CONTEMPORARY EROSION OF THE CANADIAN LANDSCAPE

Studies of contemporary patterns of erosion in the glaciated and large ly undisturbed Canadian landscape reveal spatial patterns that do not conform to the conventional concepts of drainage basin sediment delive ry. In particular stream and valley side sediment sources dominate ove r erosion of the land surface, and specific (unit) sediment yield is o ften positively, rather than inversely, related to drainage area. Much of this is a legacy of glaciation that left large quantities of sedim ent in the landscape and disrupted regional drainage patterns. The abs ence of an integrated drainage network affects sediment delivery in ma ny areas. To some extent unusual patterns of specific yield are to be expected in large drainage basins where environmental and geologic con ditions may vary considerably within the basin. Only in the agricultur al areas of the Great Lakes basin and St. Lawrence valley do more conv entional patterns of erosion occur. Applied studies related to agricul tural soil erosion and pollution have helped to illuminate the pathway s and sources of sediment in particular cases and show the effects of landscape disturbance.