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)
                                                    -2
B -    LIKELY                                     10                            VH                         VH                       H                       M                       L
C -    POSSIBLE                                   10-3                          VH                          H                       M                       M                      VL

D -    UNLIKELY                                   10-4                           H                         M                        L                       L                      VL
                                                    -5
E -    RARE                                       10                             M                          L                       L                      VL                      VL
                                                    -6
F -    BARELY CREDIBLE                            10                             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.
                                                                 Acceptable. Manage by normal slope maintenance procedures.
         VL                      VERY LOW RISK

       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
 Form No. Landslide
    68039 68039 RL2Risk
                    August 2010
                        Management           Issued 10/7/07


[OCR of page images]
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 107 H MorL (5)
B - LIKELY 107 H M L
C - POSSIBLE 10° M M VL
D - UNLIKELY 10" L L VL
E - RARE 10° M L L VL VL
F - BARELY CREDIBLE 10° 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
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

la SN 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
Form No. 68039 RL2 August 2010