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A simple model for current speed in tidal channels

A simple model for current speed in tidal channels
Coastal environment ; Denmark ; Hydrodynamics ; Model ; Sea level ; Storm ; Tidal creek ; Tidal current ; Wind
This paper presents a simple non-distributed, PC-based model describing current speed in a tidal channel based on the continuity equation with tide gauge water level as the only time dependent input parameter. This model is tested in a tidal channel
in the Danish Wadden Sea. This type of model can be used to extend and/or complete time series of current speed in a particular tidal channel and to make quick estimates of the current speed, with a minimum of information and CPU consumption.

The tidal character of the formation of Tegelen in northern Belgium

The tidal character of the formation of Tegelen in northern Belgium
Small scale current ripples with opposed high-angle cross lamination indicate tidal movements during deposition. A fresh or brackish subtidal environment is suggested. - (AIS)

A parameterization of the wavelength of tidal dunes

A parameterization of the wavelength of tidal dunes
Atlantic Ocean ; Coastal dynamics ; Coastal environment ; Hydrodynamics ; Intertidal zone ; Model ; North Sea ; Sand wave ; Sediment transport ; Tidal current ; Tidal dune
of tidal dunes as a function of the parameters of the problem. The wavelength of the dunes is found to increase when the water depth is increased and/or the strength of the tidal current is decreased. On the other hand, the size of the bottom material
In this study, the model of Besio et al. (2006) is used to generate a database that allows a parameterization of the length of tidal dunes to be obtained. The predictions are then analysed and a formula is proposed to estimate the wavelength
(if medium sand is considered) and the tidal ellipticity are found to have a relatively small influence on the length of the bottom forms. The formula proposed provides results which are consistent with field observations.

Threshold of erosion of submarine bedrock landscapes by tidal currents

Threshold of erosion of submarine bedrock landscapes by tidal currents
Atlantic Ocean ; Erosion ; Geophysics ; Marine abrasion ; Mediterranean Sea ; North Atlantic Ocean ; Sea floor ; Submarine geomorphology ; Tidal current
The AA. examine multibeam sonar datasets from areas of extreme tidal currents to see if there is any evidence for erosion of bedrock. A dataset of shear stresses beneath typically strong tidal currents is developed and compared with a dataset
for bedrock-eroding rivers. In the Minas Passage (Bay of Fundy), Canada, the Bristol Channel off Nash point, UK, and in the Straits of Messina, Italy, sonar data are collected and discussed. Holocene tidal currents have apparently been generally ineffective
at eroding bedrock. The AA. examine this issue further by compiling extreme tidal streams around the UK and from them estimate shear stresses, representing a macro-tidal environment where peak surface currents reach 9-7 knots. Those data are compared

Residual sediment transport directions on a tidal sand bank. Comparison of the « MacLaren Model » with bedform analysis

Residual sediment transport directions on a tidal sand bank. Comparison of the « MacLaren Model » with bedform analysis
In this paper the validity of the models will be tested in a tidal shelf environment where currents are continuously changing and where each tidal cycle presents current maxima of different value. Results will be compared to net sediment transport

Downdrift coarsening of beach foreshore sediments at tidal inlets : an example from the coast of New Jersey

Downdrift coarsening of beach foreshore sediments at tidal inlets : an example from the coast of New Jersey
This study was conducted to examine differences in grain size characteristics of beach foreshore sediments at tidal inlets in greater detail and to provide additional explanations for their differences. It is suggested that tidal currents play
a role in sediment coarsening at inlets, but coarser grain sizes are also related to offshore diversion of fine sediments moved to the inlet flank by longshore currents and to the removal of fine sediments from inlet flank beaches by winds and by low

Tidal variation in field settling velocities of suspended sediment in a tidal channel

Tidal variation in field settling velocities of suspended sediment in a tidal channel
In this study, field settling velocities of the suspended sediment have been measured during two tidal periods, in Ho Bugt, on October 17, 1989 and July 24, 1990. During both periods, the current velocity, salinity, water temperature and suspended

The effect of bidirectional flow on tidal channel planforms

The effect of bidirectional flow on tidal channel planforms
Aerial photography ; Bank erosion ; California ; Channel geometry ; Coastal environment ; Intertidal zone ; Meander ; Model ; Tidal creek ; Tidal current ; Tidal marsh ; United States of America
Field surveys and aerial photographs were used to characterize the planform of tidal channels at China Camp Marsh in the San Francisco Bay, California. To model the planform evolution, the AA. assume that the topographic curvature of the channel
centreline is a key element driving meander migration. The curvature calculations, combined with data from numerous cross-sections along the tidal channel, were used to parameterize a computer model. With this model, based on recent theoretical work

The tidal flats morphological development and the coastal land reclamation in Shanghai

The tidal flats morphological development and the coastal land reclamation in Shanghai
Carrying capacity ; China ; Coastal dynamics ; Coastal environment ; Estuary ; Foreshore ; Sedimentation ; Shanghai ; Silting ; Soil ; Soil improvement ; Suspended load ; Tidal current
. It is of great significance to utilize tidal flats and reclamation of land in Shanghai.

