Archaeologists have discovered the remains of one of Australia’s earliest bridges within the structure of another historic bridge during the supervision of controversial construction work in Parramatta.
The Gaol Bridge, which was built between 1802 and 1804, is only mentioned in a few extant historical sources, and until now historians and archaeologists had failed to uncover any physical signs of its existence.
Despite the scarcity of written or archeological evidence of the bridge, historians believe it played a vital role in the development of the greater Sydney region during the early colonial period, providing the first major crossing over the Parramatta River.
Controversial work on the Lennox Bridge has finally solved the mystery of the Gaol Bridge's location, with the discovery of the piers of the earlier bridge within the structure of its successor.
While drilling tunnels through the sides of the Lennox Bridge, archaeologists found a set of sandstone pier and timber girders belonging to the Gaol Bridge.
Archaeologist Anne Bickford said she and her team were stunned by the discovery, as they had been unaware of the presence of any remains at the site.
It turns out that state heritage-listed Lennox Bridge had simply been built on top of the Gaol Bridge, with developers in the early 19th century opting to simply leave the pre-existing pier in its original place in lieu of taking the trouble to remove it completely.
Archaeologists speculate that the pier could extend much further into the ground alongside other undiscovered parts of the original structure. Excavation will only proceed, however, to the extent required by the current tunnel project.
A small section of the bridge's pier has been removed by archaeologists and timber girdings have been scrubbed up and catalogued with the hope of eventually placing them on public exhibition.
The remainder of the pier has been scientifically preserved and reburied by archaeologists beneath the floor of the controversial new tunnel being built along the Lennox Bridge.
According to Bickford, their intention is to preserve the pier of the Gaol Bridge in its original position for future generations, should they decide to perform further amendments of the Lennox Bridge many decades or even centuries from now.
Archaeological excavations have delayed the construction of tunnels through the Lennox Bridge, a project that is scheduled for completion in April next year.
The drilling of three-metre wide rectangular tunnels through the sandstone bridge has proven immensely controversial given the historic significance of the infrastructure work.
The Lennox Bridge is believed to be second oldest bridge in the state of NSW. It was designed by David Lennox, the colony's first superintendent of bridges, and built by convicts between 1836 and 1839.
Heritage advocates vehemently opposed the tunnelling project for nearly two years prior to the start of the tunnelling project, arguing that it would ruin the heritage value and architectural grace of a Parramatta icon, as well as potentially cause irreversible damage to its structure.
Parramatta Council nonetheless managed to obtained the approval of the NSW Heritage Council for the $8 million project in 2012, arguing that the tunnels would enhance the heritage value of the bridge by granting pedestrians, bikers and people with impeded mobility better access to the river.