USE OF A RADIO-ACTIVE TRACER FOR THE MEASUREMENT OF SEDIMENT TRANSPORT IN THE NETHERLANDS

The "Rijkswaterstaat" has developed a method based on the use of radio-active tracers for the evaluation of sediment transport due to the combined action of waves and currents. The results of preparatory studies and a laboratory test were published in a previous report by J.J. Arlman, P. Santema and J.N. Svasek [1]. The main principles of the method were 1. Detection by a sledge-mounted unit towed by a survey vessel and continuous registration on board of the radio-activity measured on the sea bottom. 2. Employment of low specific radio-activity of tracer material and a large quantity thereof. 5> Use of a long-life isotope and high radio-activity. k. Measurement of the vertical distribution of radioactivity in core samples or if possible by discrimination. In March 1958 the first lot of tracer material was placed on the sea bed. The tracer material consisted of the radio-active isotope Scandium^" emitting 2 curies incorporated in 100 kg "greensand". Scandium^" has a half-life of 8^ days and emits strong gramma radiations with energies of 0.89 and 1.12 MeV. Afterwards, in 1959, two series of measurements were taken near the entrance to the Rotterdam Waterway. Four droppings formed one series; they were generally carried out in the following manner: 50 kg greensand labeled with 2 Curies Scandium was dropped in k places at a safe distance from each other. 2 of the 8 portions consisted of smaller quantities of both radio-activity and greensand. In the following paragraphs the preparation, dropping and detection of the tracer, the working out of the registrations and the interpretation of the results of the 1959 measurements are discussed.

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Modelling of sediment transport and morphological evolution under the combined action of waves and currents

Ocean Science ◽

10.5194/os-13-673-2017 ◽

2017 ◽

Vol 13 (5) ◽

pp. 673-690 ◽

Cited By ~ 5

Author(s):

Guilherme Franz ◽

Matthias T. Delpey ◽

David Brito ◽

Lígia Pinto ◽

Paulo Leitão ◽

...

Keyword(s):

Sediment Transport ◽

Morphological Changes ◽

Morphological Evolution ◽

Research Effort ◽

Beach Erosion ◽

Model Complexity ◽

Invariant Equilibrium ◽

Waves And Currents ◽

Combined Action ◽

Modelling System

Abstract. Coastal defence structures are often constructed to prevent beach erosion. However, poorly designed structures may cause serious erosion problems in the downdrift direction. Morphological models are useful tools to predict such impacts and assess the efficiency of defence structures for different scenarios. Nevertheless, morphological modelling is still a topic under intense research effort. The processes simulated by a morphological model depend on model complexity. For instance, undertow currents are neglected in coastal area models (2DH), which is a limitation for simulating the evolution of beach profiles for long periods. Model limitations are generally overcome by predefining invariant equilibrium profiles that are allowed to shift offshore or onshore. A more flexible approach is described in this paper, which can be generalised to 3-D models. The present work is based on the coupling of the MOHID modelling system and the SWAN wave model. The impacts of different designs of detached breakwaters and groynes were simulated in a schematic beach configuration following a 2DH approach. The results of bathymetry evolution are in agreement with the patterns found in the literature for several existing structures. The model was also tested in a 3-D test case to simulate the formation of sandbars by undertow currents. The findings of this work confirmed the applicability of the MOHID modelling system to study sediment transport and morphological changes in coastal zones under the combined action of waves and currents. The same modelling methodology was applied to a coastal zone (Costa da Caparica) located at the mouth of a mesotidal estuary (Tagus Estuary, Portugal) to evaluate the hydrodynamics and sediment transport both in calm water conditions and during events of highly energetic waves. The MOHID code is available in the GitHub repository.

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Sediment transport by waves and currents

Canadian Journal of Civil Engineering ◽

10.1139/l83-015 ◽

1983 ◽

Vol 10 (1) ◽

pp. 142-149 ◽

Cited By ~ 3

Author(s):

Michael C. Quick

Keyword(s):

Sediment Transport ◽

Mass Transport ◽

Power Relationship ◽

Zero Current ◽

Transport Direction ◽

Transport Velocity ◽

Waves And Currents ◽

Mass Transport Velocity ◽

Combined Action ◽

The Waves

Sediment transport is measured under the combined action of waves and currents. Measurements are made with currents in the direction of wave advance and with currents opposing the wave motion. Theoretical relationships are considered that predict the wave velocity field and the mass transport velocity for zero current and for steady currents.Following Bagnold's approach, a transport power relationship is developed to predict the sediment transport rate. Making assumptions for the mass transport velocity, the transport power is shown to agree with the measured sediment transport rates. It is particularly noted that the sediment transport direction is mainly determined by the direction of wave movement, even for adverse currents, until the waves start to break. Keywords: sediment transport, waves and currents, coastal engineering.

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Modelling of sediment transport and morphological evolution under the combined action of waves and currents

10.5194/os-2017-8 ◽

2017 ◽

Cited By ~ 1

Author(s):

Guilherme Franz ◽

Matthias T. Delpey ◽

David Brito ◽

Lígia Pinto ◽

Paulo Leitão ◽

...

