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Rahman MM, Haque A, Nicholls RJ, Darby SE, Urmi MT, Dustegir MM, Dunn FE, Tahsin A, Razzaque S, Horsburgh K, Haque MA. Sustainability of the coastal zone of the Ganges-Brahmaputra-Meghna delta under climatic and anthropogenic stresses. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 829:154547. [PMID: 35302026 DOI: 10.1016/j.scitotenv.2022.154547] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 03/08/2022] [Accepted: 03/09/2022] [Indexed: 05/13/2023]
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.
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Affiliation(s)
- Md Munsur Rahman
- Institute of Water and flood Management (IWFM), Bangladesh University of Engineering & Technology (BUET), Dhaka, Bangladesh.
| | - Anisul Haque
- Institute of Water and flood Management (IWFM), Bangladesh University of Engineering & Technology (BUET), Dhaka, Bangladesh
| | - Robert J Nicholls
- Tyndall Centre for Climate Change Research, University of East Anglia, Norwich, UK
| | - Stephen E Darby
- School of Geography and Environmental Science, University of Southampton, Highfield, Southampton, UK
| | - Mahmida Tul Urmi
- Institute of Water and flood Management (IWFM), Bangladesh University of Engineering & Technology (BUET), Dhaka, Bangladesh
| | - Md Maruf Dustegir
- Institute of Water and flood Management (IWFM), Bangladesh University of Engineering & Technology (BUET), Dhaka, Bangladesh
| | - Frances E Dunn
- Faculty of Geosciences, Utrecht University, the Netherlands
| | - Anika Tahsin
- Institute of Water and flood Management (IWFM), Bangladesh University of Engineering & Technology (BUET), Dhaka, Bangladesh
| | - Sadmina Razzaque
- Institute of Water and flood Management (IWFM), Bangladesh University of Engineering & Technology (BUET), Dhaka, Bangladesh
| | - Kevin Horsburgh
- Green Climate Fund, 175 Art center-daero, Yeonsu-gu, Incheon 22004, Republic of Korea
| | - Md Aminul Haque
- Water Resources Planning Organization (WARPO), Dhaka, Bangladesh
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