Currency Creek Bridge, SA

South Australia was founded in 1836 and in its first 13 years little was done about the construction of roads and bridges. Most of the early bridges were rough timber logs thrown across streams. These bridges generally were washed away by floods.

There was pressure on the government to provide better roads and bridges and in 1849 the Central Roads Board was created.

The Central Roads Board identified a need for a reliable form of bridge that could survive most floods and be cheaply constructed from local materials. The use of iron for bridge construction was compromised by the necessity to be fabricated in Britain.

Edmund Wright, an engineer, and architect wrote a prize-winning essay identifying laminated timber arch bridges using local or imported timbers as suitable.

Initially the Board constructed 15 bridges with horizontal laminations that cost about one quarter of an iron bridge. These bridges were found to lack durability. Engineers then changed the standard design to use Red Gum soaked in paraffin to deter white ants. The laminations were changed from horizontal to vertical and the joints then covered with iron to prevent ingress of water.

A crossing of Currency Creek was part of the Goolwa to Strathalbyn Road. Originally a simple timber bridge was used for the crossing. In 1852 a contract was awarded to Trenouth and Dick of Strathalbyn for the construction of the forty-foot span vertically laminated timber bridge.

The bridge was officially opened on 17 January 1873. A new bridge was constructed adjacent the bridge and opened in 1968 and the laminated timber bridge closed at the same time.

The Currency Creek Bridge represents an example of a unique South Australian innovation to solve a local problem of using durable local materials to construct large span bridges.

Fifteen laminated timber bridges were constructed in South Australia. Of the fifteen, twelve no longer exist, one at Angle Park collapsed in 2023 leaving only the abutments and wing walls and the Sunnyhill Bridge was inundated by the filling of the Millsbrook Reservoir. The Currency Creek Bridge is the only visible one left.