North Coast Comboyne Road embankment restorations
Contact point
Client
Port Macquarie Hastings Council (PMHC)
Services provided
Project management
Background
In March 2021, the Mid North Coast region experienced extreme flooding. Low-lying areas were inundated with several public assets destroyed or damaged, including roads, bridges and stormwater assets. As a result, large sections of Comboyne Road embankments failed and reduced the road asset to a single lane with multiple changes in traffic.
PMHC engaged NSW Public Works (NSWPW) to provide on-site project management services to procure, manage and supervise the remediation of three large landslip sites. We also investigated an additional 13 minor sites. The remediation works improved road safety and reduced delays for road users.
The project was funded under the NSW Natural Disaster Essential Public Assets Restoration program via Transport for NSW.
Key facts
- Three large landslip sites, comprising of both upslope and down slope works
- Various remediation works ranging from soil nails, shotcrete walls, earthworks, and drainage
- 871 soil nails installed for a total of 6,933 lineal metres drilled. 3,230 m2 of rockfall retention mesh installed and a total of 8,783 m3 of earthworks
- 300 lineal metres of dual lane pavement reconstruction to full depth with AC overlay
Our role
NSWPW provided end to end project management including:
Phase 1: Investigations and scoping
- Engagement of Environmental Consultant (REFs)
- Engagement of geotechnical investigations
Phase 2: Design phase
- Procurement of detailed design consultant
- Management of detailed design phase
Phase 3: Delivery
- Procurement of construction contractor
- Delivery of construction
This project was the first of multiple slope remediation projects with PMHC and helped us build knowledge and efficiencies to be utilised in future works of a similar nature.
With an emphasis on maintaining traffic flow, we limited the works to a maximum of two sets of traffic lights across the three sites. We also implemented a two-week road closure to construct critical works. The latent conditions of the sites had a significant impact on the construction phase.
The contractor gained more experience as a Principal Contractor, including their understanding of using a GC21 Contract, where we facilitated and engaged an external contracts training officer to conduct a GC21 training session.
Outcomes
Works were completed in August 2024, aligned within both funding timeframe requirements and the client’s deadline for completion. This was a key outcome as further remediation works depended on the completion of the embankment restorations.
The remediations have mitigated the risk of future landslips and created safer passage along the road. The project was well received by the local community, especially because the road is a regular route for local farmers and suppliers, and the landslip caused dramatic delays in travel time.
Our successful delivery of the remediations has led to NSWPW completing works on a further 26 landslip sites with PMHC.
This project was part of a broader package of works. Read more about the Port Macquarie road embankment restorations.
