Throughout the mountainous regions of BC and Alberta, alluvial fans have been chosen as sites for residential and industrial development, in part due to the perception that flood, erosion and landslide risks are lower on fans than on surrounding floodplains and steep hillsides. Extreme events such as the 2013 floods affecting the southwestern Rocky Mountains of Alberta demonstrate that alluvial fans are subject to catastrophic stream channel instability that threatens residential areas, affects transportation infrastructure and puts lives at risk.

This project will be focussed on the results of a set of stream table experiments, to conducted on a newly constructed physical model of a steep gravel bed channel located in the Biogeomorphic Experimental Laboratory at UBC. These experiments will test the hypothesis that catastrophic stream channel instability in unconfined gravel-cobble bed streams is associated with the onset of full mobility of the largest particles in the stream. The geometry of the experimental channel, the design flows of water and sediment, and the  grain size distribution of the sediment making up the stream bed and banks will be scaled to represent streams on alluvial fans in the southwestern Rocky Mountains of Alberta, using a Froude scaling approach that maintains dynamic similarity of the gravity forces.

This project is a collaboration between the University of British Columbia and BGC Engineering and is funded in large part by an NSERC ENGAGE grant.

Contact: Lucy MacKenzie lucy.mackenzie(at)geog.ubc.ca