Assessment Rapid Urban Inundation Method Based on Urban Terrain: Depth, surface and volume of inundation

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 is proposed an urban storm-inundation simulation method (USISM) based on Geographic Information System (GIS). 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 shows that in all four-storm event, the average relative depth errors of depth in all inundation sites are less than 20%, while the average relative errors of area and volume are more than 60% Therefore, the USISM method has a higher ability to simulate the final depth of inundation than the surface and volume of inundation. The result reveals that the USISM method could find the inundation locations in the Damghan Urban Watershed and calculate inundation depth and area quickly and therefore display a significant role in the management of the urban crisis.