Approved Plan - EXE230029

                                                               TABLE A1: LANDSLIDE RISK ASSESSMENT
                                                  QUALITATIVE TERMINOLOGY FOR USE IN ASSESSING RISK TO PROPERTY
            QUALITATIVE MEASURES OF LIKELIHOOD
               Approximate Annual Probability
               Indicative         Notional          Implied Indicative Landslide Recurrence Interval                                Description                                      Descriptor            Level
                 Value            Boundary
                  10-1                                     10 years                                   The event is expected to occur over the design life.                      ALMOST CERTAIN              A
                                 510-2                                       20 years
                                                                                                      The event will probably occur under adverse conditions over the
                  10 -2                                   100 years                                                                                                             LIKELY                      B
                                                                                                      design life.
                                 510 -3                                      200 years
                                                                                                      The event could occur under adverse conditions over the design
                  10-3                                   1000 years                                                                                                             POSSIBLE                    C
                                 510 -4                                                              life.
                                                                              2000 years
                                                                                                      The event might occur under very adverse circumstances over the
                  10-4                                  10,000 years                                                                                                            UNLIKELY                    D
                                      -5                                                              design life.
                                 510                                         20,000 years
                     -5                                                                               The event is conceivable but only under exceptional circumstances
                  10                                   100,000 years                                                                                                            RARE                        E
                                      -2
                                                                                                      over the design life.
                                 510                                         200,000 years
                  10-6                                1,000,000 years                                 The event is inconceivable or fanciful over the design life.              BARELY CREDIBLE              F
            Note: (1)     The table should be used from left to right; use Approximate Annual Probability or Description to assign Descriptor, not vice versa.

            QUALITATIVE MEASURES OF CONSEQUENCES TO PROPERTY
                Approximate cost of Damage
                 Indicative       Notional                                                               Description                                                                 Descriptor            Level
                   Value         Boundary
                                              Structure(s) completely destroyed and/or large scale damage requiring major engineering works for stabilisation. Could
                   200%                                                                                                                                                       CATASTROPHIC                  1
                                  100%        cause at least one adjacent property major consequence damage.
                                              Extensive damage to most of structure, and/or extending beyond site boundaries requiring significant stabilisation works.
                   60%                                                                                                                                                        MAJOR                         2
                                   40%        Could cause at least one adjacent property medium consequence damage.
                                              Moderate damage to some of structure, and/or significant part of site requiring large stabilisation works. Could cause at
                   20%                                                                                                                                                        MEDIUM                        3
                                   10%        least one adjacent property minor consequence damage.
                    5%                        Limited damage to part of structure, and/or part of site requiring some reinstatement stabilisation works.                      MINOR                         4
                                    1%        Little damage. (Note for high probability event (Almost Certain), this category may be subdivided at a notional boundary of
                  0.5%                                                                                                                                                        INSIGNIFICANT                 5
                                              0.1%. See Risk Matrix.)
            Notes: (2)      The Approximate Cost of Damage is expressed as a percentage of market value, being the cost of the improved value of the unaffected property which includes the land plus the
                            unaffected structures.
                      (3)   The Approximate Cost is to be an estimate of the direct cost of the damage, such as the cost of reinstatement of the damaged portion of the property (land plus structures), stabilisation
                            works required to render the site to tolerable risk level for the landslide which has occurred and professional design fees, and consequential costs such as legal fees, temporary
                            accommodation. It does not include additional stabilisation works to address other landslides which may affect the property.
                      (4)   The table should be used from left to right; use Approximate Cost of Damage or Description to assign Descriptor, not vice versa.
            Extract from PRACTICE NOTE GUIDELINES FOR LANDSLIDE RISK MANAGEMENT as presented in Australian Geomechanics, Vol 42, No 1, March 2007, which discusses the matter more fully.
            February 2019



Document Set ID: 22532435
Version: 1, Version Date: 07/08/2023