Chu, Z.; Li, Y., and Li, B., 2015. Human impacts could affect natural periodicity of river runoff entering the sea.

The periodicity analysis and correlation analysis about river runoff and basinwide precipitation in a river are widely used. While there exists a problem in previous periodicity analysis and correlation analysis, which here refers to lacking consideration of human impacts on river runoff. This problem may obscure the results of periodicity analysis and correlation analysis. For the case of the Yangtze River and the Yellow River, we carried out periodicity analysis and correlation analysis about river runoff and basinwide precipitation. The primary analyses without consideration of human impacts show that there are clear periods and high correlation between annual runoff and annual precipitation of the Yangtze River in humid zone, while the periods and correlation are not clear in the Yellow River in arid and semiarid zones. The discussion indicates that water consumption within the Yellow River basin is often in the same order of magnitude as that of actual water discharge, which could affect the periodicity analysis and correlation analysis. Therefore, one argument is presented that human impacts (i.e. water diversions) on the river runoff should be considered in the process of periodicity analysis and correlation analysis of a river between arid and semi-arid climatic zones, where water consumption is often in the same order of magnitude as that of actual water discharge.