Following the Public Environmental Report (PER) and the supplementary PER, it was identified that whilst impacts to nearby sensitive receptors could be managed if material was placed at the PER site (now approved), proponents were willing to consider other offshore relocation options within a defined zone. Based on the EPBC approval conditions related to the DSAP and the proposed requirements detailed by the Great Barrier Reef Marine Park Authority (GBRMPA), it was deemed necessary for a comparative assessment of relocation sites to be undertaken.
The scope of work was to undertake a comparative assessment of the short-term and long-term response of dredge material relocated at three different placement sites offshore of Abbot Point as part of a capital dredging program. The approach adopted was developed in collaboration with the regulators. This comparative dredge material relocation site assessment within the Great Barrier Reef Marine Park (GBRMP) included the collection of water level, current and wave data at the three sites. The numerical modelling undertaken required the representation of ocean circulation in the model and applied a stochastic approach for the modelling of sediment plumes and as such is considered to be leading practise.
The project met the very tight deadlines set by the client and also came in to budget. Both the client and the regulators were impressed with the study. The approach adopted to represent ocean circulation in the hydrodynamic model was validated using measured data. This was the first study in the Great Barrier Reef to adopt a stochastic approach for dredge plume modelling and as such was commended by the regulators as it increases the confidence which can be placed in the modelling results and therefore any associated potential environmental impacts.