考虑有效不透水下垫面的城市雨洪模拟模型——Ⅱ.雨洪模拟及水文响应分析

Development of an urban stormwater model considering effective impervious surface:Ⅱ:urban stormwater simulation and anaysis of hydrological response

为了分析有效不透水下垫面在城市雨洪模拟中的水文响应机理,以常州市双桥浜径流小区为研究区域,构建考虑有效不透水下垫面的城市雨洪模型。利用实测资料先确定屋顶中有效不透水面积的比例,再率定模型其余参数。采用不同的方法表征不透水性,设置不同的模拟方案,分析有效不透水面积及总不透水面积的水文响应。结果表明:与正确使用有效不透水面积的模拟结果相比,用总不透水面积表征模型不透水性且直接移用有效不透水面积模型参数,会高估洪峰流量及洪量;使用总不透水面积表征不透水性,进而率定模型,低重现期时洪峰流量偏大,高重现期时洪峰流量偏低,并且会低估洪量。

An urban stormwater model was developed to analyze the hydrological response mechanism of effective impervious surfaces under urban stormwater simulation.The model focused on effective impervious area,and the Shuangqiaobang runoff-plot in Changzhou City was used as the study area.The model was calibrated using measured data,where the effective impervious area of roofs was first determined,followed by the remaining parameters.Different methods were adopted to characterize the imperviousness,and distinct simulation scenarios were set up to analyze the hydrological response of both the effective and total impervious areas.The results show that,the peak discharge and flood volume are overestimated when the total impervious area is used rather than the effective impervious area to characterize the imperviousness and when the parameters of the effective impervious area model are directly used;however,the peak discharge is higher in the low return period and lower in the high return period,and the flood volume is underestimated when a calibrated total impervious area model is used.