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Reconstruction of debris-flow activity at Grosse Grabe (St. Niklaus, Valais)

Based on a detailed geomorphic map of the currently active and former flow paths on the cone of the Grosse Grabe torrent, obviously disturbed trees were cored so as to assess the frequency as well as spatial patterns of past debris-flow activity.

In addition, unaffected trees growing in the outermost part of the cone where no affected trees are present due to forestry actions were sampled in order to assess the minimum age of the trees and therefore be able to determine the latest possible moment of debris-flow events in these channels. It is the purpose of this study to highlight how and where on the cone material has been deposited in the last centuries.

Project applicant : Swiss Federal Office for the Environment; Forest and Landscape Authority of the Canton of Valais; St. Niklaus community

Project duration : November 2005 to December 2006

 
     
 

Contact : Markus Stoffel

Publications :

Bollschweiler, M., Stoffel, M., Schneuwly, D. M. (2008): Assessing the last moment of debris-flow activity on a fan using tree-ring data. Proceedings of the International Conference “Debris Flows: Disasters, Risk, Forecast, Protection”. Pyatigorsk, Russia, 22-29 September 2008, pp. 83–86. [PDF]

Bollschweiler M., Stoffel M., Schneuwly D.M., (2008): Dynamics in debris-flow activity on a forested cone – a case study using different dendroecological approaches. Catena 72: 67-78. [PDF]

Bollschweiler, M., Stoffel, M., Schneuwly, D.M., (2007): Dynamics in debris-flow activity on a forested cone – a case study using different dendroecological approaches. Catena. [PDF]

Bollschweiler, M., Stoffel, M., Schneuwly, D. (2007). Assessing the spatial dynamics of debris-flow activity on a forested cone using dendroecological methods. Geophysical Research Abstract 9, 09220. [PDF]

Bollschweiler, M., Stoffel, M., Schneuwly, D., 2006. Assessing the spatio-temporal debris-flow activity on a forested cone using tree-ring data. Proceedings International Symposium Interpraevent “Disaster Mitigation of Debris Flows, Slope Failures and Landslides”, September 25–27, 2006, Niigata, Japan. Universal Academic Press, Tokyo, pp. 597–604. [PDF]

 
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