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Impacts of climate change and socio-economic scenarios on flow and water quality of the Ganges, Brahmaputra and Meghna (GBM) river systems: low flow and flood statistics

Impacts of climate change and socio-economic scenarios on flow and water quality of the Ganges, Brahmaputra and Meghna (GBM) river systems: low flow and flood statistics
Impacts of climate change and socio-economic scenarios on flow and water quality of the Ganges, Brahmaputra and Meghna (GBM) river systems: low flow and flood statistics
The potential impacts of climate change and socio-economic change on flow and water quality in rivers worldwide is a key area of interest. The Ganges–Brahmaputra–Meghna (GBM) is one of the largest river basins in the world serving a population of over 650 million, and is of vital concern to India and Bangladesh as it provides fresh water for people, agriculture, industry, conservation and for the delta system downstream. This paper seeks to assess future changes in flow and water quality utilising a modelling approach as a means of assessment in a very complex system. The INCA-N model has been applied to the Ganges, Brahmaputra and Meghna river systems to simulate flow and water quality along the rivers under a range of future climate conditions. Three model realisations of the Met Office Hadley Centre global and regional climate models were selected from 17 perturbed model runs to evaluate a range of potential futures in climate. In addition, the models have also been evaluated using socio-economic scenarios, comprising (1) a business as usual future, (2) a more sustainable future, and (3) a less sustainable future. Model results for the 2050s and the 2090s indicate a significant increase in monsoon flows under the future climates, with enhanced flood potential. Low flows are predicted to fall with extended drought periods, which could have impacts on water and sediment supply, irrigated agriculture and saline intrusion. In contrast, the socio-economic changes had relatively little impact on flows, except under the low flow regimes where increased irrigation could further reduce water availability. However, should large scale water transfers upstream of Bangladesh be constructed, these have the potential to reduce flows and divert water away from the delta region depending on the volume and timing of the transfers. This could have significant implications for the delta in terms of saline intrusion, water supply, agriculture and maintaining crucial ecosystems such as the mangrove forests, with serious implications for people's livelihoods in the area. The socio-economic scenarios have a significant impact on water quality, altering nutrient fluxes being transported into the delta region.
2050-7887
1-13
Whitehead, P.
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Barbour, E.
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Futter, M.
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Sarkar, S.
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Rodda, H.
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Ceasar, J.
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Butterfield, D.
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Jin, L.
53827541-9b74-4222-b5ae-7d573e964b51
Sinha, R.
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Nicholls, R.J.
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Salehin, M.
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Whitehead, P.
5223e7f5-ca15-4ff4-aee9-5b845164e5fb
Barbour, E.
c5ddeccb-28b3-4ac0-a2c5-c401e2cec9bd
Futter, M.
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Sarkar, S.
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Rodda, H.
d2590e9b-1a38-4e6b-b8d6-f113c9a07c3d
Ceasar, J.
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Butterfield, D.
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Jin, L.
53827541-9b74-4222-b5ae-7d573e964b51
Sinha, R.
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Nicholls, R.J.
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Salehin, M.
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Whitehead, P., Barbour, E., Futter, M., Sarkar, S., Rodda, H., Ceasar, J., Butterfield, D., Jin, L., Sinha, R., Nicholls, R.J. and Salehin, M. (2015) Impacts of climate change and socio-economic scenarios on flow and water quality of the Ganges, Brahmaputra and Meghna (GBM) river systems: low flow and flood statistics. Environmental Science: Processes & Impacts, 1-13. (doi:10.1039/C4EM00619D).

Record type: Article

Abstract

The potential impacts of climate change and socio-economic change on flow and water quality in rivers worldwide is a key area of interest. The Ganges–Brahmaputra–Meghna (GBM) is one of the largest river basins in the world serving a population of over 650 million, and is of vital concern to India and Bangladesh as it provides fresh water for people, agriculture, industry, conservation and for the delta system downstream. This paper seeks to assess future changes in flow and water quality utilising a modelling approach as a means of assessment in a very complex system. The INCA-N model has been applied to the Ganges, Brahmaputra and Meghna river systems to simulate flow and water quality along the rivers under a range of future climate conditions. Three model realisations of the Met Office Hadley Centre global and regional climate models were selected from 17 perturbed model runs to evaluate a range of potential futures in climate. In addition, the models have also been evaluated using socio-economic scenarios, comprising (1) a business as usual future, (2) a more sustainable future, and (3) a less sustainable future. Model results for the 2050s and the 2090s indicate a significant increase in monsoon flows under the future climates, with enhanced flood potential. Low flows are predicted to fall with extended drought periods, which could have impacts on water and sediment supply, irrigated agriculture and saline intrusion. In contrast, the socio-economic changes had relatively little impact on flows, except under the low flow regimes where increased irrigation could further reduce water availability. However, should large scale water transfers upstream of Bangladesh be constructed, these have the potential to reduce flows and divert water away from the delta region depending on the volume and timing of the transfers. This could have significant implications for the delta in terms of saline intrusion, water supply, agriculture and maintaining crucial ecosystems such as the mangrove forests, with serious implications for people's livelihoods in the area. The socio-economic scenarios have a significant impact on water quality, altering nutrient fluxes being transported into the delta region.

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More information

Accepted/In Press date: 16 February 2015
e-pub ahead of print date: 17 February 2015
Organisations: Energy & Climate Change Group

Identifiers

Local EPrints ID: 376018
URI: http://eprints.soton.ac.uk/id/eprint/376018
ISSN: 2050-7887
PURE UUID: fc1a6bf1-c9a3-4c0c-a970-3f4ef3f64d7a
ORCID for R.J. Nicholls: ORCID iD orcid.org/0000-0002-9715-1109

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Date deposited: 21 Apr 2015 13:55
Last modified: 15 Mar 2024 03:18

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Contributors

Author: P. Whitehead
Author: E. Barbour
Author: M. Futter
Author: S. Sarkar
Author: H. Rodda
Author: J. Ceasar
Author: D. Butterfield
Author: L. Jin
Author: R. Sinha
Author: R.J. Nicholls ORCID iD
Author: M. Salehin

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