The Port of Melbourne Corporation is halfway through an intensive, year-long program of scientific investigations and analyses designed to give the most complete hydrographical and environmental picture possible of Port Phillip Bay.
The program is the latest - and by far the most complex - stage in the proposed Port Phillip Bay Channel Deepening Project.
This is a project that has been on the Victorian Government agenda for years. However, it has acquired new momentum recently as part of a plan to ensure that the Port of Melbourne can retain its crown as Australia's largest port. It is currently facing mounting competition from Brisbane, Sydney and Adelaide for large-scale container and bulk cargo shipping - and the industry growth that goes with it.
The core issue is the increasing size and capability of container ships. The new bulk cargo vessels require a minimum 14.2 metre draught to enter and exit any port fully laden. Melbourne currently handles about 40 per cent of Australia's entire container trade. The depth of its shipping channel has somewhat constrained further growth for the port, especially in the size of the vessels that it can handle, or the number of containers they can hold.
That depth reaches a maximum of 11.6 metres, compared with the 14.2 metres of Sydney and Brisbane. Flinders Ports recently completed dredging the Adelaide port to the same depth.
The Port of Melbourne has a lot at stake in seeking to deepen its shipping channels. Using larger ships reduces costs, which translates into lower freight rates for business. The alternative is a whole range of risks, not the least that increased freight costs will be passed on to consumers, or that large container ships may choose to avoid Melbourne altogether.
'More than 30 per cent of vessels leaving the Port of Melbourne are not fully loaded,' the Corporation's chief executive, Stephen Bradford, told the ABC in 2005. 'They are constrained by the depth of the channel. This, in turn, constrains the Port of Melbourne. It will consign Melbourne to secondary port status unless the channels are deepened. This will allow larger vessels to come, and it will also provide greater export potential for Victorian producers.'
According to Professor Henry Ergas of the prime minister's infrastructure task force, ships typically call at two or three Australian ports in the one voyage, but are constrained by the shallowest of them. If Melbourne is the weakest link in this chain, it puts the growth of Victorian industry at some risk, and actually makes channel deepening an issue of national importance.
The Australian Council for Infrastructure Development rates channel deepening as Australia's most important infrastructure project, one that is ultimately expected to add $14.8 billion to gross domestic product by 2030.
The corporation and the Victorian state government have both been keen to emphasise that a key objective of the project is to ensure that it is conducted in an economic and environmentally-friendly way. Many are not convinced by such arguments. Conservation, tourism and fishing groups are opposed to the project on the grounds that it will ruin the ecology of the bay. They registered their protests loudly late last year during a nine-week trial dredge of Port Phillip Bay.
The trial involved using the world's largest dredging vessel, the Queen of the Netherlands, to test the environmental effects and engineering capability of the channel deepening project. There were three key objectives of the exercise. It would demonstrate the ripper drag head technology proposed for dredging the entrance to the bay, and test aspects of the proposed capital dredging environmental management plan. It would also provide data to help refine the turbidity models in South Channel and Port Melbourne Channel.
In an effort to address environmental and community concerns, the corporation recently appointed Phillip Toyne, a former head of the Australian Conservation Foundation, as an adviser to the Channel Deepening Project. Currently director of EcoFutures Pty Ltd, an environment consulting firm, Toyne is charged with providing independent advice to the port, specifically on those issues that relate to environmental groups and organisations.
A rigorous program of data collection and evaluation is taking place this year. The results will then be collated to produce a supplementary environment effects statement. Its aim will be to address the 130-plus recommendations made in an independent panel report produced in 2004.
The program includes a range of field activities in the bay, such as underwater geo-technical investigations at Port Phillip Heads. There will also be intensive studies of turbidity, water currents and quality, sedimentation movement and contaminants.
The project brief also includes a study of penguins and marine mammals, project and channel design, denitrification and bay ecological processes. Scientists are also studying dredged material management, dredging methodology, environmental risk methodology and risks for marine habitats.
So far, the project has included extensive surveying in and around existing shipping channels, and in areas identified as possible options for alternative dredged material grounds. The corporation is also carrying out surveying to new depths at the entrance of the bay.
'This surveying is providing valuable data and information. We will know more about the bay than ever before, and thus be better placed to protect it,' said Nick Easy, the executive general manager of the Channel Deepening Project.
'While the corporation has vast knowledge of areas that are of specific interest to the port - such as shipping channels, anchorages and existing dredged material grounds - the channel deepening project requires new work.
'Essentially, we are surveying areas more intensely, and with an even better level of accuracy. This will help minimise any uncertainty in the survey results and get consistency in the data over repeated surveys.'
The Corporation is using a Reson 8125 multibeam echo sounder for this work. The corporation says it was chosen because it could provide better resolution of the sea bed than any other device commercialy available.
The more unusual and complex process of hydro surveying is taking place at the entrance of the bay, where project teams are using multi-beam hydro survey equipment to create and analyse new depths and vertical profiles. For example, they have built up an environmental profile of an area commonly known as The Canyon.
The Canyon is part of the old course of the Yarra River between Point Lonsdale and Point Nepean. It has a maximum depth of 100 metres. The deep reef areas - at 20 to 40 metres - are inhabited by a range of sponges and corals amongst varying rock formations.
While the full environmental impact of the proposed dredging remains an unknown as yet, Easy insists that one of the objectives of the channel deepening project is to develop and deliver the project subject to strict environment requirements.
'The port is doing everything it can to ensure we have an environmentally sustainable project,' he said. 'We are keenly aware of the environmental importance of the bay and the place it has in the hearts of all Victorians. We have assembled the best team of environmental and scientific expertise available to ensure we get this project right.'
As part of the next stage in the government approval process for the project, all work carried out so far will be subject to extensive independent peer review by scientific specialists and a government-appointed group of independent experts.
Whatever the outcome of the studies being undertaken this year, there is no doubt that the hydrographical surveying being carried out in Port Phillip Bay is the most extensive ever undertaken in Victoria, and possibly in Australia.
The approval process for the project is expected to be complete by the end of 2007.
Hazel Baker is a freelance journalist working in Sydney.
