Sedimentation and coastal area management in the human-modified Ganges–Brahmaputra tidal delta plain of Bangladesh

ABSTRACT

The present work is an effort to expose the sedimentation rate of the Ganges–Brahmaputra (GB) tidal delta plain from the subsurface-dated sediments samples. The study reveals that the average sedimentation rates (about 2.12–4.59 mm yr⁻¹) of the area are not as good to minimize as the estimated range of relative sea-level rise (RSLR) (1–9 mm yr⁻¹). Moreover, the sediments cannot be distributed properly in the tidal and fluvio-tidal plains due to different anthropogenic activities like poldering and embankments. In addition, the upstream diversion of the Ganges and the Brahmaputra rivers water reduces the suspended sediment load to the downstream and consequently, the sedimentation rates. Finally, the GB tidal delta plain and its coastal area are in a vulnerable situation in consideration of sedimentation rates, RSLR, and different anthropogenic activities. Therefore, regular monitoring and evaluation is essential about sedimentation, coastal and upstream anthropogenic practices, RSLR, etc., for the implementation of effective and efficient mitigation and adaptation measures in the deltaic plains.

KEYWORDS:

• Ganges–Brahmaputra delta
• sedimentation
• sea-level rise
• coastal area management

Acknowledgements

The authors would like to express their deep gratitude and cordial thanks to the Director General (DG), Geological Survey of Bangladesh (GSB) for giving permission to conduct the work. The authors also express their thanks and gratitude to Dr. A. K. M. Khorshed Alam, former DG and Project Director of the project entitled ‘Geological Exploration for the Identification of Mineral Resources and the Areas Vulnerable to Natural Hazards in the Coastal Parts of Bangladesh’ under the GSB to make the work successful. The authors also highly acknowledge the efforts rendered by Md. Khairul Islam, former DG, GSB. The authors also express their thanks to Dr. Md. Ahosan Habib, Md. Ashraf Hossain, Aktarul Ahsan, Mohammad Feruj Alam, and Md. Hossain Khasru, Deputy Directors, GSB for rendering their optimum support during the field work. The authors would also like to pay their special thanks to Md. Abu Bakar Siddique, Bangladesh Council of Scientific and Industrial Research (BCSIR) and Dr. Rahat Khan, Bangladesh Atomic Energy Commission for their help in proofreading the manuscript for its improvement. The authors also express their thanks to the Local administrations, Forest Department, Roads and Highways Department, LGED, Water Board, etc., for rendering their optimum support during field investigation.

Disclosure statement

No potential conflict of interest was reported by the author(s).