scholarly journals MODELING MORPHOLOGICAL EVOLUTION IN THE VICINITY OF COASTAL STRUCTURES

2011 ◽  
Vol 1 (32) ◽  
pp. 68 ◽  
Author(s):  
Pham Thanh Nam ◽  
Magnus Larson ◽  
Hans Hanson
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
Transport Model ◽  
Morphological Evolution ◽  
Transformation Model ◽  
Quality Data ◽  
Wave Transformation ◽  
Random Wave ◽  
Army Corps ◽  
Wave Induced

A numerical model of beach topography evolution was developed. The model includes five sub-models: random wave transformation model, surface roller model, wave-induced current model, sediment transport model, and morphological change model. The model was validated by two unique high-quality data sets obtained from experiments on the morphological impact of a detached breakwater and a T-head groin in the basin of the Large-scale Sediment Transport Facility (LSTF) at the US Army Corps of Engineer Research and Development Center in Vicksburg, Miss. The simulations demonstrated that the model well reproduced the wave conditions, wave-induced currents, and morphological evolution in the vicinity of the structures.

scholarly journals Long shore sediment transport computation for Hai Hau beach-Nam Dinh province

2003 ◽  
Vol 25 (1) ◽  
pp. 39-48
Author(s):  
Nguyen Manh Hung
Keyword(s):  
Sediment Transport ◽  
River Mouth ◽  
Wave Climate ◽  
Large River ◽  
Sediment Supply ◽  
Red River ◽  
Transformation Model ◽  
Wave Transformation ◽  
Random Wave ◽  
Red River Delta

Several stretches of shore line in the Red River Delta (RRD) are suffering from severe erosion, especially an area between too large river mouths Balat in the North and Day in the South, known as Hai Hau beach. Several different hypothesis have been put forward to explain this erosion. The cut off of the Ha Lan river mouth (in 1955) which discharged sediment at the upstream end of the beach, possibly affects Hai Hau beach. Also, the construction of Hoa Binh dam in the upstream part of Red river has reduced the sediment supply to the area. In this study, it is shown that the prevailing wave climate in connection with the complex topography of Balat river mouth and Hai Hau beach promotes erosion along the coastal line. A two dimensional random wave transformation model was used with 20-year time series of hindcast waves to compute the long shore sediment transport along the study beach.

scholarly journals Large-scale suspended sediment transport and sediment deposition in the Mekong Delta

2014 ◽  
Vol 18 (8) ◽  
pp. 3033-3053 ◽  
Author(s):  
N. V. Manh ◽  
N. V. Dung ◽  
N. N. Hung ◽  
B. Merz ◽  
H. Apel
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Large Scale ◽  
Transport Model ◽  
Mekong Delta ◽  
Sediment Dynamics ◽  
Sediment Deposition ◽  
Mineral Fertilizers ◽  
Suspended Sediment Transport ◽  
Extreme Flood

Abstract. Sediment dynamics play a major role in the agricultural and fishery productivity of the Mekong Delta. However, the understanding of sediment dynamics in the delta, one of the most complex river deltas in the world, is very limited. This is a consequence of its large extent, the intricate system of rivers, channels and floodplains, and the scarcity of observations. This study quantifies, for the first time, the suspended sediment transport and sediment deposition in the whole Mekong Delta. To this end, a quasi-2D hydrodynamic model is combined with a cohesive sediment transport model. The combined model is calibrated using six objective functions to represent the different aspects of the hydraulic and sediment transport components. The model is calibrated for the extreme flood season in 2011 and shows good performance for 2 validation years with very different flood characteristics. It is shown how sediment transport and sediment deposition is differentiated from Kratie at the entrance of the delta on its way to the coast. The main factors influencing the spatial sediment dynamics are the river and channel system, dike rings, sluice gate operations, the magnitude of the floods, and tidal influences. The superposition of these factors leads to high spatial variability of sediment transport, in particular in the Vietnamese floodplains. Depending on the flood magnitude, annual sediment loads reaching the coast vary from 48 to 60% of the sediment load at Kratie. Deposited sediment varies from 19 to 23% of the annual load at Kratie in Cambodian floodplains, and from 1 to 6% in the compartmented and diked floodplains in Vietnam. Annual deposited nutrients (N, P, K), which are associated with the sediment deposition, provide on average more than 50% of mineral fertilizers typically applied for rice crops in non-flooded ring dike floodplains in Vietnam. Through the quantification of sediment and related nutrient input, the presented study provides a quantitative basis for estimating the benefits of annual Mekong floods for agriculture and fishery, and is an important piece of information with regard to the assessment of the impacts of deltaic subsidence and climate-change-related sea level rise on delta morphology.

scholarly journals The Method for Evaluating Cross-Shore Migration of Sand Bar under the Influence of Nonlinear Waves Transformation

