Abstract

Vulnerability caused by the flood is complex and fluctuation. The flood vulnerability is depended on the phenomena such as precipitation, runoff and its accumulated and amount of vulnerability lowland areas of flood. Flood vulnerability be varied over time and from region to another that its reason for natural special circumstances . In order to drawing schematic of vulnerability surface caused by flood in Babul city, we used Analytical Hierarchy Process model (AHP) with variables namely: lands use, old texture, distance from transportation network and river, runoff height, slope, channel density and height. Priority and determination relationship between these variables with the vulnerability carried out through AHP method. The weight of criteria were: land use and old texture 0.35, distance transportation network 0.24, distance from river 0.16, runoff height 0.10, slope 0.07, density of channel 0.044 and for variable height 0.03. Therefore, land use and old texture gained minimum and maximum weights. After calculating the relative weights and using the equation obtained from the coefficients of the variables, Babul city flood vulnerability map was prepared by using the analysis formats in Arc Map in five vulnerability class: very low, low, medium, high and very high. Very high vulnerability class based on old texture mapping of the old texture of Babul and parts it is that density is highest or impermeable surfaces is highest. Very high vulnerability area is visible more in downtown and the river surrounding. However, the expansion of agriculture lands and reduced density of impermeable surfaces (use of residential and passageways) led to reduce flood vulnerability in city. Area of very low vulnerable class and very high vulnerable are 4.3, 9.3, 5.9, 4.7 and 7.7, kilometers respectively. The low vulnerable class and very high vulnerable class including 29.1 and 23.9 percentage of Babul city area, respectively. Finally locating 38 percentages from Babul city in very high and very high vulnerable is indicating high relatively vulnerable of this city in flood.