Sediment supply from shoreface to dunes: linking sediment transport measurements and long-term morphological evolution

Geomorphology ◽  
2004 ◽  
Vol 60 (1-2) ◽  
pp. 205-224 ◽  
Author(s):  
Troels Aagaard ◽  
Robin Davidson-Arnott ◽  
Brian Greenwood ◽  
Jørgen Nielsen
Keyword(s):  
Sediment Transport ◽  
Morphological Evolution ◽  
Sediment Supply ◽  
Transport Measurements

scholarly journals EXPERIMENTAL INVESTIGATION ON DYNAMIC EQUILIBRIUM BAY SHAPE

2012 ◽  
Vol 1 (33) ◽  
pp. 37
Author(s):  
Sutat Weesakul ◽  
Somruthai Tasaduak
Keyword(s):  
Experimental Investigation ◽  
Sediment Transport ◽  
Dynamic Equilibrium ◽  
Shoreline Change ◽  
Sediment Supply ◽  
Coastal Protection ◽  
Supply Source ◽  
Wave Condition ◽  
Longshore Sediment Transport

Equilibrium bay is a bay that its shoreline is stable and does not change with time in long term. This concept can be applied for coastal protection. Experiments on dynamic equilibrium bay planform are conducted in a laboratory. There is one location of sediment supply source into a bay near upcoast headland and its magnitude vary from case to case. Wave obliquity varies from small to moderate values. These are two main parameters while wave condition is kept constant. The final bay planforms are investigated and recorded once they reach equilibrium with condition that sediment transport gradient approaches zero and no further shoreline change are observed. The parabolic equation similar to that for static equilibrium is newly proposed. The coefficients are originally derived and found to be a function of wave obliquity and the ratio of sediment supplied into bay to longshore sediment transport. The new dynamic equilibrium bay equation can be used and applied to study morphology change with variation of supplied sediment from inland.

scholarly journals A Numerical Investigation on Tidally Induced Sediment Transport and Morphological Changes with Changing Sea Level in South-East England

Geosciences ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 140
Author(s):  
Nicoletta Leonardi ◽  
Xiaorong Li ◽  
Iacopo Carnacina
Keyword(s):  
Sediment Transport ◽  
Sea Level Rise ◽  
Water Level ◽  
Sea Level ◽  
Large Scale ◽  
Morphological Changes ◽  
Morphological Evolution ◽  
Morphodynamic Equilibrium ◽  
South East England

The impact of tide-induced morphological changes and water level variations on the sediment transport in a tidally dominated system has been investigated using the numerical model Delft3D and South-East England as a test case. The goal of this manuscript is to explore the long-term changes in morphology due to sea level rise and the large-scale morphodynamic equilibrium of the South-East England. Our results suggest that the long term (century scale) tidally-induced morphological evolution of the seabed slows down in time and promotes a vanishing net transport across the large scale system. Century-scale morphologically updated simulations show that both morphological changes and net transport values tend to decrease in time as the system attains a dynamic equilibrium configuration. Results further suggest that the presence of a gradual increase in mean sea level accelerates the initial morphological evolution of the system whose morphological rate of change gradually attains, however, same plateau values as in the absence of sea level rise. Given the same base morphology, increasing water levels enhance residual currents and the net transport near the coastline; and vice-versa, decreasing sea levels minimize both residuals and net transport near the coastline. The areas that are more affected by, water level and morphological changes, are the ones where the net transport is the highest. This manuscript explores and allows extending the idea of morphodynamic equilibrium at a regional scale, larger than the one for which this concept has been generally explored i.e., estuarine scale.

scholarly journals Recent Evolution of the Intertidal Sand Ridge Lines of the Dongsha Shoal in the Modern Radial Sand Ridges, East China

2021 ◽  
Vol 18 (4) ◽  
pp. 1573
Author(s):  
Binglin Liu ◽  
Haotian Wu ◽  
Zhenke Zhang ◽  
Guoen Wei ◽  
Yue Wang ◽  
...  
Keyword(s):  
Morphological Evolution ◽  
Central Area ◽  
Research Area ◽  
Sediment Supply ◽  
Sand Ridge ◽  
Ecological Value ◽  
Ridge Line ◽  
Sand Ridges ◽  
Radial Sand Ridges

