test Browse by Author Names Browse by Titles of Works Browse by Subjects of Works Browse by Issue Dates of Works
       

Advanced Search
Home   
 
Browse   
Communities
& Collections
  
Issue Date   
Author   
Title   
Subject   
 
Sign on to:   
Receive email
updates
  
My Account
authorized users
  
Edit Profile   
 
Help   
About T-Space   

T-Space at The University of Toronto Libraries >
University of Toronto at Scarborough >
Physical and Environmental Sciences >
Environmental Science >

Please use this identifier to cite or link to this item: http://hdl.handle.net/1807/3086

Title: Frequency dependent cross-shore suspended sediment transport. 1. A non-barred shoreface
Authors: Osborne, Philip D.,
Greenwood, Brian,
Issue Date: 1992
Publisher: Elsevier Science
Citation: Marine Geology, 106 (1992) 1-24
Abstract: The local, time-varying and time-averaged suspended sediment transports across a marine, non-barred shoreface were obtained from field measurements of the near-bed velocity and sediment concentration vectors using electromagnetic current meters and optical backscatterance suspended solids sensors. Co-spectral analyses of velocity and sediment concentration revealed the contributions of waves of different frequencies to the total transport; the transport attributable to quasi-steady currents was determined from the product of the time-averaged cross-shore velocity and sediment concentration. Estimates of the local, time-integrated sediment volume flux (total and net) and the associated erosion or accretion were determined using depth-of-activity rods. Suspended sediment transport was associated with: (1) local wind-forced waves; (2) swell; (3) low frequency waves (group-bound long waves) and (4) offshore-directed mean currents (undertow). These transport components varied spatially and temporally in response to changes in the wave height to water depth ratio. The local net oscillatory transport rate at wind-wave and swell-wave frequencies was directed onshore predominantly, and increased as water depth decreased in association with wave shoaling. The local mean sediment transport rate was predominantly offshore and dominated the net transport rate wherever wave-induced components were weak relative to the mean currents. Under breaking waves the suspended sediment transport contribution associated with wind-waves and swell-waves was reduced as a result of dissipation. The net suspended sediment transport rate exhibited a distinct vertical structure, reflecting the balance at each elevation between the opposing mean and oscillatory components of transport. The local time-averaged total and net sediment volume flux and resulting erosion and accretion patterns support the hypothesis of a near balance in sediment flux for the complete storm event.
URI: http://hdl.handle.net/1807/3086
Appears in Collections:Environmental Science

Files in This Item:

File Description SizeFormat
12_frequency_dependent_1.PDF2.33 MBAdobe PDF
View/Open

Items in T-Space are protected by copyright, with all rights reserved, unless otherwise indicated.

uoft