Abstract

The Mekong River has recently been suffering from environmental degradation despite its global significance of biodiversity. The monitoring of important constituents of ecosystems is critical for implementing effective environmental management. Meanwhile, the application of remote sensing to assess inland water quality has recently escalated due to its scanning wide water bodies within a short time period. In this study, the applicability for monitoring suspended sediment load (SSL) in the Mekong River over temporal and spatial dimensions was investigated. Landsat scenes captured between 1988 and 2000, including 110 Thematic Mapper (TM) images and 21 Enhanced Thematic Mapper Plus (ETM+) images, were analysed in correspondence with ground observations. The three visible and near infrared bands were included in the analysis. The polynomial relationship of the NIR exoatmospheric reflectance, band 4 wave length: 760-900 nm, to SSL based on the ground observations at 9 sites along the river demonstrated the best agreements (overall R2, 0.76). Subsequently, the equation enables us to reasonably estimate the suspended sediment load longitudinal profiles and its temporal changes. Thus, the results confirmed a high applicability of satellite image for monitoring SSL in relatively large rivers such as the Mekong River.

Keywords: Suspended sediment; Mekong river; Satellite image; Longitudinal profile; Temporal change.