Wildlife Infometrics Inc.

Coarse Sediment Hazard Modeling in the Fort St. James and Kootenay Lake Regions

Deposition of coarse sediment into stream channels, and onto fluvial fans and deltas is a natural part of sediment transport processes. Bedload material is essential to creating aquatic habitat diversity and stabilising stream channels. However catastrophic events, usually landslides, that deposit coarse sediment into stream channels often result in at least temporary destabilisation of the channel itself, and can sometimes result in long-term changes to a channel. Increases in coarse sediment inputs may result in:

  • channel infilling and channel evulsion,
  • triggering of debris floods or debris flows (debris torrents)
  • downstream damage to stream-side property
  • loss of aquatic habitat, and
  • increased bank erosion and loss of riparian habitat.

By comparing various scenarios, we estimate the potential for changes in coarse sediment inputs between particular management scenarios and background levels, and between various management options themselves. Our results identified relative impacts to watersheds across the study area for each of the management scenarios ranging from full harvest of mountain pine beetle killed timber to an idealized state of a landscape that is fully forested and mature.

Excerpted from:
Utzig, G, M Carver, R Sulyma, V Brumovsky, and I Parfitt 2008. A Coarse Sedimentation Hazard Model for Disturbances in Forested Watersheds. Report prepared for the BC Ministry of Environment and the BC Ministry of Healthy Living and Sport.