东湾流域下垫面变化及其子流域嵌套分析

Analysis of underlying surface change and its sub-watershed nested for Dongwan watershed

采用双累积曲线法和新安江模型分析东湾流域1960—2011年降水及径流变化,将东湾流域洪水系列划分为1994年前后2个系列,并以东湾流域与其潭头、栾川2个子流域为研究对象,用1994年前后东湾流域率定出来的两套参数模拟其子流域。结果表明:下垫面的变化影响到嵌套流域的降雨径流关系,1994年前东湾流域的参数对其子流域的模拟较好,1994年后东湾流域的参数模拟其子流域的精度已经达不到洪水的精度要求。

The change of precipitation and runoff from 1960 to 2011 for Dongwan watershed is analyzed by using the double mass curve method and the Xin'anjiang Model. Then the flood series of the Dongwan watershed is divided into two series before and after 1994, the Dongwan watershed and its sub-watersheds of Tantou and Luanchuan are taken as the study object, the two sets parameters calibrated by the Dongwan watershed before and after 1994 are used to simulate their sub-watersheds. The results show that the variation of the underlying surface affects the relationship between the rainfall and runoff of the nested watershed. Before 1994, the parameters of the Dongwan watershed have the better simulation for its sub-watersheds. However, after 1994, the simulation accuracy of parameters of the Dongwan watershed does not meet the accuracy requirements of the flood.