Application of remote sensing and GIS-based hydrological modelling for flood risk analysis: a case study of District 8, Ho Chi Minh city, Vietnam

Rapid and unplanned urbanization, together with climate change, have exacerbated flood risk which has caused devastating loss of human life and property in Ho Chi Minh City, Vietnam. Our study utilized remote sensing techniques combined with Geographic Information Systemsbased hydrological modelling to identify flood risk in this urban area. QuickBird imagery was used to create land-use/land-cover information, an important input into the U.S. Soil Conservation Service Technique Release 55 (SCS TR-55) model which is used for predicting rainfall-induced flood. Tidal floods were examined using a Digital Elevation Model in a GIS framework with water level in rivers as an input. The findings indicated that rainfall-induced flood is not a serious problem with the flood depth of 2-10 cm while tidal flood is a substantial issue with 10-100 cm flood depths. Increasing impervious surfaces and decreasing flow length areas resulting from the growth of urbanization in combination with tidal effects contributed significantly to increased flood risk. These findings have implications on solutions for flood risk control in the district, including managing urbanization processes with appropriate infrastructure and improving the infiltration capacity of the runoff with optimized drainage systems.