The Dongsha Shoal is one of the largest shoals in the South Yellow Sea and has important marine ecological value. The shoal extends in a south–north direction and is controlled by the regional dominating tidal currents. Recently, due to human activities and some natural factors, the geomorphic dynamics of the Dongsha Shoal has undergone drastic changes. However, few people have proposed quantitative research on the changes of tidal flat morphology, let alone the long-term sequence analysis of sand ridge lines. Hence, we attempt to take the Dongsha Shoal in the Radial Sand Ridges as the research area, and analyze the trends of the long-term morphological evolution of the sand ridge lines over the period 1973–2016 based on a high-density time series of medium-resolution satellite images. The sand ridge line generally moves from southeast to northwest, and the position distribution of the sand ridge line from north to south has gradually changed from compact to scattered. We also found that the geomorphological dynamics at different positions of the sand ridge line are inconsistent. The north and south wings are eroded on the west side, while the central area is eroded on the east side. Most of the sand ridge line is moving eastward. In addition, the change of sand ridge line is affected by multiple factors such as sediment supply, typhoon, reclamation and laver cultivation.

scholarly journals AEOLIAN SEDIMENT TRANSPORT AT A MAN-MADE DUNE SYSTEM; BUILDING WITH NATURE AT THE HONDSBOSSCHE DUNES

2018 ◽  
pp. 83 ◽  
Author(s):  
Marloes Wittebrood ◽  
Sierd De Vries ◽  
Petra Goessen ◽  
Stefan Aarninkhof
Keyword(s):  
Sediment Transport ◽  
Transport Model ◽  
Morphological Changes ◽  
Morphological Evolution ◽  
Sediment Supply ◽  
Dune System ◽  
Morphological Response ◽  
Profile Type ◽  
Building With Nature ◽  
Aeolian Sediment

This paper presents the influence of aeolian sediment transport on the initial morphological evolution of beach and dunes at the man-made dune system ‘Hondsbossche Dunes’ at the Dutch coast. In total 35 million m^3 dredged material was used for the construction of a beach, dune and foreshore system. This study focused on differences in morphological response within the five different realized dune profile types. A conceptual framework was developed, based on the assessment of (1) environmental forcing, (2) sediment supply from aeolian and marine sources and (3) dune types. These three components were quantified from an analysis of measured profile evolution and the application of an aeolian sediment transport model for the first 19 months since the project delivery date in May 2015. Morphological changes were most pronounced in the first seven months after construction. Dune growth of a profile type at this location is determined by a temporal and alongshore variability in local processes that determines the aeolian sediment supply towards the dunes and the dune geometry that determines the capacity of the profile type to capture the sediments. The model simulations managed to qualitatively reproduce alongshore variations in dune growth as a result of spatial variations in sediment availability, grain size, profile shape and interaction with vegetation. Overall, this study shows the relevance of both marine and aeolian processes in such man-made dynamic systems that are comparable to natural systems. Continuing the monitoring and modelling of this system will improve the quantitative knowledge for design optimization of the Building with Nature philosophy.

scholarly journals Sand spit morphological evolution at tidal inlets by using satellite images analysis: Two case studies in Vietnam

2020 ◽  
Vol 14 (2) ◽  
pp. 17-27
Author(s):  
Nguyen Quang Duc Anh ◽  
Hitoshi Tanaka ◽  
Nguyen Xuan Tinh ◽  
Nguyen Trung Viet
Keyword(s):  
Sediment Transport ◽  
Satellite Images ◽  
Morphological Changes ◽  
Morphological Evolution ◽  
Google Earth ◽  
Sluice Gate ◽  
Landsat Images ◽  
Longshore Sediment Transport ◽  
Sand Spit

This paper presents the long-term morphological changes of the sand spits at the Ken Inlet in Ha Tinh Province and Phan Inlet in Binh Thuan Province, Vietnam. The analysis results show that the sand spit morphology at Ken Inlet was drastically changed before the completion of the Da Bac sluice gate construction in 1992, after that the sand spit elongation rate became stable at a rate of about 68 meters per year. Meanwhile, the sand spit at Phan Inlet was breached three times during the winter months of 1990-1991, 1998-1999 and 2014-2015. Moreover, the results of remote sensing image analysis also show that after the sand spit have been breached, it continued elongating at a relatively stable rate of 170÷200 meters per year. Based on the analytical model by Kraus (1999) for predicting the sand spit elongation, the estimated long-shore sediment transport rates of Phan Inlet and Ken Inlet are 145,000 m3/year and 133,500 m3/year, respectively. These longshore sediment transport rates are a main contribution for the sand spit elongation in these study areas. Keywords: sand spits; tidal Inlet; breaching; elongation; Landsat images; Google Earth images.

scholarly journals Current and Future Study Topics on Reservoir Sediment Management by Bypass Tunnels

2018 ◽  
Vol 13 (4) ◽  
pp. 668-676 ◽  
Author(s):  
Sohei Kobayashi ◽  
◽  
Takahiro Koshiba ◽  
Tetsuya Sumi
Keyword(s):  
Sediment Transport ◽  
Future Study ◽  
International Workshop ◽  
Sediment Management ◽  
Sediment Supply ◽  
Reservoir Sediment ◽  
Efficient Operation ◽  
Abrasion Rate ◽  
Runoff Model

