An urban storm-inundation simulation method based on GIS

Abstract

Summary With the increase of urbanization, conditions of the underlying surface and climate have been changed by human activities. This results in more frequent flooding 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). Simulation models are complex and difficult to build and run. To determine inundation conditions quickly with only a few commonly available input data, an urban storm-inundation simulation method (USISM) based on geographic information systems (GIS) is proposed in this paper. The method is a kind of simplified distributed hydrologic model based on DEM, in this method, depressions in the 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 catchment area and maximum storage volume of a depression, and the flow direction between these depressions are all considered in the final inundation simulation. GIS technology is used to find the depressions in an area, divide the subcatchment for each depression, and obtain the flow order of the depressions based on a digital elevation model (DEM). The SCS method is used to calculate storm runoff, and a water balance equation is used to calculate water storage in each depression. Nangang District in Harbin City, China, is selected as the study area to verify the USISM. The result reveals that the USISM could find inundation locations in the urban area and quickly calculate inundation depth and area. The USISM is valuable for simulating storms of short duration in an urban area with a few commonly available input data.