Effects of slope vegetation patterns on erosion sediment yield and hydraulic parameters in slope-gully system

Abstract

Slope-gully system is an important watershed component of the Loess Plateau and the main source of erosion and sediment yield in small watersheds. Its forest and grass measures are of great significance to vegetation restoration and reconstruction and water and soil conservation. In the experiment, the effects of different slope vegetation patterns (upper slope, middle slope, lower slope, bare slope) on hydrodynamic characteristics and sediment yield of slope-gully system were studied by field flushing test under the condition of 75 % vegetation coverage and 12 L/min discharge. The results showed that: (1) Vegetation distribution in the lower part of the slope had the most obvious effect on reducing runoff shear force while vegetation distribution in the middle of the slope had the most obvious effect on reducing runoff power of the slope-gully system. (2) The water storage benefits of vegetation distributed on upper slope, middle slope, lower slope was 88 %, 87 %, and 81 %, and the benefits of sediment reduction was 96 %, 98 %, and 97 % (compared with bare slope). (3) The sediment reduction effect of the slope-gully system under different slope vegetation patterns is better than the water storage effect. On the whole, the effect of soil and water conservation was best when the vegetation was placed in the middle and lower of the slope. The results of this study provide a scientific basis for optimizing vegetation allocation in the Loess Plateau and promote the effective development of soil and water conservation.