Dredging of bay opening kicks off

Dredging of bay opening kicks off

David Rood April 4, 2008

THE deepening of Port Phillip Bay's shipping channels has moved into its most controversial phase with the dredging of the heads starting today.

Day 57 of the $1 billion project will see the dredger Queen of the Netherlands start work on the treacherous opening to the bay.

Removal of the 550,000 cubic metres of mainly rock material will take until October, with work continuing 24 hours a day, every day.

Coastal geologists, environmentalists and opponents of the project have said that allowing more water to rush into and out of the bay would harm beaches and marine life, damaging more than 100 species of sea sponges and coral.

Concerns have also been raised about the erosion caused by removing top layers of rock. The recovery period is estimated to be up to 30 years.

The Australian Conservation Foundation and the Australian Conservation Foundation said 115 species of underwater sponges would be damaged by rock falls that are expected to continue for 30 years.

"This particular sponge community has been noted by scientists to be highly significant to Victoria's biodiversity," Parks Association officer Megan Clinton said.

Anti-channel deepening group Blue Wedges said the 2005 trial dredge caused significant damage, with rocks spilling into the main shipping channel and the Port Phillip Heads Marine National Park. Spokeswoman Jenny Warfe expressed concern about potential environmental damage at the heads and from the rises in sea levels.

The works have removed 2.9 million cubic metres of material from Port of Melbourne shipping channels — more than 10% of the project.

The Queen of the Netherlands will give way to all commercial vessels when working in the heads. Channels will be scoured with a suction hopper dredge. Previous works, the last of which were completed in 1986, used explosives.
Project manager Nick Easy said that a small amount of material would be spilled into the national park with a short-term impact on the area.

Mr Easy said the environmental management plan had several measures in place to minimise the impact of dredging, including clearing the material left behind every week and strict requirements on the direction of dredging to minimise rockfalls and their impact.

The Victorian Greens said the project was an act of vandalism as rock scour damage was still occurring at the site of the 2005 trial dredging. "Unfortunately, once the damage has been done, it can't be undone and the people of Victoria will have forever to regret that this was ever allowed to happen," Greens MP Sue Pennicuik said.