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Temporal variations in bedload transport rates: The effect of progressive bed armouring
Author(s) -
Gomez Basil
Publication year - 1983
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.3290080105
Subject(s) - bed load , hyperconcentrated flow , streams , baseflow , stream power , geology , flood myth , hydrology (agriculture) , sediment transport , streamflow , geotechnical engineering , sediment , geomorphology , drainage basin , computer science , geography , computer network , cartography , archaeology
The quantitative bedload transport data that are presently available confirm that the generalized bedload transport rate‐stream power relationship is applicable to natural streams. However, the bedload transport rate is not solely dependent upon hydraulic parameters, but also upon the inter‐relationship between bed material characteristics and flow properties. Segregation of the surficial bed material, as expressed through the development of an armour coat, limits the availability of transportable material. Under such circumstances observed bedload transport rates are less than the predicted values. The effect which the development of an armoured surface has upon the bedload transport rate is described with reference to bedload and bed material sampling in the Borgne d'Arolla, Valais, Switzerland. The data refer to two periods when the resumption of baseflow conditions following flood events which were of a sufficient magnitude to transport all but the coarsest (0·3–0·5 m) particles on the streambed, provided the opportunity for the bed to adjust to a comparatively stable flow regime. Observed and predicted bedload transport rate‐stream power relationships are compared. The theoretical relationship does not adequately describe conditions in some gravel‐bed channels, since it fails to take into account the effect which armouring may have upon the supply of transportable material.