In April 2021, the town of Carnarvon, around 900km north of Perth in Western Australia, was impacted by Cyclone Seroja. This deadly tropical cyclone had already caused extensive flooding and landslides on Timor and neighboring islands and continued on to make landfall in Western Australia. 

It was the first cyclone to do so since Cyclone Elaine and Vance in March 1999. 

The high seas and swell resulting from the cyclone wreaked havoc on the heritage listed One Mile Jetty, which extends almost 1.5km out to sea from Babbage Island. The maximum wind gust recorded at Carnarvon was 107 km per hour overnight on 11 April 2021. 

Pierre Cassian, Agreement Manager - Critical Infrastructure says our delivery of service excellence in all that we do, is key to continuing to win work from clients like the Department of Transport.

We have 27 years of knowledge of the client's assets and have worked in close partnership to maintain their maritime assets across the state.

Program/ Project Manager Adam Smythe was responsible for the project and says that the subcontractor selected to undertake the demolition of the jetty was chosen based on providing the best value for money, and with access to appropriate specialised plant. 

Adam notes that our ability to utilise our suitably trained in-house maintenance and operation staff provided flexibility to quickly mobilise personnel and plant to site - which is important for projects like this.

Being able to use Ventia employees to deliver this project resulted in a significant cost savings for the client. Ultimately, the project came in 15% under budget. 

The initial phase of the project covered assessment and reporting of the condition of the jetty following the cyclone. The resulting report recommended the jetty be deconstructed due to extensive damage and the high potential for danger to marine vessels in the area from floating timber, which was continuing to fall from the structure. 

"Once our recommendation was approved, we were asked to develop a materials list to determine the tonnage of timber that we'd need to deconstruct," Adam says. "Once that was determined, we were able to finalise the scope and budget for the project for the client."  

One Mile Jetty extends almost 1.5km out to sea from Babbage Island. 

Stakeholder engagement is key

The Carnarvon Heritage Group (CHG) are custodians of the 125-year-old heritage listed jetty by way of a license from the WA Government via the Department of Transport (DoT). The Department's involvement in the deconstruction project was to address & remove the navigational safety issue following the cyclone, as well as fulfilling Heritage Council of WA approval requirements.

In addition, other community stakeholders, including interested locals, the wildlife agency, heritage architect and local council also needed to be engaged. 

Key to the project's success was ensuring that the diverse group of stakeholders were engaged early and with regular communication and with their support of the planned approach was paramount to the outcome achieved.

Adam says that the relatively short timeframe for the contract - six months from start to finish - was a first for the contract team, but also a challenge they took on with enthusiasm. It was also the single-largest project delivered under the broader Asset Management and Maintenance contract in place with the Department of Transport. 

Innovation in practice

From an innovation perspective, the team utilised their own drone and in-house UAV pilots to safely capture comprehensive footage of the entire site. This resulted in the discovery of an osprey nest at the end of the jetty.

"We consulted with the Department of Biodiversity, Conservation and Attractions (DBCA) on how we could work safely around the nest given it was the bird's breeding period," Adam explains.

The drone was able to confirm there were chicks in the nest, which meant we focused on the civil deconstruction works before we could undertake the marine based works.

"This allowed more time to plan how we would address the relocation of the nest, although ultimately it wasn't necessary after a second storm passed through the region."

Adam notes that the marine-based works held the majority of the project's risks, so planning that activity carefully and with safety, heritage and sustainability top of mind was important. 

The team discovered an osprey nest at the end of the jetty.

Ensuring sustainability is top of mind 

Adam and the contract team are always seeking opportunities to deliver projects sustainably. The timber removed from the jetty was salvaged and stored for reuse at the Carnarvon Heritage Group's site, with the intention to utilise it aesthetically or in interpretive projects in the precinct (it was deemed unsuitable for future repair works).

Adam says the CHG planned for some of the timber to be available to local residents. 

"They'd be able to use the timber for furniture or in other works around their home, or as a memento of the jetty," he says. 

Adam says that the jetty represents a real piece of history for many of the residents and regular visitors to the area. 

Some residents have an emotional connection with the jetty, as it has stood off the coast there for over 120 years, so it was great to be able to offer this to them.

Demolition of the damaged jetty using an excavator

The subcontractor selected to undertake the demolition of the jetty was chosen based on providing the best value for money, and with access to appropriate specialised plant. 


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