Water Stewardship Information Sources

Citation Scrivener, JC and Tripp, DB. 1998. Changes in spawning gravel characteristics after forest harvesting in Queen Charlotte Islands and Carnation Creek Watersheds and the apparent impacts on incubating salmonid eggs. In: Hogan, D.L., P.J. Tschaplinski, and S. Chatwin (Editors). B.C. Min. For., Res. Br., Victoria, B.C. Land Manage. Handb. No. 41.
Organization FLNRO
URL https://www.for.gov.bc.ca/hfd/pubs/docs/Lmh/Lmh41.htm
Abstract/Description or Keywords In earlier presentations, results were outlined and
discussed concerning landslide prediction, channel
morphology changes, channel scour and fill
processes, and fine sediment movements in coastal
streams of British Columbia. Forest harvesting
impacts on these processes were also demonstrated.
These processes are known to affect the composition
of streambed gravels and their incubating salmon
eggs in Oregon (Hall et al. 1987), Washington
(Cederholm and Reid 1987), and Alaska (McNeil
and Ahnell 1964).
Sediment composition of the streambed influences
two critical properties of salmon incubation gravels:
permeability and porosity. Permeability affects
delivery and removal rates of oxygen, carbon dioxide,
and other metabolites (Wickett 1958; McNeil
and Ahnell 1964), which influence fish embryo
survival (Alderdice et al. 1958; Rombough 1983).
Small pore size can restrict intergravel movement of
alevins and create a barrier to fry emergence (Dill
and Northcote 1970; Scrivener and Brownlee 1989).
Other studies also show that unseasonal surges of
fine sediments can reduce the number of benthic
organisms inhabiting a stream (Hall et al. 1987) and
ultimately affect fish food availability and fish
growth after emergence (Phillips 1971).
Mass movements of gravel and sand into channels
not only affected the composition of spawning
gravels, but also their stability. Stability declined for
channel structures, channel topography, and the
riparian zone when mass wasting processes increased
sediment loading of streams on the Queen Charlotte
Islands (Hogan 1986; Hogan and Schwab 1991).
Streambed scouring also increased (Tripp and
Poulin 1986), with obvious consequences for the
survival of incubating salmonid embryos.
Information Type Article
Regional Watershed Coast Region
Sub-watershed if known
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