Consequence table

Once Step 1 has been completed, the consequences from the natural hazard can be calculated. When assessing consequences, the final level of impact is assessed on the ‘first past the post’ principle’, in that the consequence with the highest severity of impact applies. For example, if a natural hazard event resulted in moderate severity of impact across all of the categories, with the exception of critical buildings which had a ‘major’ severity of impact, the major impact is what the proposal would be assessed on. If a natural hazard event resulted in all of the consequences being at the same level (for example, all of the consequences are rated moderate), then the level of consequence is considered to be moderate.

The consequence table is based on the well-beings of social, cultural and economic as identified in the Resource Management Act 1991, Building Act 2004 and the Civil Defence Emergency Management Act 2002. The consequence table does not include a column for environment well-being. The reasons for this are twofold:

  • The risk-based approach has been designed for land use planning. This means it considers the interaction between human habitation and natural hazards. We do not, and are largely unable to, plan for the interaction between natural processes. For example, if a large earthquake uplifted an estuary, there are no land use planning options that could be implemented to prevent this from occurring, as it a nature vs. nature interaction.
  • The risk-based approach also concentrates on the primary (immediate) effects associated with natural hazards. Consideration was given to the effects a natural hazard can have on the environment through damaging or interrupting a human process. For example, an earthquake ruptures a pipeline and results in an oil spill. It is considered that the damage to the pipeline is a primary effect resulting from the earthquake. However, the effects on the ecosystem from the oil spill are a secondary effect and therefore are not considered as part of this risk-based approach.
Consequence tablev2

Consequence table

The consequence table has been developed as a multi-hazard table. That is, it can be used for different natural hazards – flooding, land instability, tsunami, fault rupture, liquefaction, etc. The scale of the table is such that while it provides a multi-hazard approach, not all hazards will result in catastrophic consequences. For example, a flood may never reach ‘major’, whereas an earthquake may.

The table has been developed based on the methodology provided in the Appendices of the Report. However, if appropriate the descriptors could be refined with further research, development and testing. For example, if district GDP figures are available, these could be used within a district context instead of regional GDP.

There are a number of assumptions, limitations and uncertainties relating to the use of the consequence table. These can be found at Assumptions, uncertainties and limitations