1960—2022年洞庭湖流域多尺度径流量演变特征分析

Multi-time scale runoff variations in the Dongting Lake Basin during 1960—2022

气候变化加剧旱涝灾害,严重制约了区域水资源利用和经济发展。洞庭湖流域是长江流域重要的生态功能区,研究洞庭湖流域径流变化特征可为洞庭湖流域水资源保护、开发利用与规划、区域协调可持续发展提供科学依据。研究基于Mann-Kendall趋势检验法和小波分析法,分析了洞庭湖湘江、资江、沅江和澧水4个流域控制水文站1960—2022年的流量多时间尺度演变特征。结果表明:各子流域实测流量呈非显著性变化趋势。其中,澧水石门站年平均流量呈减少趋势,倾向率为-0.24 m^(3)/s·a^(-1),沅江桃源站、资江桃江站和湘江湘潭站实测流量均呈增加趋势,倾向率分别为2.42、0.43和3.33 m^(3)/s·a^(-1);洞庭湖流域4个水文站年内径流分配极不均匀,最大流量主要集中在6、7月份,汛期4—7月份径流量可占年径流量的50%左右,非汛期流量则相对较低;澧水流域实测径流周期与其他3个流域差异明显,澧水石门站径流变化的主周期为4 a,其他3站的主周期为24 a左右;洞庭湖各子流域实测径流具有较好的同步性,年、季、月尺度下的相关系数均在0.65以上。此外,研究发现洞庭湖各子流域不同时期降水径流关系基本保持不变,人类活动对河川径流量的影响相对较小。

Climate change aggravates drought and flood disasters,which severely constrains regional water resources utilization and economic development.The Dongting Lake Basin is an important ecological functional area of the Yangtze River Basin,and the study of runoff variation characteristics in this basin can provide a scientific basis for the protection,development,utilization and planning of water resources,as well as coordinated and sustainable development of the region.Based on Mann-Kendall trend test and wavelet analysis method,this study analyzed the multi-time scale variation characteristics of runoff in the control hydrological stations in the Xiangjiang River,Zijiang River,Yuanjiang River and Lishui River in the Dongting Lake Basin during 1960—2022.The results showed that the measured runoff for all four hydrological stations showed an insignificant variation trend,among which Shimen Station in the Lishui River showed a decreasing trend,with a linear regression rate of-0.24 m^(3)/s·a^(-1);whereas Taoyuan Station in the Yuan River,Taojiang Station in the Zijiang River and Xiangtan Station in the Xiangjiang River all showed an increasing trend,with linear regression rates of 2.42 m^(3)/s·a^(-1),0.43 m^(3)/s·a^(-1)and 3.33 m^(3)/s·a^(-1),respectively.In terms of temporal distribution,the runoff in these four stations was quite unevenly distributed within the year,with the maximum runoff mainly occurring in June and July and the runoff from April to July accounting for about 50%of the annual runoff,while the runoff in the dry season was relatively low.Moreover,the observed periodicity of runoff in the Lishui River Basin was significantly different from that in the other three river basins,the principal cycle of runoff at the Shimen Station was four years,while that of the other three stations was about 24 years.Notably,the measured runoff in the four sub-basins of the Dongting Lake was synchronized,and the correlation coefficients on annual,seasonal and monthly scales were all above 0.65.In addition,the relationship between precipitation and runoff at different periods remained basically unchanged,indicating that human activities had little influence on the runoff of rivers.