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不同草带空间分布对坡面缓流效应调控机制
1, 1, 2

(1.huangheshuiliweiyuanhuihuangheshangzhongyouguanliju, xian710021; 2.shanxishifandaxue dilikexueyulvyouxueyuan, xian 710061)

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Regulation Mechanism of Different Grass Spatial Distribution on the Runoff Retardation Effect on a Slope
JIA Lianlian1, FAN Bing1, ZHU Bingbing2

(1.upper and middle yellow river bureau, yellow river conservancy commission of the ministry of water resources, xi'an 710021, china; 2.school of geography and tourism, shaanxi normal university, xi'an 710061, china)

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备注

为了研究植被对坡面缓流效应的影响机制,研究选取坡面开展室内降雨试验,分析了植被调节下的径流、输沙变化特征,阐明了草带对径流流速的调控作用。结果表明:草带种植于13 m坡面的上坡下部60%位置,可以充分发挥出缓流效应,调控径流流速范围达到坡面70%的区域,流速降低50%,控制了坡面流速的增加,有效抑制了流速的恢复; 而且能够合理控制径流含沙量,进一步减缓径流侵蚀强度,水土流失治理效果达到试验范围内最优。随着草带位置的逐渐上移,坡面径流流速降低至最小后又逐渐增加。动力恢复空间具有临界现象,动力恢复距离超过坡面长度的54%,径流流速增加明显,草带调控径流作用减弱,甚至加剧侵蚀; 动力恢复距离小于坡面长度的54%,径流流速降低显著,草带调控径流作用增强,侵蚀强度减弱。研究结果揭示了植被通过对流速的缓流效应来调控土壤侵蚀输沙过程,可为植物措施的水土保持规划提供参考依据。
In order to study the mechanisms of influence of vegetation on the runoff retardation effect of a slope, the regulating effect of a grass strip on runoff velocity was quantified after the characteristics of runoff and sediment yield under different spatial distribution conditions of vegetation were analyzed by means of the indoor simulated rainfall experiments on a selected slope. The results show that the grass strip planted at a place about 60% from the top of the slope can fully exert its runoff retardation effect, with runoff velocity regulating scope accounting for 70% of the whole slope, and runoff velocity decreasing by 50%; the grass strip controls the runoff velocity on the slope and effectively inhibits the recovery of runoff velocity; in addition, the grass strip can reasonably control the sediment content of runoff, further reducing the runoff erosion intensity, so the soil and water loss control effect is optimal in the experimental scope; the runoff velocity decreases to its minimum and then increases with the gradual decrease in the distance between the grass strip and the slope top. There is a critical phenomenon in the hydrodynamic recovery space of runoff. When the hydrodynamic recovery distance is more than 54% of the slope length, the increase in runoff velocity is evident, the regulating effect of grass strip on runoff velocity weakens and the grass strip even aggravates the erosion; when the hydrodynamic recovery distance was less than 54% of the slope length, the decrease in runoff velocity was significant, the regulating effect of grass strip on runoff velocity enhances and the erosion intensity weakens. These research results can reveal that vegetation regulates soil erosion and sediment transport processes by the runoff retardation effect, and can provide reference bases for planning of soil and water conservation based on the vegetation measures.
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