scholarly journals Impact assessment of the three gorges reservoir on the contribution rate for diversion through the three outlets

2020 ◽  
Vol 612 (1) ◽  
pp. 012004
Author(s):  
M F Chen ◽  
Y T Li ◽  
A Q Li ◽  
W Yao
Keyword(s):  
Influencing Factors ◽  
Yangtze River ◽  
Three Gorges Reservoir ◽  
Optimal Operation ◽  
Three Gorges ◽  
The Yangtze River ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
Runoff Reduction ◽  
Reservoir Regulation

Abstract The Dongting Lake distributes water and sediment of the Yangtze River through the three outlets. Influencing factors of the diversion capacity are complicated. In order to evaluate the influences of the operation of the Three Gorges Reservoir (TGR) on the diversion of the three outlets, this paper investigates systematically the variation process of the runoff at the three outlets based on substantially raw data and principles of variable control. By using comparative analysis and the calculation method of runoff reduction, the change magnitude of the runoff at the three outlets in different periods were quantified and the contribution rates of different influencing factors were estimated. Results show that (1) Inflow difference from the Yangtze River is the primary factor causing the runoff reduction of the three outlets. After the operation of TGR, the Yangtze River was in dry years. Therefore, over 60% of runoff reduction can be attributed to the variation of natural inflow discharge. (2) As the flow is retained by TGR, the runoff of the three outlets further reduced. From 2003-2008, the contribution rates of natural flow, sediment trapping and reservoir regulation to the runoff reduction at the three outlets were 76.19%, 13.49%, 10.32%, while their counterparts after optimal operation of TGR became 66.05%, 14.20% and 19.75% respectively. (3) Reservoir operation after the flood season showed the most significant impact on runoff of the three outlets, resulting in an increase in the number of shut-off days of the three-distributary channels from September to October, especially at Shadaoguan and Kangjiagang.

Regulation of Laijiapu Waterway in Jingjiang Reach

2014 ◽  
Vol 501-504 ◽  
pp. 2001-2006
Author(s):  
Ya Liu ◽  
Li Zheng ◽  
Cheng Tao Huang ◽  
Zhao Biao Huang ◽  
Lin Liu
Keyword(s):  
Yangtze River ◽  
Three Gorges Reservoir ◽  
Three Gorges ◽  
The Yangtze River ◽  
Point Bar ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
Before And After ◽  
The Stability ◽  
Channel Bar

After impoundment of the Three Gorges Reservoir, Jingjiang reach, in the middle of the Yangtze River, has gradually shown a series of atypical fluvial features, adversely affecting the maintenance of waterways. Citing the Laijiapu Waterway, a meandering segment in the lower Jingjiang for example, this paper compared the fluvial features of the channel before and after the impoundment, summed up its navigation-obstructing features, and proposed guarding the point bar on the convex bank and channel bar in the widening section as a key to maintaining the stability of the navigation channels.

Research on Characteristics of New Water and Sediment of Yichang Station after Impoundment of the Three Gorges

2013 ◽  
Vol 779-780 ◽  
pp. 1613-1618 ◽  
Author(s):  
Yan Hua Yang ◽  
Xiao Qiang Liu ◽  
Hong Qian Zhang
Keyword(s):  
Yangtze River ◽  
Three Gorges Reservoir ◽  
Test Method ◽  
Rank Test ◽  
Sediment Runoff ◽  
Three Gorges ◽  
The Yangtze River ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
Water And Sediment

Reservoir regulation and reservoir sedimentation make conditions of flow and sediment under the dam change greatly after impoundment of the Three Gorges Project. This paper analyzes change trend and abrupt change situation of incoming water and sediment and studies characteristics of new flow and sediment of Yichang Station after impoundment of the Three Gorges with Mann-Kendall nonparametric rank test method. The result indicates that operation of the Three Gorges Reservoir has leveled runoff process and shortened dry season and extended median water period. After operation of the Three Gorges Reservoir, annual sediment runoff and monthly sediment runoff of some months changed suddenly and sediment runoff reduced sharply in Yichang Station. Sediment entering the middle and the lower reaches of the Yangtze River decreases substantially and it almost can be regarded as clean water discharge. Intorduction After operation of 175m normal water level of the Three Gorges Reservoir, total storage capacity of the reservoir is about 43 billion m3. Most of incoming sediment in the upstream is intercepted and deposited inside the reservoir and clean water and muddy water containing non-bed sand discharges. Change of water and sediment conditions destroys balance of downstream river and causes bed-rebuilding of downstream channels. And this results in a serious of long-term and long distance changes, such as on-way recovery of sand content, undercutting of bed scour, expansion of bank erosion and decline of water table, etc.[1-. Yichang Station controls a drainage area of 1005501km2 in upstream of the Yangtze River and is a major flood source for the middle and the lower reach of the Yangtze River. Thus, water regime information of Yichang Station is significant to flood control of the middle and the lower reach of the Yangtze River, regulation of the Three Gorges Reservoir, construction of water conservancy project all across the Yangtze River, industrial and agricultural production and shipping, etc. On account of this, this article analyzes data about coming water and sediment of Yichang Station to support characteristics of new flow and sediment of Yichang Station after impoundment of the Three Gorges with Mann-Kendall nonparametric rank test method.

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