Chapter 7

7.1 Landslides in Victoria

1. Landslides that result in injury and property damage of the kind experienced in McCrae in January 2025 are not common in Victoria, but they are also not unprecedented.
2. Landslides have been a natural occurrence in the evolution of Victoria’s landscape over millions of years. A range of factors have minimised their frequency, severity and impact. These include lower population density in mountainous and erosion-prone areas and the use of land planning controls.

3. Prior to 2000, some of the most notable impacts from landslides in Victoria included:

   1. loss of a house and animals, and damage to a road at the now Dandenong Ranges National Park (1891);¹
   2. road damage at Narracan in Gippsland (1934);²
   3. destruction of critical infrastructure and agricultural lands, and disruption to the East Barwon River for 14 months resulting in the formation of a new lake – Lake Elizabeth in the Otway Ranges (1952);³
   4. loss of a house at Calignee and the isolation of the farming township of Le Roy in South Gippsland (1952);⁴
   5. destruction of bridges, the town pool and construction work in Walhalla in Gippsland (1952);⁵
   6. hiatus of the Puffing Billy railway for nine years at Gembrook (1953);⁶
   7. damage to housing, property, roads and infrastructure at Wye River on the Great Ocean Road (1964);⁷ and
   8. loss of two lives and several injured at Lal Lal Falls Reserve Ballarat (1990).⁸

   Details about historical landslides in McCrae are set out in Chapter 3 of this Report.

4. Over the last two decades, urban growth and infrastructure development, coupled with a changing climate, have added new complexities to landslide management in Victoria.
5. Three recent Victorian landslides stand out for their significant economic, social and/or environmental impacts: the Yallourn Mine landslide in 2007, the Grampians landslides in 2011 and the Great Ocean Road landslides in 2016.
6. Reviews and Inquiries into those emergencies found common challenges and opportunities for policy, regulatory and planning reform. Due to funding, time and/or circumstance, many of those challenges still exist today and the opportunities for reform remain unaddressed. These are discussed further below but largely relate to the:
   1. importance of collating better data, modelling and monitoring in respect of landslide risk in Victoria;
   2. need to share information about landslide risk with stakeholders and communities to support informed decision-making, and to strengthen preparedness for landslides;
   3. need to better manage the landslide risk associated with water management including the management of groundwater and stormwater, particularly given the compounding impacts of climate change and severe weather;
   4. importance of applying land use planning controls to manage landslide risk; and
   5. importance of retaining corporate knowledge, capability and insights about landslide risk, from lived experience and lessons learnt, through to historical decisions about risk management in service and infrastructure design and delivery.

Yallourn Mine landslide in 2007

7. In 2007, electricity supply was disrupted across Victoria when a landslide occurred at the Yallourn East Field Mine. The landslide led to six million cubic metres of coal and soil, spanning over 500 metres in length, travelling down an 80 metre slope, causing the Latrobe River to flood the mine.⁹ The State of Victoria appointed a Mining Warden to lead the Yallourn Mine Batter Failure Inquiry in order to establish the circumstances surrounding, and causes of, the landslide, and to examine any mine safety issues and make recommendations to prevent or minimise the risk of similar events occurring in the future.
8. As in McCrae, water played a key role in the Yallourn landslide. The Yallourn Mine Batter Inquiry identified the principal cause of the landslide as water pressure in a naturally occurring joint connected with the Latrobe River, and water pressure in interseam clays underlying the block of coal. Water pressures created a buoyancy effect on the block of coal, reducing resistance to sliding along its base.¹⁰ There were also early signs of an impending slope failure at Yallourn, including visible cracking and subsidence, as well as monitoring data indicating imminent failure. However, unlike in McCrae where there was expert advice ahead of the 2022 landslides that the area was susceptible to landslides, the signs were not interpreted correctly at Yallourn and external consulting advice was provided that a catastrophic failure was unlikely on the day of the Yallourn landslide.¹¹
9. Importantly, the Yallourn Inquiry found that “this failure was not new or unusual and is the principal mechanism of batter failure in the Latrobe Valley Mines”.¹² It noted that changes to the Yallourn East Field Mine’s layout over time and the implementation of new mining methods had also resulted in key components of the mine’s slope design (which ensured its stability) no longer being applied. It found that technical expertise and corporate knowledge about risks had been lost over time or were no longer properly appreciated in the years prior to the failure, and that strategies were needed to better capture knowledge and historical experience in new and evolving models of risk management.¹³
10. Many of the Yallourn Inquiry’s recommendations are still relevant to landslide management more generally. The Yallourn Inquiry recommended coal mines improve groundwater and surface water control, as well as hydrogeological and geotechnical models, and their application in planning and system design. A multidisciplinary approach to planning was deemed necessary to address the many competing demands at play in managing risk and mining operations.¹⁴

