岔巴沟流域不同下垫面对降雨径流关系影响规律分析

Analysis about Effect Rules of Underlying Surface Change to the Relationship between Rainfall and Runoff in the Chabagou Catchment

随着人类活动的增强,不同下垫面对地表径流的影响日益显著。本文选择黄河岔巴沟流域,采用野外人工控制条件下的降雨实验,针对不同下垫面类型、不同下垫面覆盖度以及不同的处理方式等情况下进行了水文过程的实验研究,并对不同植被覆盖度、不同耕作措施、降雨径流系数随时间的变化规律、不同下垫面对径流系数的影响等方面进行了分析与初步研究。结果表明,土地利用类型的变化对黄土沟壑地区的降雨径流关系有很大影响,其中耕作措施的使用对降雨径流关系的影响远大于地表覆盖率变化所产生的影响。地表覆盖率单因素变化时,稳定产流时的产流量变化不超过10%,而当采用耕作措施进行单因素分析时,稳定产流时的产流量大于20%。在相同雨强下,草地与裸地的出流量有非常明显的差异,草地的出流量约为裸地出流量地50%,草地与裸地对降雨径流关系地影响差异较大,在小雨强的时候,草地对降雨有较强的滞留作用,随雨强的增加,这种功能明显减小,而裸地没有明显的差异。

Along with the increasing degree resources becomes more and more serious, experiment, which controlled by mankind experiment, different considered to analyze type of land cover, the influence to hy of human activities, the impact of land cover change on water especially on surface runoff, in this paper, the precipitation in field, is carried out in the Chabagou Catchment. In this of land cover and treating methods of surface layer are all process. Based on this experiment, the variation law of runoff coefficient with time under the condition of different and different underlaying surface are discussed. At the same time, the variation law of runoff coefficient following the time for the same rainfall intensity is analyzed. The result shows that the change of land use type greatly Additionally, affects the relationship between precipitation and runoff in the loess hilly-gully the relationship between the precipitation and runoff is influenced more by tillage measure than the change of land cover. Only when the coverage ratio is changed from 100% to 50%, variance of stabilizing runoff yield less than 10%. But only when the cultivating measurement is used-the field is ploughed from 50% to 100%, the variance of stabilizing rainfall intensity, the runoff yield in different type of land runoff yield about is 20 %. Under the same cover is very distinct, the runoff yield in grass field is 50 % of the runoff yield in the bare land. The relationship between runoff coefficient and rainfall intensity can be described by using linear equation. The coefficient of first order is greater in the grass land than in the bare land, but the constant coefficient is less in the grass land than in the bare land. This relationship can show, when the rainfall intensity is less, the grass land have stronger water storage ability. But the water storage ability in grass land weakened rapidly along with the rainfall intensity increasing. In the bare land, the runoff coefficient doesn＇t change obviously along with the rainfall intensity increasing. The relationship between runoff coefficient and the period of rain time can be described by using logarithm equation. The constant coefficient is greater in the grass land than in the bare land. The difference of the rainfall coefficient between in the grass land and in the bare land is not obvious, when the period of rain time is increasing.