Adjustments in Low-water Channel Geometry and Its Effect on the Navigation Condition of the Upper Jingjiang Reach After the Three Gorges Project Operation

被引：0
|
作者：
Zhou M. [1 ]
Xia J. [1 ]
Lin F. [1 ]
Deng S. [1 ]
机构：
[1] State Key Lab. of Water Resources and Hydropower Eng. Sci., Wuhan Univ., Wuhan
来源：
Xia, Junqiang (xiajq@whu.edu.cn) | 2017年 / Sichuan University卷 / 49期
关键词：
Channel adjustments; Flow and sediment regime; Low-water channel geometry; Navigation condition; Three Gorges Project; Upper Jingjiang Reach;
D O I：
10.15961/j.jsuese.201600844
中图分类号：
学科分类号：
摘要：
Significant channel degradation has occurred along the Upper Jingjiang Reach (UJR) because of the operation of the Three Gorges Project (TGP), leading to the corresponding adjustments in low-water channel geometry. The section-scale low-water channel dimensions at each section in the UJR were first calculated by a one-dimensional hydrodynamic model. Due to the remarkable longitudinal variability in cross-sectional geometry, a reach-averaged method was adopted to calculate the reach-scale low-water channel dimensions in this reach annually from 2002 to 2015. Calculation results indicated that:(i) the reach-scale low-water width changed slightly owing to the restriction of various river regulation practices, and the corresponding depth and cross-sectional area increased by 0.68 m and 870 m2, respectively, which led to a continuous decrease in the width-depth ratio from 5.73 in 2002 to 5.17 in 2015. Therefore, the low-water channel gradually developed into a narrow and deep shape in the UJR, with the low-water navigation condition being generally improved; (ii) however, the width-depth ratio at low water significantly increased in some sub-reaches such as the site of Huojianzhou, as well as the Shashi and Gongan bends. It was further explained that the central-bar and convex point-bar in these regions underwent dramatic degradation, which finally contributed to deteriorating the navigation condition. In addition, the empirical relationships were developed between the reach-scale low-water channel dimensions and the previous flow and sediment regime. The results showed that (i) the degree of correlation between the reach-scale low-water width and the previous flow and sediment regime was only 0.37, and thus the developed relationship couldnot be applied to predict the variation in the low-water width; (ii) the reach-scale low-water depth, cross-sectional area and width-depth ratio had a close correlation with the flow strength in the past 6 years, with the high correlation degrees of 0.92, 0.95 and 0.85, respectively. Therefore, these low-water channel dimensions can respond well to the altered flow and sediment regime caused by the TGP operation. © 2017, Editorial Department of Advanced Engineering Sciences. All right reserved.
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页码：74 / 82
页数：8
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  • [1] Li X., Lu Y., Liu H., Influences on waterway of Jingjiang River key reach after impoundment of Three-Gorges junction and research on countermeasures, Port & Waterway Engineering, 8, pp. 55-59, (2004)
  • [2] Mu D., Wang Y., Li X., Et al., Study on the effect of downstream navigation by unsteady flow caused by Xiangjiaba Daily regulation, Journal of Sichuan University(Engineering Science Edition), 46, 6, pp. 71-77, (2014)
  • [3] Cao S., Liu X., Adaptive adjustment and mutation response of river bed within changing sediment supply in mountain river, Journal of Sichuan University(Engineering Science Edition), 48, 1, pp. 1-7, (2016)
  • [4] Li G., Xu H., Song D., Et al., Study of sediment deposition in downstream approach channel of Three Gorges Project, Journal of Sediment Research, 2, pp. 1-5, (2012)
  • [5] Li Y., Chen J., Deng J., Et al., Influence of reservoir construction upstream on the navigation channel in the fluctuating backwater area of the Three Gorges Reservoir, Journal of Sediment Research, 5, pp. 31-37, (2008)
  • [6] Jiang L., Li Y., Sun Z., Et al., Channel evolution of Jingjiang reach and its influences on waterway after impoundment of the Three Gorges Project, Journal of Basic Science and Engineering, 18, 1, pp. 1-10, (2010)
  • [7] Sun Z., Li Y., Ge H., Et al., Channel erosion processes in the gravel bed to sand bed transitional recch of the middle Yangtze River, Journal of Hydraulic Engineering, 39, 7, pp. 789-797, (2011)
  • [8] Tang J., You X., Li Y., Et al., Impacts of the operation of Three Gorges Reservoir on navigation conditions in middle and lower Yangtze River, Journal of Hydroelectric Engineering, 33, 1, pp. 102-107, (2014)
  • [9] Xia J.Q., Deng S.S., Lu J.Y., Et al., Dynamic channel adjustments in the Jingjiang Reach of the Middle Yangtze River, Scientific Reports, 6, (2016)
  • [10] Xia J.Q., Li X.J., Li T., Et al., Response of reach-scale bankfull channel geometry in the Lower Yellow River to the altered flowand sediment regime, Geomorphology, 213, 4, pp. 255-265, (2014)
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