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When do logs move in rivers?
Author(s) -
Braudrick Christian A.,
Grant Gordon E.
Publication year - 2000
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/1999wr900290
Subject(s) - flume , entrainment (biomusicology) , streams , fluvial , flow (mathematics) , channel (broadcasting) , stability (learning theory) , hydrology (agriculture) , debris flow , environmental science , geology , debris , open channel flow , geotechnical engineering , mathematics , geometry , computer science , geomorphology , structural basin , physics , computer network , oceanography , machine learning , rhythm , acoustics
Large woody debris is an integral component of forested, fluvial systems throughout the world, yet we know little about hydraulic thresholds for movement and transport of logs. We developed theoretical models of entrainment and performed flume experiments to examine thresholds for wood movement in streams. Both the model and the experiments indicate that log entrainment is primarily a function of the piece angle relative to flow direction, whether or not the log had a rootwad, the density of the log, and the piece diameter. Stability increased if the pieces had rootwads or were rotated parallel to flow. Although previously reported as the most important factor in piece stability, piece length did not significantly affect the threshold of movement in our experiments or our physically based model, for logs shorter than channel width. These physically based models offer a first‐order approach to evaluating the stability of either naturally derived woody debris or material deliberately introduced to streams for various management objectives.