标准坡面人工草地减流减沙效应及其坡面流水力学机理研究

Effects of forage grass on the reduction of runoff and sediment and the hydrodynamic characteristic mechanism of slope runoff in the standard slope plot.

通过放水冲刷实验,研究草地与裸地坡面土壤水分入渗及产流产沙过程,分析草地减流减沙效益,并从水力学特性剖析草地调控水沙的机理.结果表明:①裸地与草地坡面土壤水分入渗过程均符合Horton入渗公式i=ic+(i0-ic)e-kt;与裸地相比,草地入渗率增加40%,产流时间推迟2.5 min,径流系数减少28.3%,输沙率减少78.4%.②裸地坡面输沙过程呈高—低—高变化趋势,而草地呈现先增后减趋势.③草地坡面流属于层流中的缓流流态,裸地则属于过渡流的急流流态,说明草地坡面抵抗侵蚀力和泥沙搬运的能力明显强于裸地;草地可明显降低径流流速,增加阻力系数和曼宁糙率系数,但对径流深度影响不明显.

Based on the water scouring experiments in forage grass slope and the naked one （control）, water infiltration and the generation process of runoff and sediment were studied, and the effects and hydrodynamic characteristic mechanism of grass on the reduction of runoff and sediment were analyzed quantitatively. The results showed ： 1 ） the process figure of water infiltration was coincide with Horton formula ： i=ic＋（i0-ic）^e-kt in both grass slope and the control; in comparison to the control, runoff coefficient and sediment transporting rate decreased by 28.3% and 78.4% in the grass slope, respectively. Water infiltration rate increased by 40% and runoff initiation put off 2.5 min; 2） the curve of sediment transporting on the control slope showed high-low-high trend ,while it increased first and then decreased on the grass slope; 3） the flow regimes in grass slope and the control belong to laminar flow and tardigrade flow, respectively, which proves that the capability of resisting soil erosion and sediment movement in grass slope is stronger than that in the control ; although the grass slope shows low runoff velocity and high resistance coefficient as well as roughness coefficient, its runoff depth is equal to that of the control.