摘要
近年来,世界上许多重大河流的泥沙量发生了显著变化,其原因是土地利用发生变化、修建水库和人类对其流域的其它影响。许多河流的泥沙量下降,而另外一些河流上升。这种变化对系统的自然机能及人类对河流系统的利用都有着重要意义。本文研究了湄公河泥沙量近年的变化迹象。可利用的数据在取样频率和覆盖周期上都有许多局限性,但它们经过处理,仍为研究20世纪60年代初至2002年期间该河流的泥沙量变化提供了基础。尽管有证据表明一些监测站的泥沙量升高,但总体趋势并没有重大变化的迹象,并且系统通过泥沙积存达到了缓冲。到2002年为止,在中国源头修建的大坝看来对泥沙量没有影响,尽管当更大的大坝被批准时,湄公河的泥沙量有望下降。
The sediment loads of many of the world's major rivers have changed significantly in recent years due to landuse change,reservoir construction,and other human impacts on their drainage basins.For many rivers,the loads have decreased,whereas for others,they have increased.Such changes can have important implications for both the natural functioning of the system as well as for human exploitation of the river system.This paper considers the evidence for recent changes in the sediment load of the Mekong River.The available data have a number of limitations in terms of both sampling frequency and the period of coverage,but they have been processed to provide a basis for considering the changes in the sediment load of the river over the period extending from the early 1960s to 2002.Although there is evidence of increasing loads at some measuring stations,the overall trends show little evidence of major changes,and the system provides evidence of buffering through storage. As of 2002,the construction of major dams on the headwaters in China appears to have had little impact on the sediment load,although as further larger dams are commissioned,the sediment load of the Mekong can be expected to decrease.
