WITH works to replace the old Fremantle traffic bridge well under way, there’s concerns about how the city’s traffic network is going to cope with the resulting detours and blocked roads (“Bridge works start as traffic woes grow,” Herald, April 3, 2024). That’s got Mt Pleasant “ideas” man Richard J Harding to thinking about solutions (he’s the chap who suggested the old Beaconsfield quarry would be an ideal opera house when the council was casting about for ideas back in 2017. He’s come up with a “floating” solution.

THE floating solution refers to an idea for a temporary floating, or pontoon, bridge in Fremantle for the intermediary period, when the old Fremantle Traffic Bridge has been demolished and the new bridge is not yet completed. 

The former Fremantle mayor and now MLC Brad Pettitt has highlighted the traffic chaos in the intermediary period, saying he has grave concerns that in this in-between time people will be discouraged from coming to Fremantle for at least a full year. 

• A floating bridge at Evergreen Point in Washington State.

Emergency

The idea incorporates another idea of having a temporary pontoon bridge available when a natural disaster collapses another WA bridge; such an emergency bridge will be increasingly needed from the worsening impact of climate change. 

When the Kimberley was flooded in January 2023, it would have been useful to have available a temporary pontoon bridge while the Fitzroy Crossing Bridge was being rebuilt. 

When the new Fremantle Traffic Bridge is completed, the pontoon bridge can be stored away in case of a natural disaster-induced bridge collapse or another bridge needing to be demolished. 

The federal government might part-purchase the pontoon bridge with the WA government to additionally make it available for bridge collapses in the Eastern States.

I decided to consult with transport guru Peter Newman about my idea of a temporary pontoon Fremantle Traffic Bridge. 

In his reply to my email, he endorsed the idea both as a temporary pontoon Fremantle Traffic Bridge and as an emergency bridge. 

Prof Newman did ask how much it would cost, saying: “That is always going to be a major factor in these matters.”

This meant I needed to consult an expert in floating infrastructure and there is one in Fremantle I was able to get feedback from; this being Paul Toussaint-Jackson, director of Australian Floating Decks. 

Concerning the cost, he said it is not possible to give a precise figure “without a more exact quantity assessment and detailed review of the proposal”; he did mention a rule of thumb of a pontoon bridge costing 20 per cent of an equivalent regular bridge. 

Mr Toussaint-Jackson also said there are economies of scale with pontoon bridges; the larger the equivalent regular bridge the cost of the pontoon bridge can decrease below 20 per cent. 

He also made the point that the pontoon bridge may not need to be stored away after its use, as the components may be leased out to industry; thereby making the purchase an investment rather than simply a cost. 

Yet another point he made was that floating infrastructure has a lighter impact on the environment, such as river beds and sea beds.

There are definitely costs of not having a temporary pontoon bridge in Fremantle, in going ‘bridge-less’ in this intermediary period. 

These are the costs of the loss of revenue for Fremantle businesses and organisations in a year of people avoiding the coastal city, plus miscellaneous costs incurred from traffic congestion. 

Compensation

The WA government is liable for compensation for these costs. 

People in the Town of East Fremantle incur these costs as well as in the City of Fremantle. 

People north of the river will be additionally impacted by a bridge-less period in the towns of Mosman Park, Cottesloe and Peppermint Grove. 

Therefore, in considering the expense of purchasing a pontoon bridge the WA government would need to balance that against the compensation liable to be paid to businesses and the community in a big area covering multiple local councils.

It is also very important for the WA government to consider the non-monetary consequences of a bridge-less period, particularly in the resulting crankiness of a vast number of people.