Lawrence Hargrave Drive natural disaster recovery

Work was carried out on the M1 Princes Motorway southbound off ramp at Helensburgh to repair damage caused by heavy rainfall in February last year.

The work started on Sunday 28 January and was completed by Thursday 8 February.

An intensive effort to repair landslip damage on Lawrence Hargrave Drive saw work at four sites completed one week earlier than planned.

The specialist contractors carrying out the work brought in additional resources to the project after a critical piece of machinery broke down and their extra effort paid off.

Not only did the crew manage to recover the lost time, but they also managed to get the work finished ahead of schedule.

Despite the temporary setback, the contractors were able to complete work that will add strength to the slopes at the four sites and help prevent further erosion during future severe weather events.

The work crews installed a total of 76 long steel rods (called soil nails), applied 22m3 of spray-on concrete and constructed almost 300 metres of new drains.

Completing the work at these four sites means Transport has now completed repairs at half of the 26 separate landslip damage sites that occurred on Lawrence Hargrave Drive during record-breaking rainfall in 2022.

Record-breaking rainfall during 2022 caused landslip damage on Lawrence Hargrave Drive. Further heavy rainfall in February 2023 caused additional landslip damage.

As a direct result of this rainfall, Transport added a total of 26 landslip sites to its natural disaster recovery project register. 

This accounts for around one quarter of Transport's natural disaster recovery project sites in this area.

Transport has made significant progress on repairs to these landslip sites already.

Planning is under way for repairs to the remaining sites.

Our geotechnical team is continuing to monitor all active sites until repairs are completed.

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Landslip sites on Lawrence Hargrave Drive

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Many of the landslip sites require complex repairs. 

Transport will complete repairs that, depending on each site, could include:

• removing loose rocks, soil and trees
• stabilising and adding strength to the damaged slope
• upgrading stormwater drains
• repairing road surfaces and replacing guardrails.

Some factors are out of our control and can cause delays to our progress:

• Weather - heavy rain and storms could make working conditions unsafe.
• Workload – the statewide increase in demand for qualified contractors, equipment and resources could mean longer timeframes for repairs.
• Worksite – the steep site and narrow site could create some unexpected challenges.

Transport follows a thorough process before starting natural disaster recovery repairs. This process includes:

• geotechical, biodiversity and heritage surveys
• design planning
• environmental assessment
• final design
• procurement.

Transport for NSW conducted in-depth geotechnical investigations and as a result, identified a number of sites between Otford Road and Chellow Dene Avenue where work was needed to stabilise the slope and reduce the risk of land slips.

Transport for NSW consulted the community around four options from November to December 2019 on plans for the project. The community was asked to provide feedback on closing the road in two four week stages with work taking place 24 hours a day. Following the feedback from this consultation we developed four options for further community and stakeholder feedback.

The second consultation received 720 responses, 717 of these respondents selected a preferred option to carry out the work.

The consultation was carried out to gain a better understanding of the Stanwell Park area and how our customers use this stretch of road, to help inform plans to carry out the essential slope stabilisation and maintenance work on Lawrence Hargrave Drive.

Consultation period 1 (July - August 2019) - consultation report (PDF, 607Kb)

Consultation period 2 (November - December 2019) consultation report (PDF, 404Kb)

The slope repair work was completed on schedule, with the road reopened on Sunday 9 August 2020.

Work included:

• a 29 metre-long concrete retaining wall has been built at the highest risk site to stabilise and strengthen the slope
• installation of about 900 soil nails of up to 12 metres in length
• four kilometres of drains installed
• 5000 square metres of stabilising mesh laid
• 900 square metres of shotcrete installed
• road resurfacing was carried out on sections of the road and minor guardrail repairs were completed
• about 5000 square metres of hydromulch and seeding.

• January 2024 - Repairing damage on the M1 southbound off ramp at Helensburgh (PDF, 271.68 KB)
  Transport for NSW is repairing landslip damage on the M1 Princes Motorway southbound off ramp at Helensburgh.
• November 2023 - Repairing damage at Stanwell Park (PDF, 311.76 KB)
  Transport is patching damaged sections of the road surface to make conditions smoother and safer for motorists.
• October 2023 - Repairing damage on Lawrence Hargrave Drive (PDF, 310.12 KB) 
  Transport for NSW is repairing landslip damage on Lawrence Hargrave Drive at Stanwell Park, Clifton and Scarborough.

• 23 October 2023
  Natural disaster repair work on Lawrence Hargrave Drive

• 13 April 2023
  Repairs planned for Lawrence Hargrave Drive at Stanwell Tops