结合土壤地形指数的流域下垫面水文分区方法

Methods of Soil Topographic Index Based on Basin Underlying Surface Hydrologic Division

以湿润的屯溪流域、半湿润的东湾流域为研究区,对比分析了经验方法、数值平均法、频率平均法三种方法,先修正得到两流域的CN值查找表,再结合下垫面分类信息和土壤地形指数建立水文分区表,用屯溪流域18次和东湾流域16次降水的水文数据进行了模拟验证。结果表明:采用频率平均法水文分区得到的合格率为屯溪94.44%、东湾87.50%,数值平均法水文分区得到的合格率为屯溪88.89%、东湾81.25%,经验方法水文分区得到的合格率为屯溪88.89%、东湾75.00%;就流域而言,土壤地形指数累计频率高的流域模拟效果更好。

This paper took the humid Tunxi basin and semi-humid Dongwan basin as study regions,compared three methods including theempirical method,average value and average frequency methods. Firstly it obtained the CN value search table of those two research basins bymodification,and then built the hydrologic division table by using remote sensing image classification information and soil topographic indi-ces,after that this paper validated the simulations by using the 18 and 16 times rainfall events of Tunxi basin and Dongwan basin respective-ly. The results show that the both two basins get better pass rate by using the average frequency hydrologic division method（94.44% forTunxi,and 87.50% for Dongwan）rather than which using the average value hydrologic division（88.89% for Tunxi,and 81.25% for Dong-wan）or the empirical method（88.89% for Tunxi,and 75.00% for Dongwan）. In the case of watersheds,the simulation results of watershedwith high cumulative frequency of soil topographic index are better.