Abstract:In order to obtain correct and reliable runoff regimes, and to effectively develop and utilize hydropower resources of rivers, using the Fuhe River Basin as an example, we analyzed the principal components involving ten variables of runoff samples from 12 hydrological stations on the Fuhe River. The variables included daily mean flow, minimum daily mean flow, maximum and minimum monthly mean flows, base flow index, number of days during which the streamflow is equal to or lower than 5% of annual mean flow, daily mean flow for a period of 90 days or one exceeding 90 days, standard deviation of daily mean flow, and coefficient of variation of the annual mean flow. We calculated the contribution rates of the principal components, the cumulative contribution rates, and scores of samples and their comprehensive scores, and evaluated the runoff regimes of the main stream and tributaries of the river. The results show that the first principal component reflects the threshold value range of runoff, discrete degree, and symmetry conditions; the second principal component reflects the base flow index and the coefficient of variation of runoff, and the contribution rates of the two principal components decrease successively. These research results can provide river management departments with technical support and a reliable data basis for understanding runoff regimes of different main streams and tributaries, planning programs for development of hydropower resources in river basins, and maintaining a healthy water environment for rivers.