Auckland Transport (AT) has progressed work to improve resilience of the Auckland Road network after experiencing more than 2000 landslides following the 2023 storm events. Prior to this study AT asset management was done on a repair and maintenance basis of the road network after storm events as there was little information to support preventative forward works.
The AT Science and Sustainability Group collaborated with Tetratech Coffey to develop and test a framework to assess landslide susceptibility, using the detailed information collated during the storm recovery process. The framework was then applied to assess landslide vulnerability across the 7,500km road network in Auckland. The output supports AT’s asset management practices to adapt to the changing climatic conditions and improve the resilience of the road network.
The framework incorporated various input variables, such as slope characteristics, road geometry, geological data, vegetation, overland flow paths, faults, rainfall records, and historical landslide occurrences. The framework was then extrapolated across the wider road network using AI to identify patterns and predict landslide risks under future significant rainfall event scenarios. These were then ground-truthed to confirm the accuracy of the model. The framework allows AT to identify the key triggers which contribute to the susceptibility of any one site.
Output of this work was a GIS layer showing the risk ratings at 25m intervals, permitting visualization of the vulnerable areas of the road network. This is then overlayed with the asset condition assessment information to identify locations at risk of landslides. The model and GIS layer facilitates a shift from reactive repair strategies to proactive landslide prevention.
This approach aims to significantly reduce disruption and repair costs associated with future extreme weather events, ultimately enhancing the resilience of Auckland's transport infrastructure. The framework is now utilized to support asset adaptation planning for future climate hazards.