How have the river discharges and sediment loads changed in the Changjiang River basin downstream of the Three Gorges Dam?
How have the river discharges and sediment loads changed in the Changjiang River basin downstream of the Three Gorges Dam?
复制标题
三峡大坝下游长江流域的河流流量和泥沙负荷发生了怎样的变化？
DOI：
10.1016/j.jhydrol.2018.03.035
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发表时间：
2018
影响因子：
6.4
通讯作者：
He Qing
中科院分区：
文献类型：
--
作者：
Guo Leicheng;Su Ni;Zhu Chunyan;He Qing
在气候变化和人类活动的影响下，世界河流的径流量和泥沙量都发生了显著的变化。了解它们的变化及其原因对于河流管理至关重要。以长江流域为研究对象，通过对三峡大坝下游多个水文站长时间序列的流量和输沙量资料的分析，全面揭示了长江流域的水文情势变化。我们发现深刻的河流流量减少洪峰和在湿干过渡期，并略有增加，在旱季的排放量。20世纪80年代以来，由于上游流域的产沙量减少和大坝的修建，泥沙负荷逐渐减少，自2003年TGD运行以来，泥沙负荷的减少速度明显加快。下游河道发生退化，导致水位下降幅度较大。TGD蓄水后，河流水位降低，促进了湖泊外流，从而对湖泊产生了“排水效应”。改变的河湖相互作用加速了湖泊内的低水发生，这可能会加剧干旱，因为长期以来湖泊面积缩小。此外，自2002年以来，湖泊沉积物减少，湖泊中的沉积物减少，更多的沉积物被冲出湖泊。这些水文变化对河流水旱灾害、水安全、河流生态系统和三角洲安全有着广泛的影响。(C)2018 Elsevier B.V.版权所有。
Streamflow and sediment loads undergo remarkable changes in worldwide rivers in response to climatic changes and human interferences. Understanding their variability and the causes is of vital importance regarding river management. With respect to the Changjiang River (CJR), one of the largest river systems on earth, we provide a comprehensive overview of its hydrological regime changes by analyzing long time series of river discharges and sediment loads data at multiple gauge stations in the basin downstream of Three Gorges Dam (TGD). We find profound river discharge reduction during flood peaks and in the wet-to-dry transition period, and slightly increased discharges in the dry season. Sediment loads have reduced progressively since 1980s owing to sediment yield reduction and dams in the upper basin, with notably accelerated reduction since the start of TGD operation in 2003. Channel degradation occurs in downstream river, leading to considerable river stage drop. Lowered river stages have caused a 'draining effect' on lakes by fostering lake outflows following TGD impoundments. The altered river-lake interplay hastens low water occurrence inside the lakes which can worsen the drought given shrinking lake sizes in long-term. Moreover, lake sedimentation has decreased since 2002 with less sediment trapped in and more sediment flushed out of the lakes. These hydrological changes have broad impacts on river flood and drought occurrences, water security, fluvial ecosystem, and delta safety. (C) 2018 Elsevier B.V. All rights reserved.