Implementing The AGS Landslide Risk Management Guidelines In A Municipal Planning Scheme – A Case Study In The Colac Otway Shire, Victoria

The Colac Otway Shire in south west Victoria are in the process of amending their Planning Scheme to include landslide risk assessment for new developments in landslide prone areas. The amendment is primarily intended to limit the Shire’s liability and will require consultants to assess risk using the Australian Geomechanics guidelines on landslide risk management. However data limitations, particularly the paucity of historical information on landslide events, have precluded landslide hazard mapping for all types of landslides and their likelihood of occurrence, at the site-scale required for planning controls. The solution adopted was to extend the Erosion Management Overlay to cover all areas of the Shire in which landslides are credible, and the implementation of a documented process to determine when a landslide risk assessment for any development is required. The process includes reference to existing information stored on a GIS database, a checklist for use in an initial site visit by the Shire, specific requirements for consultant’s reports, and information checking and mediation processes for the Shire. The limited landslide risk management experience of the Shire planners and some small and medium-scale consulting companies has highlighted a local desire for a more prescriptive code.