Grampians (Gariwerd) National Park landslides in 2011

11. In January 2011, an intense rainfall event in Western Victoria triggered over 200 landslides in the Grampians (Gariwerd) National Park and caused widespread regional flooding. Three arterial roads were closed for several months, urban and agricultural water supplies were impacted, and there was damage to cultural heritage sites, pavements, culverts, drains and bridges. Public and private property was damaged by boulders, trees, debris and mud.¹⁵ Given the significance of the landslides, the Northern Grampians Shire and partners, including the Victorian Department of Justice, commissioned Federation University Australia to research the social, economic and environmental impacts of the disaster, with a specific focus on addressing landslide risk and the community’s resilience to it.¹⁶
12. The Federation University Report, Understanding the 2011 Grampians Natural Disaster, addressing the risk and resilience, found the disaster had a deep and enduring impact on the local community. While no lives were lost, stress and anxiety were ongoing issues within the community. The region also experienced substantial economic losses, particularly loss of income through reduced tourist activity and disruption to normal trading. The cost of reconstruction for the State was considerable. It involved rebuilding and restoring structures and assets across private and public land, at an estimated cost of approximately $140 million.¹⁷
13. Much like McCrae, the areas impacted in the Grampians were not covered by the Council’s existing EMO despite past recognition by the Council of the need for the EMO to cover those areas. It was recommended that the EMO be extended to ensure statutory planning controls were applied to the landslide susceptible regions of the Grampians Shires, adopting the methods of the Australian Geomechanics Society National Landslide Risk Management Framework.¹⁸
14. The Federation University Report also highlighted challenges and opportunities for reform, including improvements in maintaining landslide risk data and planning in landslide management.¹⁹ It contained important insights in respect of public education programs for all hazards.

Great Ocean Road landslides in 2016

15. Similar to the Grampians, where floods and landslides became part of a complex emergency event, communities along the Great Ocean Road between Separation Creek and Wye River experienced extensive landslides following bushfires in 2015. The VicSES estimates that over 180 landslides occurred in that area.²⁰
16. The Review of the Wye River and Separation Creek Fire Recovery, commissioned by Emergency Management Victoria, and led by Nous Group, considered management of the landslides during the recovery efforts. The Review found that there were extensive challenges to and breakdowns in communications between local and state government agencies, including but not limited to the Country Fire Authority, Emergency Management Victoria, the Environment Protection Authority and VicRoads, and with the community during the landslides which “left the community feeling poorly informed, anxious and overlooked”.²¹ It recommended that agencies involved in the management of landslides develop a more flexible approach to community engagement and consider their governance and culture to ensure their organisational structures could accommodate the concurrent demands of response and recovery.
17. The Great Ocean Road Taskforce Report, Protecting our Iconic Coast and Parks, also emphasised the need for action in relation to landslide management. It identified the challenges of land instability and subsidence, cliff regression, undercutting and coastal erosion as critical issues for the region. It noted that these were likely to be further exacerbated by climate change and increasingly frequent, severe and complex weather events.²² The result would be wide-reaching, with impacts on infrastructure, the economy and the environment. The Victorian Government went on to commit $53 million “to safeguarding the geotechnical future of the road following the 2016 floods and landslides at Separation Creek and Wye River”.²³
18. The Great Ocean Road landslides reaffirmed the importance of strong planning and mitigation measures where underlying geological, engineering and topographical characteristics can lead to landslides. Climate change creates an imperative for planning and mitigation, when underlying contributing factors can be compounded by extreme weather events.

