1960-2015年洞庭湖水资源演变特征分析

Evolution characteristics of water resources at Dongting Lake from 1960 to 2015

洞庭湖是我国第二大淡水湖,也是长江流域重要的调蓄湖泊。由于受下垫面变化、人类活动和气候变化等的影响,洞庭湖流量、水位呈现新的变化趋势,研究洞庭湖水资源演变特征可为洞庭湖保护提供依据。采用Mann-Kendall突变检验方法对洞庭湖出口控制水文站城陵矶(七里山)及长江干流水文站枝城站、螺山站的1960-2015年流量、水位的年际和年内变化趋势进行分析。结果表明:洞庭湖上游长江枝城站在2000年以前径流量变化不大,但从2001年起呈现下降的趋势,水位呈现先上升后下降的趋势,洞庭湖出口城陵矶(七里山)站整体径流量呈现下降的趋势,而平均水位呈现上升的趋势,洞庭湖下游长江螺山站径流量整体上变化不显著,平均水位则呈现上升的趋势;三峡枢纽运行后,3个水文站汛期(4-10月)的径流量和水位均呈现下降趋势,枯水期(1-3月)则出现水位上升趋势;长江上水利工程尤其是三峡工程的修建,对洞庭湖水资源的调节影响明显。

Dongting Lake is the second largest freshwater lake in China and it is an important regulating lake in the Yangtze River Basin. The change of the runoff and water level of Dongting Lake shows a new trend due to the influence of the underlying surface change,human activities and climate change. We expect the study on the evolution characteristics of Dongting Lake water resources to provide some support for the protection of Dongting Lake. We analyzed the intra-annual and inter-annual variations of the runoff and the water level at the outlet control station of Dongting Lake-Chenglingji (Qilishan) station,Zhicheng and Luoshan hydrological station at Yangtze River mainstream from 1960 to 2015 using Mann-Kendall abrupt change testing method. The results showed that the runoff at Zhicheng station barely changed before 2000,whereas it started declining since 2001. The water level at Zhicheng station rose first and then fell. The runoff showed a decreasing trend at Chenglingji (Qilishan) station,whereas the average water level showed an opposite trend. The runoff had no significant change overall at Luoshan Station,but the average water level tended to rise. After the implementation of Three Gorges Project,the runoff and water level declined at the abovementioned 3 stations in flood season (April-October),whereas the water level rose in dry season (January-March next year). It indicates that the construction of Yangtze River water conservancy projects,especially the Three Gorges Project,has a significant impact on the water resources regulation of Dongting Lake.