Identification and analysis of mutations of hydrological processes is one of the hot spots in hydrological studies.It is of important theoretical and practical significance for hydrologic analysis and modeling,hydrological forecasting,and water pollution control to analyze and understand the laws of hydrology and its sequence variations.The study investigated the times and characteristics of hydrological variability within the Heihe River basin which is a typical inland river basin in the northwest and provided reference for reasonable use and development of water resources in the basin.To accurately distinguish the change-point of hydrological processes,the authors adopted annual runoff series data of 60 years at hydrological monitoring stations of Yingluoxia in the Heihe river basin during the period 1947-2006.The difference plot curve-combined method of rank test was used to identify the change-point of hydrological processes.Brown-Forsythe method,sequential clustering method,and sliding F test method were jointly used to verify the accuracy of variation points.At the same time,hydrological characteristics of the data before and after the variation points were analyzed.Results show that 1959 and 1979 were the change points in the hydrological processes at the station of Yingluoxia.Changes in hydrological series were divided into three stages.The standard deviation,coefficient of variation,and deviation coefficient changed significantly at various stages.The average values of the phase difference ranged between 125×106m3 and 189×106m3.The characteristics of trends and mutations in hydrological series reflected that natural conditions and human activities had a significant impact on the natural state of the river hydrological sequence.Factors of climate change,such as temperature,rainfall,and evaporation,and human activities,such as over farmland reclamation,overgrazing,and the construction of reservoirs,could be responsible for the mutations of the runoff.The difference plot curve-combined method of rank test has been effectively used in the Heihe river basin;it can reduce the complexity of formulas and the corresponding assumptions compared to the other methods.However,in the calculation,there have relaxed requirements for the normality of data and the same condition of different sets of data to some extent.Measured data could not satisfy the requirements of general assumptions of statistical methods.The calculated variation points were generally consistent with the actual state of the regional environment.
Heihe RiverHydrological sequencesChange pointResidual mass curve
NETL
NSTL
维普
万方数据
