ABSTRACT
Flood plain delineation is the process of determining inundation extent and depth by comparing river levels with ground surface elevations. In brief, the process involves making the observed water level points on a topographic map and extending water levels over the map until contours of higher elevation is encountered. The water level intersection points are then connected together by following the contours to get the extent of inundation. The traditional method, therefore, consists of the following steps. I. Observe river stages or simulate water levels from surface water models at different
locations along the river. II. Prepare or collect a topo map. III. Mark water levels on topo map. IV. Extend water level until impeded by higher elevation. V. Trace the contour lines to delineate the flood plain. VI. Manually prepare the flood extent map. Nowadays estimation of flooded area is generally done utilizing the remote sensing (RS) technique with the available Geographical Information System (GIS) data. This will enable preparation of a flood hazard map and a land development priority map. This will help to design operate flood control infrastructure and to provide aid and relief operations for high risk areas during future floods. GIS plays a major role in flood control techniques and the integration of these data in a spatial data base is crucial.
