Wave flume experiments on the formation of longshore bars produced by breaking waves
Coastal dynamics ; Coastal environment ; Experimentation ; Japan ; Model ; Sandbar ; Vortex
Mechanisms and processes of longshore bar formation were investigated in connection with vortices induced by breaking waves in the laboratory. Four kinds of wave-flume experiments were conducted using a two-video-camera system to examine
the vortices and bar formation in detail. Four process models on bar formation are constructed based on the action of vortices: they are models for break-point single bar, inshore single bar, successive multiple bars, and simultaneous multiple bars
. The occurrence condition for these four types of bars can be quantitatively determined.
The central aim of this research is to enhance the understanding of the behaviour of alongshore bars in a water depth of about 2 to 7 m on the time scale of years (medium scale). Such bars are a frequent morphological phenomenon along the Dutch
coast. To that end, processes on a much smaller time scale were studied; these processes may be responsible for the observed multi-year bar behaviour. The field research was carried out at the central part of the North sea coast at Terschelling
The aims of this review are to identify the dominant morphodynamic processes governing intertidal bar systems and provide a conceptual framework with which these bars can be further investigated. It is the dominant importance of tidal water level
variations and wave processes in shallow water depths (swash and surf zone bores), rather than wave height variability and deeper water wave processes (breaking and shoaling waves), that constitutes the main difference between intertidal and subtidal bar
Short-term intertidal bar mobility on a ridge-and-runnel beach, Merlimont, northern France
Coastal dynamics ; Coastal environment ; Coastal sedimentation ; Digital elevation model ; Earth surface processes ; France ; Intertidal zone ; Longshore current ; Nord-Pas-de-Calais ; Sandbar ; Sediment transport ; Topography
mobility. The beach exhibited a pronounced dual bar-trough system that showed cross-shore stationarity. The bars and throughs were, however, characterized by significant longshore advection of sand under the influence of suspension by waves and transport
Digital elevation models and topography profiles of a beach with intertidal bar and through (ridge-and-runnel) morphology in Merlimont, near Somme estuary, were analysed in order to assess patterns of cross-shore and longshore intertidal bar
The aim of this research is the increase of the knowledge of the behaviour of nearshore breaker bars on the short to medium time scale (days to weeks) and to reveal the hydrodynamic and sediment transport processes underlying this behaviour
. The research focuses on processes associated with the transformation and breaking of high-frequency wind-waves near the inner of the two nearshore breaker bars of Egmond aan Zee (Central Dutch Coast). - (AGD)
Coastal dynamics ; Coastal environment ; Denmark ; Intertidal zone ; Sandbar ; Sediment transport ; Storm ; Suspended load
This paper examines the processes responsible for the morphodynamics of an intertidal swash bar at Skallingen, Denmark, during 7 successive storms. The contributions of gravity waves, infragravity waves and mean currents to the cross-shore suspended
sediment transport are systematically described and related to the morphological response of the intertidal swash bars at Skallingen.
The central objective of this thesis was to improve the understanding of nearshore bar behaviour over time scales ranging from days to years, using a 3,4-year data set of ARGUS video images (from March 1995 to September 1998) of the double barred
Tidal transverse bars building up a longitudinal sand body (Middle Eocene, Belgium) in Tide-influenced sedimentary environments and facies.
