Tuntable Creek Road - Flood Recovery Update November 2022

Tuntable Creek Road experienced significant damage during the February 2022 natural disaster. Due to the nature and high number of damages incurred, works are being finalised on how best to provide timely improvements for the community and road users.

Road surface conditions

Pavement repairs have been approved for funding to address the road surface conditions. These works are currently being scheduled for the entire sealed road damage package. Unfortunately, this is taking longer than expected due to constraints on resources and the prolonged period of wet weather. Dates of these works will be released shortly, with temporary measures such as gravel fill being implemented to assist road users in the interim.

Road closure – between Rose Road and Beardow Road

The road closure is a result of approximately 280m of road alignment between Rose Road and Beardow Road being affected by considerable damage. The road in its current condition presents two significant landslip damage locations.

To date Lismore City Council have completed geotechnical investigations of the sites and undertaken initial design option analysis. GHD have been appointed as the Lismore City Council Road and Bridge Recovery Design Partner, with Tuntable Creek Road their top priority site for urgent design and restoration activities.

The landslip sites are extremely challenging from an engineering perspective. The soil is observed to be colluvial and residual soils derived from basalt, with large boulders and cobbles throughout. The main damage location leaves no usable width of the original roadway.

The failure has exposed several large boulders that may indicate older landslide materials naturally in place at the site. The landslide damage extends some distance below the road embankment to Tuntable Creek. Figure 1 below shows an aerial of the main landslip.

There is significant movement at the location of the landslip and the depth of loose material makes stabilisation of the site a major engineering challenge.

The second site presents a now split roadway with tension cracks on the downhill side and a heaved uphill side of the roadway. It is assumed that this is a compound landslide with both up and downhill damages incurred. Damage at road level is significant. Figure 2 shows the visible tension cracking and deformation from the landslide movements. Observations indicate that both these areas of extensive damage to the road are related, and likely part of the same landslide movement.

The large extent and length of this cracking suggests that a larger underlying failure may be present than is currently visible. This poses the risk of larger landslides in future events.

Provision of temporary access

Given the time that a permanent solution will take to design and implement, Council is currently investigating the construction of a temporary access widening at the location of the main slip. The current soil conditions and terrain makes such a solution very difficult to implement, requiring advanced geotechnical engineering solutions and ongoing monitoring to ensure the safety of users. A temporary access design is being prioritised and, if feasible, will be implemented in the shortest possible time frame.

Council understands the significant impact of this road closure on the local community, and appreciates the feedback received to date. In recognition that permanent restoration will take a significant amount of time, the following will be carried out:

• Regular updates through online channels and direct consultation with community
• Additional notification for road users of the surface conditions and road closure
• Temporary works to address road conditions until permanent works are completed
• Review of the Nimbin Community Disaster Resilience Plan and The Channon and Surrounds Disaster Resilience Plan

Additionally, to receive updates directly please contact Lismore City Council via email council@lismore.nsw.gov.au or call (02) 6625 0500 to register your preferred contact details and feedback. Please reference ‘Tuntable Creek Road AF22/1928’ in your correspondence.