Flood vulnerability assessment in Tehran city

Introduction: Flood vulnerability is variable and complex that dependents on very phenomena such as rainfall, runoff and high exposure of the flooding downstream areas. Flood vulnerability changes over time and from regions due to natural conditions, human activities, and damage culture of the community at risk. Tehran city may be experiences the difference life and property damages because the high varieties in the socio-economic and the life quality level in regions, also structural varieties in the city fabric. Methods: In this study, the blocks with weak texture, population density, land use, bridge, slope and drainage density are defined as element at risk to assess the vulnerability differences pattern. Prioritization and the relationship between this variables and vulnerability was done through Analytic Hierarchy Process; ba sed on expert opinions created a matrix with ۶×۶ dimensions to determine the variables relative weight and vulnerability map. Findings: Zonal analysis determined the vulnerability in Tehran, which the weights calculated on the basis of the hierarchical process. Zones ۱۰, ۱۷, ۸, and ۱۱ are affected against floods urban very high, while zones ۲۲, ۲۱, ۱۸ and ۵ are very low. These zones are lack of the blocks with weak texture and their population is low, especially zone ۲۲ is not weak texture, low-density population, and high potential of flow of Kan watercourse. Conclusion: The resulted relative weights show the population density with ۰.۳۸۲۵ and drainage density with ۰.۰۴۲۸ as highest and lowest relative weight, respectively. The vulnerability map defines that ۱۳۸ km۲ of the Tehran city area is located in high and very high categories of the vulnerability. Finally ba sed on zonal statistic municipal ۱۰ and ۲۲ have highest and lowest vulnerability, respectively.  

Keywords:

Flooding , Vulnerability , Analysis Hierarchical Process (AHP) , Tehran City , سیلاب , آسیب پذیری , فرآیند سلسله مراتبی , شهرتهران