical tests and laboratory experiments. In this work, the model is applied to two real events that occurred in North-Eastern Italy. The first is a debris flow that took place in the Upper Boite Valley, in the proximity of Cortina d’Ampezzo, in 1998, the second is a mud flow event located in the Stava Creek Valley in 1985. These events have been chosen thanks to the wide documentation and significant amount of field data available, which include topographical surveys, flow velocity measures and flow depth estimations. Keywords: mud flow, debris flow, wave propagation, source terms.

Keywords

mud flow, debris flow, wave propagation, source terms