7.2 Lessons from interstate and overseas

19. Landslides causing widespread social, economic and environmental consequences have been infrequent in Australia but when they have occurred, they have had an enduring impact on local communities and provided long-term lessons for disaster risk management. Between 2000 and 2011, 24 people died and 100 people were injured in Australia as a result of landslides.²⁴
20. While every context is different, past events both interstate, and overseas, have offered important insights into managing landslide risk that are relevant to this Board of Inquiry. Coronial findings and recommendations aimed at strengthening regulatory responsibility, mitigation policy and planning have been considered by this Board of Inquiry and have been instrumental in framing its work. Insights include the significance of water management and infrastructure maintenance, the importance of emergency management planning, and failings in accountability and leadership.
21. Failings in water management and infrastructure maintenance were identified as either a primary or secondary cause in the:
    1. deaths of two people in their home following the collapse of the Coledale rail embankment in 1988;²⁵
    2. cliff collapse at Gracetown, Western Australia in 1996 where rainfall was found to be the cause of a saturated cliff overhang collapsing above school students and staff who were sheltering underneath, leading to the deaths of nine people;²⁶ and
    3. deaths of five people in a landslide at the Old Pacific Highway in Somersby, which the Coroner found to have been caused by the local Council’s inadequate road maintenance which led to a collapsed water culvert.²⁷
22. Water management and infrastructure maintenance were also critical factors in the tragic landslide at Thredbo Village in Alpine New South Wales in July 1997. This event caused 18 deaths and the destruction of two ski lodges. As with the events in Coledale and Somersby, water saturation, maintenance, building and planning failures were identified as factors or causes of the landslide. Notwithstanding geotechnical, planning and engineering failures, the New South Wales State Coroner investigating the Thredbo Village landslide – Coroner Hand – found the primary causes of the landslide to be:
    1. the failure of any government authority responsible for the care, control and management of Kosciusko National Park and the maintenance of the Alpine Way to take any steps to ensure Thredbo Village was rendered safe from exposure to the marginally stable embankment;
    2. the approval and construction of a water main made of materials which could not withstand the conditions (movement taking place in the Alpine Way embankment); and
    3. leakage from that water main that saturated the soil.²⁸
23. Importantly for this Board of Inquiry, Coroner Hand also made a range of recommendations to strengthen landslide risk management in relation to land use planning, building controls and emergency management.
24. With respect to emergency management, Coroner Hand found that the local disaster plan did not take into account the risk of landslides in the Alpine area. He recommended that “both District and Local Disaster Plans (DISPLANs) be revised, taking into account the risk of landslides in the area and their management”.²⁹
25. Coroner Hand also recommended the Building Code of Australia and any local code dealing with planning, development and building approval procedures be reviewed and amended to require relevant authorities to take into account and apply proper hillside building practices and geotechnical considerations when assessing and planning urban communities in hillside environments.³⁰ At the time, Coroner Hand noted there was no detailed system requiring the submission and consideration of geotechnical or other engineering reports that took into account the difficulties of building in a steep alpine environment.
26. The Thredbo Coronial Inquest otherwise led to widespread national reform of landslide management.
27. In 1998, Engineers Australia and the AGS formed a Taskforce on the Review of Landslides and Hillside Construction Standards, which concluded that existing codes and standards were inadequate. It recommended creating four new guidelines for:
    1. landslide hazard zoning for urban areas, roads and railways;
    2. slope management;
    3. site investigations, design, construction and maintenance; and
    4. landslide risk assessment.³¹
28. Further improvements were made to the guidelines in 2000 and 2002.³²
29. In 2003, the Commonwealth Government introduced the National Disaster Mitigation Program, which funded the AGS and local governments to undertake further research into the likelihood of landslides, and to develop zoning and slope management guidelines as well as a Practice Note.³³ These were peer reviewed and completed in 2007.³⁴
30. In addition, other government entities, the subject of findings in the Thredbo Coronial Inquest, developed tools to manage landslide risks. New South Wales Transport, Roads & Maritime Services produced guidelines for slope asset management and natural disaster slope damage restoration requirements which have continued to be updated over time.³⁵

