Sediment Transfer through the Fluvial System (Proceedings of a symposium held in Moscow, August 2004). IAHS Publ. 288, 2004, 459–465

Abstract In 2001 a study in an undisturbed, highly productive salmon bearing stream (O’Ne-eil Creek) was undertaken in the northern interior of British Columbia, Canada. The aim was to determine if the structure and settling characteristics of the aggregated sediments varied significantly over the different hydrological and biological regimes of an open-water season. Sampling regimes included the hydrological conditions of the rising limb of spring freshet, falling limb flows of snowmelt and summer rainstorms, while biological conditions included sampling during spawning and die-back of 13 580 sockeye salmon. A negative relationship between shear stress and effective particle size diameter, D₅₀ is evident for the hydrological regimes, while the largest flocs occur when live and dead salmon are present in the stream. Increased organic matter quality and biological resuspension of gravel-stored material attributed to spawning salmon, reflect their physical and chemical influence on the change in size and density of aggregated fine sediment in this stream system.

Key words aggregation; Canada; effective density; floc factor; flocculation; image analysis; organic matter quality; shear stress; spawning salmon; suspended sediment