Measured cross-shore and vertical variations in grain size, sorting and composition in suspended sediments transported by longshore currents

Authors: Esteves, L.S., Williams, J.J., Lisniowski, M.A. and Perotto, H.

Journal: Journal of Coastal Research

Issue: SPEC. ISSUE 50

Pages: 615-619

eISSN: 1551-5036

ISSN: 0749-0208

Abstract:

Data defining the grain size and composition of suspended sediment transported by long shore currents is scarce. Present data was obtained on six dissipative to reflective, micro-tidal, wave-dominated beaches composed of fine to very fine sand along the southern coast of Brazil. At each site, samples of suspended sediment were collected at equally spaced heights above the bed over a 10-min period using streamer traps placed at accessible locations along the cross-shore profile. To define the relevant hydrodynamic conditions, measurements were obtained of the beach profile, long shore current speed, wave breaker height, wave period and the breaker angle relative to the shoreline. Suspended sediment samples were weighed, sieved and analysed for carbonate content. The carbonate content is highly variable and does not show any trend of changes across the surf zone or in the water column, although generally lower concentrations were found in bed than in suspended sediments, except at shallower locations. Changes in the characteristics of suspended sediments are not considerable across the surf zone. Vertical differences are more apparent in the troughs than in shallower areas across the surf zone where sediment properties are more homogeneous due to wave-generated turbulence. The median grain size of suspended sediments was up to 64% smaller than the median grain size of bed samples. Cross-shore and vertical variations in sediment grain size should be accounted for to improve results obtained by models used to quantify concentration profiles or longshore sediment transport rates.

Source: Scopus

Preferred by: Luciana Esteves

Measured Cross-Shore and Vertical Variations in Grain Size, Sorting and Composition in Suspended Sediments Transported by Longshore Currents

Authors: Esteves, L.S., Williams, J.J., Lisniowski, M.A. and Perotto, H.

Journal: JOURNAL OF COASTAL RESEARCH

Pages: 615-619

eISSN: 1551-5036

ISSN: 0749-0208

Source: Web of Science (Lite)