Risk Assessment
Risk assessment is a critical element of disaster management planning. While response capacities are vital and require constant monitoring, an understanding of the risks that underline potential hazards enhances the development of robust disaster management plans and thereby reduces the impact of disasters and community vulnerability.
Hazards often faced by communities include natural hazards such as those related to meteorological, geological, geographical/topographic or biological influences, or non-natural hazards caused by technology or those associated with consequence management concerns such as arson or sabotage.
Through the principles of risk management – in which the hazard context is established – risks are identified, analysed and evaluated, treatments are prioritised and management options are developed enabling Redland City Council to address vulnerabilities and build community resilience.
Risk Assessment for Natural Disasters
| EVENT | CONSEQUENCE | LIKELIHOOD | RISK RATING |
|---|---|---|---|
| Bushfire | Medium | Almost Certain | High (H-30) |
| Severe Storms | Medium | Almost Certain | High (H-30) |
| East Coast/Tropical Low | Medium | Likely | High (H-24) |
| Cyclone | Major | Possible | High (H-24) |
| Earthquake | Major | Possible | High (H-24) |
| Storm Surge | Medium | Possible | Medium (M-18) |
| Dam Release – Leslie Harrison Dam | Low | Likely | Medium (M-16) |
| Heat Wave | Low | Possible | Medium (M-12) |
| Prolonged Flooding | Medium | Unlikely | Medium (M-12) |
| Tsunami | Major | Rare | Medium (M-8) |
| Dam Failure – Leslie Harrison Dam | Major | Rare | Medium (M-8) |
| Landslip | Low | Unlikely | Low (L-8) |
Risk Assessment for Non-natural Disasters
| EVENT | CONSEQUENCE | LIKELIHOOD | RISK RATING |
|---|---|---|---|
| Pandemic | Major | Possible | High (H-24) |
| Marine Oil Spill | Major | Possible | High (H-24) |
| Major Industrial Accident | Medium | Possible | Medium (M-18) |
| Major Utilities/Infrastructure Failure | Medium | Possible | Medium (M-18) |
| Major Ground Transport Accident | Medium | Possible | Medium (M-18) |
| Major Commercial Shipping Accident | Medium | Possible | Medium (M-18) |
| Aircraft Crash | Major | Unlikely | Medium (M-16) |
| Hazardous Material Accident (HAZMAT) | Major | Unlikely | Medium (M-16) |
| Building Collapse | Major | Rare | Medium (M-8) |
| Terrorist Incident (chemical, biological and radiological) | Medium | Rare | Low (L-6) |
| Terrorist Incident (siege or hostage) | Medium | Rare | Low (L-6) |
| Terrorist Incident (bombing) | Medium | Rare | Low (L-6) |
Risk Methodology
Risk assessment is a process of evaluating the source and possible consequence of the risk, and the likelihood that those consequences will occur. This is achieved through the Risk Rating Matrix below, where the consequence of the risk is mapped against the likelihood that the risk will occur, which provides a risk rating level – low, medium, high or extreme. An explanation of the criteria for risk likelihood descriptors and risk consequence descriptors appears in the following tables. The risk assessment of the potential for disaster informs Council’s disaster management arrangements. Council’s risk management processes are based on Australia Standard AS/NZS ISO 31000:2009.
The following risk assessment tables for natural and non-natural disasters takes a city-wide approach toward risks and considers both the mainland areas of the city along with the islands of Moreton Bay. These risks, both natural and non-natural are discussed in further detail throughout these pages based on geographic location. It is recognised that Redland City is a community of communities, and the risks facing mainland hinterland regions will differ in severity from those of mainland coastal regions which will differ again from those facing the islands of Moreton Bay.
