Baseflow is an essential part of river water resources in arid areas, which play an important role in maintaining streamflow and ecological security in the basin. Investigation on the change characteristics of baseflow and its responses to precipitation in Wuding River Basin is of great significance for optimizing the allocation of water resources on the Loess Plateau. Based on daily precipitation and runoff data of Wuding River Basin from 1960 to 2019, and combined with digital filtering method, wavelet transform, double cumulative curve and elastic coefficient method, the study analyzed inter-annual and intra-annual variation characteristics of precipitation and baseflow depth, discussed the time-frequency relationship between precipitation and baseflow depth as well as the time lag effect of baseflow on precipitation, and clarified the change direction of precipitation-baseflow relationship. The result showed that annual baseflow depth displayed a highly significant downward trend (p<0.001), and annual baseflow index showed a non-significant upward trend (p<0.1), with perennial average values of 23.83 mm and 0.67, respectively. The values of baseflow depth and baseflow index were higher in spring and autumn, and lower in summer and winter. The control ability of precipitation on baseflow in summer and autumn was stronger in both high and low energy regions than that in spring and winter. The average annual lag time of baseflow to precipitation was 3.2 d, and the average monthly (May-October) lag time was less than 7 d. In the past 60 years, baseflow reserves in the watershed increased by more than 7 times. The relationship between precipitation and baseflow depth changed twice, the change points were 1971 and 2000, respectively. The sensitivity of baseflow to precipitation weakened gradually after 2000, and their relationship evolution became more stable. The results would provide theoretical support for sustainable development and utilization of water resources in the middle reaches of the Yellow River.
杨倩楠, 高海东, 韩勇, 李占斌, 鲁克新.无定河流域基流变化特征及其对降水的响应[J].水土保持学报,2023,37(5):235~242复制