Australia: Port Completes Maintenance Dredging Program

Port of Melbourne Corporation (PoMC) has successfully completed its 2009-11 routine maintenance dredging program ahead of time and within budget.

The staged project, which commenced in November 2009, included dredging and sweeping of the dredged material before capping this sediment with clean sand after a period of settling.

Working to remove a build-up of silt in berths and berth approaches in the Yarra and Maribyrnong Rivers, Webb Dock, Ann Street Pier and Station Pier, a total volume of around 325,600 cubic metres of sediment was dredged and disposed of in the Port of Melbourne Dredge Material Ground (DMG) three weeks ahead of schedule.

The areas dredged were not part of the Channel Deepening Project and provided no additional depth beyond that previously approved. As the name implies, maintenance dredging ensures that declared depths are maintained.

Capping of the sediment in the Port of Melbourne DMG with around 250,000 cubic metres of clean sand recovered from the South East DMG, 10 km off Mount Martha, was completed on 14 December with the deployment of the trailing suction hopper dredge Cornelis Zanen (CoZa). The volume of clean sand used to cap the dredged material was greater than was originally estimated as it was essential to ensure the minimum capping depth of half a metre was achieved as required under the Environmental Management Plan (EMP).

Recovery and placement of the clean sand over the dredged material by the CoZa was completed before the commencement of the dredging exclusion period, which came into effect on 18 December in accordance with the EMP. No dredging is permitted in the south of the bay between this time and 26 January.

With an approved EMP in place which was independently audited, the maintenance dredging program recorded one non-compliance as a result of an administrative oversight.

Commercial vessels with the ability to ballast are required to submit a ‘Ballast Water Report Form’ with the Environmental Protection Authority (EPA) before arriving in Victorian waters. This form was not submitted by one vessel working on the project. However, no ballast water was actually taken or discharged by that vessel. This form was subsequently submitted. There were no environmental consequences.


Source: portofmelbourne, January 25, 2011