不同坡度条件下“沙棘植物柔性坝”的阻水效应

目的]探讨不同坡度条件下"沙棘植物柔性坝"对水流流速和水深的影响,并分析和沟床糙率系数的变化及其主要影响参数,为"沙棘植物柔性坝"这一水土保持生态工程在山区沟道的推广应用提供理论依据。方法]基于野外水流试验,根据试验数据,运用理论分析的方法,探讨"沙棘植物柔性坝"对水流的影响及沟道糙率的变化。探讨在不同坡度条件下"沙棘植物柔性坝"对流速变幅值、水深沿程分布的影响,并对糙率系数的变化进行了分析。结果]流速变幅值的大小与沙棘柔性坝坝长、种植密度和床面坡度有关;在沙棘柔性坝较长的试验床中,流速变幅值随着坡度的增大而增大;在沙棘种植密度较大的试验床中,上游区的雍水深度和糙率系数值随坡度的增大而增大。结论]"沙棘植物柔性坝"对坝前水流流速有明显的衰减阻滞作用,其中柔性坝坝长和植物种植密度是影响"沙棘植物柔性坝"阻水效应的主要因素。

Water Blocking Effect of "Seabuckthorn Plant Flexible Dam" Under Different Slopes

Objective] The objective of the study is to investigate the effect of the seabuckthorn plant flexible dam (SPFD) on the longitudinal distribution of flow velocity and water depth, and to analyze the variation of the roughness coefficient and related influencing factors, thus providing the theoretical support for the application and extension of the SPFD, one of the ecological engineering for soil and water conservation, in the mountainous region. Methods] We carried out the field flow experiment and used the theoretical analysis to investigate the effect of the SPFD on water flow and the variation of gully roughness coefficient. We also assessed the effect of the SPFD on the longitudinal distribution of flow velocity and water depth, and analyzed the roughness coefficient variation along the pathway direction under the different slopes of the test bed. Results] The amplitude of flow velocity variation was related to the dam length, the plantation density of the seabuckthorn and the test bed slopes. The flow velocity variation amplitude increased with the increasing slope of the test bed with the longer SPFD. The heap water depth and the roughness coefficient at the upstream zone increased with increasing slope within the test bed with the higher seabuckthorn plant density. Conclusion] The seabuckthorn plant flexible dam has obvious blocking effect on flow velocity in the front of the dam, and the dam length and the plant density are the main factors affecting the bloocking effect of the SPFD.