植被分布对地表糙率影响

目的]分析在植被淹没或非淹没状态不同植被覆盖密度影响下,地表糙率的变化规律与特征,为进一步研究植被对地表糙率的影响提供参考。方法]试验以塑料棒模拟植被分布,模拟出不同密度,分别进行放水试验。结果]在植被淹没与非淹没状态下地表糙率的变化不同,在非淹没状态时,地表糙率随着平均水深的增加呈减小的趋势,在淹没水深小时,地表糙率随着平均水深的增加而先增大后减小,而当淹没水深很大时,地表糙率趋向于一个稳定值。结论]地表糙率取值随植被覆盖密度的增大而增大;同一下垫面情况下,不同的水流方向,地表糙率取值不相同。

Effects of Vegetation Distribution on Earth Surface Roughness

Objective] The change rules and characteristics of the surface roughness was analyzed under the station of submerged and unsubmerged and the different vegetation density in order to provide the reference for studying the effect of vegetation on the surface roughness.Methods] The plastic rods, as a surrogate for vegetation distribution, were used to simulate two different densities in the flushing experiments.Results] The earth surface roughness changes were different between the submerged vegetation and unsubmerged vegetation. Under the unsubmerged condition, the earth surface roughness decreased with the increase of the average water depth.While submerged depth was low, the earth surface roughness firstly increased and then decreased with the increase of the average water depth. When the submerged depth was very deep, the earth surface roughness tends to be a stable value.Conclusion] The earth surface roughness value increases along with the vegetation density. Under the same underlying surface, the surface roughness value changes with different flow direction.