Sedimentation Characteristics of the Fluctuating Backwater Area at the Tail of Cascade Reservoirs: A Case Study of the Three Gorges Reservoir

Abstract

The construction of cascade reservoirs is associated with considerable uncertainty in sedimentation in the fluctuating backwater area of the terminal reservoir and poses challenges to water safety. The sedimentation characteristics under the influence of multiple factors in the main urban area of the Chongqing river section were analyzed as a case study for the operation of cascade reservoirs in the Jinsha River via the utilization of a large dataset spanning back to the normal storage of the Three Gorges Reservoir. The results of this study indicate that, owing to factors such as upstream water, sediment inflow, reservoir operation, and river sand mining, this river section experienced deposition on the sand bars and erosion in the main channel. The rate of sedimentation increased with sediment inflow, peak flow rate, and duration, while the location of sedimentation shifted as the concentration ratio changed. These results may provide technical support not only for the operation of the Three Gorges Reservoir, but also for the governance of the fluctuating backwater areas of other cascade reservoirs.

Sulfur, Nitrogen and Heavy Metals in Headwater Streams of Upper Qinghai Lake, Northeast Qinghai–Tibet Plateau: Possible Pollution by Atmospheric Deposition

“…In aquatic systems, the majority of element inputs originate from soil, where atmospheric deposition acts as an indirect source. ,, Soil can release pollutants from atmospheric deposition, including HMs, sulfate (SO 4 2– ), and nitrate (NO 3 – ), into surface water through leaching, leading to a series of environmental issues, such as HM pollution and water acidification. − Surface water acidification was believed to increase the risk of HM contamination . However, previously acidified regions have experienced acidification recovery due to declining atmospheric S deposition .…”