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    近60年以来洞庭湖水文情势变异及生态效应

    Hydrological Regime Alteration and Ecological Effects of Dongting Lake During the Past 60 Years

    • 摘要: 为了定量评价近60年来洞庭湖水文情势的动态变化,基于洞庭湖城陵矶、南咀和杨柳潭水文站1959~2016年的日平均水位序列,运用M-K法和累积距平法分析了洞庭湖水位的时空变化特征,结合IHA-RVA法综合评估水文变异前后洞庭湖水文指标改变程度,并采用累积量斜率变化率法定量评价人类活动和气候变化对洞庭湖水位变化的贡献率.研究结果表明:(1)西洞庭湖南咀站的年均水位呈下降趋势,而东洞庭湖城陵矶站和南洞庭湖杨柳潭站的年均水位呈上升趋势,洞庭湖水位突变年份为1979年和2003年;(2)洞庭湖水文情势以1959~1978年作为水文未受干扰阶段,则水文变异I阶段(1979~2002年)城陵矶、南咀和杨柳潭水文站水文改变度分别为39%、26%和27%,洞庭湖整体水文改变程度属于低度改变;水文变异II阶段(2003~2016年)城陵矶、南咀和杨柳潭水文站水文改变度分别为60%、41%和31%,洞庭湖整体水文改变程度属于中度改变;总体上,东洞庭湖水文改变程度最大,西洞庭湖和南洞庭湖水文改变程度较小;(3)西洞庭湖和南洞庭湖1979~2002年期间水文情势受人类活动影响较大,2003~2016年受气候降水变化影响较大;东洞庭湖在1979~2002年水文情势受气候降水影响较大,2003~2016年受人类活动(尤其是三峡工程)影响较大;(4)三峡工程蓄水在一定程度上改变了长江与洞庭湖之间的关系,造成了洞庭湖水位情势改变,尤其是东洞庭湖,进而改变了湖泊湿地植被群落演替以及鱼类和鸟类的数量,对湖泊湿地生态系统安全带来不利影响.该研究可为洞庭湖水资源保护以及生态修复提供参考.

       

      Abstract: In order to quantitatively evaluate the dynamic changes of the Dongting Lake hydrological situation in the past 60 years, based on the daily average water level sequence of the Dongting Lake Chenglingji, Nanzui and Yangliutan hydrological stations from 1959 to 2016.The Mann-Kendall method and the cumulative anomaly method were used to analyze the trend and sudden change of the Dongting Lake water level, and the IHA-RVA method was used to comprehensively evaluate the changes in the hydrological indicators of Dongting Lake before and after the hydrological variation.The cumulant slope change rate method is used to quantitatively evaluate the contribution rate of human activities and climate change to the changes in the hydrological regime of Dongting Lake under the changing environment.The results showed that:(1) The annual average water level of the Nanzui hydrological station showed a downward trend, while Chenglingji and Yangliutan hydrological station showed an upward trend.The abrupt years of water level in Dongting Lake were 1979 and 2003.(2) Taking the hydrological situation of Dongting Lake from 1959 to 1978 as the natural hydrological stage, the hydrological variation stage I (1979~2002) of the hydrological stations in Chenglingji, Nanzui and Yangliutan is 39%, 26% and 26% respectively.27%, the overall hydrological change of Dongting Lake is a low-degree change;the hydrological variation stage II (2003~2016) in the Chenglingji, Nanzui and Yangliutan hydrological stations is 60%, 41% and 31% respectively.The hydrological changes of the lake are generally moderate changes.Generally, the hydrological changes of East Dongting Lake is the largest, and the hydrological changes of West Dongting Lake and South Dongting Lake are small.(3) West Dongting Lake and South Dongting Lake were greatly affected by human activities during 1979~2002, and were greatly affected by climate precipitation changes from 2003 to 2016;East Dongting Lake was greatly affected by climate precipitation during 1979~2002, human activities are relatively small, but after 2003, the impact of human activities, especially the Three Gorges Project, has increased.(4) The impoundment of the Three Gorges Project has changed the relationship between the Yangtze River and Dongting Lake to a certain extent, resulting in changes in the water level of Dongting Lake, especially in East Dongting Lake, which in turn changed the succession of vegetation communities in the lake wetland and the number of fish and birds, which will adversely affect the safety of the lake and wetland ecosystem.This research can provide references for water resources protection and ecological restoration of Dongting Lake.

       

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