The international experience

31. There are many countries and regions with far more extensive experience with significant landslides than Australia. However, many of the challenges in managing landslide risk are similar.
32. A review of significant landslides internationally highlights that water management, road maintenance, planning and development in mountainous and coastal areas are critical factors in managing vulnerability and exposure to landslides, and are relevant elements in landslide risk management.
33. Further, climate change presents new, complex challenges leading to increased risk through the greater frequency and/or magnitude of heavy rainfall and shifts in the location and periodicity of heavy rainfall.³⁶
34. Individual country efforts to better understand the risks and design mitigations, and develop and implement engineering approaches, are being pursued through a range of cooperative arrangements such as the Kyoto 2020 Commitment for Global Promotion of Understanding and Reducing Landslide Disaster Risk.³⁷ The Kyoto 2020 Commitment sets out that:

35. These international partnerships offer important insights into understanding how we can mitigate the risk of landslides into the future and have assisted to inform the Board of Inquiry’s findings and recommendations.

Chapter 7 Endnotes

• 1 Museums Victoria, ‘Item BA 1657 Lantern Slide – Landslip, Dandenongs, Victoria Jul 1891’, Museums Victoria Collections (Web Page) https://collections.museumsvictoria.com.au/items/1449178.
• 2 Public Record Office Victoria, ‘34_00059_B Allambee-Childers Road: landslide caused by heavy rainfall’, Photographic Collection, Master Negatives and Digitised Images (VPRS17684) (Record) https://prov.vic.gov.au/archive/A1D63F94-FAC7-11EA-BE8C-AB441AA0DA39/co….
• 3 ‘Big Victorian Landslide Forms Lake, Endangers Four Towns’, Sydney Morning Herald (New South Wales, 23 June 1952) 1 https://trove.nla.gov.au/newspaper/article/18269952.
• 4 ‘Victorian Landslides’, Border Watch (Mount Gambier, 26 June 1952) https://trove.nla.gov.au/newspaper/article/78668744
• 5 ‘Walhalla hit again by landslides, flood’, The Sun News (Melbourne, 13 December 1952) 11 https://trove.nla.gov.au/newspaper/article/279919417.
• 6 Victoria, Parliamentary Debates, Legislative Council, 5 April 2022 (Cindy McLeish VLA, Member for Eildon).
• 7 P G Dahlhaus, A S Miner, W Feltham and T D Clarkson, ‘The impact of Landslides and erosion in the Corangamite Region Victoria, Australia’, (Paper number 479, IAEG2006, Centre for eResearch and Digital Innovation) 8 https://www.ccmaknowledgebase.vic.gov.au/kb_resource_details.php?resour….
• 8 P G Dahlhaus, A S Miner, W Feltham and T D Clarkson, ‘The impact of Landslides and erosion in the Corangamite Region Victoria, Australia’, (Paper number 479, IAEG2006, Centre for eResearch and Digital Innovation) 8 https://www.ccmaknowledgebase.vic.gov.au/kb_resource_details.php?resour….
• 9 Parliament of Victoria, Mining Warden – Yallourn Mine Batter Failure Inquiry (Final Report, 30 June 2008) i.
• 10 Parliament of Victoria, Mining Warden – Yallourn Mine Batter Failure Inquiry (Final Report, 30 June 2008) i.
• 11 Parliament of Victoria, Mining Warden – Yallourn Mine Batter Failure Inquiry (Final Report, 30 June 2008) 96.
• 12 Parliament of Victoria, Mining Warden – Yallourn Mine Batter Failure Inquiry (Final Report, 30 June 2008) i.
• 13 Parliament of Victoria, Mining Warden – Yallourn Mine Batter Failure Inquiry (Final Report, 30 June 2008) 95, 104.
• 14 Parliament of Victoria, Mining Warden – Yallourn Mine Batter Failure Inquiry (Final Report, 30 June 2008) 103–104.
• 15 Federation University Australia, Centre for eCommerce and Communications, Understanding the 2011 Grampians Natural Disaster, addressing the risk and resilience (Final Report, 31 March 2014) 38.
• 16 Federation University Australia, Centre for eCommerce and Communications, Understanding the 2011 Grampians Natural Disaster, addressing the risk and resilience (Final Report, 31 March 2014) iii.
