3- Way coupled urban flood modelling for a part of Chennai City using high-resolution topographic data

The catastrophic flood events which caused severe damage to life and property over the Chennai region in 2005 and 2015 are considered in this study. The flood inundation extent and flood depth of this events were simulated using a 3-way coupling with MIKE FLOOD. It couples three hydrodynamic models namely MIKE 11 HD, MIKE URBAN (MOUSE), and MIKE 21, which can simulate all the sources of the flood, i.e., riverine, urban and surface runoff. HEC-HMS is used for performing hydrologic simulations. High-resolution LiDAR DEM acquired through Airborne Laser Scanning technology is used for extraction of cross section of rivers, ground level of manholes for stormwater drains and for preparing accurate bathymetry for use in MIKE 21. Flood depths were measured in widespread floodplains of Adyar River after the flood events of 2005 and 2015. Model results are validated with the measured flood depths, performance indices show (R 2 =0.772 for 2005 and R 2 =0.883 for 2015) good agreement between them. This study can be used as an effective tool for flood management and flood damage assessments.