Using check dam deposits to reconstruct changes in the sediment response of a small catchment on the Loess Plateau in China, during the period 1960-1990

Information on both the magnitude and relative contributions of inter-gully and gully areas to the sediment yield from small catchments in the Loess Plateau of China represents an important requirement for understanding catchment sediment dynamics, assessing the sensitivity of catchment sediment budgets to environmental change and developing effective soil and water conservation strategies. Contemporary catchment monitoring programmes can provide such information, but there is also a need to consider past behaviour. Where long-term records are lacking, attention has been directed to the potential for using the sediment deposits behind check dams to reconstruct the sediment response of the upstream catchment. This contribution reports a study of the 0.181 km(2) Nianyangou catchment located in the hilly region of the Chinese Loess Plateau, in Shaanxi Province, China, which has extended a previous study aimed at using individual flood couplets preserved in the check dam deposits to reconstruct the record of annual sediment yield, to include the use of sediment source fingerprinting techniques to document changes in the annual sediment contribution from inter-gully and gully areas for the period 1960-1990. The sediment response of the catchment provided evidence of two change points in 1964 (Period 1-Period 2) and 1983 (Period 2-Period 3), which reflect the introduction of soil and water conservation measures in the mid 1960s through to the 1970s and a change in the land tenure system in 1983. The annual sediment yields from inter-gully and gully areas follow the trend P1 > P3 > P2, whereas the equivalent information on the relative contribution of inter-gully and gully areas follow different trends P3 > P1 > P2 and P2 > P1 > P3, respectively.