Estimating the fluvial sediment input to the coastal sediment budget: A case study of Ghana

Geomorphology ◽  
2012 ◽  
Vol 138 (1) ◽  
pp. 100-110 ◽  
Author(s):  
Isaac Boateng ◽  
Malcolm Bray ◽  
Janet Hooke
2021 ◽  
Author(s):  
Yining Sun ◽  
Ji Li ◽  
Zhixian Cao ◽  
Alistair G.L. Borthwick

<p>For reservoirs built on a hyper-concentrated river, tributary inflow and sediment input may affect the formation and evolution of reservoir turbidity current, and accordingly bed morphology. However, the understanding of tributary effects on reservoir turbidity currents has remained poor. Here a series of laboratory-scale reservoir turbidity currents are investigated using a coupled 2D double layer-averaged shallow water hydro-sediment-morphodynamic model. It is shown that the tributary location may lead to distinctive effects on reservoir turbidity current. Clear-water flow from the tributary may cause the stable plunge point to migrate upstream, and reduce its front speed. Sediment-laden inflow from the tributary may increase the discharge, sediment concentration, and front speed of the turbidity current, and also cause the plunge point to migrate downstream when the tributary is located upstream of the plunge point. In contrast, if the tributary is located downstream of the plunge point, sediment-laden flow from the tributary causes the stable plunge point to migrate upstream, and while the tributary effects on discharge, sediment concentration, and front speed of the turbidity current are minor. A case study is presented as of the Guxian Reservoir (under planning) on the middle Yellow River, China. The present finding highlights the significance of tributary inflow and sediment input in the formation and propagation of reservoir turbidity current and also riverbed deformation. Appropriate account of tributary effects is warranted for long-term maintenance of reservoir capacity and maximum utilization of the reservoir.</p>


2020 ◽  
Vol 8 (8) ◽  
pp. 551
Author(s):  
Sahong Lee ◽  
Jung Lyul Lee

In this study, a reduction in sediment budget due to the development of a river watershed, resulting in coastal erosion, was reviewed, and the rate of background erosion was calculated through an examination of the loss of coastal sediment into the open sea. The west coast of the Korean peninsula is severely impacted by the intercept of inflowing sediments from rivers, owing to the watershed development. However, the effects have not fully propagated into the entire coastal area, and thus, the long-term coastal erosion remains insignificant. However, a serious and irrevocable disaster may occur once the coastal erosion begins. Therefore, an analysis of the coastal erosion resulting from changes in the sediment budget, due to the development of the watershed, was conducted on Janghang Songrim Beach. A littoral cell of the Geum River was selected for a quantitative analysis of the decrease in the sediment budget from the watershed development. The rate of coastal sediment loss offshore, which reflects the characteristics of the Janghang Songrim Beach, and the future rate of coastal erosion were calculated. Then, the results were verified by employing geometrically corrected satellite photographs from previous years. This will enable us to predict the time of coastal erosion in the future due to a reduction in the sediment budget and watershed development, and prepare for future disasters resulting from the coastal erosion. Based on research into the components constituting the coastal development, the present study presents theoretical formulae allowing the prediction of the sediment budget and providing a practical contribution to the prevention of coastal erosion, for which additional reliable studies need to be conducted.


Geology Today ◽  
2017 ◽  
Vol 33 (6) ◽  
pp. 216-223 ◽  
Author(s):  
Patrick Baer ◽  
Christian Huggel ◽  
Brian W. McArdell ◽  
Florian Frank

2010 ◽  
Vol 61 (2) ◽  
pp. 147-162 ◽  
Author(s):  
Slavomír Nehyba ◽  
Marie Adamová ◽  
Jiří Faimon ◽  
Tomáš Kuchovský ◽  
Ivan Holoubek ◽  
...  

Modern fluvial sediment provenance and pollutant tracing: a case study from the Dřevnice River Basin (eastern Moravia, Czech Republic)Modern fluvial deposits of a small fluvial system were studied in the area of eastern Moravia (Czech Republic) with the aim of determining the provenance of the deposits and weathering processes. Identification of the source rocks and their alongstream variations were used for the evaluation of the natural or anthropogenic source of the heavy metals. Paleogene flysch sandstones, flysch mudstones and Quaternary loesses represent source rocks and reflect both the role of recycling and local sources. Provenance from sandstones dominate upstream whereas mudstones represent dominant source rock in the downstream part of the fluvial system. The contents of Pb and Zn are highly enhanced when compared with the natural background in the entire study area. Their anthropogenic source is connected with the rubber/shoe manufacturing industry and traffic. The contents of Cr, Co, Cu, Ni and V are usually lower in modern deposits than in the identified source rocks.


2017 ◽  
Vol 50 (1) ◽  
pp. 458
Author(s):  
A. Petropoulos ◽  
I. Baziotis ◽  
Ch. Anagnostou ◽  
N. Evelpidou

Beachrocks represents a coastal deposition in the intertidal area, and studying their properties may lead to create a model which identifies the conditions of their formation (paleo-environment). This paper focuses most intently on the cement material which is able to recover the paleo-environment conditions during diagenesis of such coastal sediment. We used optical microscopy, secondary electron microscopy and Raman Spectroscopy to characterize the cement texture, mineralogy and chemistry in the beachrocks. The existence of pure calcite primarily controlled by the meteorite water, while Mg-calcite appears between the lowermeteoric and the upper marine phreatic zone. Finally, the presence of aragonite associated with the marine phreatic to lower marine vadose environment.


Sign in / Sign up

Export Citation Format

Share Document