Granite Island Causeway


Customer: Department of Infrastructure and Transport

Contract: Design and Construct

Location: Victor Harbour, South Australia

Ports & Coastal Solutions Transport Solutions Australia

Fast Facts

  • 650 m long, 6 m wide new causeway  
  • New rail line on causeway for historic horse-drawn tram
  • New boat landing facility

McConnell Dowell (MCD) partnering with the Principal, the Department for Infrastructure and Transport (DIT) continued its strong working relationship with the contract to design and construct the new Causeway as part of the $43 million Granite Island Causeway Project. The awarding of the contract followed a collaborative design development process involving DIT, MCD and MCD’s design consultant WGA. 

The Granite Island Causeway, located 83 kilometres (km) south of Adelaide, is a Victor Harbor tourism, commercial and recreational landmark. It is the only link between Granite Island and Victor Harbor and is used by pedestrians, the iconic horse drawn tram service, a small number of vehicles that service the island, tourism attractions and the fishing industry. It is estimated that the number of pedestrians accessing the Causeway is approximately 700,000 per annum. 

The project is situated on a site of cultural significance to the Traditional Owners of the area, the Ngarrindjeri and Ramindjeri, and the waters around the Causeway are in a Habitat Protection Zone of the Encounter Marine Park. 

The project involved the design and construction of a new Causeway structure including rail line provisions for the horse drawn tram, rest areas and urban design improvements including foreshore treatments at Causeway approaches. 

Several elements of the Granite Island Causeway made this a unique structure. The 650 metre long, 6 metre wide Causeway, sensitive shallow marine environment, popular holiday destination location surrounded by affected stakeholders and the tight delivery timeframe contributed to making this project very challenging.  The new structure needed to reflect and pay homage to the revered existing heritage listed Causeway which made consideration of the construction methodology further challenging. 

MCD developed a bespoke method for the execution of the project which drew on elements from several previous successful projects and the business’ vast experience in the use of marine plant, bridge launching, hand over hand construction and cantilever travellers. 

The solution leveraged best practice environmental management, reducing the number of piles to be driven into the seabed, minimising the impact of the works on seagrass and other flora and fauna. Pile installation works incorporated a piling gate design that included a highly innovative noise curtain to reduce underwater piling noise. This solution had very little in situ concrete construction over water, reducing the risk of spillage. 

The new Granite Island Causeway provides a holistic, authentic design solution with a 100-year design life that creates an elegant local landmark, respectful of heritage and place, meeting all Disability Discrimination Act 1992 (DDA) and standard requirements while also being a ‘whole of life’ solution that minimises costs over time. 

The new Causeway provides ongoing access to Granite Island with a modern structure that accentuates, reflects, and respects its historical significance. 

The successful innovative partnership between DIT, MCD, the design partners and consultants ensured the delivery of this complex multi-disciplined project was completed on time and within budget allowing the community to enjoy the new Causeway over the 2021/22 summer period. 

Client Quote: 

”I am very proud to have been a part of the team that has all come together to resolve the challenges, which allowed us as a team to achieve such an outstanding result.” 

“You all have created history for South Australia by completing this project, which will be enjoyed by many generations to come.” 

Dariusz Fanok, Delivery Manager, Department for Infrastructure and Transport 

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