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Riverine sediment balance of the Mackenzie Delta, Northwest Territories, Canada
Author(s) -
Carson M. A.,
Conly F. Malcolm,
Jasper J. N.
Publication year - 1999
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/(sici)1099-1085(199911)13:16<2499::aid-hyp937>3.0.co;2-i
Subject(s) - overbank , delta , river delta , sediment , sedimentation , sedimentary budget , geology , hydrology (agriculture) , erosion , deposition (geology) , channel (broadcasting) , levee , shore , sediment transport , oceanography , geomorphology , sedimentary depositional environment , geotechnical engineering , electrical engineering , structural basin , aerospace engineering , engineering
Data acquisition by Environment Canada and others over the last 20 years now allows the first comprehensive synthesis of the riverine sediment balance of the Mackenzie Delta. The data presented here are: sediment inputs from the Mackenzie and Peel rivers at the delta head and river sediment transfers from the Upper Delta to the Outer Delta (1974–1994); in‐channel and overbank sedimentation, including lakes (post‐1963); and in‐channel erosion along Delta channels (1950–1981). These data indicate that the mean annual sediment input to the Delta is about 128 Mt, and the corresponding loss to offshore is about 85 Mt. The net sedimentation of 43 Mt is divided almost equally between the Upper Delta (mostly on levees and lake beds) and the Outer Delta (mostly on lake shores). Gross sedimentation within the Delta, about 50% of which is on point bars, is much higher, estimated at about 103 Mt annually: the difference is the large amount of sediment reentrainment within the Delta, through bank erosion, primarily along Middle Channel. How much of this pointbar deposition is from settling of sediment delivered by the Mackenzie and Peel rivers (as distinct from local sediment derived from bank scour within the Delta) is not known. Such within‐Delta sediment exchange (which could be as high as 50 Mt) might be important in determining the quality of sediment (nutrients, contaminants, etc) that it is being delivered offshore: it would be naïve to assume that all of this sediment is from the present‐day input of the Mackenzie and Peel rivers. Copyright © 1999 John Wiley & Sons, Ltd.