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Spatio-Temporal Patterns and Impacts of Sediment Variations in Downstream of the Three Gorges Dam on the Yangtze River, China
Chen, Jilong1,2,3,4; Fang, Xinrui1; Wen, Zhaofei1; Chen, Qiao1,2; Ma, Maohua1; Huang, Yuanyang1; Wu, Shengjun1; Yang, Liang Emlyn5,6
2018-11-01
摘要Spanning the Yangtze River of China, the Three Gorges Dam (TGD) has received considerable concern worldwide with its potential impacts on the downstream side of the dam. This work investigated the spatio-temporal variations of suspended sediment concentration (SSC) at the downstream section of Yichang-to-Chenglingji from 2002 to 2015. A random forest model was developed to estimate SSC using MODIS ground reflectance products, and the spatio-temporal distributions of SSC were retrieved with this model to investigate the characteristics of water-silt variation. Our results revealed that, relatively, SSC before 2003 was evenly distributed in the downstream Yangtze River, while this spatial distribution pattern changed ce 2003 when the dam started storing water. Temporally, the SSC demonstrated a W-shaped curve of seasonal variation as one peak occurred in September and two troughs in March and November, and showed a significantly decreasing trend after three-stage impoundment. After official operation of the TGD in 2009, the SSC was reduced by over 40% than before 2003. Spatially, the most significant changes occurred in the upper Jingjiang section, where the SSC dropped by 45%. During all stages of impoundment, the water impoundment to 135 m in 2003 had the most significant impact on suspended sediment. The decreased SSC has led to emerging risks of bank failure, aggravated erosion of water front and aggressive down-cutting erosion along the downstream of the dam, as well as other ecological and environmental issues that require urgent attention by the government.
关键词suspended sediment concentration Three Gorges Dam riverbank collapse impoundment
DOI10.3390/su10114093
发表期刊SUSTAINABILITY
ISSN2071-1050
卷号10期号:11页码:17
通讯作者Yang, Liang Emlyn(lyang@gshdl.uni-kiel.de)
收录类别SCI
WOS记录号WOS:000451531700267
语种英语