Evaluation of Snowmelt and Rainfall Erosion in the Total Soil Losses in a Typical Small Watershed in Black Soil Region of Northeast China

Abstract

Snowmelt erosion and rainfall erosion are important components of soil erosion in Northeast China. Studying how snowmelt and rainfall affect runoff and sediment yield is essential to control soil erosion in this region. Based on the soil and water loss observation data in small watershed during snowmelt and rainfall periods, snowmelt and rainfall erosion processes were studied. The runoff–sediment relationship was analyzed. The results indicate that 13 snowmelt runoff events and 14 rainfall runoff events were recorded. During the snowmelt period, runoff depth (RD) and sediment yield (SY) exhibited a slow increase (early stage), rapid increase (middle stage), and then rapid decrease (late stage) trend. RD and SY in the middle stage were higher than those in the early and late stages. Moreover, during the rainfall period, soil erosion mainly occurred from July to August; during these two months, the rainfall and rainfall erosivity accounted for 66.0 and 91.1% of the total rainfall and rainfall erosivity, respectively; and the RD and SY in this period accounted for 88.4 and 89.8% of total amounts in the whole rainfall period, respectively. In addition, the contributions of snowmelt and rainfall to RD and SY were 18.6 and 81.4%, and 3.8 and 96.2%, respectively. Hysteresis analysis suggested that clockwise hysteresis loop was the dominant pattern, followed by eight-shaped anticlockwise loop, and complex anticlockwise loop.