GIS-based two-dimensional numerical simulation of rainfall-induced debris flow

Abstract

Abstract. This paper aims to present a useful numerical method to simulate the propagation and deposition of debris flow across the three dimensional complex terrain. A depth-averaged two-dimensional numerical model is developed, in which the debris and water mixture is assumed to be continuous, incompressible, unsteady flow. The model is based on the continuity equations and Navier-Stokes equations. Raster grid networks of digital elevation model in GIS provide a uniform grid system to describe complex topography. As the raster grid can be used as the finite difference mesh, the continuity and momentum equations are solved numerically using the finite difference method. The numerical model is applied to simulate the rainfall-induced debris flow occurred in 20 July 2003, in Minamata City of southern Kyushu, Japan. The simulation reproduces the propagation and deposition and the results are in good agreement with the field investigation. The synthesis of numerical method and GIS makes possible the solution of debris flow over a realistic terrain, and can be used to estimate the flow range, and to define potentially hazardous areas for homes and road section.

GIS-based numerical modelling of debris flow motion across three-dimensional terrain

“…Using the fixed bed model (Wang et al 2008), which does not consider the erosion and deposition (Figure 11), we could only simulate the thickness of deposit in one time step, but could not simulate the morphological variations, hence the result did not agree with the actual situation. Figure 12 shows the results simulated by using the New-SASS model developed by Sabo and Landslide Technical Center in Japan named.…”

A GIS-based numerical model for simulating the kinematics of mud and debris flows over complex terrain

“…Despite these difficulties, simple simulation models assuming constant flow properties have been successful in predicting the major characteristics of mud and debris slurries (e.g. Shieh et al, 1996;Chen and Lee, 2000;Laigle, 2000;Laigle et al, 2003;Bertolo and Wieczorek, 2005;Rickenmann et al, 2006;Wang et al, 2008;Medina et al, 2008). In most cases the extent and thickness of the deposited material were the only known properties, and rarely was there information about the flow velocity (e.g.…”

Modelos para simulación de procesos de remoción en masa desagregados. Comparación con el método de talud infinito

“…Existen diferentes aproximaciones propuestas en la literatura, basadas en la física mecánica y en reglas matemáticas para modelar los FMD [1,7,8,9,10,11,12]. Las leyes de la física son representadas por las ecuaciones de conservación de masa y conservación de momentum.…”