The Urban Morphology and Passages Flooding of Rasht City

In this study, the flooding passages of Rasht were assessed using Geographic Information System(GIS). The passage has been studied while flooded due to overflowing compound collection network and lack of water and sewer capacity and the hydraulic proper disposal of surface water due to the occurrence of extreme events occurring in the city. In this situation, streets and sidewalks, homes located in low land areas and large ring roads are flooded. Using GIS technique and the information in a library as well as field visits, the study was conducted to determine the characteristics of action of the different climatic, physiographic, hydrological of the city. Since the rain is the basic factor of the producing the surface and underground waters, this study focuses on important factors at flood time including the month, season, year, rain, max-dailyand the sever– durationand abundant as the most relevent varables. The Impermeability of the city basins and the changes that are made due to the growth and development of the city such as omission of the fluvial covers, the soil density and generating of the collecting system and guiding the surface water.Briefly, if there is incapacity of the discharge place for receiving and the safe repulse of the city flood water, it is possible that the runoff results from raining in inside network specially in the bottom regions pack and after completing the transmitting canal capacities, leads to distributing the water in the city specially in the deep and lowlight regions that are covered by the city drainage system. The aim of this research is to investigate the human factors which help froming the construction or destruction of natural vegetation and and passage covers in flood water as well as offering suggestions towards the repulse of the passage flood waters in the studied confined.