Modeling transport and deposition of the Mekong River sediment

Xue, Zuo; He, Ruoying; Liu, Paul; Warner, John C.

doi:10.1016/j.csr.2012.02.010

Cited by 83 publications

(57 citation statements)

References 40 publications

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“…In an earlier high-flow shelf study, river-derived SSC was observed 50-60 km offshore during the southwest summer monsoon [Anikiyev et al, 1986], and modeling studies show significant seasonality with fluvial sediment delivery and deposition near the mouth of the Mekong [Xue et al, 2012]. The findings of these studies are consistent with the river-dominated sediment export during high flow observed in the present study.…”

Section: 1002/2015jc010754supporting

confidence: 82%

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Sediment dynamics in the lower Mekong River: Transition from tidal river to estuary

et al. 2015

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A better understanding of flow and sediment dynamics in the lowermost portions of large‐tropical rivers is essential to constraining estimates of worldwide sediment delivery to the ocean. Flow velocity, salinity, and suspended‐sediment concentration were measured for 25 h at three cross sections in the tidal Song Hau distributary of the Mekong River, Vietnam. Two campaigns took place during comparatively high‐seasonal and low‐seasonal discharge, and estuarine conditions varied dramatically between them. The system transitioned from a tidal river with ephemeral presence of a salt wedge during high flow to a partially mixed estuary during low flow. The changing freshwater input, sediment sources, and estuarine characteristics resulted in seaward sediment export during high flow and landward import during low flow. The Dinh An channel of the Song Hau distributary exported sediment to the coast at a rate of about 1 t s−1 during high flow and imported sediment in a spatially varying manner at approximately 0.3 t s−1 during low flow. Scaling these values results in a yearly Mekong sediment discharge estimate about 65% smaller than a generally accepted estimate of 110 Mt yr−1, although the limited temporal and spatial nature of this study implies a relatively high degree of uncertainty for the new estimate. Fluvial advection of sediment was primarily responsible for the high‐flow sediment export. Exchange‐flow and tidal processes, including local resuspension, were principally responsible for the low‐flow import. The resulting bed‐sediment grain size was coarser and more variable during high flow and finer during low, and the residual flow patterns support the maintenance of mid‐channel islands.

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Section: 1002/2015jc010754supporting

confidence: 82%

“…Waves during the low-flow, winter-monsoon period likely resuspended previously deposited high-flow riverine sediment. A portion of this sediment may be transported toward the southwest [Xue et al, 2012], and estuarine processes enable additional transport of this sediment back into the distributary channels.…”

Section: 1002/2015jc010754mentioning

confidence: 99%

Sediment dynamics in the lower Mekong River: Transition from tidal river to estuary

et al. 2015

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“…In a normal flood year, they estimated that the sediment load to the coast was about 42ˆ10 6 tons per year [23]. A complementary study by Xue et al [24] reported that 86.9% of the sediment coming from the Mekong River system was trapped in the MRD estuaries and nearshore area. As a result, in normal years, around 5.5ˆ10 6 tons of sediments are transported alongshore and seaward.…”

Section: Discussionmentioning

confidence: 92%

Numerical Simulations of Suspended Sediment Dynamics Due to Seasonal Forcing in the Mekong Coastal Area

