Attachment 3 - Geotechnical Report

QUALITATIVE RISK ANALYSIS MATRIX -

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

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 3:
Approximate Annual 200% 60% 20% 5% INSIGNIFICANT
Probability 0.5%
A ALMOST CERTAIN 10" H Mor L (5)
B LIKELY 10° M L
Cc POSSIBLE 10° M VL
D UNLIKELY 104 L VL
E RARE 10° 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

HIGH RISK

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
tisk to Low. Work would cost a substantial sum in relation to the value of the property.

 

MODERATE RISK

May be tolerated in certain circumstances (subject to regulator’s approval) but requires investigation, planning and.
implementation of treatment options to reduce the risk to Low. Treatment options to reduce to Low risk should be
implemented as soon as practicable.

 

L

LOW RISK

Usually acceptable to regulators. Where treatment has been required to reduce the risk to this level, ongoing maintenance is
required.

 

 

VL

 

VERY LOW RISK

 

Acceptable. Manage by normal slope maintenance procedures.

 

Note: (7)

given as a general guide.

92

The implications for a pazticular 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

Australian Geomechanics Vol 42 No 1 March 2007