Attachment 3 - Revised Slope Stability Assessment

Brett Hage                                                                                                                     22328-001-Rev1
                                                                                                                             17 November 2022

Table 2: Stability Risk Levels
 Risk Level                  Example Implications(1)

                        Unacceptable without treatment. Extensive detailed investigation and research, planning and implementation
 VH      Very High Risk of treatment options essential to reduce risk to Low; may be too expensive and not practical. Work likely to cost
                        more than value of property.

                             Unacceptable without treatment. Detailed investigation, planning and implementation of treatment options
 H       High Risk
                             required to reduce 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 regulators’ approval) but requires investigation, planning
 M       Moderate Risk       and implementation of treatment options to reduce 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
 L       Low Risk
                             maintenance required.

 VL      Very Low Risk       Acceptable. Manage by normal slope maintenance procedures.

 Note: (1) 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.

Considering the existing site conditions (Ref. Section 2), and proposed development works, it is assessed that
there would be a Low (L) Risk of global slope instability affecting the proposed development subject to the
implementation of recommendations given below. Regulators (NC) normally require that a Very Low or Low
Risk of landslide affecting the property must be demonstrated to enable development approval. Summarised
in Table 3 on the page below is our qualitative assessment of landslide risk for the site. A summary of
qualitative terminology for use in assessing risk to property is attached (taken from AGS 2007).




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