Contemporary erosion of the Canadian landscape

Abstract

Studies of contemporary patterns of erosion in the glaciated and largely undisturbed Canadian landscape reveal spatial patterns that do not conform to the conventional concepts of drainage basin sediment delivery. In particular stream and valley side sediment sources dominate over erosion of the land surface, and specific (unit) sediment yield is often positively, rather than inversely, related to drainage area. Much of this is a legacy of glaciation that left large quantities of sediment in the landscape and disrupted regional drainage patterns. The absence of an integrated drainage network affects sediment delivery in many areas. To some extent unusual patterns of specific yield are to be expected in large drainage basins where environmental and geologic conditions may vary considerably within the basin. Only in the agricultural areas of the Great Lakes basin and St. Lawrence valley do more conventional patterns of erosion occur. Applied studies related to agricultural soil erosion and pollution have helped to illuminate the pathways and sources of sediment in particular cases and show the effects of landscape disturbance.