Calibration of numerical models for small debris flows in Yosemite Valley, California, USA

Natural Hazards and Earth System Sciences
By:  and 



This study compares documented debris flow runout distances with numerical simulations in the Yosemite Valley of California, USA, where about 15% of historical events of slope instability can be classified as debris flows and debris slides (Wieczorek and Snyder, 2004). To model debris flows in the Yosemite Valley, we selected six streams with evidence of historical debris flows; three of the debris flow deposits have single channels, and the other three split their pattern in the fan area into two or more channels. From field observations all of the debris flows involved coarse material, with only very small clay content. We applied the one dimensional DAN (Dynamic ANalysis) model (Hungr, 1995) and the two-dimensional FLO2D model (O'Brien et al., 1993) to predict and compare the runout distance and the velocity of the debris flows observed in the study area. As a first step, we calibrated the parameters for the two softwares through the back analysis of three debris- flows channels using a trial-and-error procedure starting with values suggested in the literature. In the second step we applied the selected values to the other channels, in order to evaluate their predictive capabilities. After parameter calibration using three debris flows we obtained results similar to field observations We also obtained a good agreement between the two models for velocities. Both models are strongly influenced by topography: we used the 30 m cell size DTM available for the study area, that is probably not accurate enough for a highly detailed analysis, but it can be sufficient for a first screening. European Geosciences Union ?? 2005 Author(s). This work is licensed under a Creative Commons License.
Publication type Article
Publication Subtype Journal Article
Title Calibration of numerical models for small debris flows in Yosemite Valley, California, USA
Series title Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-5-993-2005
Volume 5
Issue 6
Year Published 2005
Language English
Publisher European Geosciences Union
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Natural Hazards and Earth System Science
First page 993
Last page 1001
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