Debris-flow susceptibility map of Slovenia 1: 250.000

Marko Komac, Špela Kumelj, Mihael Ribičič; 2010

Price (VAT not includet): 30,00 EUR

For the area of Slovenia (20,000 km2) a debris-flow susceptibility model at scale 1: 250,000 was elaborated. To calculate the susceptibility to debris-flow occurrence several information layers were used including geology (lithology and distance from structural elements), intensive rainfall (48-hour rainfall intensity), derivates of digital elevation model (slope, curvature, energy potential related to elevation), hydraulic network (distance to surface waters, energy potential of streams). Locations of sixteen existing debris-flows were used for the evaluation of susceptibility-models. A linear model weighted sum modelling was selected on the basis of easy-to-acquire spatio-temporal factors to simplify the approach and to make it easily transferable to other regions. Based on the calculations of 672 linear models with different weight combinations for used spatio-temporal factors and based on results of their success to predict debris-flow susceptible areas, the best factors’ weight combination was selected. To avoid over-fitting of the prediction model, an average of weights from the first hundred models was chosen as an ideal combination of factor weights. For this model also error interval was calculated. A debris-flow susceptibility model at scale 1: 250,000 is a basis for spatial prediction of the debris flow triggering and transport areas. It also gives a general overview of susceptible areas in Slovenia and gives guidance for more detailed research and further spatial and numerical analyses. The results show that approximately 4 % of Slovenia land is extremely susceptible to debris-flows and in approximately 11 % of Slovenia the susceptibility is high. As expected, these areas are related to mountainous terrain in north-western and northern Slovenia.

ISBN 978-961-6498-17-3