Mindarie Breakwater Management
The Mindarie Marina Breakwater structures were built in 1988 as part of the Mindarie Keys Development. These structures provide protection for close-by infrastructure including parking, road, pedestrian pathways, residential properties and commercial businesses. It also provides calm marina conditions for private berths and a public boat ramp. In 2005 the Mindarie Breakwater and Spur Groyne were passed into the City’s care and control. Since this time the City has undertaken a number of technical investigations, monitoring, risk mitigation measures and maintenance works.
Ongoing structural and safety issues with the Mindarie Breakwater includes:
- Regularly displaced limestone obstructing the roads and pathways.
- Unstable armour, armour slumping and void formation.
- Large waves overtopping the breakwater structure during storm events.
Displaced limestone onto road and path
Core loss resulting in armour slumping and void formation
Wave overtopping
Unstable armour
The City conducts annual condition assessments of the breakwater structures by coastal engineers for each 20m segment. These are rated from 1 (Good) to 5 (Very Poor). This assessment along with the ongoing issues has prompted the need for significant breakwater maintenance works.
19 May 2023
Breakwater works are underway at the head of the breakwater (Segment 5/6).
Construction will progress from the breakwater head back to meet the completed section of Segment 4.
Completion of breakwater segment 5/6 is expected for September 2023 subject to suitable weather conditions during this period.
24 March 2023
Segment 4 construction works are continuing as planned. All lower breakwater slope sections have been completed and works are now underway on the upper slope and breakwater crest.
10 February 2023
Major breakwater construction works have commenced on Segment 4 of the Mindarie Breakwater. Currently, the City’s contractor, WA Limestone, are reworking and stabilising existing limestone armour which will shortly be followed by the import and placement of additional limestone material over the coming weeks. The northern section of breakwater, adjacent footpath, parallel parking and the northern section of Alexandria View will remain closed to the public during these works and Segment 4 is expected to be completed in April 2023.
Phase 1 Upgrade Works for Segment 3
Phase 1 Maintenance works undertaken in 2017/18 focussed on a 160m length of the Mindarie Breakwater which experienced significant wave overtopping and displacement of rock debris onto the road during storms. The completion of these works increased and widened the crest level of the structure successfully resulting in less wave overtopping and associated safety issues.
Mindarie Breakwater - Phase 1 Maintenance Works
Phase 2 Options Assessment and Detailed Design Study
In 2022 the City of Wanneroo completed the Mindarie Breakwater Options Assessment and Detailed Design Study. This assessed potential breakwater maintenance options and provide a detailed design for future breakwater maintenance. The recommended maintenance works will address the existing issues relating to breakwater damage, rock movement and wave overtopping and will ensure that the structures remain safe and functional into the future.
The Mindarie Breakwater Options Assessment and Detailed Design Study consisted of the following stages:
- Desktop review and data collection of all previous works to determine the existing condition of the breakwater structures.
- Options assessment and design basis to identify potential maintenance options and the preferred priorities.
- Detailed design drawings and technical specifications suitable for the construction.
Study recommendations have informed the scope of breakwater maintenance and upgrade works for 2022/23 to 2023/24.
Phase 3 Upgrade works for Segments 1, 2, 4, 5 and 6
Upgrade works for the Mindarie will commence in January 2023.
Breakwater upgrades include reworking of existing rock and placement of new material to increase the height, improve rock stability and reduce wave overtopping. These works will include the replacement/upgrade of adjacent civil infrastructure including parking, drainage, footpaths, kerbing and vehicle safety barriers. The Claytons Beach carpark will also be expanded to accommodate for the loss of parallel parking bays along Alexandria View as a result of the Segment 2 breakwater works.
All breakwater upgrades and associated works will be completed by January 2024 subject to suitable site and weather conditions during construction.
Upgrade works for the Mindarie Breakwater segments 5 and 6 is scheduled to commence in June 2023 following completion of the Phase 3 breakwater upgrade works. All breakwater upgrade works will be completed by December 2023 subject to suitable site and weather conditions during construction.
