Advances in sediment transport under combined action of waves and currents

Lü, Yongjun; Li, Shouqian; Zuo, Liqin; Liu, Huaixiang; Roelvink, J.A.

doi:10.1016/j.ijsrc.2015.01.003

Cited by 30 publications

(16 citation statements)

References 61 publications

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“…Coarser particles of sand and gravel though are often exchanged cross-and alongshore, which can result in short-or long-term changes in the shore profile (Pruszak et al, 2011). During storms, large waves erode sediment from the beach and dunes, and it is transported by offshore currents (Lu et al, 2015). During periods of calm wave conditions, the oscillatory motion is not strong enough to cause sediments to be suspended high in the water column, and flow through the undertow offshore is weak, which results in the promotion of onshore sediment movement (Lu et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Kelp beds as coastal protection: wave attenuation of Ecklonia radiata in a shallow coastal bay

et al. 2019

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Background and Aims Coastal protection from erosion and flooding is a significant ecosystem service provided by vegetated marine systems. Kelp beds are a dominant habitat-forming species on temperate reefs worldwide. While they are valued as hotspots of biodiversity, there is a paucity of information that supports their use in nature-based coastal defence. This includes the effectiveness of kelp beds in attenuating waves approaching the shore and how this influences sediment transport. Methods Wave loggers were deployed at paired kelp bed and control (urchin barren) treatments at four sites in Port Phillip Bay, Australia. The significant wave height offshore (exposed side) to onshore (sheltered side) of the treatment were compared to determine wave attenuation. Key Results At three sites, the wave attenuation of kelp beds was significantly less than the control. This result was consistent across the environmental conditions recorded in this study. At the fourth site, on average there was no significant difference in wave transmission between kelp and control. However, wave attenuation at kelp beds was 10% greater than the control during periods of northerly winds. We highlight the importance of disentangling the effects of the reef substratum and kelp when evaluating the efficacy of kelp at providing coastal protection. Conclusions We have highlighted a significant gap in the research on ecosystem services provided by kelp beds. A greater understanding is needed on which kelp species are able to provide coastal protection, and under what conditions. Such future research is essential for providing managers and policy makers with actionable information on sustainable and cost-effective solutions for coastal defence when faced with a changing climate.

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Section: Introductionmentioning

confidence: 99%

Kelp beds as coastal protection: wave attenuation of Ecklonia radiata in a shallow coastal bay

et al. 2019

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“…Sediment dynamics in coastal waters therefore has relevance to a broad spectrum of marine science ranging from the physical and chemical, to the biological and ecological. In spite of the obvious importance of sediment transport, the predictive capability of models is still highly uncertain, particularly in the presence of bedforms and mixed sediments, therefore field measurements continue to be required for both site specific model tuning and validation (Davies et al, 2002;Davies and Thorne, 2008;Amoudry and Souza, 2011;Lu et al, 2015). It is also widely recognised that one of the components to improving large scale sediment transport modelling, requires accurate parameterisations of small scale sediment processes (Baumert et al, 2000;James, 2002;Ribberink et al, 2008;O'Hara Murray et al, 2012;Malarkey et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Developments in acoustics for studying wave-driven boundary layer flow and sediment dynamics over rippled sand-beds

Thorne

Cooke

Caceres

et al. 2018

Continental Shelf Research

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The processes of sediment entrainment, transport, and deposition over bedforms are highly dynamic and temporally and spatially variable. Obtaining measurements to understand these processes has led to ongoing developments in instrumentation for studying near-bed sediment dynamics, with the outputs applied to the development and assessment of sediment transport modelling. In the present study results are reported from three acoustic systems deployed to make observations of bedforms, bedload, suspended concentration and horizontal and vertical velocity components. To evaluate the instruments a series of near-bed boundary layer measurements were collected in a large scale flume facility over a rippled bed of medium sand under regular waves. The observations were conducted as part of Joint Research Activities within the EU funded Hydralab project. The suite of acoustic instruments consisted of a Bedform And Suspended Sediment Imager, BASSI, a three dimensional acoustic ripple profiler, 3D-ARP, and three Acoustic Concentration and Velocity Profilers, ACVP's. Here results are reported from the deployment of the instruments, to illustrate the ongoing developments in acoustics and the expanding capability of the application of acoustics to the study of near-bed flow and sediment dynamics.

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“…The need for improved and redundant estimates of bed shear stress -the main driver of sediment transport -is underscored by Grant and Madsen [1986] in their review of continental shelf bottom boundary layer dynamics. Nielsen [1992] summarizes sediment dynamics theory and knowledge of waveand current-forced conditions, both separately and in combination; Van Rijn et al [2013] and Lu et al [2015] provide recent reviews of the topic. Models of coastal sediment transport are limited by the need for better understanding of detailed transport processes over all sediment types and bedforms [ and improved observations of sheet flow and bedload transport [Van Rijn et al, 2013].…”

Section: Introductionmentioning

confidence: 99%

Pulse Coherent Doppler Profiler Measurement of Bedload Transport

et al. 2021

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Prior studies demonstrate that bottom velocity measurements from Doppler sonar systems are proportional to bedload transport rates. These observations suggest that acousticallybased systems offer a capability for rapid sampling of bedload transport processes. Before these measurements can be fully utilised, validation and understanding of the sampling mechanism are essential. We explore the measurement mechanism through a series of laboratory trials with a field instrument, the MFDop. The MFDop system is a multifrequency (1.2 -2.2 MHz), bistatic Doppler sonar that provides 3-component ensembleaveraged velocity profiles over a ∼30 cm depth interval with up to 1 mm resolution at a rate of 50 profiles/sec. Tests of the MFDop system were carried out in the main flume in field-scale conditions at the St. Anthony Falls Laboratory (SAFL) using 1 m s −1 mean flows over a mobile bed of sand with median grain size d 50 = 0.4 mm. We find agreement between MFDop transport measurements and measurements based on bedform migration rates, and sediment traps built into the SAFL flume. Predictions using the Meyer-Peter and Müller [1948] empirical equation closely match our observations while in contrast, predictions using the Nielsen [1992] equation are a factor of two higher.

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Advances in sediment transport under combined action of waves and currents

Cited by 30 publications

References 61 publications

Kelp beds as coastal protection: wave attenuation of Ecklonia radiata in a shallow coastal bay

Kelp beds as coastal protection: wave attenuation of Ecklonia radiata in a shallow coastal bay

Developments in acoustics for studying wave-driven boundary layer flow and sediment dynamics over rippled sand-beds

Pulse Coherent Doppler Profiler Measurement of Bedload Transport

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