Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): T. E. Lisle; M. A. Madej
    Date: 1992
    Source: In: P. Billi, R.D. Hey, C.R. Thorne, and P. Tacconi (ed.), Dynamics of Gravel-bed Rivers. John Wiley and Sons, London. p. 277-293.
    Publication Series: Miscellaneous Publication
    PDF: View PDF  (347 KB)

    Description

    Abstract - Recent advances in our understanding of the origin and function of armouring in gravel-bed rivers have not addressed the role of non-uniformity and unsteadiness of flow. These flow attributes have important influences on both the surface and subsurface bed material size distributions which are observed at low flow, from which we commonly make inferences concerning bedload transport at high flow. Bed armouring, measured as the ratio of surface to subsurface bed material grain size, is highly variable spatially in a channel in which past and present bed aggradation indicates that the sediment supply has exceeded the transport capacity. Alternate bar topography induces strong variations in boundary shear stress, especially at low flow. The resulting winnowing of fine sediment from zones of high stress, such as riffles, and its deposition as thin sheets in zones of low stress, such as pools, produce wide variations in armouring. Linked winnowing and deposition of fine sediment in each bar pool sequence creates pronounced, local, streamwise sorting by grain size.

    Publication Notes

    • You may send email to psw_communications@fs.fed.us to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

    Citation

    Lisle, T. E.; Madej, M. A. 1992. Spatial variation in armouring in a channel with high sediment supply. In: P. Billi, R.D. Hey, C.R. Thorne, and P. Tacconi (ed.), Dynamics of Gravel-bed Rivers. John Wiley and Sons, London. p. 277-293.

    Keywords

    PSW4351, armouring, gravel bed, aggradation, sediment supply, transport capacity, bedload transport, boundary shear stress

    Related Search


    XML: View XML
Show More
Show Fewer
Jump to Top of Page