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Sediment resuspension mechanisms and their contributions to high‐turbidity events in a large lake
Author(s) -
Valipour Reza,
Boegman Leon,
Bouffard Damien,
Rao Yerubandi R.
Publication year - 2017
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.10485
Subject(s) - turbidity , sediment , turbidite , turbidity current , environmental science , turbulence , geology , hydrology (agriculture) , oceanography , geomorphology , geotechnical engineering , meteorology , physics , sedimentary depositional environment , structural basin
High‐resolution field data, collected during April to October of 2008–2009, were analyzed to investigate the quantitative contribution of sediment resuspension to high‐turbidity events in central Lake Erie. Resuspension events were distinguished within high‐turbidity events according to turbidity, fluorescence and acoustic backscatter timeseries, as well as satellite images. We observed 16 high‐turbidity events, causing a total duration of ∼20 d (out of 344 d) with elevated nearbed turbidity (> 10 NTU). Of these events, 64% were correlated with algal biomass, with the remaining 18%, 5%, and 4% being attributed to sediment resuspension by surface waves, storm‐generated currents and enhanced nearbed turbulence induced by high‐frequency internal waves, respectively. This is the first time that resuspension by enhanced nearbed turbulence from high‐frequency linear internal wave degeneration has been observed in a large lake. Resuspension was parameterized as a function of the instantaneous critical bottom velocity, bottom shear stress and the Shields parameter. From the in situ measurements, we suggest an extended Shields diagram for silty bed material that can be used to predict resuspension in other aquatic systems with similar sediment composition (∼20% cohesive sediment).