• 17 Federation University Australia, Centre for eCommerce and Communications, Understanding the 2011 Grampians Natural Disaster, addressing the risk and resilience (Final Report, 31 March 2014) 34.
• 18 Victoria State Emergency Service, State Landslide Hazard Plan (Version 1, September 2018) 6.
• 19 Federation University Australia, Centre for eCommerce and Communications, Understanding the 2011 Grampians Natural Disaster, addressing the risk and resilience (Final Report, 31 March 2014) vii–viii.
• 20 Victoria State Government – Great Ocean Road Taskforce, Protecting Our Iconic Coasts and Parks: Governance of the Great Ocean Road, its land and seascapes (Final Report, August 2018) 33–34.
• 21 Nous Group, Review of the Wye River and Separation Creek Fire Recovery (Review, 2 June 2017) 38–39.
• 22 Victoria State Government – Great Ocean Road Taskforce, Protecting Our Iconic Coasts and Parks: Governance of the Great Ocean Road, its land and seascapes (Final Report, August 2018) 33–34.
• 23 Victoria State Government – Great Ocean Road Taskforce, Protecting Our Iconic Coasts and Parks: Governance of the Great Ocean Road, its land and seascapes (Final Report, August 2018) 13.
• 24 Marion Leiba, ‘Impact of Landslides in Australia to December 2011’ (2013) 28(1) Australian Journal of Emergency Management 28, 30.
• 25 Derrick Hand (New South Wales State Coroner), Report of the inquest into the deaths arising from the Thredbo landslide (Report, 29 June 2000) 51 [219].
• 26 Australian Institute for Disaster Resilience, ‘Landslide – Gracetown, Western Australia’, Australian Disaster Resilience Knowledge Hub (Web Page) https://knowledge.aidr.org.au/resources/landslide-gracetown-western-aus….
• 27 ‘Inquest Found Council Responsible For Family’s Death’, Government News (online, 19 September 2008) https://www.governmentnews.com.au/inquest-found-council-responsible-for….
• 28 Derrick Hand (New South Wales State Coroner), Report of the inquest into the deaths arising from the Thredbo landslide (Report, 29 June 2000) 5 [5].
• 29 Derrick Hand (New South Wales State Coroner), Report of the inquest into the deaths arising from the Thredbo landslide (Report, 29 June 2000) 192 [929].
• 30 Derrick Hand (New South Wales State Coroner), Report of the inquest into the deaths arising from the Thredbo landslide (Report, 29 June 2000) 190 [919].
• 31 Australian Geomechanics Society Landslide Zoning Working Group, ‘Guideline for landslide susceptibility, hazard and risk zoning for land use planning’ (2007) 42(1) Australian Geomechanics Journal 13, 13. https://australiangeomechanics.org/admin/wp-content/uploads/2010/11/LRM…
• 32 Australian Geomechanics Society Landslide Zoning Working Group, ‘Guideline for landslide susceptibility, hazard and risk zoning for land use planning’ (2007) 42(1) Australian Geomechanics Journal 13, 13.
• 33 Bruce Walker, Warwick Davies and Grahame Wilson, ‘Practice Note Guidelines for Landslide Risk Management’ (2007) 42(1) Australian Geomechanics Journal 69.
• 34 Australian Geomechanics Society Landslide Zoning Working Group, ‘Guideline for landslide susceptibility, hazard and risk zoning for land use planning’ (2007) 42(1) Australian Geomechanics Journal 13, 14.
• 35 New South Wales Transport Roads & Maritime Services, AM21 Guidelines for slope asset management (Guidelines, Version 4.0, 1 July 2019); Transport for New South Wales, Guide for Natural disaster slope damage restoration requirements (Guidelines, September 2023).
• 36 International Consortium on Landslides, ‘The Kyoto Landslide Commitment 2020’, International Programme on Landslides (Web Page) https://www.landslides.org/ipl-info/the-kyoto-landslide-commitment-2020/.
• 37 International Consortium on Landslides, ‘The Kyoto Landslide Commitment 2020’, International Programme on Landslides (Web Page) https://www.landslides.org/ipl-info/the-kyoto-landslide-commitment-2020/.
• 38 International Consortium on Landslides, ‘The Kyoto Landslide Commitment 2020’, International Programme on Landslides (Web Page) https://www.landslides.org/ipl-info/the-kyoto-landslide-commitment-2020/.