River bank instability from unsustainable sand mining in the lower Mekong River
River bank instability from unsustainable sand mining in the lower Mekong River
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DOI：
10.1038/s41893-019-0455-3
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发表时间：
2020-01-13
影响因子：
27.6
通讯作者：
Houseago, Robert C.
中科院分区：
文献类型：
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作者：
Hackney, Christopher R.;Darby, Stephen E.;Houseago, Robert C.
近年来，建筑业的增长推动了对沙子的需求，从世界各大河流中提取了大量沙子。来自上游的沉积物输送自然会使河床中储存的沉积物增加，但缺乏来自大河的沙通量数据阻碍了对正在进行的采砂可持续性的评估。在这里，我们证明，推移质（0.18 +/- 0.07吨年（-1））是一个小的（1%）的一部分，湄公河下游的年总泥沙负荷。即使考虑到悬浮沙（6 +/- 2 Mt/yr（-1）），进入湄公河三角洲的总沙通量（6.18 +/- 2.01 Mt/yr（-1））也远低于目前的采砂率（50 Mt/yr（-1））。我们表明，在目前的速度，河床水平可以降低到足以引起河岸不稳定，可能会破坏住房和基础设施，并威胁到生命。我们的研究表明，在湄公河和其他受过度采砂影响的大河上，必须建立监管框架，将开采率限制在允许在沙子的自然供应/储存和沙子被移除的速度之间建立可持续平衡的水平。城市化和经济发展推动了对用于混凝土的沙子的需求。这项研究发现，沉积物负荷不足以取代湄公河三角洲开采的沙子，开采率高到足以使河岸不稳定。
Recent growth of the construction industry has fuelled the demand for sand, with considerable volumes being extracted from the world's large rivers. Sediment transport from upstream naturally replenishes sediment stored in river beds, but the absence of sand flux data from large rivers inhibits assessment of the sustainability of ongoing sand mining. Here, we demonstrate that bedload (0.18 +/- 0.07 Mt yr(-1)) is a small (1%) fraction of the total annual sediment load of the lower Mekong River. Even when considering suspended sand (6 +/- 2 Mt yr(-1)), the total sand flux entering the Mekong delta (6.18 +/- 2.01 Mt yr(-1)) is far less than current sand extraction rates (50 Mt yr(-1)). We show that at these current rates, river bed levels can be lowered sufficiently to induce river bank instability, potentially damaging housing and infrastructure and threatening lives. Our research suggests that on the Mekong and other large rivers subject to excessive sand mining, it is imperative to establish regulatory frameworks that limit extraction rates to levels that permit the establishment of a sustainable balance between the natural supply/storage of sand and the rate at which sand is removed.Urbanization and economic development fuel demand for sand, used for concrete. This study finds that sediment loads are insufficient to replace the sand mined from the Mekong River delta, with mining rates high enough to make river banks unstable.