Debris flooding magnitude estimation based on relation between dendrogeomorphological and meteorological records

Andrej Novak (Author), Tomislav Popit (Author), Tom Levanič (Author), Andrej Šmuc (Author), Ryszard J. Kaczka (Author)

Abstract

Debris floods are mass movement events which are usually triggered by intense short duration rainfall events. They often occur on alluvial fans in an alpine environment. Due to their sever geohazard potential they pose a serious threat to infrastructure and human life. To minimize their threat understanding of their past magnitude occurrence is crucial. Dendrogeomorphology has proven to be a highly useful method in studies of past slope mass movements. However, establishing magnitudes of past events has so far been based on indirect indicators, such as: spatial distribution of affected trees, characteristics of tree injures and sedimentological records. In this study we present a method that directly estimates the magnitudes of past debris flood events on an alluvial fan using dendrogeomorphological and meteorological data sets. The studied dendrogeomorphological data set is based on tree-ring series from 105 sampled trees (Picea abies, Abies alba and Larix decidua) growing on an active alluvial fan in a typical alpine environment of the Julian Alps in NW Slovenia. Based on sudden growth suppression thirteen debris flood events since 1903 were dated. Meteorological data from a nearby meteorological station was used to determine the exact triggering meteorological event for ten events. Comparing the I$_t$ index of affected trees and calculated return period of an individual triggering meteorological event established the magnitude of debris flooding. We showed that more trees are affected at high return period/intensity of the triggering meteorological event and therefore higher magnitudes of debris floods. This research presents the first combined use of dendrogeomorphological and meteorological data sets for magnitude estimation of historic debris flood events which could be successfully applied in similar environments.

Keywords

debris flood;dendrogeomorphology;precipitation records;magnitude estimation;

Data

Language:	English
Year of publishing:	2020
Typology:	1.01 - Original Scientific Article
Organization:	UL NTF - Faculty of Natural Sciences and Engineering
UDC:	55
COBISS:	20205315
ISSN:	0169-555X
Views:	361
Downloads:	145
Average score:	0 (0 votes)
Metadata:

Other data

Type (COBISS):	Article
Pages:	str. 1-52
Chronology:	2020
DOI:	10.1016/j.geomorph.2020.107303
ID:	13167145