scholarly journals Prediction of Shoreline Change for the Calculation of the Integrated Littoral Sediment Budget

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 232
Author(s):  
Yeon-Joong Kim ◽  
Jong-Sung Yoon
Keyword(s):  
Sediment Transport ◽  
Coastal Erosion ◽  
Evaluation System ◽  
Shoreline Change ◽  
Sediment Budget ◽  
Prediction Performance ◽  
Sediment Supply ◽  
Sediment Runoff ◽  
Observation Data ◽  
Sediment Volume

The severe coastal erosions are being accelerated along the east coast of South Korea owing to the intermittent erosions and depositions caused by the imbalance between the effective sediment volume supplied from coasts and rivers and the sediment transport rate. Consequently, many studies are being conducted to develop coastal-erosion reduction measures. To accurately determine the cause of coastal erosion, the causes of the erosion and deposition should be accurately diagnosed, and a comprehensive evaluation system for the sediment transport mechanism in the watershed and sea while considering regional characteristics is required. In particular, realizing the evaluation of the effective sediment volume that flows from the river to the sea through observations is a highly challenging task, and various research and developments are required to realize it, as it is still in the basic research stage. The purpose of this study was to systematically analyze the comprehensive sediment budget for coastal areas. First, an analytical system was developed. Then, a shoreline model was constructed by considering the size of the mixed particles. The parameters required for developing the model were determined using the observation data to improve the shoreline model. A sediment runoff model was applied to evaluate the effective sediment volume supplied from the river to the sea, and the applicability of this model was evaluated by comparing it with the sediment supply volume according to the soil and water assessment tool model. The representative wave and the input parameters of the model were set using the observation data of several years. It was found that the prediction performance of the shoreline change model improved when the effective sediment volume was considered, and the particles of the sediment on the shore were assumed to comprise multiple sizes. In particular, the prediction performance improved when the balance of the sediment budget was adjusted by applying a groin having a structurally similar performance to take into consideration the geographic features of the Deokbongsan (island) in front of the river mouth bar. The model demonstrated a good performance in reproducing long-term shoreline changes when the characteristics of the sea waves and the effective sediment volume were considered.

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 Sediment dynamics of mountain streams as a function of variation in sediment deposition

2018 ◽  
Vol 55 (1) ◽  
pp. 23-29
Author(s):  
Ryunosuke Nakanishi ◽  
Yuki Okajima ◽  
Akira Baba ◽  
Yasuhiro Mitani ◽  
Hiro Ikemi
Keyword(s):  
Sediment Transport ◽  
Catchment Area ◽  
Heavy Rain ◽  
Sediment Dynamics ◽  
Sediment Deposition ◽  
Observation Data ◽  
Sediment Discharge ◽  
Regional Geology ◽  
Sediment Volume ◽  
Dam Reservoirs

 In Japan, the management of sediment in dam reservoirs has become challenging owing to heavy rain. Unexpected increase of sediment volume in dam reservoirs can increase flood risk owing to a rise in the level of the riverbed. It is therefore necessary to conduct sediment management to clarify the area of sediment production to control the amount of sediment transported and the timing of its movement. Sediment discharge from tributaries is often calculated based on catchment area and the deposited sediment volume already present in the dam reservoir. However, our preliminary surveys have implied that it is also necessary to consider regional geology in the evaluation of sediment transport. Moreover, variations in sediment deposition should be evaluated for each site where the geology changes. In this study, we observe in detail changes in the riverbed in two tributaries with different regional geologies. Changes in the shape of the riverbed were analyzed from unmanned aerial vehicle observation data, following which the effects of erosion and sedimentation on the riverbed were quantitatively evaluated. Finally, sediment discharge was calculated by a one-dimensional numerical model of sediment transport. These results indicate that the tributary that is mostly composed of mudstone produced considerably more sediment than the tributary composed mainly of sandstone. This suggests that an understanding of regional geology is necessary in the evaluation of sediment dynamics and should be considered in addition to the catchment area.

scholarly journals Video Monitoring of Shoreline Positions in Hujeong Beach, Korea

2019 ◽  
Vol 9 (23) ◽  
pp. 4984 ◽  
Author(s):  
Chang ◽  
Jin ◽  
Jeong ◽  
Kim ◽  
Do
Keyword(s):  
Wave Propagation ◽  
Sediment Transport ◽  
Coastal Erosion ◽  
Bottom Topography ◽  
Shoreline Change ◽  
Normal Direction ◽  
Video Monitoring ◽  
Phase Coupling ◽  
Video Cameras ◽  
Sheltering Effect

Shoreline processes observed by a video monitoring system were investigated under different wave conditions. A 30 m-high tower equipped with video cameras was constructed in Hujeong Beach, South Korea, where coastal erosion was suspected to occur. Two-year shoreline data since December 2016 showed that beach area, Ab, has decreased, but periods of rapid increase in Ab were also observed. Shoreline change was closely related to the wave propagation directions and bottom topography. Ab increased when waves approached the shore obliquely, whereas it decreased when they approached in a normal direction. The shoreline became undulated when Ab increased, while it became flatter when Ab decreased. The undulation process was influenced by nearshore bedforms because the shoreline protruded in the lee area where underwater rocks or nearshore sandbars actively developed, with a sheltering effect on waves. Specifically, the locations of shoreline accretion corresponded to the locations where the sandbar horns (location where a crescentic sandbar protrudes toward the shore) developed, confirming the out-of-phase coupling between sandbars and shoreline. When waves with higher energy approached normal to the shore, the sheltering effect of sandbars and underwater rocks became weaker and offshore sediment transport occurred uniformly along the coast, resulting in flatter shorelines.

