Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 414231
Title Hydraulic sedimentary processes causing anastomosing morphology of the upper Columbia River, British Columbia, Canada
Author(s) Makaske, B.; Smith, D.G.; Berendsen, H.J.A.; Boer, A. de; Nielen-Kiezebrink, M.F. van; Locking, T.
Source In: 27 th IAS Meeting of sedementology, Sedimentary environments of Mediteranean Island(s), Alghero, Italy, 20 - 23 September, 2009. - Alghero, Italy : EDES - ISBN 9788860251237 - p. 259 - 259.
Event Alghero, Italy : EDES - ISBN 9788860251237 27 th IAS Meeting of sedementology, Sedimentary environments of Mediteranean Island(s, Alghero, Italy, 2009-09-20/2009-09-23
Department(s) Landscape Centre
Publication type Abstract in scientific journal or proceedings
Publication year 2009
Abstract The upper Columbia River, British Columbia, Canada, shows typical anastomosing morphology — multiple interconnected channels that enclose floodbasins — and lateral channel stability. We analysed field data on hydraulic and sedimentary processes and show that the anastomosing morphology of the upper Columbia River is caused by sediment (bedload) transport inefficiency, in combination with very limited potential for lateral bank erosion because of very low specific stream power (= 2.3 W/m2) and cohesive silty banks. In a diagram of channel type in relation to flow energy and median grain size of the bed material, data points for the straight upper Columbia River channels cluster separately from the data points for braided and meandering channels. Measurements and calculations indicate that bedload transport in the anastomosing reach of the upper Columbia River decreases downstream. Because of lateral channel stability no lateral storage capacity for bedload is created. Therefore, the surplus of bedload leads to channel bed aggradation, which outpaces levee accretion and causes avulsions because of loss of channel flow capacity. This avulsion mechanism applies only to the main channel of the system, which transports 87% of the water and > 90% of the sediment in the cross-valley transect studied. Because of very low sediment transport capacity, the morphological evolution of most secondary channels is slow. Measurements and calculations indicate that much more bedload is sequestered in the relatively steep upper anastomosing reach of the upper Columbia River than in the relatively gentle lower anastomosing reach. With anastomosing morphology and related processes (e.g., crevassing) being best developed in the upper reach, this confirms the notion of upstream rather than downstream control of upper Columbia River anastomosis.
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