Temporal changes in suspended sediment transport in a gullied loess basin: The lower Chabagou Creek on the Loess Plateau in China

Suspended sediment dynamics are still imperfectly understood, especially in the loess hilly region on the Loess Plateau, with strong temporal variability, where few studies heretofore have been conducted. Using a dataset up to eight years long in the Lower Chabagou Creek, the variability in suspended sediment load at different temporal scales (within-flood variability, monthly-seasonal and annual) is analyzed in this paper. The results show that, on the within-flood scale, most of the sediment peaks lag behind peak discharges, implying that slope zones are the main sediment source area; independent of the occurring sequences of the peaks of sediment and discharge, all the events could present an anti-clockwise hysteresis loop resulting from the abundant material and the influence of hyperconcentrated flows on suspended sediment concentration. At monthly and seasonal scales, there is a 'store-release' process, i.e. sediment is prepared in winter, spring and late autumn, and exported in summer and early autumn. At the annual scale, the high variability in concentration and sediment yield are highly correlated with water yield, resulting from the number and magnitude of floods recorded yearly, and almost all the suspended load is transported during these events. Copyright © 2008 John Wiley & Sons, Ltd