坡面径流的快速测评技术研究

Research on Rapid Assessment Technique of Slope Surface Runoff

长江上游地区土层薄,蓄水容量差,由于雨量集中,容易导致洪、旱灾害交替发生,进行坡面径流调控降低土壤含水量是流域治理的有效手段,坡面径流的快速测评可为径流调控提供数据支持。研究采用野外调查和取样分析的方法,得到长江上游不同土壤类型土层厚度和物理性质;统计分析长江上游不同地区5年一遇最大24 h降雨量,基于径流形成原理,计算得到长江上游地区径流系数为0.53;不同地区壤中流占总径流量的比例均值为30%,研究结果可为坡面径流调控提供理论依据。

Soil thickness in the upstream region of Yangtze River is thin with a poor water storage capacity.Because of concentrated rainfall,flood and drought disasters occurred alternately.Runoff regulation of reducing soil moisture to control soil erosion should be taken as an important approach for watershed management.A rapid runoff assessment can provide data support for the runoff regulation.Through field survey and soil samples test,we got thicknesses and physical parameters of different soils in the upstream of Yangtze River,and counted the 24-hour maximum rainfall that encountered once within 5 years.According to the runoff formation theory,the surface runoff coefficient of the counted result is 0.53 and the subsurface runoff occupies a mean ratio 30% of the total runoff in different region of the Yangtze River upper reaches.All of these could provide theoretical support for the runoff regulation.