Landslide susceptibility

A landslide is the movement of a mass of rock, debris, or earth down a slope. Sometimes this can be a slow process taking months or years and primarily pose a risk to property and the environment. However, landslides pose a significant risk to the safety of people, especially if they happen quickly.  

Landslides can occur by natural processes but can also be caused or exacerbated by human activity. This makes them difficult to predict and a complex problem to deal with.  

Some of the common natural factors which contribute to landslides include: 

• Geology (including the thickness and type of soil overlying bedrock)
• The slope (steepness) of the land
• Aspect (direction the slope faces)
• Depth of the water table or perched water tables
• Poor drainage of soils
• Soil erosion lost through rain/wind
• Weather events such as intense storms/floods or bushfires and climatic conditions such as drought and rising sea levels.

Some of the common human induced factors that contribute to landslides include:

• Buildings and earthworks (including excavation or filling of land and inappropriate design or response to the site conditions)
• Vegetation removal
• Poor drainage of soils or concentration of water as a result of works
• Soil erosion lost through repeated movement of people, animals and vehicles

Some factors which can trigger a landslide include:

• Heavy or prolonged rainfall (including from major storms)
• Flooding, and
• Earthquakes 

Landslides are generally more likely to occur where soils are thicker, slope angles are steeper, or the amount of water in the ground is higher. Therefore, the more we can preserve the natural landform, vegetation and drainage, the less susceptible slopes will be to landslide. 

The Shire helps minimise landslide risk in many ways, including through land use and development planning, development engineering, drainage infrastructure maintenance, stormwater and flood management, asset management, coastal planning, capital works and erosion monitoring.

A part of managing risk is applying planning controls to land that is susceptible to landslides to ensure future development responds appropriately to risk.

Of the factors above that contribute to landslide risks, there are primarily three (3) that can be controlled by the planning system or used to avoid or control the negative impacts or likelihood of landslides occurring. These are:

• Buildings and earthworks (including excavation or filling of land)
• Vegetation removal
• Drainage 

While there are many controls in the Mornington Peninsula Planning Scheme which address erosion or landslide risk, the main control is the Erosion Management Overlay (EMO).

An Erosion Management Overlay (EMO) is a type of planning control that’s applied to land to protect areas prone to erosion, landslip and other land degradation or coastal processes by minimising land disturbance and inappropriate development.

More information about erosion and landslide planning controls is also available on the Department of Transport and Planning website.

There are six permanent EMOs which currently apply to parts of the Peninsula. The EMOs have been introduced since the 1970s and generally cover areas based on specific geotechnical studies:

• EMO1 and EMO2  apply to hinterland areas, generally from Arthurs Seat southwards to Cape Shank and Flinders.
• EMO3 applies to land around Ballar Creek in Mount Eliza
• EMO4 Landslide Susceptibility Area A and EMO5 Landslide Susceptibility Area B apply to land around Tanti Creek in Mornington and Flinders township.
• EMO6 Erosion Hazard – Beach and Foreshore Areas applies to the Westernport coastline from Somerville to Cape Schanck.

You can view and download a free planning map and property report that outlines the zones and overlays that apply to your property at the VicPlan website: VicPlan website.

It means you might need a planning permit before you can develop your land (including removing vegetation), and a report from a geotechnical expert explaining how your proposed development is safe from landslide risks.

In rare cases, parts of a property may be unsuitable for development – depending on the nature of the buildings and works and associated risks.

Importantly:

• Development outside mapped EMO7 areas can proceed as normal, subject to any other planning controls that may apply to the land.
• Not all development needs a permit under the EMO7. There are exemptions for certain types of minor buildings and works.
• Council will waive application and enquiry fees where the EMO7 is the only permit trigger and there’s clearly no landslide risk needing geotechnical analysis or permit conditions.

If you’re unsure what planning controls apply to your land, or whether you might need a planning permit, call our Statutory Planning team on 5950 1010 or email planning@mornpen.vic.gov.au. You can also book an appointment to discuss a specific planning permit application proposal. 

