Performance of 2D debris flow simulation model RAMMS. Back-analysis of field events in Italian Alps.

Zoning and emergency plans require the definition of debris flow scenarios that can be defined only by means of simulations with mathematical models. To test the RAMMS code in reproducing the depositional behavior of the events, we backanalyzed 7 debris flows, ranging in volume from 3.000 to 95.000 m3, selected from a database of documented events in alpine mountain catchments of northeastern Italy. Simulations, carried out with the support of high-resolution topographic information derived from LiDAR, used rheological characteristics μ and ξ as calibration parameters which allowed to measure objectively the prediction reliability. Results indicate that the model is capable to reproduce the observed behavior in terms of inundated areas, by using a narrow range of rheological parameters.