[1] To control the severe soil erosion in the Loess Plateau, China, a great number of soil conservation measures including terracing, afforestation, and construction of sedimenttrapping dams have been implemented since the 1950s. These measures have resulted in large-scale land use and land cover change. It is important to evaluate the impacts of these soil conservation measures on streamflow as streamflow is an important determinant on catchment sediment yield and obviously is related to water security in the region. In this study, data from 11 catchments in the Loess Plateau were analyzed to investigate the responses of streamflow to the land use/cover changes. The nonparametric MannKendall test and the Pettitt test were used to identify trends and change points in the streamflow records. All 11 catchments had significant negative trend in annual streamflow of À0.13 to À1.58 mm a À1 . Change points in streamflow occurred between 1971 and 1985. A method was employed to evaluate the impacts of climate variability and land use/ cover changes on mean annual streamflow on the basis of precipitation and potential evaporation. It was estimated that the land use/cover changes accounted for over 50% of the reduction in mean annual streamflow in 8 out of the 11 catchments. However, climate (i.e., precipitation and potential evaporation) played a more important role in reducing the streamflow in the three remaining catchments. Among the soil conservation measures, construction of sediment-trapping dams and reservoirs, with associated irrigation water extractions from the latter, appeared to be the main cause of the reduced streamflow.Citation: Zhang, X., L. Zhang, J. Zhao, P. Rustomji, and P. Hairsine (2008), Responses of streamflow to changes in climate and land use/cover in the Loess Plateau, China, Water Resour. Res., 44, W00A07,

To reduce the sediment load of China's Yellow River, soil conservation measures have been progressively implemented across the Loess Plateau region since the 1950s. The effectiveness of these soil conservation measures (which were also coincident with reduced rainfall and streamflow) in controlling sediment movement remains to be ascertained. Here the association between sediment movement, hydrological variability, and the implementation of soil conservation measures is examined for the Coarse Sandy Hilly Catchments region of the Yellow River basin. The hypothesis that the soil conservation measures have reduced suspended sediment yields beyond that associated with rainfall reductions alone, principally by reducing sediment concentration, is examined. Annual sediment yield decreased significantly over time in all subcatchments, and the timing of the change (between 1971 and 1985) was consistent with the timing of change in streamflow. Annual mean sediment concentration in 7 of the 11 catchments exhibited a statistically significant decreasing trend over time, indicating that soil conservation practices reduced the mobilization of sediment in most areas, typically accounting for ∼75% of the observed reductions in annual sediment yield. Lesser reductions in area‐specific sediment yield at larger catchment areas after the soil conservation measures were emplaced suggests that larger rivers may be reeroding stored sediment. As these sediment stores are likely to be relatively large given the high historic yields, relatively high area‐specific sediment yields may persist at larger catchment areas even with improvements to sediment management in smaller tributaries.

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