This project is carried out under fuding from the Western Australia Marine Science Institution (WAMSI)
Large scale coastal dredging operations can produce extensive plumes characterized by very high suspended sediment concentrations, extreme turbidity, low light levels at the benthos and significant amounts of sediment deposition. These turbid plumes can cause significant damage to the marine environment so large scale dredging proposals are subject to environmental impact assessment (EIA). The assessment process requires proponents to make scientifically sound predictions of the likely extent, severity and persistence of environmental impacts. Prediction of the transport and fate of sediments, and the impact of these sediments on the environment, is typically achieved by using coupled hydrodynamic, wave and sediment transport models. The accuracy or confidence of the predictions of sediment deposition and erosion rates, benthic light availability, based on the likely extent, severity, and persistence of dredge plumes generated from the dredging operation depends, in part, on realistic input parameters. Particle size distributions, settling rates, characteristics of the sediment source, benthic processes, response of organisms to sediment deposition and decreased light levels. Also, analysis, testing and validation of the model outputs requires accurate field data.
The key management issues addressed by this project are to develop protocols for
(i) the incorporation of contemporary understanding, algorithms and parameters in representative numerical models;
(ii) the collection of data to optimize plume modelling;
(iii) the process of testing and validating model assumptions and predictions. Uncertainty in model predictions can cause delays through the assessment and approvals processes and lead to onerous and costly regulatory regimes. Results from this research will improve the confidence in model predictions and the efficiency and effectiveness of monitoring and managing impacts during dredge operations.
Project partners
| Dr. Peter Fearns, Mr. Passang Dorji, Dr. Mark Broomhall, M/s Helen Chedzey, RSSRG |  |
| Dr. Graham Symonds, Mr. Nick Mortimer, Dr. Paul Branson, Mr. Stephanie Contardo, Dr. Kenji Shimizu, Dr. Chaojiao Sun, Commonwealth Scientific and Industrial Research Organisation, Perth |  |
Final report available here
Published Articles
DORJI, P. & FEARNS, P. 2016. A Quantitative Comparison of Total Suspended Sediment Algorithms: A Case Study of the Last Decade for MODIS and Landsat-Based Sensors. Remote Sensing, 8, 810.
DORJI, P. & FEARNS, P. 2017. Impact of the spatial resolution of satellite remote sensing sensors in the quantification of total suspended sediment concentration: A case study in turbid waters of Northern Western Australia. PLOS ONE, 12, e0175042.
DORJI, P., FEARNS, P. & BROOMHALL, M. 2016. A Semi-Analytic Model for Estimating Total Suspended Sediment Concentration in Turbid Coastal Waters of Northern Western Australia Using MODIS-Aqua 250 m Data. Remote Sensing, 8, 556.