Aiming to deal with the water disaster in Yangtze River,the large-scale and high-frequency human activities are carried out in Jingjiang River and Dongting Lake area since 1950s, which lead to the river runoff series change obviously of three streams (Songzi River,Hudu River and Ouchi River)in the southern Jingjiang River,and the water exchange and water security in Dongting Lake area are seriously influenced.In order to quantify the variation characteristics of runoff series of three streams in the southern Jingjiang River,the STARS and ICSS methods were employed to identify the mean and variance variation,and the variation position and variation level of runoff series;meanwhile,some significant human activities during the variation periods were analyzed to explore the causes of hydrological variation through the physical mechanism.The results show that the runoff series of Xinjiangkou,Shadaoguan,Mituosi, Kangjiagang and Guanjiapu stations of three streams in the southern Jingjiang River have change points in mean with the decrease range of 24%-78%,and the runoff is severely reduced, moreover,the runoff series of Kangjiagang station has a change point in variance with 74%decrease;these variations mainly result from the river cutoff of three streams in the southern Jingjiang River from 1969 to 1971 and Three Gorges Dam impoundment from 2001 to 2006;the river cutoff has significant influence on the runoff at Shadaoguan,Mituosi,Kangjiagang and Guanjiapu stations and causes 614×108water not entering Dongting Lake;the Three Gorges Dam impoundment has noticeable effect on the runoff at Xinjiangkou,Shadaoguan and Mituosi stations and results in a decreasing lake inflow with 174×108water;through analyzing the runoff series at Shadaoguan and Mituosi stations effected by two types of human activities,the variation levels caused by river cutoff and Three Gorges Dam impoundment are equivalent,but river cutoff has more significant influences than Three Gorges Dam impoundment on change in absolute value.%20世纪50年代以来,为治理长江水患,洞庭湖区和长江荆江河段发生了大规模、高频次的人类活动,导致荆南三河(松滋河、虎渡河和藕池河)径流序列发生显著变化,严重影响了洞庭湖区的江湖水量交换与水安全情势.为了量化荆南三河径流序列的变异特征,引入 STARS法和 ICSS法分别用于识别径流序列的均值与方差变化,确定其变异位置与变异水平;同时,通过梳理同期发生的重大人类活动,从物理机制层面探索荆南三河径流变异的驱动成因.结果表明:荆南三河新江口站、沙道观站、弥陀寺站、康家岗站和管家铺站径流序列均发生了均值跳跃变异(变异幅度24%~78%),径流量严重减少,康家岗站还发生了振幅缩减的方差变异(变异幅度74%);径流变异的主要原因是1969~1971年的荆南三河河道裁弯和2001~2006年的三峡水库蓄水;河道裁弯主要影响荆南三河的沙道观站、弥陀寺站、康家岗站、管家铺站,减少流入洞庭湖水量约614×108m3,三峡水库蓄水影响新江口站、沙道观站、弥陀寺站,减少流入洞庭湖水量约174×108m3;从受双重影响的沙道观站和弥陀寺站来看,河道裁弯和三峡水库蓄水所引起的径流变异幅度基本相当,但在绝对量值上,河道裁弯引起的影响更大.
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