Effects of different measures on water erosion control of dump slope at opencast coal mine in typical steppe

Abstract: Due to the natural factors and the irrational actions of human being, grassland ecological environment is very vulnerable. Though the resource exploitation in recent years has greatly accelerated the economic and social development, a series of ecological environmental disasters are brought up, and the soil erosion is aggravated at the same time. Environmental problem has become one of the most important issues which need to be resolved urgently in China's economic and social development. Therefore, this paper takes the different measures of dump slope at large opencast coal mine in typical steppe as the study object, the process of runoff and sediment yield was positionally observed by using the standard runoff field facility under different control measures in the vegetation growth stage. The results showed that the amount of soil erosion in the slope caused by unreasonable measures was greater than the bare land in the early stage of vegetation restoration on the slope, which indicated the strong disturbance from the implementation of management measures on the slope. If the vegetation coverage was greater than 35%, the capacity of sediment, water storage and infiltration of the slope under different measures were obviously stronger than the bare land. The rainfall and rainfall intensity were the main controlling factors of slope runoff and sediment yield, which was increased with the increasing of the rainfall intensity and rainfall. Erosion modulus of the bare slope was 14183 t/(km2·a), which was biggest among the treated slopes. Soil erosion modulus under the measure of the eco-bags with linear shape was 5179 t/(km2·a), which was the minimum among the treated slopes. It was 36.5% of the bare slope and 81.5% of Sabina vulgaris + Spiraea shrub (after 4-year restoration). So, the dump slope is a kind of artificial remodeling topography with very strong erosion. The effect of combining biological measures and engineering measures was much better than the single biological measure to control the soil erosion in the dump slope, and it was one of the most effective ways to control the soil erosion in the dump slope. In summary, by setting up different control measures on the mine slope, the surface water and sediment changes are observed during individual rainfall so as to clarify the dynamic rule among rainfall, runoff and sediment yield change. The result obtained may provide certain reference for the erosion control of typical steppe mine slope and its ecological restoration and reconstruction.