Impacts of Rainfall and Land Use on Sediment Regime in a Semi-Arid Region: Case Study of the Wuqi Catchment in the Upper Beiluo River Basin, China

Abstract

The middle reaches of the Yellow River Basin transport the vast majority of sediment (>85% of the basin's total available sediment load), which has had profound effects on the characteristics of the middle and lower reaches of the Yellow River. With recent land use and land cover change, the Yellow River Basin has experienced significant sediment regime fluctuations. In this study, we analyzed the sediment regime from the Wuqi catchment which feeds into the upper reaches of the Beiluo River. Results show that a significant decreasing trend in annual suspended sediment discharge and suspended sediment concentration has existed from 1985 to 2008. The change-point year (the year that abrupt changes in sediment regime occurred in the catchment) was detected in 2001 (p < 0.05) for suspended sediment discharge and sediment concentration. There was a significant decreasing trend in streamflow discharge with the change-point year detected in 2002. Meanwhile, erosive rainfall and heavy rainfall exhibits an increasing but not significant trend. Coevally, land use has undergone considerable transformation. Compared to rainfall, land use, and land cover change and soil and water conservation have played a major role in influencing the sediment regime post-2000. In order to reduce soil erosion and sediment yield, more attention should be paid to changes in land use pattern and the impacts of soil and water conservation.