Effects of land-use change and climate variability on streamflow in the Woken River basin in Northeast China

In this study, the soil and water assessment tool, which is a widely used hydrological model, is applied to study the response of streamflow to land-use changes and climate variability in the Woken River basin in northeastern China. This model is calibrated and verified based on sensitivity analysis to simulate the effects of land-use change, climate variability, and extreme land-use scenarios on streamflow. Simulations are performed to construct different scenarios for quantitative analysis. Compared with the base period, the land-use change reduced the annual average streamflow and had little effect on the monthly streamflow. Climate variability increased the average annual streamflow and had a substantial effect on monthly streamflow. The effect of climate variability on streamflow was much greater than that of land-use changes. Under the extreme land-use scenarios, the annual average streamflow under the forestland scenario decreased, and the average annual streamflow under the grassland and agricultural land scenarios increased. Both the forestland and grassland scenarios exhibited lower monthly streamflow from March to August with especially large influences in June-August, which was when floods were more likely to occur. The agricultural land scenario exhibited the opposite trend. These results indicate that climate variability will obviously change streamflow and that natural disasters related to both high and heavy precipitation must be emphasised. Relevant departments can optimize the land-use structure and spatial layout to mitigate the negative effects of climate variability.