Herein, we summarized the current and future study topics of sediment management using bypass tunnels based on the discussions at the Second International Workshop on Sediment Bypass Tunnels (SBTs) at Kyoto in May 2017. Although reservoir sediment management using bypass tunnels has appeared since the beginning of the 20th century in Kobe, the number of SBTs worldwide is still limited. To promote the installation of SBTs as an effective sediment management measure, it is essential to appropriately evaluate their long-term advantages economically and for the restoration of the aquatic ecosystem. An abrasion model has been developed to predict the abrasion rate of tunnels from the volume of sediment transport. Further, methods to monitor sediment transport in tunnels have advanced. With a significant amount of sediment supply by SBTs, the ecosystems in the downstream reaches of dams can be restored within a few years. A precise rainfall and runoff model for predicting the inflow hydrograph and sediment is essential for the efficient operation of dam gates and SBT (e.g., diverting minimum amount of water for sediment transport). Further studies are needed to clarify the suitable grain size for transportation through SBTs in terms of both the mitigation of tunnel abrasion and promotion of the restoration of downstream ecosystems.

Multigrain seabed sediment transport modelling for the south-west Australian Shelf

2009 ◽  
Vol 60 (7) ◽  
pp. 774 ◽  
Author(s):  
F. Li ◽  
C. M. Griffiths ◽  
C. P. Dyt ◽  
P. Weill ◽  
M. Feng ◽  
...  
Keyword(s):  
Climate Change ◽  
Sediment Transport ◽  
Continental Shelf ◽  
Morphological Changes ◽  
High Energy ◽  
Sediment Supply ◽  
Climate Change Scenarios ◽  
The South ◽  
South West

With increasing concerns about climate change and sea-level rise, there is a need for a comprehensive understanding of the sedimentary processes involved in the erosion, transport and deposition of sediment on the continental shelf. In the present paper, long-term and large-scale seabed morphological changes on the south-west Australian continental shelf were investigated by a comprehensive sediment transport model, Sedsim. The investigated area covers the continental shelf and abyssal basins of the south-western region. The regional seabed is sensitive to environmental forces and sediment supply, and most terrigenous sediment carried down by major rivers is trapped in inland lakes or estuaries. Only a small fraction of fine-grain sediment reaches the continental shelf. The simulation has also confirmed that the Leeuwin Current and high-energy waves play the most important roles in regional long-term seabed evolution. Although the numerical implementation only approximates some forcing and responses, it represents a significant step forward in understanding the nature of potential long-term seabed change as a response to possible climate change scenarios. The 50-year forecast on the seabed morphological changes provides a reference for the management of coastal and offshore resources, as well as infrastructure, in a sustainable way.

EVENT-SCALE GEOMORPHIC CHANGE EVALUATED ALONGSIDE SEDIMENT TRANSPORT MEASUREMENTS IN A FLOOD-DRIVEN EPHEMERAL CHANNEL

2019 ◽  
Author(s):  
Kyle Stark ◽  
◽  
Daniel Cadol ◽  
Jonathan B. Laronne ◽  
Madeline Richards ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Event Scale ◽  
Transport Measurements

scholarly journals The Response of Turbidity Maximum to Peak River Discharge in a Macrotidal Estuary

Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 106
Author(s):  
Yuhan Yan ◽  
Dehai Song ◽  
Xianwen Bao ◽  
Nan Wang
Keyword(s):  
River Discharge ◽  
Recovery Time ◽  
Morphological Evolution ◽  
Spring Tide ◽  
River Estuary ◽  
Sediment Concentration ◽  
Ocean Model ◽  
Turbidity Maximum ◽  
Sediment Supply ◽  
Three Dimensional Model

The Ou River, a medium-sized river in the southeastern China, is examined to study the estuarine turbidity maximum (ETM) response to rapidly varied river discharge, i.e., peak river discharge (PRD). This study analyzes the difference in ETM and sediment transport mechanisms between low-discharge and PRD during neap and spring tides by using the Finite-Volume Community Ocean Model. The three-dimensional model is validated by in-situ measurements from 23 April to 22 May 2007. In the Ou River Estuary (ORE), ETM is generally induced by the convergence between river runoff and density-driven flow. The position of ETM for neap and spring tides is similar, but the suspended sediment concentration during spring tide is stronger than that during neap tide. The sediment source of ETM is mainly derived from the resuspension of the seabed. PRD, compared with low-discharge, can dilute the ETM, but cause more sediment to be resuspended from the seabed. The ETM is more seaward during PRD. After PRD, the larger the peak discharge, the longer the recovery time will be. Moreover, the river sediment supply helps shorten ETM recovery time. Mechanisms for this ETM during a PRD can contribute to studies of morphological evolution and pollutant flushing.

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