Sedimentation and Survival of the Mekong Delta A Case Study of Decreased Sediment Supply and Accelerating Rates of Relative Sea Level Rise
Sedimentation and Survival of the Mekong Delta A Case Study of Decreased Sediment Supply and Accelerating Rates of Relative Sea Level Rise
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DOI：
10.5670/oceanog.2017.318
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发表时间：
2017-09-01
期刊：
影响因子：
2.8
通讯作者：
Nguyen, Thanh T.
中科院分区：
文献类型：
--
作者：
Allison, Mead A.;Nittrouer, Charles A.;Nguyen, Thanh T.
21世纪初的湄公河三角洲正处于可持续发展的临界点。三角洲受到以下影响的威胁：(1)流域的筑坝和土地利用变化，(2)正在快速发展的国家(越南)三角洲人口的迅速增长，(3)海平面上升的速度加快，以及(4)可能影响热带气旋频率和流域季风降水模式的不确定的未来气候。这些威胁也存在于发源于喜马拉雅山脉的其他大河中。根据越南和美国最近对湄公河最大分流(宋侯)、沿岸红树林和邻近水下三角洲的联合研究，对两个主要威胁进行了审查。我们考虑了流域泥沙负荷下降(以及年过程线的修改)以及相对海平面上升(海平面上升+下沉)带来的洪水和盐度入侵的影响。这项2014-2015年的研究表明，河流泥沙供应三角洲这些地区的相互连通性：泥沙负荷下降和海平面上升可能会影响分流河道形态，并将改变河口环流和泥沙捕获效率，所有这些都对红树林和陆架的泥沙供应有反馈作用。
The Mekong Delta, early in the twenty-first century, is at a tipping point for sustainability. The delta is threatened by the implications of (1) damming and land-use changes in the drainage basin, (2) a burgeoning delta population in a nation (Vietnam) undergoing rapid development, (3) accelerating rates of rising sea level, and (4) an uncertain future climate that may impact tropical cyclone frequency and monsoonal precipitation patterns in the basin. These threats are present in other great rivers that emerge from the Himalayas. Two primary threats are examined in light of recent joint Vietnam-US studies in the largest distributary (Song Hau) of the Mekong River, in the shore-fringing mangroves, and on the adjacent subaqueous delta. We consider the implications of declining sediment loads from the catchment (as well as modification of the annual hydrograph) and flooding and salinity intrusion associated with relative sea level rise (eustatic + subsidence). This 2014-2015 study shows the interconnectivity in fluvial sediment supply to these parts of the delta: declining sediment loads and rising sea levels will likely impact distributary channel morphology and will alter estuarine circulation and sediment-trapping efficiency, all of which have feedbacks on sediment provision to the mangrove forests and the shelf.