WLS Report 18: Documentation und numerical simulation of the Moschergraben debris flow on 17.6.1997

Report18 To distinguish hazard zones and constructive measures on a deposit cone which threatened by floods or mudflow events a high knowledge of flow dephs, velocities and deposit length of such events is required. With the well studied mudflow event in the Morschergraben (Steiermark) the possible applications of the simulation programm FLO-2D, developed by the Colorado State University, should be tested. This programm allows to do calculations both in two dimensional transient flow channel and the lateral spreading during overflow. All transitions from clear water to real mudflow events can be modelled. Basic data are a digital topografic model to build raster elements, information about the surface texture and the material behavior of the solid-water mixture. To describe the flow behavior a quadratic rheological model is used. From the deposit have been taken samples of the bedload deposit directly after the event. The most important rheologic parameters as the threshold value of the shear stress and the viscosity are determined in laboratory using a rehometer and a new developed mudflow channel.