The Gascoyne Bridge

This fall, I took a vacation in the northwestern region of Western Australia. I visited Shark Bay, Monkey Mia, Denham, and Coral Bay. My favourite part was when I went snorkelling in the Point Quobba Aquarium; I've never been surrounded by so many fish while swimming in the ocean. But beyond the beaches and sea life, one unexpected highlight was learning about how a bridge transformed life in Carnarvon.

I'll share what I learned about the Gascoyne River and the incredible engineering story behind its bridge.

The Gascoyne River is the longest in Western Australia, at 764 km long, and was named by the explorer George Grey in 1839 in honour of his friend, Captain J. Gascoyne. Known as "the upside-down river", the Gascoyne River only has surface water for 6-8 weeks from when it flows. The river has its source between Meekatharra and Newman, flowing into the Indian Ocean in Carnarvon. The floor lever marker on the side of the bridge marks significant years of high flood levels, such as 1960 and 1961, with water levels exceeding 7 meters above ground level. The Gascoyne River is the heart of Carnarvon and serves as the town's main water supply.

Between 1931 and 2002, the Gascoyne bridge provided the only permanent crossing point over the river and contributed significantly to the development of Carnarvan. This bridge was demolished in 2002 to make way for the new two-lane bridge.

The original Gascoyne bridge was constructed from timber, as it was cheap and available to the people. However, an enormous amount of stress was placed on the bridge due to frequent flooding, causing concerning decay of the wood. Therefore, the single-lane timber deck of the bridge was fixed to a superstructure of rolled steel joints, which was supported by 18 reinforced concrete piers, each of which was founded on reinforced concrete piles driven 6 meters into the sand of the riverbed.

After construction in 2002, the Gascoyne River bridge was the first concrete and steel bridge built in the north-west of WA. It was also one of the first bridges in the state designed to withstand seasonal flooding and provide an all-weather crossing.

Learning about the Gascoyne River and its bridge made me realise the profound role that engineering plays in connecting and protecting communities in remote regions, such as Western Australia's north. As someone who was just passing by, it gave me a new appreciation for the stories hidden beneath the surface of the places we travel.