This ranging sheds light on the lack of bedload reaching the coastal zone and it is likely one of the reasons to yield coastal erosion.
Usually, the bedload transport rate of a river is about 5–25% of the suspended sediment transport. The ratio between QB and SSQ ranged from 0.12% to 27.3% with 76% of all values lower than 5%. Thus, a three years field sampling (2009-2011) was carried out to measure the sediment yield of Capibaribe Watershed, and also its contribution to coastal erosion. Based on the foregoing, the impact of dams on sediment transport and yield of an important Brazilian watershed with multiple dams will be the focus of this chapter. In terms of sediment retention and transport, China stands out the most impacted country by dams, followed by United States, and continents such as Europe, Africa, and South America. In addition, the multiple trapping through sequential dams has impacted the sediment transfer from terrestrial to coastal zone, triggering the coastal erosion. The sediment load has been reduced by more than 75% for major rives, such as Nilo, Orange, Volta, Indus, Ebro, Kizil Irmark, Colorado, and Rio Grande and more than 40% of its lux is trapped within large dams.
Recent effects of dam construction have been widely reported.
On the other hand, the bedload should be considered in order to assess the impacts of dams on sediment transport and sediment yield. The suspended sediment plays the most important role on the land-ocen sediment flux. Sediment transport relates to suspended sediment and bedload.
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