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 214
Author(s):  
Margarita Shtremel ◽  
Yana Saprykina ◽  
Berna Ayat
Keyword(s):  
Sediment Transport ◽  
Nonlinear Wave ◽  
Maximum Amplitude ◽  
Field Measurements ◽  
Wave Transformation ◽  
Sandy Bottom ◽  
Divergence Point ◽  
Sand Bar ◽  
Wave Induced ◽  
Second Wave

Sand bar migration on the gently sloping sandy bottom in the coastal zone as a result of nonlinear wave transformation and corresponding sediment transport is discussed. Wave transformation on the intermediate depth causes periodic exchange of energy in space between the first and the second wave harmonics, accompanied by changes in the wave profile asymmetry. This leads to the occurrence of periodical fluctuations in the wave-induced sediment transport. It is shown that the position of the second nonlinear wave harmonic maximum determines location of the divergence point of sediment transport on the inclined bottom profile, where it changes direction from the onshore to the offshore. Such sediment transport pattern leads to formation of an underwater sand bar. A method is proposed to predict the position of the bar on an underwater slope after a storm based on calculation of the position of the maximum amplitude of the second nonlinear harmonic. The method is validated on the base of field measurements and ERA 5 reanalysis wave data.

scholarly journals Re-design Breakwater di PPI Tulandale Berdasarkan Analisis Hidrodinamika dan Sedimentasi. (Hal. 30-41)

2019 ◽  
Vol 5 (3) ◽  
pp. 30
Author(s):  
Regina Eugeny Destin Wirawan ◽  
Yessi Nirwana Kurniadi ◽  
Fitri Suciaty
Keyword(s):  
Sediment Transport ◽  
Neap Tide ◽  
Spring Tide ◽  
Current Speed ◽  
Transformation Model ◽  
Wave Transformation ◽  
North East ◽  
South West ◽  
Result Show ◽  
Mike 21

ABSTRAKPangkalan Pendaratan Ikan Tulandale berada di Kabupaten Rote Ndao, Provinsi Nusa Tenggara Timur. Breakwater di PPI Tulandale tidak dapat melindungi kolam pelabuhan dari gelombang tinggi. Tujuan dari penelitian ini adalah re-design breakwater pada PPI Tulandale agar dapat melindungi kolam pelabuhan. Simulasi hidrodinamika, transpor sedimen dan transformasi gelombang dilakukan dengan bantuan perangkat lunak Mike 21 untuk 2 buah skenario. Pada skenario alternatif 1, mulut pelabuhan di perkecil menjadi 50 m dan skenario alternatif 2 pada kondisi breakwater eksisting ditambah bangunan breakwater tegak lurus garis pantai sepanjang 200 m. Simulasi dilakukan selama 15 hari. Hasil analisis pada pemodelan, kondisi arus saat pasang purnama dan perbani bergerak dari arah barat daya kearah timur laut dengan kecepatan 0,00–0,08 m/s untuk alternatif 1, sedangkan kecepatan arus alternatif 2 arus sebesar 0,08–0,16 m/s. Hasil pemodelan hidrodinamika, transpor sedimen dan transformasi gelombang menunjukan bahwa bentuk re-design breakwater pada alternatif 2 efektif untuk melindungi kolam pelabuhan di PPI Tulandale karena dapat mereduksi gelombang sebesar 46,7% dari gelombang diluar kolam pelabuhanKata kunci: re-design breakwater, hidrodinamika, sedimentasi ABSTRACTTulandale Fishing Port Tulandale is located in Rote Ndao district, The province of Nusa Tenggara Timur. The Breakwater in Tulandale Fishing Port could not protect the port basin from the height of waves. The aimed of this study is to re-design breakwater in Tulandale Fishing Port in order to protect the port basin. The Hydrodynamic, sediment transport and waves transformation simulation are applied in this study by using mike 21 software for 2 scenarios. In the first scenario, the port basin width is reduced to 50 m and the second scenario is using the existing breakwater condition with the added breakwater building Perpendicular along the coast line for 200m. The simulation run of 15 days. The result show that the condition during the spring tide and neap tide move from south west to north east with 0.00-0.08 m/s for first scenario, while the current speed for the second scenario is is 0.08-0.16 m/s. Hydrodynamic result, sediment transport and wave transformation model that the shape of re-design breakwater on the second scenario more effective to protect the port basin at The Tuandale Fishing Port because the wave decrease at 46.7% from outside the port basin.Keywords: re-design breakwater, hydrodynamics, sedimentation

scholarly journals Bayesian Calibration and Validation of a Large‐Scale and Time‐Demanding Sediment Transport Model

2020 ◽  
Vol 56 (7) ◽  
Author(s):  
Felix Beckers ◽  
Andrés Heredia ◽  
Markus Noack ◽  
Wolfgang Nowak ◽  
Silke Wieprecht ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
Transport Model ◽  
Bayesian Calibration ◽  
Calibration And Validation ◽  
Sediment Transport Model

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.

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