Carnarvon Fascine Entryway and Boat Harbour Pen Project

The Fascine is a waterway bordering the Carnarvon townsite and the Gascoyne River. It is one of the Carnarvon’s key assets, linking the community to the coast.

As the waterway manager the Shire of Carnarvon engaged a coastal engineering consultancy, to establish a plan for rebuilding and maintaining a navigation channel from the Fascine to Teggs Channel. This study was completed in June 2020 and it identified a dredged channel with north-south alignment on the east side of the Fascine entrance as the preferred solution. The study noted that training walls may be required to prevent the channel from filling in with sediment. In addition, medium to high level of ongoing maintenance dredging would be expected. Please see link to report below.

DoT has developed a program to deliver the long-term strategy for Fascine access. While the aim is to deliver a sustainable strategy as soon as possible, there is high risk of ongoing maintenance. It is important to gain a good understanding of the coastal processes and carefully investigate the options to try and minimise siltation of the channel and future maintenance costs. While this is being done, to provide some relief to the community more immediate actions are being implemented:

• bringing forward the construction of additional boat pens in Carnarvon Boat Harbour to allow the relocation of vessels trapped in the Fascine to the Carnarvon Boat Harbour;
• providing pen fee relief to relocated vessels once the new pens are complete;
• regularly surveying the Fascine entrance to assist safe navigation; and
• regularly re-assessing location of the channel markers in the entrance and relocating the markers as appropriate.

Long-term strategy for Fascine access

Hydrographic surveys have been completed approximately every three months during 2020 and 2021. These surveys are being used in ongoing studies by helping to understand how sediment moves around in the Fascine entrance. Regular surveys will continue.

Wave and currents are the main drivers of sediment movement. However very little measured data was available when the funding announcement was made in August 2020. DoT deployed instruments to collect wave and current data in early September 2020 that remain in place. As it becomes available, the data is being used to support the technical and environmental studies being undertaken as part of the project.  

DoT held a technical workshop with various stakeholders and technical consultants in November 2020 to identify potential conceptual solutions and some of these are being further investigated. Conceptual cost estimates for these potential channel alignments have been completed and areas for the expected dredged material have been identified. A coastal processes study, assessing the alignments and estimating maintenance dredging requirements is nearing completion underway. A key challenge of this study is accounting for the ongoing changes in the Fascine entrance. Figure below illustrates how quickly the sand spit moves in the Fascine entrance.

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Figure above: November 2020 and November 2021 (150 m change in 1 year)

Once the coastal processes study is complete, work will start on geotechnical investigations, followed by a more detailed dredge design.

A project of this nature requires approval by the environmental authorities. Both the state and federal authorities need to be considered. DoT is currently progressing studies to support the environmental approval process. A migratory bird survey has been completed and confirmed that no environmental referral to the Commonwealth is necessary for the project, simplifying the environmental approval process. A benthic habitat survey, mapping the seabed in the area, and survey of the mangroves the Fascine entrance have been completed. Both surveys will support the environmental approval process with WA’s environmental authorities.

Short-term measures

As use of the Fascine Boat Ramp is severely restricted, DoT has upgraded and reopened the boat ramp at the Carnarvon Boat Harbour. The intent is that this facility will remain open and available to recreational boat users until a long-term strategy to improve the Fascine entrance is implemented.

Regular hydrographic surveys of the Fascine entrance are being completed. The latest hydrographic survey data of the Fascine entrance is available for vessels who wish to navigate the area. The entrance is too shallow to be formally considered as being navigable and vessels enter and exit at their own risk. Download the latest Carnarvon and environs hydrographic survey below. Markers indicating the navigable parts of the channel were relocated in November 2020 and redundant navigational aids were removed. An additional channel marker was installed in late 2021 to indicate changes in the channel. 

Additional boat pens for Carnarvon Boat Harbour

DoT has commenced work to construct new boat pens at the Carnarvon Boat Harbour and is working with stakeholders to ensure the best result for users.

There will be a temporary fee relief until a long-term strategy for Fascine access is implemented. Vessels that are currently in the boat harbour and are relocated to the new pens will keep paying their current fees. Vessels coming from the Yacht Club will have to maintain their Yacht Club membership and keep paying pen fees at the Yacht Club but will have no additional fees to pay at the new pens. Other vessels will pay pen fees, in line with at facilities such as Exmouth. Once a long-term strategy for Fascine access is implemented, all fees will be aligned with fees charged at DoT facilities.

If you would like register interest in a new pen in the boat harbour, or wish to subscribe to project newsletters by email, please send your contact details to Fascine@transport.wa.gov.au