Brisbane wins interstate dredging contracts

11 June 2002

Within less than two years of operation, the Port of Brisbane Corporation’s state-of-the-art dredger, the Brisbane, has already won four dredging contracts, beating national and international competition.

In March, the Brisbane completed a maintenance contract with the Port of Devonport Corporation Pty Ltd in Tasmania to dredge the port’s entrance channel, swing basin and berth areas. In one month, and on schedule, the dredger removed about 200,000 cubic metres of sand, gravel and silt from the designated dredged areas.

Peter Witt, Port Engineer, Port of Devonport Corporation said the project had been a great success. “Our experience with the Port of Brisbane Corporation, from the communications aspect to the mechanical manoeuvrability of the dredger itself, which was necessary to get to some of the berth areas in the port, was excellent. The project was completed on time and under budget.”

The Brisbane’s contract at Twofold Bay at Eden, NSW involved the combination of development dredging and environmental monitoring. Commencing work in April, the Brisbane dredged a ship-turning basin for a new $40 million navy provisioning and ammunitions handling wharf.

Dredging was the first component of the $25 million design and construction contract that was awarded to Baulderstone Hornibrook Pty Ltd to build the wharf, jetty and access road to the facility.

As part of the project, the Corporation commissioned WBM Oceanics Pty Ltd to monitor the turbidity plumes over the adjacent existing seagrass area in the bay. Three rows of monitoring stations were placed at regular intervals from the Posidonia seagrass beds to monitor the level of turbidity as it extended from the dredge site to the seagrass. If the turbidity reached a level of concern, the dredging process was altered until the plumes settled.

Last year, under a four-month contract negotiated with the Bundaberg Port Authority, the Brisbane removed one million cubic metres to deepen the port’s access channel to accommodate deeper drafted sugar vessels.

And, just recently, the Brisbane was successful in winning the contract to deepen the access channel to the Fisherman’s Landing berth at the Port of Gladstone. The deepening is associated with the construction of wharf facilities to handle bauxite and alumina for the new Comalco alumina refinery.

The four-month contract, proposed to commence at the end of this year, will involve removing up to 800,000 cubic metres of material, which will be pumped ashore for reclamation purposes.

These contracts are in addition to the Brisbane’s scheduled annual maintenance dredging in its home port of Brisbane, as well as its northern Queensland ports campaign, which includes the dredging of channels and berths at Bundaberg, Gladstone, Rockhampton, Mackay, Townsville, Cairns and Weipa.