A Bit of Perth

I’m out of Perth for a week so I dropped in on Applecross, just over the Canning Bridge to get some bits of Perth.

Firstly, Canning Bridge itself. There have been four Canning Bridges across this, the most downstream crossing of the Canning River. Just 100 metres wide, it is a watery bottleneck with strong currents as the tide moves in and out.

The first bridge was designed in 1846 by Henry Trigg, then Superintendent of Public Works. Its deck sat just 8 feet (2 m) above the river water stopping all but the lowest and smallest vessels from accessing the upper reaches of the Canning. It cost £425 to construct.

Flooding in the Swan and Canning Rivers in 1862 damaged the Canning and Helena Bridges, as well as The Causeway. As a result, a new Canning Bridge was built in 1867 by convicts. This second bridge had a clearance of 12 feet (4 m) above the river water; the bridge deck was raised to have a clearance of 18 feet (6 m) in 1892.

Construction on a replacement for the third bridge began in 1938. The new bridge, which cost £24,830, was opened in December 1939. It was a timber pile-driven bridge and features three navigation spans, two of 24 metres and one of 18 metres. It is 175 metres long.

The 1939 bridge remains standing today, however it has been extensively modified since it was first opened and only carries Eastbound traffic on Canning Highway. In 1958, another pile-driven timber bridge was constructed alongside the existing 1939 bridge on its upstream (Southern) side, effectively doubling the traffic capacity of the structure. This newer structure featured a fishing platform below, but in most other respects was very similar to the original carriageway.

The separation between the two bridges is visible from beneath.

Approaching the main navigation span is a nerve-wracking time for inexperienced skippers as the swirling waters of the tidal surge create some handling problems. Just as well the speed limit is just 8 knots!

 

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