Abstract It is generally supposed that specific sediment yield declines as the area drained increases. In British Columbia this hypothesis does not appear to apply and sediment yields increase at all spatial scales up to 3 X l(r km2. This effect results from ,the ,dominance ,of secondary remobilization of Quaternary sediments along river valleys over primary denudation,of the land surface in
... [Show full abstract] catchments larger than 1 km 2. The present study uses lake sediments to establish late Holocene sediment yields for three small catchments (less than 1 km2) that straddle the alpine- subalpine ecotone (1620 to 1850 m above sea level) in the Pacific Ranges of the Coast Mountains of British Columbia. Sediment yields for the three catchments,range from 0.005 to 0.2201 km"2 year"1 and show an increase in yield with a decrease in elevation. The sediment yields established are orders of magnitude lower than regional rates for larger scale basins. These results are not inconsistent with the scale effects noted for the sediment yields of larger basins in British Columbia and confirm the existence of low yields in small pristine alpine and subalpine catchments. THE CONVENTIONAL MODEL At present, it is widely held that specific sediment yield - the quantity of