Sub-Watershed Contributions to the Suspended Sediment Yield of Spring Creek Watershed, Alberta

Sub-watershed contributions to the suspended sediment yield of Spring Creek Watershed, a 113 km2 forested area in northwestern Alberta, were examined. The analysis was based on a five year record of suspended sediment and water discharge from Spring Creek Watershed and five of its sub-watersheds, compiled as part of the Canadian contribution to the International Hydrological Decade Programme. The gauged sub-watersheds accounted for 76 percent of the total area of Spring Creek Watershed, 82 percent of its total water yield, but only 8 percent of its total sediment yield. Annual sediment yield patterns and sediment rating curve analysis indicated that sediment discharge from Spring Creek Watershed was largely independent of the erosional processes operating in the sub-watersheds. A simple conceptual model is proposed which explains the interaction between the sediment discharge of the sub-watersheds and that of Spring Creek Watershed by identifying the major sediment sinks and sources in the study area. The model suggests that runoff and sediment generation are not spatially coincident processes and that over 90 percent of the watershed sediment yield is derived from less than 1 percent of its area. The model is considered to be generally applicable to the sediment regime of other, similar watersheds in the region.