scholarly journals ANALISIS ABRASI DAN AKRESI PERAIRAN PANTAI BARUS TAPANULI TENGAH DENGAN MODEL CEDAS 2.0

2021 ◽  
Vol 17 (2) ◽  
pp. 104-124
Author(s):  
Novi Andhi Setyo Purwono
Keyword(s):  
Sediment Transport ◽  
Shoreline Change ◽  
Forecast Model ◽  
Sediment Supply ◽  
East Side ◽  
Flat Area ◽  
The People ◽  
Building Area ◽  
Western Side ◽  
The Stability

Barus is an area where most of the people are fishermen, this is because Barus is an area located on the coast. The existing condition shows the shoreline on the east side of the seawall building, the condition of the shoreline is experiencing abrasion resulting in the retreat of the coastline and almost reaches the fisherman's flat building area, this is due to the port building in the form of a massive trester jutting into the sea resulting in sediment supply to the retained flat towers and the coastline has declined.To maintain the stability of the coastline, it is necessary to make an effort to control the damage to water in this area. The shoreline model is a numerical forecast model based on the sediment continuity equation and the sediment transport rate equation along the coast. Sediment transport rates along the coast are a function of the variation in height and direction of waves along the coast formed by the effects of refraction and diffraction. The results of the shoreline change model with the protection of the fisherman's flat area from waves by building sea walls is the east side of the fisherman's towers abrasion ± 7 m and sedimentation ± 5 m, the front area of the fisherman's towers does not occur sedimentation or abrasion, the western side of the fisherman's towers does not sedimentation and abrasion occurred, the east side of Barus Jetty did not occur abrasion or sedimentation, the area of Barus Jetty occurred ± 20 m sedimentation, and the west side of Barus Jetty occurred sedimentation ± 9 m. These results indicate that for handling conditions by making a seawall in front of the flat area shows that the location is safe from scouring of waves

scholarly journals FIELD STUDY ON SEDIMENT TRANSPORT AROUND RIVER MOUTH OPENING AT THE TENRYU RIVER IN JAPAN

2018 ◽  
pp. 69
Author(s):  
Yuya Sasaki ◽  
Shinji Sato
Keyword(s):  
Sediment Transport ◽  
Coastal Erosion ◽  
Mouth Opening ◽  
River Mouth ◽  
Sediment Supply ◽  
Optimal Management ◽  
Central Japan ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Near Future

The Tenryu River mouth and its surrounding coast, located on the Pacific Ocean side in the central Japan, have been suffered from severe coastal erosion. Although increasing sediment supply from river to coast is planned by sand-bypassing through the upstream dams in near future, a better understanding on morphology change around river mouth is needed to facilitate optimal management of the river mouth. Especially, understanding on sediment transport around the river mouth opening is essential to prevent river mouth closure which leads to many problems. The purpose of this study is to reveal the mechanism of sediment transport around river mouth opening.

Shoreline Change Analysis along the Udupi-Dakshina Kannada Coastal Stretch in Karnataka, West Coast of India using DSAS

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
N.A. Anjita ◽  
G.S. Dwarakish
Keyword(s):  
Remote Sensing ◽  
West Coast ◽  
Shoreline Change ◽  
Sediment Supply ◽  
Shoreline Changes ◽  
West Coast Of India ◽  
Erosion Rates ◽  
Wide Range ◽  
Cyclic Changes ◽  
Accretion And Erosion

Study of morphological variations and the effects of oceanographic processes such as erosion and accretion at different temporal scales are important to understand the nature of the coast and the cyclic changes occurring during different seasons. The Udupi-Dakshina Kannada coast along the west coast of India exhibits a wide range of changes depending on the interactions of tide and wave energy, sediment supply and more importantly human intervention. In view of this, the present work has been carried out to study the changes in shoreline changes along the Udupi-Dakshina Kannada coast over a period of 29 years from 1990 to 2019. Remote Sensing and GIS techniques have been used to demarcate shorelines and calculate the shoreline change rates. Overall accretion and erosion rates were found to be 1.28 m/year and 0.91 m/year respectively along the coast. Highest accretion and erosion rates of 12.57 m/year and 5.34 m/year was noticed along the Dakshina Kannada coast. The study also suggests that multi-dated satellite data along with statistical techniques can be effectively used for prediction of shoreline changes. Keywords: remote sensing, GIS, Dakshina Kannada coast, oceanography, shoreline.

Influence of ground ice and permafrost on coastal evolution, Richards Island, Beaufort Sea coast, N.W.T.

