Remote sensing of water quality in the Singapore-Johor-Riau growth triangle

Abstract

Remote sensing has not been used extensively in southeast Asia for resource development, partly for reasons of perennial cloud cover and low image availability. However, the low level of awareness of remote sensing among planning and environmental agencies is unjustified in view of the capabilities of high spatial and spectral resolution sensors such as the Landsat Thematic Mapper (TM), coupled with a general lack of physical resources data throughout the region. The main objective of this study is to demonstrate the application of Landsat MT imagery to the survey and monitoring of water quality in coastal regions affected by land drainage from peat swamp catchments, which are common in southeast Asia, thus where dissolved organic matter (yellow substance) dominates the volume reflectance of coastal water. The Thematic Mapper 0.45–0.52 μmv waveband was found to be capable of differentiating water with high concentration of yellow substance from nonplume water, but the addition of the 0.63–0.69 μm waveband was required for differentiating lower concentrations of yellow substance. The higher temperature of yellow substance dominated river plumes observed on the 10.5–12.5 μm waveband confirmed field observations. These findings have implications for water resource management in the region, since image derived classes of water quality can be related to environmental standards for the main types of water use.