The Halls Gap Community Safety Committee developed the 'Halls Gap Landslide Interim Guidelines' to provide information for emergency agencies and the community on landslides in Halls Gap. The Interim Guidelines were adopted by Council at their Ordinary Council meeting on 26 May 2011.
The January 2011 floods triggered in excess of 190 landslides throughout the Grampians National Park. A small number of these landslides impacted on private property in the Halls Gap area. The properties impacted by landslide are currently being mapped by geotechnical experts who have been engaged by Council to prepare maps to identify land that is susceptible to landslide. Council will contact property owners who have land that is identified as susceptible to landslide once the mapping work has been finalised.
The Halls Gap Community Safety Committee has refined the Interim Guidelines with the help of experienced geotechnical engineers. This work has identified a correlation between landslides in Halls Gap and 1 in 100 year rainfall events.
The 2011 landslide activity in the Halls Gap area is known as debris flow landslides. They were triggered by a 1 in 100 year rainfall event and then moved downslope carrying rocks and vegetation. These landslides will often have flooding events associated with them.
The Interim Guidelines will be superseded in time by a Grampians Landslide Contingency Plan (GLCP). The GLCP will be prepared by a Steering Committee and Reference Group appointed by the Northern Grampians Shire Council Municipal Emergency Management Committee.
Below is a copy of the Halls Gap Landslide Interim Guidelines for you to view.