Sustainability of the coastal zone of the Ganges-Brahmaputra-Meghna delta under climatic and anthropogenic stresses

Rahman, Md. Munsur, Haque, Anisul, Nicholls, Robert J., Darby, Stephen E., Urmi, Mahmida Tul, Dustegir, Md. Maruf, Dunn, Frances E., Tahsin, Anika, Razzaque, Sadmina, Horsburgh, Kevin and Haque, Md. Aminul (2022) Sustainability of the coastal zone of the Ganges-Brahmaputra-Meghna delta under climatic and anthropogenic stresses. Science of the Total Environment, 829. ISSN 0048-9697

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Abstract

The Ganges-Brahmaputra-Meghna (GBM) delta is one of the world's largest deltas. It is currently experiencing high rates of relative sea-level rise of about 5 mm/year, reflecting anthropogenic climate change and land subsidence. This is expected to accelerate further through the 21st Century, so there are concerns that the GBM delta will be progressively submerged. In this context, a core question is: can sedimentation on the delta surface maintain its elevation relative to sea level? This research seeks to answer this question by applying a two-dimensional flow and morphological model which is capable of handling dynamic interactions between the river and floodplain systems and simulating floodplain sedimentation under different flow-sediment regimes and anthropogenic interventions. We find that across a range of flood frequencies and adaptation scenarios (including the natural polder-free state), the retained volume of sediment varies between 22% and 50% of the corresponding sediment input. This translates to average rates of sedimentation on the delta surface of 5.5 mm/yr to 7.5 mm/yr. Hence, under present conditions, sedimentation associated with quasi-natural conditions can exceed current rates of relative sea-level rise and potentially create new land mass. These findings highlight that encouraging quasi-natural conditions through the widespread application of active sediment management measures has the potential to promote more sustainable outcomes for the GBM delta. Practical measures to promote include tidal river management, and appropriate combinations of cross-dams, bandal-like structures, and dredging.

Item Type: Article
Additional Information: Acknowledgements: Collecting the bathymetry data was supported by the ‘ESPA Deltas (NE/J002755/1)’ project supported by the ESPA programme, funded by the Department for International Development (DfID), the Economic and Social Research Council (ESRC) and the Natural Environment Research Council (NERC), UK, and the National Water Resources Database hosted at Water Resources Planning Organization (WARPO), Ministry of Water Resources (MoWR), Government of the People's Republic of Bangladesh (GoB). The model development was supported by the DECCMA Project (Grant No. IDRC 107642), part of the Collaborative Adaptation Research Initiative in Africa and Asia (CARIAA), with financial support from the UK Government's DfID and the International Development Research Centre (IDRC), Canada, the WARPO Projects, ‘Research on the Morphological processes under Climate Changes, Sea Level Rise and Anthropogenic Intervention in the coastal zone’ and ‘Research on Sediment Distribution and Management in South-West Region of Bangladesh’ funded from MoWR, GoB and the ACCORD project (NE/R000123/1) funded by the UK NERC (through National Oceanographic Center, NOC).
Uncontrolled Keywords: sdg 13 - climate action ,/dk/atira/pure/sustainabledevelopmentgoals/climate_action
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Depositing User: LivePure Connector
Date Deposited: 15 Mar 2022 17:30
Last Modified: 24 May 2022 14:52
URI: https://ueaeprints.uea.ac.uk/id/eprint/84065
DOI: 10.1016/j.scitotenv.2022.154547

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