Simulation of surface runoff and sediment yield under different land-use in a Taihang Mountains watershed, North China

The maintenance of water and soil resources has attracted the attention of governments and scientists world-wide. The loss of these resources is a serious problem in the Taihang Mountains, and the emerging issue with water has threatened the livelihoods of local residents and the sustainability of this region. A simple distributed soil erosion and sediment yield model (DSESYM) has been developed based on WetSpa extension. The effect of land-use change on surface runoff and sediment yield was then analyzed through applying the model in the Chongling watershed. Taking the land-use distribution of the watershed in 2000 as the baseline, fourteen scenarios were performed to characterize the effect of land-use change on surface runoff and sediment load relative to the baseline condition. These scenarios involved converting the mixed land-use to 93.89% of the area being forestland (scenario 1), shrubland (scenario 2), grassland (scenario 3), cropland (scenario 4), mixed crop/forest land (scenarios 5 and 6), mixed crop/shrub land (scenarios 7 and 8), mixed crop/grass land (scenarios 9 and 10), mixed crop/shrub/forest land (scenarios 11 and 12), and mixed crop/grass/forest land (scenarios 13 and 14). The scenario analysis revealed that when land-use was changed to 93.89% of the respective land-use in scenarios 4, 5, 7 and 9, an increase in runoff and sediment yield for single rain events compared to the baseline whereas a change to forest and shrubland caused a decrease (scenarios 1 and 2). Slope is an important factor in soil erosion, but in the study area, when the slope is more than 10 degrees, the difference of stream flow and sediment between forest, shrub and grass was not obvious (scenarios 5, 7 and 9). The model can be used to predict surface runoff, erosion, deposition and sediment yield of each grid cell and the whole watershed in response to land-use scenarios for single rain events in the Taihang Mountains. It is easy to execute if the precipitation process data, the relationships of water and sediment for different land-use, and GIS maps of the study area are available, which makes it suitable for widespread application. Crown Copyright (C) 2015 Published by Elsevier B.V. All rights reserved.