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Changing sediment budget of the Mekong: Cumulative threats and management strategies for a large river basin

Changing sediment budget of the Mekong: Cumulative threats and management strategies for a large river basin
Changing sediment budget of the Mekong: Cumulative threats and management strategies for a large river basin
Two decades after the construction of the first major dam, the Mekong basin and its six riparian countries have seen rapid economic growth and development of the river system. Hydropower dams, aggregate mines, flood-control dykes, and groundwater-irrigated agriculture have all provided short-term economic benefits throughout the basin. However, it is becoming evident that anthropic changes are significantly affecting the natural functioning of the river and its floodplains. We now ask if these changes are risking major adverse impacts for the 70 million people living in the Mekong Basin. Many livelihoods in the basin depend on ecosystem services that will be strongly impacted by alterations of the sediment transport processes that drive river and delta morpho-dynamics, which underpin a sustainable future for the Mekong basin and Delta.

Drawing upon ongoing and recently published research, we provide an overview of key drivers of change (hydropower development, sand mining, dyking and water infrastructures, climate change, and accelerated subsidence from pumping) for the Mekong’s sediment budget, and their likely individual and cumulative impacts on the river system. Our results quantify the degree to which the Mekong delta, which receives the impacts from the entire connected river basin, is increasingly vulnerable in the face of declining sediment loads, rising seas and subsiding land. Without concerted action, it is likely that nearly half of the Delta’s land surface will be below sea level by 2100, with the remaining areas impacted by salinization and frequent flooding. The threat to the Delta can be understood only in the context of processes in the entire river basin. The Mekong River case can serve to raise awareness of how the connected functions of river systems in general depend on undisturbed sediment transport, thereby informing planning for other large river basins currently embarking on rapid economic development.
0048-9697
114-134
Kondolf, G.M.
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Schmitt, Rafael
c48ac00d-a5ac-4c94-9431-899b092de0ad
Darby, Stephen
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Carling, Paul
8d252dd9-3c88-4803-81cc-c2ec4c6fa687
Arias, M.
9a1a3a03-0ec2-4380-b7bd-ee7b69f314bc
Bizzo, Simone
32b415ca-1a93-44fe-93e4-2dc88d855064
Castelletti, Andrea
be719c8b-5599-42a5-8404-259074a780d6
Cochrane, Tom
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Gibson, Stan
201f27bc-ff9e-4163-bda9-e13e04f3d0b6
Kummu, Matti
b663f033-34e2-45e4-a5a3-d9987f72ca3b
Oeurng, Chantha
cfba86c9-5a75-4e86-8cca-c18efaf7ff98
Rubin, Zan
607d6f04-f8d8-46ee-988b-427514af26c6
Wild, Thomas
3a61226e-3b1f-4b43-b583-c2ec170cd2fb
Kondolf, G.M.
6db53710-6df9-4034-83d6-a731c0866825
Schmitt, Rafael
c48ac00d-a5ac-4c94-9431-899b092de0ad
Darby, Stephen
4c3e1c76-d404-4ff3-86f8-84e42fbb7970
Carling, Paul
8d252dd9-3c88-4803-81cc-c2ec4c6fa687
Arias, M.
9a1a3a03-0ec2-4380-b7bd-ee7b69f314bc
Bizzo, Simone
32b415ca-1a93-44fe-93e4-2dc88d855064
Castelletti, Andrea
be719c8b-5599-42a5-8404-259074a780d6
Cochrane, Tom
0a1d4f8e-9de8-4d9b-8c33-975dd57b9da3
Gibson, Stan
201f27bc-ff9e-4163-bda9-e13e04f3d0b6
Kummu, Matti
b663f033-34e2-45e4-a5a3-d9987f72ca3b
Oeurng, Chantha
cfba86c9-5a75-4e86-8cca-c18efaf7ff98
Rubin, Zan
607d6f04-f8d8-46ee-988b-427514af26c6
Wild, Thomas
3a61226e-3b1f-4b43-b583-c2ec170cd2fb

Kondolf, G.M., Schmitt, Rafael, Darby, Stephen, Carling, Paul, Arias, M., Bizzo, Simone, Castelletti, Andrea, Cochrane, Tom, Gibson, Stan, Kummu, Matti, Oeurng, Chantha, Rubin, Zan and Wild, Thomas (2018) Changing sediment budget of the Mekong: Cumulative threats and management strategies for a large river basin. Science of Total Environment, 625, 114-134. (doi:10.1016/j.scitotenv.2017.11.361).

Record type: Article

Abstract

Two decades after the construction of the first major dam, the Mekong basin and its six riparian countries have seen rapid economic growth and development of the river system. Hydropower dams, aggregate mines, flood-control dykes, and groundwater-irrigated agriculture have all provided short-term economic benefits throughout the basin. However, it is becoming evident that anthropic changes are significantly affecting the natural functioning of the river and its floodplains. We now ask if these changes are risking major adverse impacts for the 70 million people living in the Mekong Basin. Many livelihoods in the basin depend on ecosystem services that will be strongly impacted by alterations of the sediment transport processes that drive river and delta morpho-dynamics, which underpin a sustainable future for the Mekong basin and Delta.

Drawing upon ongoing and recently published research, we provide an overview of key drivers of change (hydropower development, sand mining, dyking and water infrastructures, climate change, and accelerated subsidence from pumping) for the Mekong’s sediment budget, and their likely individual and cumulative impacts on the river system. Our results quantify the degree to which the Mekong delta, which receives the impacts from the entire connected river basin, is increasingly vulnerable in the face of declining sediment loads, rising seas and subsiding land. Without concerted action, it is likely that nearly half of the Delta’s land surface will be below sea level by 2100, with the remaining areas impacted by salinization and frequent flooding. The threat to the Delta can be understood only in the context of processes in the entire river basin. The Mekong River case can serve to raise awareness of how the connected functions of river systems in general depend on undisturbed sediment transport, thereby informing planning for other large river basins currently embarking on rapid economic development.

Text R1-ChangingSedBudgetMekong-AsSubmitted - Accepted Manuscript
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Text R1-ChangingSedBudgetMekong-AsSubmitted
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More information

Accepted/In Press date: 30 November 2017
e-pub ahead of print date: 27 December 2017
Published date: 1 June 2018

Identifiers

Local EPrints ID: 416346
URI: https://eprints.soton.ac.uk/id/eprint/416346
ISSN: 0048-9697
PURE UUID: ac5e8707-e995-46ad-a15a-1fb715feaeab
ORCID for Stephen Darby: ORCID iD orcid.org/0000-0001-8778-4394

Catalogue record

Date deposited: 13 Dec 2017 17:30
Last modified: 06 Jun 2018 12:58

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