The EPA's Role

As South Australia’s independent environment protection regulator, the EPA focused on ensuring mitigation measures and controls were in place throughout the dredge trial to prevent and/or minimise environmental harm. The EPA regulated the trial through an authorisation in the form of a licence (EPA Licence #42842) with MC Dredging and Port Development Pty Ltd, which was contracted by DEW to undertake the dredging works.

The licence required MC Dredging and Port Development to prepare a DMP detailing proposed measures to minimise adverse impacts from the dredging. The DMP for the trial also required a water quality monitoring plan, a seagrass monitoring plan, and a noise management plan. The DMP included turbidity triggers to protect water quality and seagrass. Turbidity was continuously monitored at six sites to ensure it remained similar to background levels recorded before the trial. Maintaining pre-trial water quality was an important indicator that the dredging was undertaken in a manner that would not cause harm, particularly to seagrass.

The EPA assessed the DMP against the EPA Dredge Guideline 2020, and provided its approval of the DMP and dredge trial.

The EPA monitored compliance with the DMP during dredging works and required seagrass monitoring to be undertaken by suitably qualified experts before and after the trial. The monitoring is important to understand any impact on seagrass and will inform mitigation requirements for any future dredging activities along the Adelaide metropolitan coastline.