Geography of Sand and Gravel Mining in the Lower Mekong River
Sand and gravel mining from rivers has increased throughout the developed countries since at least the mid-1900s, for construction (concrete) and for landfill (railways, motorways, land reclamation in flooded areas, offshore reclamation). Over the past 30 years, this phenomenon has spread due to the...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | fra |
| Published: |
Pôle de Recherche pour l'Organisation et la diffusion de l'Information Géographique
2013-12-01
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| Series: | EchoGéo |
| Subjects: | |
| Online Access: | https://journals.openedition.org/echogeo/13659 |
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| Summary: | Sand and gravel mining from rivers has increased throughout the developed countries since at least the mid-1900s, for construction (concrete) and for landfill (railways, motorways, land reclamation in flooded areas, offshore reclamation). Over the past 30 years, this phenomenon has spread due to the economic development of countries such as China, India and other fast-growing economies of South-East Asia. The detrimental impacts of aggregate extraction have been well documented in Europe and in the U.S. since the early 1980s and studies are now available on extraction in S.E. Asia, notably in China.The lower Mekong River and its tributary watersheds are hotspots for biodiversity, but have seen considerable dam construction, particularly along the Lancang, the upper course of the Mekong in China. Currently, the most important issue in the Mekong basin is certainly the threat to the delta coastline because of its importance in terms of food security for the growing populations of Vietnam and Cambodia. The reasons most often cited to explain the retreat of the delta are the trapping of sediment in the existing upstream reservoirs and climate change. Sand and gravel mining in the Mekong River bed and in the tributary channels has not been taken into consideration to date.This paper provides the first assessment of sediment extraction along the 2 400-kilometre channel of the main stem of the lower Mekong River, from the Chinese border to the delta. The World Wide Fund for Nature ran a survey in 2011-2012. Systematic interviews assessing the types of aggregates, extraction techniques, extracted volumes, trends over the past years and the expected changes in the geography of extraction were carried out in the four countries drained by the Lower Mekong. The survey results reveal that the yearly volume of sand and gravel extracted, despite its undervaluation, exceeds the transported volume of sand and gravel in the Mekong sediment load. The results also highlight the extreme importance of this factor in the geomorphologic and ecological changes of the Mekong reaches and the delta. |
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| ISSN: | 1963-1197 |