CGRG Bibliography of Canadian Geomorphology
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Author : Blair, J.A.A.
Date : 2001.
Title : Tidal influence on flow structure and dune morphology, Fraser River Estuary, British Columbia, Canada
Publication : Unpublished M.Sc. thesis. University of Guelph, Guelph.
Issue : 100 p.
Page(s) :
Abstract
This study examines the influence of tidal motion on velocity flow structure and dune morphology in the Fraser River Estuary near Vancouver, British Columbia. An acoustic Doppler Profiler (ADP) and high resolution survey echosounder were used to simultaneously record flow velocity and dune form over the course of one tidal cycle along a 250 m reach of the Main Channel of the Fraser River on June 20, 2000. Eight large symmetric dunes were analyzed During the tidal cycle mean velocity follows changes in tidal stage although deceleration on the flood tide is more rapid than during the ebb tide. Due to continuous flow disequilibrium in the estuary, a ‘memory’ of previous flow conditions is retained next to the bed. This results in kinked velocity profiles that must be regarded with caution when calculating shear stress estimates. Dune height increased on the failing tide and decreased on the rising tide, indicating that the response time required for the adjustment of dune height to mean velocity is considerably less than one tidal cycle.
Bibliography of Canadian Geomorphology