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The influence of coarse particle mobility on scour depth in salmonid spawning habitat
Author(s) -
Dusterhoff S.R.,
Sloat M.R.,
Ligon F.K.
Publication year - 2017
Publication title -
river research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.679
H-Index - 94
eISSN - 1535-1467
pISSN - 1535-1459
DOI - 10.1002/rra.3178
Subject(s) - particle (ecology) , watershed , shear stress , environmental science , oncorhynchus , geotechnical engineering , hydraulics , hydrology (agriculture) , sediment transport , flow (mathematics) , geology , geomorphology , sediment , fishery , fish <actinopterygii> , mechanics , physics , oceanography , machine learning , computer science , biology , thermodynamics
This study examined the influence of flow hydraulics and coarse particle mobility on bed scour adjacent to coho salmon ( Oncorhynchus kisutch ) redds in a coastal California watershed for a bankfull flood. It was theorized that coarse particle mobility (i.e., mobility of particles larger than the median bed particle size, D 50 ) exerts a strong control on bed scour depth. Maximum scour depth at the study sites was found to be negatively correlated with flow shear stress, which is dissimilar to findings from previous scour studies in spawning reaches. This resulted from a relatively similar coarse particle size ( D 84 ) for all study sites and a negative relationship between shear stress and coarse particle exposure to flow (or the D 84 / D 50 ratio), which together caused sites with low shear stress to have a high degree of localized coarse particle mobility and an associated high maximum scour depth. This study provides new insights into the vulnerability of spawning reaches with low flow energy to redd scour and highlights the need to consider the mobility of coarse particle sizes explicitly when examining the dominant controls on redd scour.