双EXP函数径流系数计算模型——以武汉为例

A Model with Double EXP Function for Runoff Coefficient Calculation in Wuhan

基于国标对综合径流系数取值的技术条件——城市建筑密度和设计重现期,利用区域平均人口密度和累计降雨量两个径流计算指标形成双EXP函数径流系数计算模型,从而将国标固定取值转化为动态取值。本模型计算的瞬时综合径流系数满足0~1的数值特征和S曲线变化形态。以武汉市人口密度最高区域——天津路排水系统和人口密度一般区域——港西排水系统为例,以瞬时综合径流系数计算的雨峰流量与国标取值对比,城市雨水排放系统平均提高35.7%,城市防涝系统平均提高11.6%。该计算模型对优化雨水工程设计和完善城市防涝系统有显著效益。

The national standard evaluates the comprehensive runoff coefficient based on the technical conditions of urban building density and design recurrence period.In this paper,the runoff coefficient calculation model with double EXP function was established by using two runoff calculation indexes of regional average population density and cumulative rainfall,and the fixed values specified in the national standard was transformed into dynamic values.The instantaneous comprehensive runoff coefficient calculated by this model conformed to the numerical characteristics of 0-1 and the S-curve variation.The storm peak flows of Tianjin Road drainage system with the highest population density area and Gangxi drainage system with the general population density area in Wuhan calculated by the instantaneous comprehensive runoff coefficient were compared with those specified in the national standard,which indicated that the performances of urban rainwater drainage system and the urban waterlogging control system increased by 35.7%and 11.6%,respectively.The calculation model has significant benefits for optimizing stormwater engineering design and improving urban waterlogging control system.