Geological Evolution of the Ganges­Brahmaputra Delta During the Holocene time and Hazard Assessment and Zonation Along the Deltaic Coastal plain, Bangladesh

Abstract

An extensive deltaic plain of Bangladesh has been formed by the sediments of the Ganges-Brahmaputra (GB) river system that carries an annual suspended load of more than a billion tons into Bangladesh. In spite of the huge sediment discharge, the seaward growth of the subaerial delta is insignificant since quite sometime especially for the last two centuries. The coastal part of Bangladesh has more recently been threatened by sea level rise due to much talked global warming. This study investigates stratigraphy, evolution, active processes and coastal hazard in the lower subaerial deltaic part of the GB delta in Bangladesh. The delta plain under investigation can broadly be divided into three geomorphological domains on the basis of it's origin. These are river floodplains, tidal plains and estuarine plains. The landforms under river floodplains are levee or levee complex, abandoned meander belt and beels or depressions. Interdistributary tidal plains, tidal swamp/depression, beach and beach ridge complex and mangrove swamp constitute the landforms of the tidal plain domain. The landforms constituting the estuarine plain are estuarine plain and mud flat. ------