复杂下垫面城市暴雨内涝汇水区划分方法研究

汇水区(catchment)是径流控制的结构单元,也是水文模型中重要的输入数据。在城市地区,由于复杂的下垫面特征,使用传统的汇水区划分方法得到的结果和现实情况差异较大。在已有的汇水区划分方法基础上,结合城市地区实际径流特点,提出了新的汇水区划分方法。首先,将影响地表汇流路径的不同地物高程信息融入到DEM中;然后,对概化后的排水管网进行缓冲区分析并修正对应范围内的DEM数据,进一步优化DEM;再次,结合研究区范围确定合适的DEM空间分辨率,保证子汇水区划分的合理性;最终,根据精细化的DEM数据,利用D8算法划分子汇水区。以海宁地区为研究区,并将新方法与3种传统方法进行对比。结果表明:细化后的DEM能够更加真实地反映地表高程,汇水区划分结果可以准确刻画地表径流过程,提高了汇水区划分的合理性。

Study on dividing method of rainstorm waterlogging catchment area in urban area with complex underlying surface

Catchment area is not only the structural unit of runoff control, but also an important input data in hydrological model. In urban areas, the results obtained using the traditional catchment division method are quite different from the actual situation due to the complex underlying surface characteristics. In this paper, a new catchment division method is proposed based on the existing watershed division methods and by combining with the actual runoff characteristics of urban areas. First, the elevation information of different objects affecting the surface confluence path was integrated into DEM. Then the buffer analysis of the generalized drainage pipe network was carried out and fused into the DEM data in the corresponding range, and the DEM was further optimized. We determined the appropriate DEM spatial resolution to ensure the rationality of the division of sub-catchment area based on the study area ranges. Finally, the traditional D8 algorithm was used to draw the molecular catchment area according to the refined DEM data. Taking Haining area as the study area, and comparing the new method with three traditional methods, the experimental results showed that the refined DEM reflects the surface elevation more truly, and the watershed division results can accurately depict the surface runoff process and improve the rationality of the division of catchment area.