长江荆南三口地区水系连通变异前后的径流变化特征研究

Runoff changing characteristics before and after river system connectivity variation in the Three Outlets of the South of Jingjiang River

以长江荆南三口河系1956-2016年的实测径流量资料为基础,以1989年为水系连通变异分界点,运用趋势分析法和小波分析法研究基准期和变化期的径流量时空变化特征。结果表明:基准期和变化期年均径流量呈现下降趋势,下降速率分别为1.9457×10^(8)和0.7682×10^(8) m^(3)/a;径流主要集中在丰水季节,占比达60%~70%,变化期在4个水文季节的径流量比基准期下降了40%~80%,枯水季节下降幅度高达77%;径流量存在3类周期变化,变化期比基准期的小周期丰枯交替次数约增多2次,长周期范围和中心值约缩短6 a;新江口和管家铺两个水文站的径流量约为三口地区总流量的2/3,集中于松滋河的西支和藕池河的东支。研究结果可为荆南三口地区及洞庭湖的水资源调蓄提供科学技术参考。

Based on the measured runoff data of the Three Outlets of the South of Jingjiang River from 1956 to 2016,the temporal and spatial variation characteristics of runoff were studied in the base period and change period by trend analysis and wavelet analysis methods,presuming 1989 as the dividing point of water system connectivity variation.The results showed that the decline rates of average annual runoff in the base period and change period were 194.57×10^(6) m^(3)/a and 76.82×10^(6) m^(3)/a,respectively,which showed a downward trend.The runoff was mainly concentrated in the wet season,accounting for 60%-70%.Runoffs in the four hydrological seasons decreased by 40%-80%in the change period,and the decline rate in the dry season was as high as 77%.Runoff changes presented three types of periodic cycles,the number of short-term cycle alternation between wet and dry phases in the change period was about two times more than that in the base period;whereas the range and central value of the long-term cycles were shortened by about six years.The runoff in Xinjiangkou and Guangjiapu hydrological stations were about 2/3 of the total flow of the Three Outlets area,which were concentrated in the west branch of Songzi river and the east branch of Ouchi river.The results can provide a scientific and technical support for the regulation and storage of water resources in the Three Outlets area and the Dongting Lake.