. Foresets dip parallel to the main axis of the sand body. The sedimentary structures suggest that the sand body was deposited during a short period, built up by a series of large, transverse bars. Their migration was governed by strongly asymmetrical tidal
In the Middle Eocene shallow-marine Brussels Sands a long sand body is partly exposed, bordering a channel which marks the erosional base of the Formation. This Kraaiberg facies shows a uniform sequence of metre-scale tabular, cross-bedded sets
Swash bar morphodynamics in the Danish Wadden Sea : sand bed oscillations and suspended sediment flux during an accretionary phase of the foreshore cycle
Coastal dynamics ; Coastal environment ; Denmark ; Dune ; Intertidal zone ; North Sea ; Sandbar ; Sediment transport ; Suspended load ; Wave ; Wind speed
In this paper, small-scale accretion/erosion cycles are documented in association with the vertical and horizontal translation of a swash bar during a major accretionary phase of the beach cycle. The local hydrodynamics responsible for sand
The influence of intertidal bar-trough morphology on sediment transport on macrotidal beaches, northern France
Beach ; Coastal environment ; Coastal geomorphology ; France ; Intertidal bar ; Intertidal zone ; Nord-Pas-de-Calais ; Sand ; Sediment transport ; Trough
The aim of this paper is to present the results of sediment transport measurements, coastal hydrodynamics and beach morphological surveys carried out on 3 sandy barred macrotidal beaches of Northern France (Zuydcoote, Wissant, Hardelot). Using sand
trapping, the AA. examine the possible role played by intertidal bar and through morphology on longshore and onshore-directed sand transport. Results show that intertidal bars are responsible for significant wave energy dissipation leading to a decrease
of sand transport towards the upper beach. Sediment transport appeared to be substantially higher on the bars than within the troughs due to wave breaking processes that are responsible for intense sand remobilization. The comparison of onshore sediment
The Trabucador Bar is a barrier coast linking the main lobe of the Ebro Delta with its southern spit. During the second week of October 1990 a severe storm affected the Ebro Delta causing serious erosion, in which the Trabucador Bar was one
The intertidal drainage channels on a macrotidal bar-trough (ridge-and-runnel) beach, the Leffrinckouke beach in the southern North Sea, were monitored during a 17-day survey. This beach is characterized by 2 intertidal drainage channel types : type
1, dominantly longshore systems essentially limited to the wide intertidal zone; smaller and ephemeral type 2, dominantly cross-shore systems incising bars during spring tides. Channel mobility and impact on beach morphology are expected to increase
Coastal dynamics ; Coastal environment ; Denmark ; Earth surface processes ; Intertidal zone ; North Sea ; Sandbar ; Sediment transport
The formation of an inner nearshore bar was observed during a 19-hour high-energy event at the sandy beach of Vejers, Denmark. Suspended sediment transport and cross-shore sediment transport gradients were obtained from a cross-shore array
Grain-size distribution patterns of a point bar system in the Usri River, India
Grain-size distribution patterns in a point bar system of the Usri River, India, were critically analysed in the light of log-normal, log-hyperbolic and log-skew-Laplace distribution models. Sand samples were collected from the cross-bedding foreset
of different sizes of bedform; the aims were to : study whether bedforms heights have any role in grain-size distribution patterns, offer a best-fit statistical model, study the downstream variation of size-sorting in a point bar system, and study the mechanism
Study of sedimentation zones in a large sand-bed braided river : an example from the Hanjiang River of China
The concept of sedimentation zone is applied to the study of spatial and temporal variations of mid-channel bars in the middle Hanjiang River, a large sand-bed braided river in China. A sytematic comparison between sedimentation and transport zones
is made in this study, including the flow shear stress, stream power, mid-channel bar features and channel stability.
-stationary ridges and runnels may reflect swash-bar growth by constructive short-period waves, especially on macrotidal coasts| 2) mobile ridges and runnels may be muted expressions of longshore bars and throughs migrating onshore| 3) ridges and runnels may
develop episodically by runnel erosion within a part-fluidized sand sheet under favorable tidal and surf conditions.
in favour of the latter with an increase in waterdepth variability along the outer-bar crest. Furthermore, they find that the typical alongshore variability in inner-bar rip-channel scale is indicative of a mixture of self-organization and morphological
coupling rather than self-organization alone. Morphological coupling may thus be more important to understanding and predicting the evolution of inner-bar rip channels than previously envisaged.
-month data set of daily time-averaged video images (Argus) has been analyzed to describe the spatial and temporal variability of the rip channels on a multiple-barred coast at Noordwijk aan Zee, The Netherlands. The spatial and temporal variability
and subtidal alongshore bar rhythmicities confirmed the influence of the subtidal morphology on the intertidal bar system.