SEDIMENT LOAD ESTIMATES AND VARIATIONS IN THE LOWER MEKONG RIVER

Although sediment issues have critical implications for aquatic ecology, agriculture, water supply and river navigation, studies regarding the sediment production, deposition and transportation in the Lower Mekong River are relatively sparse. With the construction and operation of dams in the Upper Mekong River, this issue has attracted more attention in recent years. The estimation of sediment loads has been hindered by the serious lack of sediment measurements in the Lower Mekong River. This study aimed to investigate the possibility of estimating the sediment loads for the years without good quality SSC measurements in the Lower Mekong River. To make this estimate, this study classified the rating curves on the basis of the synchronous nature of the suspended sediment concentration (SSC) and the water discharge among the adjacent stations (e. g. Chiang Saen, Luang Prabang, Nong Khai, Mukdahan and Khong Chiam). Together with other methods, it was possible to estimate the yearly sediment loads for the period of 1962-2003 at the five mainstream Lower Mekong River stations. Consequently, the spatial and temporal variations in the sediment loads and water discharge in the Lower Mekong River were examined. In addition, the possible impacts of Chinese dams as well as the annual sediment load of the Mekong River into the sea were also investigated. Copyright (C) 2009 John Wiley & Sons, Ltd.