Physically-based modelling of granular flows with Open Source GIS

Abstract

Abstract. Computer models, in combination with Geographic Information Sciences (GIS), play an important role in up-to-date studies of travel distance, impact area, velocity or energy of granular flows (e.g. snow or rock avalanches, flows of debris or mud). Simple empirical-statistical relationships or mass point models are frequently applied in GISbased modelling environments. However, they are only appropriate for rough overviews at the regional scale. In detail, granular flows are highly complex processes and physicallybased, distributed models are required for detailed studies of travel distance, velocity, and energy of such phenomena. One of the most advanced theories for understanding and modelling granular flows is the Savage-Hutter type model, a system of differential equations based on the conservation of mass and momentum. The equations have been solved for a number of idealized topographies, but only few attempts to find a solution for arbitrary topography or to integrate the model with GIS are known up to now. The work presented is understood as an initiative to integrate a fully physicallybased model for the motion of granular flows, based on the extended Savage-Hutter theory, with GRASS, an Open Source GIS software package. The potentials of the model are highlighted, employing the Val Pola Rock Avalanche (Northern Italy, 1987) as the test event, and the limitations as well as the most urging needs for further research are discussed.

Modelling of cave-in occurrence using AHP and GIS

“…GIS is widely applied in many branches of economics and science (Forte et al, 2005;Hejmanowski and Malinowska, 2010;Ju et al, 2012;Mergili et al, 2012;Taramelli et al, 2008;Theilen-Willige, 2010 GIS surveys were performed on raster surfaces. The first stage of spatial data work lay in defining boundary conditions, on the basis of which the most extreme values could be rejected (Step 5).…”

Evaluation concepts to compare observed and simulated deposition areas of mass movements

“…2 D empirical models like LAHARZ [29], DFLOWZ [5], TopRunDF [49] or TopFLowDF [50] provide a quick view on potential endangered areas and have been applied for several hazard analyses [17,21,40,45,54]. More complex simulation models in engineering practice are based on an "equivalent fluid" approach [25], routing such mass flows in one or two dimensions along the talweg or over a digital elevation model solving depth averaged flow equations [11,16,26,35,36,39]. Such models, like DAN3D [25], Flo2D [39], RAMMS [11] or SAMOS [47], are physically based and consider the momentum or energy conservation of the flow.…”

r.randomwalk v1, a multi-functional conceptual tool for mass movement routing

“…Physically based dynamic models are used for in-detailed analyses of specific events or situations (e.g., Savage and Hutter, 1989;Takahashi et al, 1992;Iverson, 1997;Pudasaini and Hutter, 2007;Hungr, 2004, 2005;Pitman and Le, 2005;Christen et al, 2010a, b;Mergili et al, 2012b;Pudasaini, 2012;Hergarten and Robl, 2015;. Since the processes are complex in detail and the input parameters are uncertain, simplified conceptual models for the motion of mass flows are today used in combination with GIS (Geographic Information System).…”