What are landslides and rockfalls?
Landslides and rockfalls are the principal geological hazards (sometimes called geohazards) which may be a risk to park visitors, to workers (i.e. National Parks and Wildlife Service staff, contractors or volunteers) in parks, or to neighbouring landowners.
- A landslide is the movement of a mass of rock, debris, or earth (soil) down a slope.
- A rockfall is the action of boulders, rocks or slabs of rock falling or toppling.
Other geological hazards that may affect parks include areas of karst (caves formed from the erosion of soluble rocks such as limestone), mining subsidence, sinkholes, and earthquakes. Weather events such as heavy rainfall, flooding, temperature extremes or high winds can affect the stability of geological or geomorphological features in parks. Earthquakes may also destabilise geological features.
What is the difference between hazard and risk?
Hazard and risk are often used interchangeably, but in a risk management context they have quite different meanings.
A hazard is something that has the potential for doing harm or damage, e.g. a venomous snake, a slippery floor, an uncontrolled bushfire or an active volcano. A geological hazard can be an unstable part of the landscape, e.g. a steep hillside, loose or unsecured boulders or rocks, a fractured cliff or a rocky escarpment.
Risk is a conceptual construct for measuring how likely it is that a hazard will do harm or damage, and how severe the consequences will be.
In the context of landslides and rockfalls, a steep, unstable hillside may be a hazard. This hazard may pose multiple risks, such as the risk of a landslide impacting property, infrastructure assets or people, or the risk of damage from small rockfalls. The severity of each of these risks can be measured qualitatively (e.g. using a risk matrix to rate the risk on a scale from 'low' to 'extreme' by considering its likelihood and consequences), or quantitatively (e.g. using a risk formula to represent the risk as a number).
This policy is supported by detailed procedures
Implementation of this Policy is supported by National Parks and Wildlife Service (NPWS) Landslides and Rockfalls Procedures that provide more detailed guidance on how to record and respond to landslide and rockfall incidents and hazards in parks.
- NPWS has a duty of care to minimise the risk of landslides and rockfalls to people in parks and to neighbouring landholders.
- NPWS follows accepted risk management and safety practices; conforms with international and Australian standards; and follows corporate Risk Management Procedures and the Work, Health and Safety (WHS) System in its management of risk from landslides and rockfalls.
- NPWS bases the management of landslide and rockfall risks on:
- the systematic identification of hazards
- a realistic assessment of risks
- consideration of a range of management options before making decisions, and
- managing risks under the principle of ALARP (As Low As Reasonably Practicable), consistent with industry practice.
- NPWS gives priority, in its management of landslide and rockfall risks, to the protection of life, consistent as far as possible with the protection of the natural and cultural values of parks. The protection of property, including park infrastructure, is also an important consideration but is secondary to the protection of life.
- NPWS manages landslide and rockfall risks as part of its regular park management activities - that includes identifying, analysing, assessing and treating risks. NPWS obtains expert geotechnical advice on assessing landslide and rockfall risks where necessary.
- NPWS focuses its hazard identification efforts on more developed, high visitation or high-use areas in parks. NPWS treats and monitors hazards according to their assessed risk. Hazards with the highest assessed risk receive the greatest attention, followed by other hazards as resources permit.
- NPWS considers landslides and rockfalls as part of the assessment of planned construction and maintenance activities for park and visitor assets.
- NPWS maintains a record of identified landslides and rockfalls and management responses. NPWS will, over time, progressively identify and assess potential risks from landslides and rockfalls at a strategic level (i.e. across multiple locations in a park or several parks).
- NPWS assesses landslide and rockfall risks using a combination of qualitative and quantitative methods, and has adopted organisational thresholds for acceptable and tolerable risks.
- NPWS documents the process of assessing landslide and rockfall risks, determining a management response, and implementing the response.