Risk Rating Matrix
| Likelihood | Level 1
Insignificant |
Level 2
Low |
Level 3
Medium |
Level 4
Major |
Level 5
Severe |
|---|---|---|---|---|---|
| 5 – Almost Certain | M-10 | H-20 | H-30 | E-40 | E-50 |
| 4 – Likely | M-8 | M-16 | H-24 | E-32 | E-40 |
| 3 – Possible | L-6 | M-12 | M-18 | H-24 | E-30 |
| 2 – Unlikely | L-4 | L-8 | M-12 | M-16 | H-20 |
| 1 – Rare | L-2 | L-4 | L-6 | M-8 | M-10 |
Risk Methodology – Likelihood Descriptors
Risk Methodology – Consequence Descriptors
| RISK | SOCIAL/COMMUNITY | INFRASTRUCTURE | ENVIRONMENTAL | ECONOMIC |
|---|---|---|---|---|
| Insignificant | Inconsequential short term reduction of services, no damages to objects of cultural significance, no adverse emotional and psychological impacts. No known injuries or illnesses. | Inconsequential short term failure of infrastructure and service delivery, no disruption to the public services and utilities. | No or minimal impact on the environment - very limited direct damage to ecosystems or elements of place. | Minor financial loss that can be managed within standard financial provisions (e.g. insurance), inconsequential disruptions at business level. |
| Low | Isolated and temporary cases of reduced services within community, repairable damage to objects of cultural significance, impacts within emotional and psychological capacity of the community. Minor injury/illness managed within existing resources (first aid personnel and readily available equipment). | Isolated cases of short- to mid-term failure of infrastructure and service delivery, localised inconvenience to the community and business anticipated to extend up to 72 hours. No long term impact on integrity or operation of the infrastructure. | Limited and/or localised impact on the environment that can be readily rectified but effort is still required to minimise. One off recovery effort is required. | Financial loss requiring activation of reserves to cover loss, disruptions at business level leading to isolated cases of loss of employment. |
| Medium | Ongoing reduced services within community, permanent damage to objects of cultural significance, impacts beyond emotional and psychological capacity in some parts of the community. Single fatality or permanent incapacity. Multiple serious injury/illnesses requiring professional medical care and/or hospitalisation. Small number of people displaced for <24 hrs. | Mid-term failure of (significant) infrastructure and service delivery affecting some parts of the community, widespread inconveniences. Repair/replacement expected to take greater than 72 hours. | Isolated but significant cases of impairment or loss of ecosystem functions, intensive efforts for recovery required. Event can be managed under normal procedures. | Direct moderate financial loss in the region requiring adjustments to business strategy to cover loss, disruptions to selected industry sectors leading to isolated cases of business failure and multiple loss of employment. |
| Major | Reduced quality of life within community, significant loss or damage to objects of cultural significance, impacts beyond emotional and psychological capacity in large parts of the community. Majority of services unavailable to community. Multiple fatalities or permanent incapacities (up to 1 per 100 000). Regional health care system stressed. External resources required to contain and resolve the incident. Large number of people displaced for >24 hours. | Mid to long term failure of significant infrastructure and service delivery affecting large parts of the community, external support required. | Severe impairment or loss of ecosystem functions affecting many species or landscapes, progressive environmental damage. | Significant financial loss requiring major changes in business strategy to (partly) cover loss, significant disruptions across industry sectors leading to multiple business failures and loss of employment. |
| Severe | Community unable to support itself, widespread loss of objects of cultural significance, impacts beyond emotional and psychological capacity in all parts of the community, long term denial of basic community services. Widespread loss of lives (at least 1 per 10 000), regional health care system unable to cope, large displacement of people beyond regional capacity to manage. | Long term failure of significant infrastructure and service delivery affecting all parts of the community, ongoing external support at large scale required. | Widespread severe impairment or loss of ecosystem functions across species and landscapes, irrecoverable environmental damage. Total incongruence with preferred elements of place. | Unrecoverable financial losses. Multiple major industries in the region seriously threatened or disrupted for foreseeable future. Asset destruction across industry sectors leading to widespread business failures and loss of employment. |