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Normandin C, Frappart F, Bourrel L, Blarel F, Biancamaria S, Wigneron JP, Galenon L, Bernard E, Coulon L, Lubac B, Marieu V, Vantrepotte V, Pham-Duc B, Do HT, Prigent C, Aires F, Yamazaki D, Ciais P. Sharp decline in surface water resources for agriculture and fisheries in the Lower Mekong Basin over 2000-2020. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175259. [PMID: 39127208 DOI: 10.1016/j.scitotenv.2024.175259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 07/22/2024] [Accepted: 08/01/2024] [Indexed: 08/12/2024]
Abstract
Water resources play a crucial role in the global water cycle and are affected by human activities and climate change. However, the impacts of hydropower infrastructures on the surface water extent and volume cycle are not well known. We used a multi-satellite approach to quantify the surface water storage variations over the 2000-2020 period and relate these variations to climate-induced and anthropogenic factors over the whole basin. Our results highlight that dam operations have strongly modified the water regime of the Mekong River, exhibiting a 55 % decrease in the seasonal cycle amplitude of inundation extent (from 3178 km2 to 1414 km2) and a 70 % decrease in surface water volume (from 1109 km3 to 327 km3) over 2000-2020. In the floodplains of the Lower Mekong Basin, where rice is cultivated, there has been a decline in water residence time by 30 to 50 days. The recent commissioning of big dams (2010 and 2014) has allowed us to choose 2015 as a turning point year. Results show a trend inversion in rice production, from a rise of 40 % between 2000 and 2014 to a decline of 10 % between 2015 and 2020, and a strong reduction in aquaculture growth, from +730 % between 2000 and 2014, to +53 % between 2015 and 2020. All these results show the negative impact of dams on the Mekong basin, causing a 70 % decline in surface water volumes, with major repercussions for agriculture and fisheries over the period 2000-2020. Therefore, new future projects such as the Funan Techo canal in Cambodia, scheduled to start construction at the end of 2024, will particularly affect 1300 km2 of floodplains in the lower Mekong basin, with a reduction in the amount of water received, and other areas will be subjected to flooding. The human, material and economic damage could be catastrophic.
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Affiliation(s)
- Cassandra Normandin
- ISPA, UMR 1391 INRAE, Bordeaux Sciences Agro, F-33140 Villenave d'Ornon, France.
| | - Frédéric Frappart
- ISPA, UMR 1391 INRAE, Bordeaux Sciences Agro, F-33140 Villenave d'Ornon, France
| | - Luc Bourrel
- GET, Université de Toulouse, CNRS, IRD, UPS, CNES, OMP, Toulouse, France
| | - Fabien Blarel
- LEGOS, Université de Toulouse, CNES, CNRS, IRD, UPS, OMP, Toulouse, France
| | | | | | - Léonie Galenon
- LEGOS, Université de Toulouse, CNES, CNRS, IRD, UPS, OMP, Toulouse, France
| | - Emilie Bernard
- LEGOS, Université de Toulouse, CNES, CNRS, IRD, UPS, OMP, Toulouse, France
| | - Ludovic Coulon
- LEGOS, Université de Toulouse, CNES, CNRS, IRD, UPS, OMP, Toulouse, France
| | - Bertrand Lubac
- EPOC, UMR 5805, Avenue des Facultés, Université de Bordeaux, 33405 Talence, France
| | - Vincent Marieu
- EPOC, UMR 5805, Avenue des Facultés, Université de Bordeaux, 33405 Talence, France
| | - Vincent Vantrepotte
- Univ. Lille, CNRS, Univ. Littoral Côte d'Opale, IRD, UMR 8187 - LOG - Laboratoire d'Océanologie et de Géosciences, 59000 Lille, France
| | - Binh Pham-Duc
- Department of Space and Applications, University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology, Hanoi, Viet Nam
| | - Huy Toan Do
- World Wide Fund for Nature in Viet Nam, No 6 Lane 18 Nguyen Co Thach, Bac Tu Liem, Hanoi, Viet Nam; Center For Environmental Fluid Dynamics, VNU University of Science, Hanoi, Viet Nam
| | - Catherine Prigent
- LERMA, Observatoire de Paris, CNRS, PSL, 61 avenue de l'Observatoire, 75 014 Paris, France
| | - Filipe Aires
- LERMA, Observatoire de Paris, CNRS, PSL, 61 avenue de l'Observatoire, 75 014 Paris, France
| | - Dai Yamazaki
- Institute of Industrial Science, University of Tokyo, Komaba, Tokyo, Japan
| | - Philippe Ciais
- LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
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