Appendix F - Geo-Environmental Investigation Report · RAL24/0003

                                        PROPOSED SUBDIVISION
                                        41 TALLOWWOOD PLACE, BLACK MOUNTAIN

5.2         Slope Stability Assessment
5.2.1          Qualitative Assessment
The risk assessment for this project has been carried out following AGS 2007 Practice Note Guidelines for
Landslide Risk Management. Relative levels of risk and their implications are given in Table 1 and the
Qualitative Terminology for Use in Assessing Risk to Property is also attached in Appendix B.
Table 1: Stability Risk Levels
 Risk Level                   Example Implications(1)

                              Unacceptable without treatment. Extensive detailed investigation and research, planning and implementation of
 VH      Very High Risk       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 and
 M       Moderate Risk        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, and subject to the implementation of recommendations given in
Section 6, it is assessed that there would be a Low (L) Risk of global slope instability affecting the proposed
subdivision. Regulators (NC) normally require that a Very Low or Low Risk of landslide affecting property
must be demonstrated to enable development approval. Summarised in Table 2 overleaf is our qualitative
assessment of landslide risk for the site. A summary of qualitative terminology for use in assessing risk to
property is attached in Appendix C (taken from AGS 2007).
This risk assessment excludes geotechnical risk associated with the existing structures and areas outside the
recommended building zone.




22 May 2023
Report No. 23099-001-Rev0                                                 10