摘要
水沙变化是洞庭湖演变和江湖关系调整的关键因子。综合运用数理统计、小波分析、Mann-Kendall法和累加过滤器等方法,分析1956～2008年洞庭湖入湖和出湖径流和输沙量的变化特征。结果表明:①洞庭湖入湖水量以湘、资、沅、澧四水入流为主,洞庭湖入湖泥沙以荆江三口分沙为主。四水年均入湖水量约占洞庭湖出湖总水量的59.2%;三口入湖沙量约占入湖总沙量的80.9%。②由于荆江裁弯、葛洲坝工程运用、三峡水库拦蓄以及长江上游的水土保持措施的影响,从三口河道进入洞庭湖的水沙呈现明显的衰减趋势,入湖水量所占比重已由荆江裁弯前的42.6%下降到了三峡水库运用初期的21.7%;入湖沙量所占比重已由荆江裁弯前的87.7%下降到了三峡水库运用初期的59.6%。③近50年洞庭湖的泥沙沉积总量达52.9×108t,但泥沙沉积比已由荆江裁弯前的73.3%下降到了三峡水库运用初期的34.0%,洞庭湖泥沙淤积的趋势明显减弱,有利于保持洞庭湖的调洪湖容,延长洞庭湖的寿命;但三峡水库运用初期,三口分流的衰减将加剧洞庭湖区西部地区枯水供水的紧张态势,并使水环境容量下降;同时城陵矶下游长江河道的淤积导致洞庭湖洪水位抬升。
The water-sediment variation is the key factor for the Dongting Lake evolution and the river-lake relationship adjustment. The variation characteristics of runoff and sediment transport at the important hydrometric stations of the Dongting Lake were analyzed according to the data from 1956 to 2008, with the methods of mathematical statistics, Mann-Kendall, wavelet analysis and accumulating filter. The results show that： 1） The runoff entering the Dongting Lake mainly come from the 4 rivers of Hunan Province （accounting for 59.2% of the total outflow） and the sediment mainly come from the 3 outlets of Jinjiang River （accounting for 80.9% of the total）. 2） The runoff and sediment entering Dongting Lake from the 3 outlets decreased significantly, because of the impact of cutting off the Jinjiang River, operating Gezhouba water structure, using the Three Gorges Reservoir and water and soil conservation of the upper reaches of the Yangtze River. The runoff and sediment entering from the three outlets have respectively decreased from 42.6% and 87.7% before cutoff to 21.7% and 59.6%. 3） In recent 50 years, the total sediment deposition has reached up to 52.9×10^8t, however, the sediment deposition rate significantly dropped from 73.3% before the Jinjiang cutoff to 34.0% in the initial operation of the Three Gorges Reservoir. The sediment decrease is favorable for the lake maintenance and prolonging the lake life. In the initial operation of the Three Gorges Reservoir, however, the decrease of runoff and sediment from the 3 outlets may also aggravate the shortage of water supply in low water period in the west of Dongting Lake and decrease the water environmental capacity. Meanwhile, the sediment accumulation in the lower reach below Chenglingji station will lead to the rising of flood level in Dongting Lake.
出处
《水文》
CSCD
北大核心
2011年第1期45-53,40,共10页
Journal of China Hydrology
关键词
洞庭湖
水沙变化
三峡水库
四水
三口
Dongting Lake
runoff-sediment variation
Three Gorges Reservoir
Sishui
Sankou
