Persistence of a scour hole on the East Channel of the Mackenzie Delta, N.W.T.

• Published in: Canadian Journal of Civil Engineering
• Main Authors: Fassnacht, Steven R, Conly, F Malcolm
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2000
• Subjects: Mackenzie Delta; Mackenzie river
• Online Access: http://dx.doi.org/10.1139/l00-022; http://www.nrcresearchpress.com/doi/pdf/10.1139/l00-022

Anomalies in the bathymetry of river channels are of great practical concern for designing sub-bed pipeline crossings. Of particular interest is the long-term stability of deep holes. Bathymetric evidence indicates that one unusually deep hole in the East Channel of the Mackenzie River, referred to as a scour hole, has existed as early as 1956. Detailed hydraulic and morphologic data were first collected in 1985, and again in 1992 to assess the spatial and temporal stability of the feature. Even with a record flood on the Mackenzie River in 1988, the hole, with a maximum depth approaching 30 m, was vertically stable over the 7-year period. However, lateral erosion and sedimentation have resulted in a shift in the horizontal position of the scour hole, with a maximum horizontal erosion of approximately 2 m/a. The average rate of lateral outward movement was observed to be 0.8 m/a.Key words: Mackenzie Delta, rivers, fluvial sediment, channel stability, scour, scour hole.