| 摘要: |
| 根据1956-1995年洞庭湖水文泥沙原型观测和地形测绘等翔实资料, 运用输沙量法和地形法对洞庭湖(湖区各站)冲淤变化进行了认真的统计分析分析,结果表明,洞庭湖来水量以四水为主,占 57.8%;来沙量以四口为主,占 79.5%,多年平均沉积率为 74.0%,出湖仅占26.0%;淤积量及出湖水沙量随着四口分流分沙比的减小而减少.洞庭湖年淤积量为 49.3×108t,其中四口水系约17.3×108t,占35.1%,天然湖泊约32.0×108t,占64.9%;天然湖泊年均淤积量、淤积体积、淤积厚度分别为0.8×108t、0.57×108m30.018m洞庭湖水系中,松滋河的东西两支、资水尾闾、草尾河、西洞庭湖两个出口等测站河床呈冲刷趋势,其他水系湖泊呈淤积状态洞庭湖出口河道从1988年起显冲刷迹象,指示洞庭湖的衰亡呈缓解状态 |
| 关键词: 泥沙淤积 冲淤变化 洞庭湖 |
| DOI：10.18307/1999.0302 |
| 分类号: |
| 基金项目:“九五”国家重点科技攻关三峡工程泥沙科研项目资助 |
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| Sediment Deposition and Erosion in Dongting Lake(1956-1995) |
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SHI Xiu-duan, XIA Wei, YANG Bing
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The Yangtze River Middle Reaches Bureau, The Yangtze River Valley Planning Commission, Wuhan 430012
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| Abstract: |
| By using the hydrological and topographical data collected from hydrological stations around Dongting Lake, the amount of sediment deposition and erosion from the lake(1956-1995) is analyzed with sediment budget method and topographical method. The results demonstrate that the inflow from the Lishi River, Yuanjiang River, Xiangjiang River and Zishui River contributes 57.8% of the total water into Dongting Lake, while the runoff from the Yangtze River through 4 intakes and channels which connect the Yangtze River and the lake occupies 33.6%.Among the sediment transported into the lake, 79.5% is from the Yangtze River, 18.2% from the four tributaries and only 2.3% from the local area.Up to 74% of the sediment into the lake is deposited in the lake, with the rest carried out of the lake to the Yangtze River. The runoff flowing from the Yangtze River into the lake has been reducing because of the siltation of the lake. Hence the siltation rate and the flow returning into the Yangtze River decrease. The total amount of sediment deposition in the lakes in the past 40 years (1956-1995) was calculated at 4.93 billion cubic meters that made the lake silled up by 0.63-0.74 m. The rate of siltation is estimated at 0.018 m/a1 with the sediment budget method and 0.016 m/a1with the topographical method. Sedimentation in the period 1983-1995 led eastern part of Dongting lake shrank by 1.5%, southern part of Dongting Lake by 2.5%, Muping Lake by 5.4% and Qili Lake by 22.5%.In the past 40 years, the East and West branches of the Songzi River, the lower reaches of the Zishui River, the Caowei River, the south and north outlets of Dongting lake have exhibited a bed degradation by 1.03m, 0.5m, 0.26m, 0.67m, 0.15m and 0, 52m respectively, whereas the rest have silted up. In the main outlet of the lake, Chenglingji Station, erosion has been observed since 1988.The impoundment of the Three Gorges Reservoir will probably reduce the inflow of water and sediment to lake and the rate of siltation of the lake will slow down. |
| Key words: uongting Lake sand deposition sediment budget |
