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Siltation

About: Siltation is a research topic. Over the lifetime, 1420 publications have been published within this topic receiving 20983 citations.


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Journal ArticleDOI
TL;DR: Wang et al. as mentioned in this paper developed a three-dimensional wave-current-sediment coupled numerical model with wetting and drying process to understand hydrodynamics and sediment transport dynamics in the Deepwater Navigation Channel (DNC), the North Passage of the Yangtze River Estuary (YRE), China.
Abstract: [1] A three-dimensional wave-current-sediment coupled numerical model with wetting and drying process is developed to understand hydrodynamics and sediment transport dynamics in the Deepwater Navigation Channel (DNC), the North Passage of the Yangtze River Estuary (YRE), China. The model results are in good agreement with observed data, and statistics show good model skill scores and correlation coefficients. The model well reproduces the spring-neap variation between a well-mixed estuary and a highly stratified estuary. Model results indicate that the estuarine gravitational circulation plays the most important role in the estuarine turbidity maximum (ETM) formation in the DNC. The upstream nonlocal sediment intrusion through the spillover mechanism is a major source of sediment trapping in the North Passage after the morphological changes. Numerical studies are conducted to show scenarios in the YRE under the effects of different forcings (river discharges, waves, and winds). Between these study cases, surface-wave-breaking relieves the sediment trapping and bottom-wave-current-interaction aggravates the bed erosion and elevates the SSC in the ETM; the former and the latter have the least and largest influence on the suspended sediment transport in the DNC. The wind effects have a greater influence on sediment trapping than the river discharges, and the steady northwesterly wind condition favors the siltation in the DNC most. The significance of density-driven turbidity current is also assessed, which can enhance the saline-water intrusion and suppress the turbulent mixing in the bottom boundary layer.

72 citations

Journal ArticleDOI
TL;DR: In this article, an assessment of soil erosion risk by wind and water was performed based on soil erosion models, and it was assumed that the areas with erosion intensity higher than slight were at risk of erosion; by this criterion, more than 34% of the total area of the watershed of the Ningxia-Inner Mongolia Reach of the Yellow River would be at erosion risk.

72 citations

Journal ArticleDOI
TL;DR: In this article, the effects of large-scale coastal developments on the sedimentation processes in the Keum River Estuary were analyzed and numerical experiments of hydrodynamics were performed.
Abstract: The macro-tidal Keum River Estuary located in the eastern Yellow Sea has been suffering siltation and morphological change since 1994. To understand the effects of the large-scale coastal developments on the sedimentation processes in the estuary, hydrodynamic and sedimentary data collected from 1985 to 2002 were analyzed and numerical experiments of hydrodynamics were performed. The sedimentation rate in the estuary increased by a factor of 1.9, from 3.5 × 10 6 to 6.7 × 10 6 m 3 y −1 , after the construction of a dam in the upper reaches of the estuary in 1994. Large part of the estuary is veneered by the muddy sediments noticeably, which were rarely found before dam construction. Since then, siltation has concentrated in the upper estuary rather than the lower. The upstream transport and accumulation of fine-grained sediments is due to: (1) the change to flood-dominance in the main channel, i.e. the relative intensification of flood current and the flood-directed residual current; and (2) the decrease in transport capacity in the upper estuary, i.e. the marked decrease in current velocity, which was induced by dam construction. The former has resulted in the ebb-dominance of the Gaeya channel, a distributary in the north of the main channel. The tidal pumping of fine sediments was reinforced not by the freshwater/saltwater interaction but by the residual tidal circulation. The sediment fluxes observed in 2001–2002 demonstrate year-round net inflow both at the entrance of the jetties and at the Gaeya channel, which implies that the sediments delivered by the Keum River are entirely confined to the estuary, incapable of escaping to the sea. The net inward transport of fine sediments may accumulate pollutants adsorbed to or absorbed in the sediment grains in the estuary, thus deteriorating the benthic environment gradually and the water quality eventually.

70 citations

Journal ArticleDOI
TL;DR: In this article, the authors present an up-to-date inventory of soil erosion in Brazil caused by crop and livestock activities and provide estimates based on three different hypothetical land-use scenarios to accommodate the expansion of Brazilian agricultural activity by 2020.

70 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023122
2022214
202159
202072
201964
201871