Evaluation of satellite remote sensing for operational monitoring of sediment plumes produced by dredging at Hay Point, Queensland, Australia

This study describes the potential of multi-temporal Landsat Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+) and Moderate Resolution Imaging Spectroradiometer (MODIS) data for the operational monitoring of sediment plume produced by dredging between 8 May and 31 October 2006 at Hay Point, Northern Queensland, Australia. The methodology involved atmospheric correction of the TM, ETM+ and MODIS images, the development and verification of a Total Suspended Sediment (TSS) model, and the evaluation of the image derived TSS maps for tracking sediment plume movements and its influence on the fringing coral environment. TSS empirical models are developed from TM/ETM+ Band 3 with R-2 = 0.92 and from MODIS Band 12 with R-2 = 0.61. The accuracy of the TSS model for TM/ETM+ is +/- 3.2 (mg l(-1)) and for MODIS is +/- 16.0 (mg l(-1)). The estimated sediment plume displacement and rate of dispersion show high correlation with the tidal amplitude. Wind speed greater than 6 m s(-1) increases the sediment plume movements during the ebb tide. The frequency of the plume extending beyond the fringing coral islands during dredging operations is in agreement with the field observed coral mortality due to sediment accumulation.