Unless specific exemptions apply, you may need to provide detailed geotechnical information from a suitably qualified and experienced geotechnical engineer or engineering geologist.

In many cases, a landslide risk assessment (LRA) report will be required. The LRA will be specific to your land and will ensure risks are properly identified and managed for the particular ground and slope conditions of your property (which vary widely across the Shire) and the type of development or works you want to do, including the amount of vegetation you may propose to remove.

Some minor works may not require a full landslide risk assessment, but this must be guided by a suitably qualified and experienced geotechnical engineer or engineering geologist.

Importantly, Council can vary or lessen these requirements if they are not relevant to the assessment of an application.

Council is undertaking a staged approach to updating EMOs across the Peninsula. 

Stage 1: Interim EMO7 for high landslide susceptibility areas (Finished)

Following urgent recommendations from the McCrae Landslide Board of Inquiry, Council resolved on 17 November 2025 to request the Victorian Minister for Planning to approve Planning Scheme Amendment C312morn.

The amendment applied the interim EMO7 to all land identified as highly susceptible to landslides that did not already have an EMO. The purpose of EMO7 is to help ensure new development is safe from landslides until permanent controls are in place.

The EMO7 is based on the best available data about landslides on the Peninsula: Landslide Susceptibility Assessment, Stage 2, Mornington Peninsula Shire, Victoria (Cardno Lane Piper, 2012).

The Minister for Planning approved Amendment C312morn on 6 January 2026.

Stage 2: Updates to interim EMO7 based on expert geotechnical advice (Underway)

On 11 August 2026, Council resolved to request the Victorian Minister for Planning to approve Planning Scheme Amendment C314morn. This amendment substantially improves the mapping and planning requirements of the interim EMO7 based on expert geotechnical engineering advice.

It is expected that the Minister for Planning will decide Amendment C314morn by the end of 2026.

Stage 3: Comprehensive new shire-wide landslide susceptibility study and permanent EMOs

Council will undertake a comprehensive new Shire-wide landslide susceptibility study to replace the existing best available data in the Landslide Susceptibility Assessment, Stage 2, Mornington Peninsula Shire, Victoria (Cardno Lane Piper, 2012).

The new study will inform permanent new landslide planning controls to replace the interim EMO7 implemented by Stages 1 and 2. It will also review and rationalise all other existing permanent EMOs (i.e. EMOs 1-6).

Stage 3 is expected to be completed within the next 2-4 years and will involve community consultation.

Speak to a suitably qualified Geotechnical Engineer or Engineering Geologist with experience in managing slope stability problems and landslide risk. They should be degree qualified, a member of a professional institute and be a Chartered Professional Engineer (CPEng), Registered Professional Engineer, Victoria (under Part 2 of the Victorian Professional Engineers Registration Act 2019), Chartered Professional Geologist (CPGeo), or Registered Professional Geologist (RPGeo). 

Some things you can do to help reduce landslide risks include:

• Understand the landslide susceptibility of your property by consulting a qualified and experienced geotechnical engineer for advice
• Find out whether you need a planning permit before carrying out any buildings or works
• Do not carry out any buildings or works without a planning permit if a permit is required
• Minimise any changes in slope, vegetation, and drainage if you develop your land in accordance with the conditions on your planning permit
• Use properly designed and engineered retaining walls of durable materials (steel/concrete)
• Remove any surplus excavated material from your land
• Install subsurface drains for water tanks, pools and retaining walls. 
• Direct stormwater runoff to a Legal Point of Discharge
• Use modern wastewater treatment if you don’t have access to sewer
• Do not build in drainage paths
• Mark underground structures like septic tanks or bunkers
• Regularly inspect and maintain pools, water tanks, water features, drains and retaining walls to prevent leaks
• Ensure automated watering systems and pool auto-fillers are in good working order
• Keep records of work done to your land
• Contact the Shire or emergency services if you have a safety concern or to report landslides
• Contact South East Water about any blocked or leaking water mains: South East Water | Faults and Works