基于SCS模型的城市内涝灾害风险评价

Risk Assessment of Urban Waterlogging Disaster Based on SCS Model

开展城市内涝灾害风险识别,可为防灾减灾决策提供科学依据,有利于提高城市应对内涝灾害水平。针对采用暴雨强度公式进行模拟降水量输入、存在生成的面雨量分布精细化程度不高等缺陷,提出采用自动气象观测站降水资料,运用皮尔逊Ⅲ型曲线法获取不同重现率下的面降雨量分布的方法。结合SCS-CN水文学模型估算不同重现期降雨产流量并作为致灾驱动因子,综合考虑地形情况、植被覆盖等自然因素和人口密度、地均GDP等社会经济条件,从致灾因子、孕灾环境、承灾体3个方面选取评价指标,定量化开展城市内涝灾害风险等级划分。以贵阳市区为研究对象,选取研究区域及周边31个气象站点近10年的最大持续降雨量资料,结果表明:最大连续面雨量分布大致呈现由北向南递减;降雨产流高值区随重现期的减小、面降雨量的增加而变化,分布在西北部的白云区、观山湖区及老城区周边两个区域;高风险区域集中在老城区、花溪大道中部及南二环区域、龙洞堡等部分区域。

The risk identification of urban waterlogging disaster can provide a scientific basis for disaster prevention and mitigation decision-making,and help improve urban response to waterlogging disasters.In view of the shortcomings of using the rainstorm intensity formula to simulate the precipitation input and the low refinement degree of the generated areal rainfall distribution etc.,we proposed a method that could obtain the areal rainfall distribution under different recurrence rates by using the precipitation data of the automatic meteorological observation station and Pearson type Ⅲ curve method.Combined with SCS-CN hydrological model,we estimated the rainfall yield and discharge in different recurrence periods and took it as the driving factors of disasters.Taking the natural factors of topography,vegetation coverage,etc.and the socio-economic conditions of population density,average GDP,etc.into account,we selected evaluation indicators from disaster causing factors,disaster pregnant environment,disaster bearing body,and quantitatively conducted the risk level of urban waterlogging disaster risk classification.Taking the urban area of Guiyang City as the research object,we selected the maximum continuous rainfall data from the 31 meteorological stations in the study area and the surrounding areas for the past 10 years.As the results show,the distribution of the maximum continuous areal rainfall generally shows a decrease from north to south.The high value area of rainfall runoff production,changing with the decrease of the recurrence period and the increase of the areal rainfall,is distributed in Baiyun District,Guanshanhu District and the surrounding areas of the old city.The high-risk areas are concentrated in the old city,the middle of Huaxi Avenue,the areas around the southern second ring road,and Longdongbao etc..