Analysis on variation characteristics of the minimum flow at Datong Station under the influence of the Three Gorges Reservoir

Abstract

As an important hydrological control station in the lower reaches of the Yangtze River, the Datong Station can provide guidance for regulating downstream water withdrawal activities by studying the characteristics of its changes during the dry season. This study selected the annual minimum flow index, applied linear trend method, Mann-Kendall method and wavelet analysis method to analyze its trend and periodic change characteristics, and analyzed the empirical frequency changes before and after the operation of the Three Gorges Reservoir, and obtained the following conclusions: The annual minimum flow series shows a significant increase trend, showing the characteristics of multi-period nesting in periodic changes, in which the first main period is 35-year. At the same frequency, the corresponding flow after the Three Gorges Reservoir operation was all larger than that before.