Experimental study on runoff and sediment yield from engineering deposition with gravel in the northern windy-sandy region,Shaanxi
摘要
Engineering deposition is a special geomorphic unit which exhibits very serious soil and water loss in improvement and construction projects. Experimental research regarding the soil erosion laws of geomorphic units with different compositions and ratios under different rainfall conditions is an urgent concern. In the present study,indoor artificial rainfall simulation was applied to investigate the processes of runoff generation and sediment yield on the slope of deposition with gravel in the northern windy-sandy region of Shaanxi province,China. The results reveal the following: ① The runoff coefficient influenced by infiltration rate,which changed due to the existence of gravel,first increased and then decreased linearly when the gravel content increased with a critical content of 10%,and increased linearly with the increase in rainfall intensity. ② The overland flow velocity on rocky deposition was lower than the velocity on homogeneous deposition. Stronger effects of gravel on delaying runoff were found with the increase in rainfall intensity,but the effects of rainfall intensity on velocity were weaker when the gravel content increased. ③ The soil detachment rate increased significantly after 24—33 min in the period of runoff generation. Gravel mainly affected the erosion rate after the significant increase. ④ The gravel increased the sediment yield under 1.0 mm/min rainfall intensity,while it decreased the total sediment when the rainfall intensity was higher. The results of this study are useful for providing reliable experimental information for the erosion model development of national engineering depositions.