黄土高原小流域水土保持林空间配置对场降雨径流影响的模拟

合理的水土保持林空间配置是黄土高原植被恢复和水土保持功能持续提高的关键。在对HEC-HMS分布式水文模型参数进行率定的基础上,探讨该模型在黄土高原小流域中的适用性,模拟水土保持林覆被率以及水土保持林空间配置对场降雨径流的影响。结果表明：HEC-HMS分布式水文模型在黄土高原小流域中的应用效果良好,径流系数、洪峰流量均随森林植被覆盖率的增加而减少,随着水土保持林覆被率的提高,流域对高强度暴雨的调控能力将得到极大的提高;当水土保持林位于流域的上游、中游时,场降雨的径流量、洪峰流量均降低,水文调节效果较好。因此,在干旱的黄土高原应该适度造林,在小流域中配置水土保持林时,应该配置在上中游。

Effect of spatial distribution of soil and water conservation forest on the runoff of single-rainfall events in a small watershed on the Loess Plateau

Disposition of soil and water conservation forest is a crucial problem to accelerate the recovery of vegetation and enhance soil and water conservation efficiency on the Loess Plateau.Based on calibration and validation of the distributed rainfall-runoff model HEC-HMS,effect of coverage of soil and water conservation forest and its spatial disposition on rainfall runoff process in a small watershed were analyzed in this paper.HEC-HMS was found to well represent the major storms that account for high percentage of soil loss.As forest coverage increased,runoff coefficient and peak discharge were reduced significantly,which implies an improved modulation of rainfall events with high intensity.And runoff coefficient and peak discharge of certain rainfall event reached the lowest level when soil and water conservation forest was disposed on the upper and middle part of watershed,indicating that disposition of soil and water conservation forest on the upper and middle reaches can help result in a better effect on water conservation.