Urban Storm-Inundation Simulation Based-on GIS In Damghan Urban Watershed

With the increasing of urbanization, conditions of the underlying surface and climate conditions have been changed by human activities. This resulted in more frequent floods and inundation problems in urban areas. Storm-inundation Models based on hydrology and hydrodynamics require a large amount of input data (detailed terrain, sewer system and land use data). In this paper, in order to determine inundation conditions quickly with only a few usually available input data, an urban storm-inundation simulation method (USISM) based on geographic Information System (GIS) is proposed. The USISM is a simplified method of distributed hydrological model based on DEM, in this method depressions in terrain are regarded as the basic inundated area. The amount of water that can be stored in a depression indicates the final inundation distribution. The runoff and maximum storage volume for each depression and the flow direction between these depressions are all considered in the final inundation simulation. The SCS method is used to calculate storm runoff and a water balance equation is used to calculate the water storage in each depression. The result reveals that the USISM method could find the inundation locations in the Damghan Urban Watershed and quickly calculate inundation depth and area. The USISM is valuable for simulating storms of short duration in an Urban Watershed with a few in commonly available input data.