Deer Vale Road

BSC - TC Alfred - Deervale Slip (2) - 2025_03_11.JPG

About the Project

The major landslip caused by Ex-Tropical Cyclone Alfred has severely damaged Deer Vale Road, affecting a large section between Prices Road and Deer Vale village. The road is currently closed, limiting residents to a single access route. Council is working with geotechnical experts and Transport for NSW to assess the damage and determine potential funding through the Disaster Recovery Funding Arrangements (DRFA).

Timeframe

The landslip damage is complex, and repairs may take an extended period. Council is actively engaging with the Deer Vale community to understand immediate and long-term needs.

SHORT TERM - Current Works Timelines:

Additional borehole drilling

Timeline: Anticipated to start W/C 13 May (weather permitting)

Status: Works will take approximately 3 Weeks from start date

Additional geotechnical investigations will involve drilling 4–5 boreholes at key points across the slip area and installing a piezometer to measure water pressure within underground cracks.

Monitoring this pressure will help assess the stability and load-bearing capacity of the subsurface materials. The data gathered will inform future decisions regarding the easing of load restrictions and support the design of long-term restoration works.

4–5 boreholes drilling at key points across the slip
Installation of a piezometer to measure water pressure within underground cracks.
Traffic management will be in place at the slip site during the works and short delays may occur.

SHORT TERM - Works Complete:

Essential works to address temporary access over the slip site

Timeline: Commenced Thursday 10 April

Status: COMPLETE

Please be advised that the Deer Vale Road slip site re-opened to traffic on Thursday 17 April. It is important to note that these short-term repairs require traffic management measures, with restrictions outlined in more detail below:

One lane of the road will be open only - ‘give way’ directions will be in operation
There is no longer vehicle weight restrictions on the temporary road, allowing all vehicle types to pass - Updated 9 May 2025
Ongoing assessments should be undertaken by a Geotechnical Engineer to identify if any cracking or displacement has occurred
A speed restriction to 40km/hr must remain in place
Ongoing inspections during periods of rainfall (greater than 100mm of rainfall over 24 hours and where greater than 300mm over 7 days)
Light weight traffic barriers have been placed on the road to keep traffic at least 1.5m away along the edge of the slip cracks
ROAD CLOSURES likely to be triggered where greater than 150mm occurs over a 24-hour period and where greater than 350mm occurs over a 3-day period.

If no further failures are observed in the short term, it is likely larger load restrictions can be removed. Further advice on this will be provided by Council.

However, if additional failures such as cracks or displacement are identified, Council must be contacted for advice without delay and the above advice may change.

While these short-term access measures are in place, Council is continuing to advocate for long-term solutions that will provide a permanent fix for the significant damage.

Subsurface investigations

Timeline: Commenced Wednesday 2 April

Status: COMPLETE

Drill boreholes to a depth of 10-15 metres
Undertake sampling and testing of road and embankment materials and groundwater levels
Install monitoring instrumentation for measurement of movement of slip and groundwater

LONGER TERM SOLUTIONS

Geotechnical drilling has revealed that hard rock lies at a depth of 29 metres, indicating the slip is serve and complex. Monitoring equipment has been installed to track ground movement and groundwater, providing critical data for the design of both temporary and permanent solutions.

To support this ongoing work, additional boreholes will be drilled and a piezometer installed to inform the engineering design required for long-term restoration.

Access to the East

Council recognises the need to ensure access for the community is maintained in the event of wet weather or further issues at the slip site. As such, works to upgrade the road alignment to the East and both the Little Murray and Deer Vale Quarry bridges are being planned. We will provide more detail on this in upcoming updates.

Community Engagement

Council is actively consulting with the Deer Vale community to assess impacts and gather insights to support funding applications for road reinstatement. Residents, businesses, and service providers are encouraged to complete the survey below to share their experiences and help strengthen Council’s case for funding.

Click here to view form.