Keyword(s):

Sediment Transport ◽

Morphological Changes ◽

Morphological Evolution ◽

Research Effort ◽

Beach Erosion ◽

Model Complexity ◽

Invariant Equilibrium ◽

Waves And Currents ◽

Combined Action ◽

Modelling System

Abstract. Coastal defence structures are often constructed to prevent beach erosion. However, poorly designed structures may cause serious erosion problems in the downdrift direction. Morphological models are useful tools to predict such impacts and assess the efficiency of defence structures for different scenarios. Nevertheless, morphological modelling is still a topic under intense research effort. The processes simulated by a morphological model depend on model complexity. For instance, undertow currents are neglected in coastal area models (2DH), which is a limitation for simulating the evolution of beach profiles for long periods. Model limitations are generally overcome by predefining invariant equilibrium profiles that are allowed to shift offshore or onshore. A more flexible approach is described in this paper, which can be generalised to 3D models. The present work is based on the coupling of the MOHID modelling system and SWAN wave model. The impacts of different designs of detached breakwaters and groynes were simulated in a schematic beach configuration following a 2DH approach. The results of bathymetry evolution are in agreement with the patterns found in the literature for several existing structures. The model was also tested in a 3D test case to simulate the formation of sandbars by undertow currents. The findings of this work confirmed the applicability of the MOHID modelling system to study sediment transport and morphological changes in coastal zones under the combined action of waves and currents. The same modelling methodology was applied to a coastal zone (Costa da Caparica) located at the mouth of a mesotidal estuary (Tagus Estuary, Portugal) to evaluate the hydrodynamics and sediment transport in calm water conditions and during events of highly energetic waves.

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Advances in sediment transport under combined action of waves and currents

International Journal of Sediment Research ◽

10.1016/j.ijsrc.2015.01.003 ◽

2015 ◽

Vol 30 (4) ◽

pp. 351-360 ◽

Cited By ~ 9

Author(s):

Yongjun Lu ◽

Shouqian Li ◽

Liqin Zuo ◽

Huaixiang Liu ◽

J.A. Roelvink

Keyword(s):

Sediment Transport ◽

Waves And Currents ◽

Combined Action

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Sediment Transport Beyond the Surf Zone Under Waves and Currents of the Non-Tidal Sea: Lubiatowo (Poland) Case Study

Archives of Hydro-Engineering and Environmental Mechanics ◽

10.1515/heem-2016-0005 ◽

2016 ◽

Vol 63 (1) ◽

pp. 63-77 ◽

Cited By ~ 2

Author(s):

Rafał Ostrowski ◽

Magdalena Stella

Keyword(s):

Sediment Transport ◽

Surf Zone ◽

Coastal Region ◽

Wave Climate ◽

Soil Parameters ◽

Shear Stresses ◽

Research Station ◽

Sea Bed ◽

Waves And Currents ◽

Bed Changes

Abstract The paper deals with the sandy coastal zone at Lubiatowo in Poland (the south Baltic Sea). The study comprises experimental and theoretical investigations of hydrodynamic and lithodynamic processes in the coastal region located close to the seaward boundary of the surf zone and beyond the surf zone. The analysis is based on field data collected at the IBW PAN Coastal Research Station in Lubiatowo. The data consist of wind velocity reconstructed from the long-term wave climate, deep-water wave buoy records and sea bottom soil parameters. Nearbed flow velocities induced by waves and currents, as well as bed shear stresses are theoretically modelled for various conditions to determine sediment motion regimes in the considered area. The paper discusses the possibility of occasional intensive sediment transport and the occurrence of distinct sea bed changes at bigger water depths.

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Review of the manuscript Modelling of sediment transport and morphological evolution under the combined action of waves and currents, submitted to Ocean Science by Franz et al.

10.5194/os-2017-8-rc1 ◽

2017 ◽

Author(s):

A.B. Fortunato

Keyword(s):

Sediment Transport ◽

Morphological Evolution ◽

Ocean Science ◽

Waves And Currents ◽

Combined Action

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Numerical Investigation of Sediment Transport for Combined Waves and Currents

Coastal Engineering 1998 ◽

10.1061/9780784404119.226 ◽

1999 ◽

Author(s):

Juan Savioli

Keyword(s):

Sediment Transport ◽

Numerical Investigation ◽

Waves And Currents

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Application of remote sensing technology to the relation of submarine pipelines and coastal morphology

Water Science & Technology ◽

10.2166/wst.1995.0077 ◽

1995 ◽

Vol 32 (2) ◽

pp. 77-83

Author(s):

Y. Yüksel ◽

D. Maktav ◽

S. Kapdasli

Keyword(s):

Remote Sensing ◽

Sediment Transport ◽

Surf Zone ◽

Hydrodynamic Forces ◽

Construction Site ◽

Coastal Morphology ◽

Remote Sensing Technology ◽

Sensing Technology ◽

Sea Bed

Submarine pipelines must be designed to resist wave and current induced hydrodynamic forces especially in and near the surf zone. They are buried as protection against forces in the surf zone, however this procedure is not always feasible particularly on a movable sea bed. For this reason the characteristics of the sediment transport on the construction site of beaches should be investigated. In this investigation, the application of the remote sensing method is introduced in order to determine and observe the coastal morphology, so that submarine pipelines may be protected against undesirable seabed movement.

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