Routine activity to move build-up of seabed sand
23 March 2023
The Whyalla Port will undertake a marine “sweeping” process next week as part of routine maintenance for the GFG Alliance operation.
The sweeping process is necessary to move the build-up of seabed sand that has lowered water depth, by up to a metre, at the Port’s outer harbour berthing facility. The lower water depth can affect efficiency when loading ships and create adverse environmental effects through turbidity.
The build-up will be moved into deeper water, within the Port’s exclusion zone, with the use of an Edi Sweeper Tug. This vessel uses a 20-tonne sweeper bar to incrementally move the material in 20-25cm cuts.
Through this controlled sweeping process, we will lower the seabed level by up to a metre giving the ships greater clearance when coming into Port and less disturbance to the bottom
Mark Henderson
To ensure there is minimal disruption to water quality, buoys have been placed around the Port for the past two months to measure background water quality prior to the sweeping. During the sweeping, these buoys will send data back to the Port in real-time to monitor water quality.
Whyalla Port Manager Mark Henderson said this necessary work will increase efficiency at the Port and reduce impacts on the surrounding marine environment.
“When the seabed is raised in the Port due to seabed sand build up, this actually creates a turbidity problem with the ship’s hulls coming too close to the bottom and stirring the sand up,” Mr Henderson said.
“Through this controlled sweeping process, we will lower the seabed level by up to a metre giving the ships greater clearance when coming into Port and less disturbance to the bottom. This process also ensures the material is not removed or dumped on land but simply moved back into deeper water.”
Mr Henderson said there would be no impact on Whyalla boaties or water activities around the area as the sweeping work was contained entirely within the Port’s exclusion zone. While not requiring permits for this work Whyalla Port has still, however, kept the Environmental Protection Authority (EPA) informed.
“We have undergone a strict risk assessment for the marine environment, in and around the Port, and proactively consulted with the EPA,” Mr Henderson said.
“Our environmental team has assessed the sea grasses around the Port and established there will be minimal disturbance to this environment, through this strictly controlled work.
“The sweep tug is very slow and deliberate to minimise disturbance … stirring up the bottom excessively would defeat the purpose of the trying to move this material in the first place.”
Weather conditions permitting, the sweep work will commence on Monday, March 27 and finish on Friday, March 31.
For all enquiries, please contact GFG Alliance Community Stakeholder and Engagement Advisor Denise Sharp on (08) 8640 4418 or via email denise.sharp@gfgalliance.com