Water Stewardship Information Sources

Citation Guthrie, RH. 2002. Landslide frequencies and logging on Vancouver Island: An analog showing varied yet significant changes. In: Jordan, P and Orban, J. Terrain Stability and Forest Management in the Interior of British Columbia: Workshop Proceedings: May 23-25, 2001, Nelson, British Columbia. Technical Report 003, BC Ministry of Forests and Range
Organization FLNRO
URL https://www.for.gov.bc.ca/hfd/pubs/Docs/Tr/Tr003.htm
Abstract/Description or Keywords Despite a long history of landslide research in British Columbia, there remain
few data on the actual change in rates of landslides following harvesting
activities other than from the Queen Charlotte Islands and the Clayoquot
Sound region of Vancouver Island. The application of these data to other
areas in British Columbia is problematic. This paper discusses implications
of the results of a study of three watersheds on Vancouver Island: Macktush
Creek, Artlish River, and Nahwitti River watersheds. Some 363 landslides,
from 0.02 to > 1 ha, were identifi ed in three watersheds from air photographs,
beginning at a date that essentially preceded logging up to the present. Landslide
frequencies increased in Macktush Creek, Artlish River, and Nahwitti
River by approximately 11, 3, and 16 times, respectively. Two to 13 times more
landslides reached streams following logging; most of these were between 0.2
and 1 ha. Landslide density analyses produced variable results, ranging from
2.4 to 24 times increases in number of landslides. Road landslide frequencies
increased by 27, 12, and 94 times for Macktush, Artlish, and Nahwitti,
respectively. Landslide frequencies need to be determined for many more
watersheds to provide better information on the effects of logging activities
on both Vancouver Island and the Interior of British Columbia. It is against
this baseline that geoscientists and geotechnical engineers practising in the
forest sector can measure their successes at reducing the impact of landslides
in British Columbia.
Information Type article
Regional Watershed Vancouver Island North, Vancouver Island South
Sub-watershed if known
Aquifer #
Project status
Contact Name Richard Guthrie
Contact Email [email protected]