| 引用本文: | 朱玲玲,陈迪,杨成刚,陈柯兵,李思璇.金沙江下游梯级水库泥沙淤积和坝下河道冲刷规律.湖泊科学,2023,35(3):1097-1110. DOI:10.18307/2023.0327 |
| Zhu Lingling,Chen Di,Yang Chenggang,Chen Kebing,Li Sixuan.Sediment deposition of cascade reservoirs in the lower Jinsha River and scouring of river channel under dam. J. Lake Sci.2023,35(3):1097-1110. DOI:10.18307/2023.0327 |
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| 摘要: |
| 金沙江下游4个梯级水电站总装机容量相当于两座三峡水库，是“西电东送”中部地区的源头工程，工程效益发挥对经济社会发展意义重大。2012年以来，向家坝、溪洛渡、乌东德和白鹤滩电站等陆续蓄水运行，层层拦截金沙江的泥沙，2013—2020年向家坝出库年输沙量均值下降至152万t，减幅超过99%。大量泥沙淤积在梯级水库内，同时向家坝以下河道发生长距离冲刷。本文以自金沙江下游工程筹建以来的观测资料为基础，针对梯级水库的泥沙淤积和坝下游河道冲刷规律开展研究，结果表明：金沙江下游四个梯级电站自建成运行至2020年底，累计淤积泥沙约5.98亿m3，其中溪洛渡库区淤积量占比达92.5%，2013—2020年溪洛渡和向家坝水库排沙比分别为2.64%和22.2%，其水库泥沙主要淤积在常年回水区的干流河道内，以死库容内淤积为主，侵占有效库容的比例小于1.3%。金沙江下游库区干流河道的峡谷特征明显，淤积多表现为主河槽的平铺式淤高。溪洛渡和向家坝库区淤积的泥沙沿程分选特征明显，越靠近坝前，中数粒径减小、细颗粒泥沙沙量百分数增加，极细颗粒泥沙会在库区一定范围内大量沉积。向家坝下游河床普遍冲刷，但冲刷强度减弱明显，重要涉水工程局部冲刷并未超出预期范围。向家坝下游河道深泓高凸段相对稳定，使得坝下游枯水位未大幅下降，2000 m3/s下枯水位累计降幅约0.43 m；坝下游河床粗化明显。 |
| 关键词: 金沙江下游 梯级水库 泥沙淤积 河道冲刷 |
| DOI：10.18307/2023.0327 |
| 分类号: |
| 基金项目:长江水科学研究联合基金重点支持项目（U2040218）资助。 |
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| Sediment deposition of cascade reservoirs in the lower Jinsha River and scouring of river channel under dam |
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Zhu Lingling1, Chen Di2, Yang Chenggang1, Chen Kebing1, Li Sixuan1
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1.Bureau of Hydrology, Changjiang Water Resources Commission, Wuhan 430010, P. R. China;2.Changjiang Institude of Survey, Planning, Design and Research, Wuhan 430010, P. R. China
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| Abstract: |
| The total installed capacity of the four cascade hydropower stations in the lower reaches of the Jinsha River is equivalent to two Three Gorges reservoirs. They are the source project of the central region of the "west to East power transmission". The benefits of the project are of great significance to economic and social development. Since 2012, Xiangjiaba, Xiluodu, Wudongde and Baihetan power stations had successively stored water and operated to intercept the sediment of Jinsha River layer by layer. From 2013 to 2020, the average annual sediment discharge from Xiangjiaba decreased to 1.52 million tons, a decrease of more than 99%. A large amount of sediment was deposited in the cascade reservoirs and scoured to the river channel below Xiangjiaba. Based on the observation data since the preparation of the lower Jinsha River project, this paper studied the sediment deposition of cascade reservoirs and the scouring law of the river channel downstream of the dam. The results showed that from the completion and operation of the four cascade hydropower stations in the lower reaches of Jinsha River to the end of 2020, the accumulated sediment deposition was about 598 million m3, of which the sediment deposition in Xiluodu Reservoir accounted for 92.5%. The sediment discharge ratios of Xiluodu and Xiangjiaba reservoirs from 2013 to 2020 were 2.64% and 22.2%, respectively. The reservoir sediment was mainly deposited in the main stream channel of the perennial backwater area, mainly in the dead storage capacity, and the proportion of occupying the effective storage capacity was less than 1.3%. The canyon characteristics of the main stream channel in the reservoir area of the lower reaches of Jinsha River were obvious, and the siltation was mostly the flat siltation of the main channel. The sediment deposited in Xiluodu and Xiangjiaba reservoir areas had obvious sorting characteristics along the way. The closer to the front of the dam, the medium particle size decreasd, the percentage of fine sediment increased, and the very fine sediment would be deposited in a large amount in a certain range of the reservoir area. The downstream riverbed of Xiangjiaba was generally scoured, but the scouring intensity was weakened obviously. The thalweg high convex section of the downstream channel of Xiangjiaba was relatively stable, so that the low water level at the downstream of the dam had not decreased significantly, and the cumulative decline of the low water level at 2000 m3/s was about 0.43 m. The riverbed at the downstream of the Xiangjiaba dam was obviously coarsened. |
| Key words: The lower reaches of Jinsha River cascade reservoirs sediment deposition channel scouring |
