Modelling the flood behavior of upper Meghna river

Abstract

Floods are probably the most recurring, widespread, disastrous and frequent natural hazards of the world. Bangladesh is one of the worst flood-affected countries due to its unique geographical and geological condition. Geographically Bangladesh is surrounded by India from north, east and west and by Bay of Bengal from south. Geologically Bangladesh is situated in a depression area which is called Bengal Basin. This is why all major rivers meet in this basin. This is the one of the main reason of flood in Bangladesh. The north east zone of Bangladesh is one of the most susceptible areas which are prone to flooding. Flood forecasting and flood warning, flood hazard mapping and flood risk zoning are quite effective non-structural procedures in managing floods that decreases the risks and disasters which floods may cause. In view of this an attempt has been made in the present work to simulate flood inundation for Upper Meghna River and also to verify the inundation with RADARSAT imagery. Flood patterns and inundation behavior has also been derived from satellite imagery. This study introduces the verification of inundation from 1D- 2D hydrodynamic modeling and flood inundated area mapping for Upper Meghna River. Time series analysis of satellite imagery and model output has been analyzed to look for the inundation behavior in Upper Meghna River. DEM of 300m resolution is used to generate the various maps for the floodplain depended on Upper Meghna River. SOBEK 1D and 2D hydrodynamic module have been used for floodplain inundation modelling. Results indicate that upstream of the Upper Meghna River in Brahmanbaria and Kishoregonj is more vulnerable to flooding compared to downstream. Flooding in the Upper Meghna follows a common pattern except 1998 flood. Brahmanbaria in the study area is vulnerable to flood inundation compare to other district.Model results also show that the upstream of the Upper Meghna River in Brahmanbaria and Kishoregonj is susceptible to flooding. Both model and satellite images show that left bank of the Upper Meghna River is vulnerable to flood inundation.