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1 BC Ministry of Forests, Bag 6000, Smithers, BC, Canada V0J 2N0 dave.wilford{at}gems3.gov.bc.ca
2 Bulkley Valley Centre for Natural Resources Research and Management, Box 4274, Smithers, BC, Canada V0J 2N0
3 UBC Faculty of Forestry, 2424 Main Mall, Vancouver, BC, Canada V6T 1Z4
4 Geohazards Division, Disaster Prevention Research Institute, Gokasho, Uji, Kyoto, 611-0011, Japan
Alluvial and colluvial fans with forest cover are common in the valleys of west central British Columbia, Canada. Given the low population density of the region, most of these fans are uninhabited and the primary land use is forestry. The fans are desirable for timber harvesting due to the combination of the relatively easy access to their valley-bottom locations and their high-quality timber. However, they are also sites influenced by debris flows, debris floods and floods, and the interaction between conventional forest practices and these natural hydrogeomorphic processes has led to substantial financial costs and disturbance to forests and stream channels. Basic watershed morphometrics can be used to predict the dominant hydrogeomorphic process influencing forested fans. The hydrogeomorphically active zones of forested fans have characteristic site and stand features, and are referred to as the hydrogeomorphic riparian zone. Features within these zones can be used to determine the frequency and disturbance extent of hydrogeomorphic events. Appropriate management strategies can be developed to limit the effect of forestry activities on natural hydrogeomorphic processes.
