WATER-QUALITY MONITORING IN ESTUARINE WATERS USING THE LANDSAT THEMATIC MAPPER

Due to the impacts of rural and urban development on southwestern Aust ralian estuaries, and the general isolation of these water bodies, the re is a need to develop water quality monitoring systems that are both repetitive and cost-effective. The literature suggests that Landsat T hematic Mapper (TM) has spectral and spatial characteristics that are suited to monitoring small coastal water bodies. This study examined t he potential for the satellite-based TM sensor to serve as a regular m onitoring tool. Atmospherically corrected TM digital data acquired on four dates over summer 1990/91 and concurrent field measurements colle cted at the time of the satellite over-pass over the Peel-Harvey Estua rine System (32 degrees 30'S lat. 115 degrees 40'E long.) were used to obtain multitemporal, empirical algorithms for predicting pigment con centration, Secchi disk depth (SDD), and salinity. Highly significant, predictive algorithms were developed for these parameters. It is conc luded that Landsat TM has the resolution and accuracy to be a potentia lly very useful monitoring tool. However, cloud cover and delays in da ta acquisition seriously diminish its usefulness for monitoring an any thing less than a seasonal basis. Laboratory-based radiometric studies also indicated that Landsat TM was unlikely to be useful in determini ng the taxonomic composition of phytoplankton blooms in coastal waters .