Vinh¹,

Ouillon

Thao³

et al. 2016

Water

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Abstract:The Mekong River is ranked as the 8th in terms of water discharge and as the 10th in terms of sediment load in the world. During the last 4500 years, its delta prograded more than 250 km to the south due to a tremendous amount of sediments deposited, and turned from a "tide-dominated" delta into a "wave-and-tide dominated" delta. This study aims at completing our knowledge on the fate of sediments that may be stored in estuarine or coastal systems, or dispersed over the continental shelf and slope. Sediment transport in the Mekong River Delta (MRD) coastal area was studied by numerical simulations using the Delft3D model. The model configuration was calibrated and validated from data collected in situ during 4 periods from 2012 to 2014. Then, 50 scenarios corresponding to different wave conditions (derived from the wave climate) and river discharge values typical of low flow and flood seasons enabled us to quantify the dispersal patterns of fluvial sediments close to the mouths and along the coast. Sediments mostly settled in the estuary and close to the mouths under calm conditions, and suspended sediment with higher concentrations extend further offshore with higher waves. Waves from the Southeast enhanced the concentration all along the MRD coastal zone. Waves from the South and Southwest induced coastal erosion, higher suspended sediment concentrations in front of the southern delta, and a net transport towards the Northeast of the delta. Because of episodes of Southern and Southwestern waves during the low flow season, the net alongshore suspended sediment transport is oriented Northeastward and decreases from the Southwestern part of the coastal zone (~960ˆ10 3 t yr´1) to the Northeastern part (~650ˆ10 3 t yr´1).

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“…Transpor sedimen kohesif bergantung pada pergerakan massa air yang diakibatkan oleh pasang surut, arus, gelombang dan debit sungai (Zhou et al, 2015). Xue et al (2012) mengemukakan penyebab utama transpor dan deposit sedimen yang membentuk delta pada muara Sungai Mekong (sungai terbesar di Asia Tenggara) adalah pasang surut, arus dan gelombang. Kejadian lain juga menunjukkan secara spesifik penyebab utama erosi sedimen kohesif di Estuari Tagus (Portugal) oleh dinamika arus pasang surut dan gelombang (Franz et al, 2014).…”

Section: Pendahuluanunclassified

Cohesive Sediment Transport Modeling on Inner Ambon Bay

Noya¹,

Purba²,

Koropitan³

et al. 2017

J. Ilmu dan Teknologi Kelautan Tropis

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ABSTRAKAdanya sedimen kohesif di perairan dapat mengurangi penetrasi cahaya ke dalam air dan fotosintesis sehingga produktifitas primer perairan dapat terganggu. Pengendapan sedimen kohesif di perairan pesisir dapat mengakibatkan sedimentasi. Tujuan peneltian ini menunjukkan pola sebaran sedimen kohesif dan hubungannya dengan sedimentasi yang terjadi di Teluk Ambon Dalam (TAD). Pemodelan menggunakan MIKE 3 FM untuk menginterpretasikan proses sedimentasi pada TAD. Pengerjaan pemodelan dibagi menjadi 2 tahap yaitu pemodelan hidrodinamika (baroclinic) dan transport sedimen (sedimen transport). Hasil model menunjukkan bahwa pola pergerakan arus yang terjadi pada perairan TAD dipengaruhi oleh faktor pasang surut. Pola penyebaran sedimen kohesif secara vertikal mulai dari permukaan sampai dengan kedalaman 30m sekitar 3,5-15 Kg/m 3 . Konsentrasi sedimen kohesif tertinggi terjadi pada pangkal teluk (di sekitar Waiheru, Passo, dan Lateri). Hasil simulasi model selama 30 hari menunjukan bahwa tingkat erosi pada ambang (sill) berkisar antara 1,04-6,15 Kg/m 2 /s, sedangkan pada TAD hanya terjadi pada stasiun T1 yaitu 9,07x10 -8 Kg/m 2 /s. Sedimentasi yang berhubungan akumulasi sedimen kohesif ditunjukan oleh ketebalan lapisan (bed level). Ketebalan lapisan sedimen pada area ambang yaitu 0,01-0,19 cm atau rata-rata 0,47 mm/hari, sedangkan pada TAD berkisar antara 1,75-10,01 cm, atau dengan nilai rata-rata sekitar 39,9 mm/hari.

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Modeling transport and deposition of the Mekong River sediment

Cited by 83 publications

References 40 publications

Sediment dynamics in the lower Mekong River: Transition from tidal river to estuary

Sediment dynamics in the lower Mekong River: Transition from tidal river to estuary

Numerical Simulations of Suspended Sediment Dynamics Due to Seasonal Forcing in the Mekong Coastal Area

Cohesive Sediment Transport Modeling on Inner Ambon Bay

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