Present the pattern in vulnerability levelzoning and analysis of urban areas at floodriskCase study: Regions 10 and 22 of Tehran

Vulnerability is the main construct in flood risk management. One of the most significant aims of flood vulnerabilityassessment is to make a clear association between the theoretical conceptions of flood vulnerabilityand the daily administrative process. Flood vulnerability is complex and has a wide range depending on variousphenomena such as rainfall, runoff concentration and high exposure of the flooding downstream areas. Floodvulnerability changes over time and shifts its location due to natural conditions, human activities, and damagesthe culture of the community at risk. Tehran city has experienced various life and property damages because ofhigh varieties in the socio-economic and the life quality level in regions as well as structural varieties in the cityfabric. In this study, the blocks with weak texture, population density, land use, bridge, and slope and drainagedensity are defined as elements at risk for assessing the patterns of vulnerability between districts No. 10 and 22of Tehran. Prioritization and relationship among these variables as well as vulnerability were examined throughAnalytic Hierarchy Process; based on expert opinions creating a matrix with 6×6 dimensions to determine thevariables’ relative weight and vulnerability map. According to the results of relative weights, population densityof 0.3825 and drainage density of 0.0428 were revealed to be the highest and lowest relative weights respectively.The obtained vulnerability values from AHP method for districts No. 10 and 22 showed numbers 7.8 and 2.6 respectively.Tehran flood vulnerability has Multiple-scale analysis due to the amount of change or destruction ofthe urban natural watercourse, kind of land use, various densities of urban fabric and non-uniform distribution ofpopulation, as well as the socio-economic level and quality of life in urban neighborhoods.