分布式SCS-CN有效降雨修正模型建立及应用

A distributed SCS-CN model with revised effective precipitation

  • 摘要: 为解决SCS-CN模型改进后方程结构复杂的问题, 基于SCS-CN标准模型, 经与SCS-CN改进模型比较, 引入有效降雨修正系数建立SCS-CN有效降雨修正模型, 并对城市低影响开发复杂区域综合考虑LID设施蓄存容积对降雨径流的影响, 构建基于水文响应单元的分布式SCS-CN有效降雨修正模型, 以北京双紫园小区为例开展降雨径流模拟与效果检验。分析SCS-CN有效降雨修正模型, 当对修正系数取值等于1.0时其等同于标准模型, 当对修正系数取值小于1.0时其等效于改进模型; 修正系数表征了径流系数随降水量增大而变化趋向稳定的极限值。模型应用结果表明, 分别对渗透地表有效降雨修正系数取值等于1.0与小于1.0, 两者对不同场次降雨径流深的计算值与实测值散点均位于45°线附近、符合较好, 确定性系数与Nash-Sutcliffe效率系数值分别为0.91与0.83、0.92与0.91, 后者效果优于前者, 说明对渗透地表有效降雨修正系数取值小于1.0能够有效提高模拟效果。

     

    Abstract: To solve the problem of the equation structure becoming more complex in the improved soil conservation service curve number (SCS-CN) model, a SCS-CN model with revised effective precipitation (SCS-CN-REP) is proposed by introducing a revised coefficient after a comparison between the standard SCS-CN model and the improved model.Furthermore, for the complex area with low impact development (LID) in a city, a distributed SCS-CN-REP model was developed based on a hydrological response unit division in which the effects of the LID facility's storage capacity on rainfall-runoff are also considered.Finally, taking the Shuangzi residential district in Beijing City as a study area, the rainfall-runoff is simulated and compared using the distributed SCS-CN-REP model.An analysis of the SCS-CN-REP model showed that when the revised coefficient is 1.0, it is equivalent to the standard model, when the revised coefficient is smaller than 1.0, it is equivalent to the improved model.In essence, the revised coefficient is a limit value of the runoff coefficient varied with the increase in precipitation.The distributed SCS-CN-REP model application results demonstrated that the calculated runoff depth values are in good agreement with the measured values.The determination coefficients and Nash efficiency coefficient are 0.91 and 0.83 when the adopted value of the revised coefficient for permeable surfaces is 1.0, and are 0.92 and 0.91 when the adopted value is less than 1.0.The effects of the latter model are better than the former, indicating that the simulation effect can be effectively improved when the adopted value of the revised coefficient for permeable surfaces is less than 1.0 in the distributed SCS-CN-REP model.

     

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