城市坡地小汇水区暴雨设计及参数敏感性研究

Study on Rainstorm Design and Parameter Sensitivity in Small Catchment Area of Urban Slope Land

摘要:

随着城市化进程持续推进，坡地小汇水区域逐步纳入城市建设范围。暴雨设计洪水是城镇防洪工程建设及运行管理的重要依据。以浙江某市坡地小汇水区为研究对象，阐述了推理公式法、室外排水公式法和经验公式法等方法的基本原理，采用Sobol法分析了流域、暴雨和产汇流参数敏感性，研究各类计算方法的原理差异、适用条件和误差来源，开展了不同重现期城市坡地小汇水区设计洪峰流量计算。研究结果表明：部分暴雨和产汇流参数估计误差是设计洪峰流量主要的计算误差来源。采用推理公式法得到的结果作为设计依据，能够满足城市防洪安全需求，对于2、5、10、15、25、50 a洪水重现期，对应的区域整体防洪设计洪峰流量分别为40.1、45.0、48.7、50.6、54.0、57.3 m³/s，研究成果可为完善城市综合防洪体系提供技术支撑。

Abstract:

As urbanization process continues to advance, the small catchment areas of slope land are gradually incorporated into urban construction range. The design flood of rainstorm is a crucial basis for the construction and operational management of town flood control projects. Taking a small catchment area of the slope land in a city in Zhejiang as a study object， the basic principles of the rational formula method, the outdoor drainage formula method and the empirical formula method are set forth. The Sobol method is used to analyze the sensitivity of watershed,rainstorm and runoff parameters. The principles, differences, applicable conditions, and error sources of various computational methods are studied. The design peak flow calculations are conducted for small catchment areas of urban slope land with different return periods. The results indicate that estimation errors of some rainstorm and runoff parameters are the main sources of calculation errors for design peak flow rates. Using the results obtained by the rational formula method as the design basis can meet the urban flood control safety requirements. For flood return periods of 2, 5, 10, 15, 25 and 50 years, the corresponding regional overall flood control design peak flow rates are 40.1, 45.0, 48.7, 50.6, 54.0 and 57.3 m3/s respectively. The research findings can provide the technical support for improving the comprehensive urban flood control system.