OPTIMIZATION OF DRAINAGE NETWORK TO MINIMIZE URBAN FLOODS USING REMOTE SENSING AND GIS TECHNIQUES

The frequency of the occurrence of disasters is increasing day by day. Urban flooding has become one of severe problems faced by Sri Lanka seasonally leading to various social and environmental interruptions. With the increasing of the occurrence it has become a necessity to find a proper solution to overcome the problem. This study was mainly focused to optimize the drainage network in Panadura urban council area, Sri Lanka to minimize the urban flood hazard susceptibility.using Remote Sensing (RS) and Geographical Information System (GIS) techniques. Light Detection AndRanging (LiDAR) Digital Elevation Model (DEM) was utilized to delineate requisite drainage and mini water catchments using Environmental Systems Research Institute (ESRI) Arc Hydro Model. Prior to LiDAR DEM processing an accuracy assessment was performed with respect to the ground truth elevation measured by Total Station and GPS surveys. Current available drainage system in the area was assessed in two ways as alignment and capacity for large water volumes in heavy rainfalls with respect to the delineated natural drainage system. Highly flood vulnerable locations in the current drainage system were identified by performing the comparison of natural drainage network and existing drainage paths. Finally adjustments to the current drainage network and new drainage paths were proposed