Water Stewardship Information Sources

Citation Fannin, J, Bonin, D and Dunkley, D. 2008. Quantitative back-analysis of partial risk: Jamieson Creek debris flow. In: In : J. Locat, D. Perret, D. Turmel, D. Demers et S. Leroueil, (2008). Proceedings of the 4th Canadian Conference on Geohazards : From Causes to Management. Presse de l’Université Laval, Québec, 594 p.
Organization UBC
URL http://www.geohazards.ggl.ulaval.ca/evaluation/fannin.pdf
Abstract/Description or Keywords Storm precipitation during November 1990 caused a debris slide within a forest clearcut in the Jamieson Creek watershed.
The debris slide progressed to a debris flow as it moved over the logged terrain, then entered and resulted in sedimentation
of Jamieson Creek. Post-event analysis of the factor of safety of a potential failure plane at the point of origin in the cutblock
suggests the probability of a specific hazardous landslide occurring, in this case the debris slide, to be 0.26. The slope
stability analysis is based on measured soil properties, interpretation of groundwater monitoring data, and some assumed
geotechnical parameters. Attributes of the slope below the point of origin indicate the probability of the resulting debris flow
entering Jamieson Creek to be certain or 1, given the occurrence of the debris slide. The travel distance analysis is based
on a consideration of slope angle, and a flow behaviour that was unconfined for most of the travel path. Accordingly, the
post-harvesting back-analysis shows that the partial risk to Jamieson Creek from a debris slide initiating near the top of the
cutblock and the resulting debris flow entering the creek to be 0.26.
Information Type conference article
Regional Watershed Lower Fraser
Sub-watershed if known
Aquifer #
Comments
Project status complete
Contact Name Jonathan Fannin
Contact Email [email protected]