slope stability report

                                          PRACTICE NOTE GUIDELINES FOR LANDSLIDE RISK MANAGEMENT 2007
                             APPENDIX C: – QUALITATIVE TERMINOLOGY FOR USE IN ASSESSING RISK TO PROPERTY (CONTINUED)


      QUALITATIVE RISK ANALYSIS MATRIX – LEVEL OF RISK TO PROPERTY
                       LIKELIHOOD                                            CONSEQUENCES TO PROPERTY (With Indicative Approximate Cost of Damage)
                                     Indicative Value of          1: CATASTROPHIC                   2: MAJOR                 3: MEDIUM              4: MINOR                    5:
                                    Approximate Annual                     200%                         60%                       20%                   5%              INSIGNIFICANT
                                         Probability                                                                                                                          0.5%
A   – ALMOST CERTAIN                         10-1                           VH                           VH                        VH                    H                 M or L (5)
B   - LIKELY                                 10-2                           VH                           VH                        H                     M                      L
C   - POSSIBLE                               10-3                           VH                            H                        M                     M                     VL
D   - UNLIKELY                               10-4                            H                            M                         L                     L                    VL
E   - RARE                                   10-5                            M                            L                         L                    VL                    VL
F   - BARELY CREDIBLE                        10-6                            L                           VL                        VL                    VL                    VL
      Notes: (5) For Cell A5, may be subdivided such that a consequence of less than 0.1% is Low Risk.
             (6) When considering a risk assessment it must be clearly stated whether it is for existing conditions or with risk control measures which may not be implemented at the current
                 time.


      RISK LEVEL IMPLICATIONS
                          Risk Level                                                                                     Example Implications (7)
                                                                      Unacceptable without treatment. Extensive detailed investigation and research, planning and implementation of treatment
         VH                        VERY HIGH RISK                     options essential to reduce risk to Low; may be too expensive and not practical. Work likely to cost more than value of the
                                                                      property.
                                                                      Unacceptable without treatment. Detailed investigation, planning and implementation of treatment options required to reduce
          H                            HIGH RISK
                                                                      risk to Low. Work would cost a substantial sum in relation to the value of the property.
                                                                      May be tolerated in certain circumstances (subject to regulator’s approval) but requires investigation, planning and
          M                        MODERATE RISK                      implementation of treatment options to reduce the risk to Low. Treatment options to reduce to Low risk should be
                                                                      implemented as soon as practicable.
                                                                      Usually acceptable to regulators. Where treatment has been required to reduce the risk to this level, ongoing maintenance is
          L                            LOW RISK
                                                                      required.
         VL                        VERY LOW RISK                      Acceptable. Manage by normal slope maintenance procedures.
      Note:    (7)     The implications for a particular situation are to be determined by all parties to the risk assessment and may depend on the nature of the property at risk; these are only given as a
               general guide.




                                   Australian Geomechanics Vol 42 No 1 March 2007