1996 ◽  
Vol 33 (5) ◽  
pp. 664-675 ◽  
Author(s):  
Scott R. Dallimore ◽  
Stephen A. Wolfe ◽  
Steven M. Solomon
Keyword(s):  
Coastal Erosion ◽  
Sediment Budget ◽  
Storm Event ◽  
Ground Ice ◽  
Coastal Evolution ◽  
Thermal Erosion ◽  
Ice Wedge ◽  
Mechanical Erosion ◽  
Sea Coast

A long-term sediment budget (1947−1985) for northern Richards Island shows that, when ground ice and offshore erosion are accounted for, there is a near balance between headland erosion and coastal deposition. Excess ice constitutes about 20% of the total volume of eroded material from the headlands, with massive ground ice contributing nearly 9% and segregated ice lenses and ice wedges making up the remainder. Coastal response to major storms in 1987 and 1993 suggests that erosion is episodic, with short periods of intense disruption followed by readjustment of cliff profiles. Processes characteristic of this environment include mechanical erosion of ice-bonded sediments creating unstable erosional niches, mechanical failure of niches along ice-wedge planes, and longer term thermal erosion of ice-bonded sediments. Where ice contents are high, localized thaw slumps initiated by coastal erosion may retreat at rates substantially higher than those observed at other sections of the coast. Cliff-top retreat rates may be out of phase with storm-event chronology.

Sediment slugs: large-scale fluctuations in fluvial sediment transport rates and storage volumes

1995 ◽  
Vol 19 (4) ◽  
pp. 500-519 ◽  
Author(s):  
A.P. Nicholas ◽  
P.J. Ashworth ◽  
M.J. Kirkby ◽  
M.G. Macklin ◽  
T. Murray
Keyword(s):  
Sediment Transport ◽  
Sediment Supply ◽  
Fluvial Systems ◽  
Event Scale ◽  
Fluvial Sediment ◽  
Sediment Routing ◽  
Basin Scale ◽  
Wide Range ◽  
And Storage ◽  
Fluvial Sediment Transport

Variations in fluvial sediment transport rates and storage volumes have been described previously as sediment waves or pulses. These features have been identified over a wide range of temporal and spatial scales and have been categorized using existing bedform classifications. Here we describe the factors controlling the generation and propagation of what we term sediment slugs. These can be defined as bodies of clastic material associated with disequilibrium conditions in fluvial systems over time periods above the event scale. Slugs range in magnitude from unit bars (Smith, 1974) up to sedimentary features generated by basin-scale sediment supply disturbances (Trimble, 1981). At lower slug magnitudes, perturbations in sediment transport are generated by local riverbank and/or bed erosion. Larger-scale features result from the occurrence of rare high- magnitude geomorphic events, and the impacts on water and sediment production of tectonics, glaciation, climate change and anthropogenic influences. Simple sediment routing functions are presented which may be used to describe the propagation of sediment slugs in fluvial systems. Attention is drawn to components of the fluvial system where future research is urgently required to improve our quantitative understanding of drainage-basin sediment dynamics.

scholarly journals Assessment of shoreline changes for setback zone establishment from Son Tra (Da Nang city) to Cua Dai (Hoi An city), Vietnam

2020 ◽  
Vol 42 (4) ◽  
pp. 363-383
Author(s):  
Ngo Van Liem ◽  
Dang Van Bao ◽  
Dang Kinh Bac ◽  
Ngo Chi Cuong ◽  
Pham Thi Phuong Nga ◽  
...  
Keyword(s):  
Linear Regression ◽  
Coastal Erosion ◽  
Regression Line ◽  
Central Area ◽  
Remote Sensing Data ◽  
Shoreline Change ◽  
Shoreline Changes ◽  
Climate Change Response ◽  
Changes Over Time ◽  
Change Response

The most important function of the coastal setback is to minimize damage due to coastal erosion, climate change response, and sea-level rise. There are many directions and methods of researching and assessing coastal changes and coastal erosion. This study presents the results of the shoreline changes in the area from Son Tra (Da Nang City) to Cua Dai (Hoi An City), Central Vietnam based on remote sensing data from 1965 to 2019. Three methods are used to include End Point Ratio (EPR), Linear Regression Rate (LRR), and Weighted Linear Regression (WLR). The results show that the EPR method is effective when calculating the rate of shoreline changes only at two different times. For more objective and reliable calculation, it is necessary to assess the shoreline changes over time. Meanwhile, the LRR method was shown to be superior because all shoreline data were taken into account during the construction of the regression line. However, when there is much shoreline data with different reliability, the WLR method proved more superior because of limited objective errors. The results show that from 1965 to 2019, the coast of the Son Tra - Cua Dai area had quite complicated fluctuations, of which the northern area (Son Tra) tended to accretion, the central area tends to be alternate between accretion and erosion, while the south area (Cua Dai) is strong to very strong erosion. The coast with sudden changes is the Cua Dai area with the shoreline change envelope (SCE) reaching 512m. The results also allow us to divide the coast of the Son Tra - Cua Dai area into 30 segments. They are clustered into 8 groups with different levels of erosion and accretion. This is an important basis for the setback zone establishment in the study area.

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