Multiscale Correlation Analysis between Runoff and Sediment and Possible Underlying Causes in Jinsha River in a Changing Environment

Abstract

Great changes have taken place in the sediment processes in Jinsha River because of human activities. The wavelet analysis and the cross wavelet transform was applied to analyze the variation of streamflow and sediment in Shigu, Panzhihua, and Pinshan hydrometric station. The multiscale correlation between Jinsha River sediment and runoff data was discussed. The result showed that the power spectrum of streamflow had the same variation in Shigu, Panzhihua, and Pinshan stations. The trends exhibited a great difference for sediment changes. For Shigu and Panzhihua stations, visible regions of six-month and below six-month bands in the entire time coordinate, which is a great significance period for sediment observation, were found. The significant variation was especially powerful from 1987 to 2009. These findings indicated that soil erosion in the upper and middle streams of Jinsha River became more serious starting in the 1980s. The sediment load in Pinshan station exhibited another trend over the significant periods. The six-month fluctuations disappeared from 2000 to 2009. This result showed that sediment content decreased from the Panzhihua to the Pinshan range. The sediment content of Jinsha River will continue to decrease in the future with ongoing water and soil conservation projects and hydropower development.