东江流域基流变化特征及影响因素

Variation characteristics and influencing factors of base flow in Dongjiang River Basin

基于东江流域控制性水文站博罗站1954—2010年实测日径流数据,采用数字滤波法和平滑最小值法进行基流分割,从不同的时间尺度上探讨博罗站基流的变化特征,从降水和人类活动两方面分析基流影响因素。结果表明:数字滤波法更适用于研究区;东江博罗站基流量的年内分布先增大后减小,基流指数先减小后波动增大;东江博罗站年均基流量和基流指数总体呈增大的趋势,多年平均基流量为414.04 m^3/s,多年平均基流指数为0.56。枯水年和偏枯水年的平均基流指数均为0.55,平水年为0.57,偏丰水年和丰水年分别为0.57和0.55;降水对东江流域基流量有年际影响;年内不同月份的突变规律说明大型水库是东江流域基流变化的关键性因素,水库的水量调度使基流量在枯水期呈显著增长趋势。

Based on the measured daily runoff data from 1954 to 2010 at the Boluo Station of the Dongjiang River,the digital filtering method and the smoothing minimum method were used for the base flow separation. The variation characteristics of the base flow and the base flow index at Boluo station were discussed on different time scales, and the influence factors of base flow were analyzed from precipitation and human activities.It was found that the digital filtering method was more suitable than the smooth minimum method in the study area. The annual distribution of the base flow of Boluo Station increased first and then decreased, while the base flow index decreased first and then increased. The average annual base flow and base flow index at Boluo Station showed an increasing trend. The average annual base flow was 414.04 m^3/s, and the average annual base flow index was 0.56. The average base flow index in both dry and partial dry years were 0.55, that in the normal year was 0.57, and that in partial wet and wet years were 0.57 and 0.55, respectively. Precipitation has an interannual impact on the base flow in Dongjiang River Basin. The change of the runoff in different months indicates that the large reservoir is a key factor in the change of the base flow in Dongjiang River Basin. The water regulation of the reservoir makes the base flow increase significantly in the dry season.