典型对比小流域降水特征及其对径流泥沙的影响——以南小河沟流域为例

Characteristics of Precipitation and Its Influence to Runoff and Sediment in Typical Check Small Watershed

为深入了解黄土高塬沟壑区水土保持对流域径流泥沙的影响机理、特点及规律,基于小流域平行对比观测法,以南小河沟流域中杨家沟、董庄沟小流域为主要研究对象,采用统计学、双累积曲线、统计模拟、综合归因等方法研究了小流域深度治理对流域地表径流的作用和影响。结果表明:经过治理的杨家沟小流域年产流次数、泥沙量均明显减少,蓄水量显著增加,特别是年产流降水量明显小于处于自然恢复状态的董庄沟小流域;杨家沟次径流量变率明显大于董庄沟,即治理使地表径流变化剧烈;治理流域比未治理流域平均洪水历时缩短了21.03 h,即水土流失治理可以缩短小流域洪水历时,减轻水土流失灾害。

In order to understand the influencing mechanism,characteristics and laws of soil and water conservation on runoff and sediment of the gullied loess plateaus,the paper studied the effect and influence of deep treatment to the surface runoff in small watershed based on the parallel comparative observation method of small watershed,taking Yangjiagou and Dongzhuanggou small watersheds in the Nanxiaohegou watershed as the main research object and using the methods of statistics,double cumulative curve,statistical simulation and comprehensive attribution.The results show that a)the annual runoff-producing times and sediment quantity of treated Yangjiagou small watershed are obviously reduced and the quantity of water storage is significantly increased,in particular,the annual runoff precipitation is significantly less than that of Dongzhuanggou small watershed in the state of natural recovery;b)the variation rate of secondary runoff in Yangjiagou is obviously larger than that in Dongzhuanggou,that is to say,the treatment makes the surface runoff change violently and;c)the average flood duration of the treated watershed is shortened by 21.03 h than that of the untreated watershed,that is to say,the soil and water conservation measures can shorten the flood duration and reduce the soil and water loss disasters of small watersheds.