Sediment storage and transfer in the Mekong: generalizations on a large river

摘要

Our knowledge regarding sediment transfer and storage by a large river is limited,. The morphology of the Mekong River and the physiography of its basin restrict sediment storage to its channel, or very close to it, for 4000 km, due to limited overbank accommodation space. Only for the last 600 km does the river move laterally to deposit sediment. This paper reviews: (a) the nature of sediment storage in the upper and middle Mekong; (b) sediment deposition in a wide flood basin in its lower course; (c) transfer of flood sediment into Tonle Sap Lake; and (d) the seasonal pattern of sediment collection, transfer and storage along the river and into the South China Sea, The discussion is based mainly on satellite imagery at various resolutions, hydrological information from the Mekong River Commission, and field visits. It is suggested that the sediment storage pattern and the volume stored in the Mekong can be extensively disturbed by anthropogenic environmental alteration, such as the ongoing series of dam construction in the upper reaches.