Power intermittency, redundancy and tidal phasing around the United Kingdom

Power intermittency, redundancy and tidal phasing around the United Kingdom
Continental shelf ; Energy ; Northwestern Europe ; Renewable energy ; Tidal current ; Tidal energy ; United Kingdom

Sediment transport across a tidal divide in the Danish Wadden Sea

Sediment transport across a tidal divide in the Danish Wadden Sea
Coastal environment ; Denmark ; Estuary ; Hydrodynamics ; Model ; North Sea ; Sediment transport ; Spatial variation ; Suspended load ; Tidal current ; Tide
The aim of this study is to examine the spatial and temporal variation of water and sediment transport across a tidal divide in the Danish Wadden Sea. This is exemplified by 2 low-energy and 2 high-energy case studies selected from a 2-month

Current trends of coastal research in the Netherlands

Current trends of coastal research in the Netherlands
Recent Dutch coastal research has also emphasized several other areas of study, including the geologic history of the coastal belt, coastal ecology, and coastal processes. In the latter area, the complex interaction between tidal currents, waves

Sediment transport by tidal currents and implications for slope stability: Fraser River delta, British Columbia

Sediment transport by tidal currents and implications for slope stability: Fraser River delta, British Columbia
British Columbia ; Canada ; Coastal environment ; Coastal erosion ; Delta ; Dune ; Sand ; Sediment transport ; Sedimentology ; Slope gradient ; Tidal current

Evolution of sedimentary environments of the middle Jiangsu coast, South Yellow Sea since late MIS 3

Applied geomorphology ; C 14 dating ; China ; Coastal geomorphology ; Coastal sedimentation ; Holocene ; Isotope ; Jiangsu ; River ; Sea level ; Sedimentology ; Stratigraphy ; Tidal creek
as sea-level rise covered the middle Jiangsu coast at ca. 9.0 cal ka BP. The paleo-Xiyang tidal channel that was determined by the paleo-tidal current field and significantly different from the modern one, was in existence during the Holocene
to strong tidal current scouring and anthropogenic activities.
This article analyses the evolution of sedimentary environments of the middle Jiangsu coast, South Yellow sea since late Marine Isotope Stage 3. The results first show the tidal sand ridges began to develop during the postglacial transgression
transgressive maxima and lasted until AD 1128. Following the capture of the Huaihe River in AD 1128 by the Yellow River, the paleo-Xiyang tidal channel was infilled with a large amount of river-derived sediments from AD 1128 to 1855, causing the emergence
of some of the previously submerged tidal sand ridges. From AD 1855 to the present, the infilled paleo-Xiyang tidal channel has undergone scouring, resulting in its modern form. The modern Xiyang tidal channel continues to widen and deepen, due both

Patterns of tidal flow asymmetry on shoreface-connected ridge topography off Spiekeroog island, German bight

Patterns of tidal flow asymmetry on shoreface-connected ridge topography off Spiekeroog island, German bight
Germany ; North Sea ; Sea current ; Tidal current ; Tide

Temporal and spatial changes of suspended sediment concentration and resuspension in the Yangtze River estuary

of the estuary. It is concluded that wave and tidal current are 2 predominant factors of sediment resuspension and control the distribution and changes of SSC, in which tidal currents control neap-spring tidal cycles, and wind waves control seasonal variations

Acoustic Doppler current profiler measurments in coastal and estuarine environments : examples from the Tay Estuary, Scotland

Acoustic Doppler current profiler measurments in coastal and estuarine environments : examples from the Tay Estuary, Scotland
Coastal environment ; Current ; Estuary ; Geophysics ; Model ; Scotland ; Suspended load ; United Kingdom ; Water circulation
Acoustic Doppler current profilers (ADCPs) provide a means to measure the components of water current velocities in three dimensions. Using examples of ADCP datasets acquired from the macrotidal Tay Estuary, eastern Scotland, the principles of field
deployment, data acquisition and forms of output are critically summarised. It is shown for the first time in the Tay Estuary, that vertical current velocities are significant and are particularly so in downwelling zones associated with the development
and passage of axially convergent tidal fronts.

The backbarrier sediments of the Skallingen Peninsula, Denmark

Coastal dynamics ; Coastal environment ; Denmark ; Estuary ; Grain size distribution ; Sediment transport ; Sedimentology ; Suspended load ; Tidal current ; Tidal marsh

Estimate of long-term sediment discharge at tidal inlets using water level data from a tide gauge

Estimate of long-term sediment discharge at tidal inlets using water level data from a tide gauge
Carrying capacity ; Coastal current ; Coastal environment ; England ; Estuary ; Hydrodynamics ; Intertidal zone ; Salinity ; Sediment budget ; United Kingdom
It is the purpose of this contribution to develop a simple, low cost approach to the estimate of sediment discharge through the entrance channel. Such a method is based upon an understanding of the hydroynamic behaviour of tidal inlets. According

Tidal transverse bars building up a longitudinal sand body (Middle Eocene, Belgium) in Tide-influenced sedimentary environments and facies.

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
currents and was also affected by occasional storm erosion. - (Les AA.).

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