Appendix E_Geotechnical Investigation

                                 PROPOSED UNIT DEVELOPMENT
                                 PRECINCTS E2 & F, NOOSA SPRINGS

Table 1: Stability Risk Levels
 Risk Level             Example Implications(1)
                         Unacceptable without treatment. Extensive detailed investigation and research, planning
        Very High
 VH                      and implementation of treatment options essential to reduce risk to Low; may be too
        Risk
                         expensive and not practical. Work likely to cost more than value of property.
                         Unacceptable without treatment. Detailed investigation, planning and implementation of
 H      High Risk        treatment options 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
        Moderate
 M                       investigation, planning and implementation of treatment options to reduce risk to Low.
        Risk
                         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
 L      Low Risk
                         to this level, ongoing maintenance required.
        Very Low
 VL                     Acceptable. Manage by normal slope maintenance procedures.
        Risk
 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 subject to the implementation of
recommendations given below, it is our opinion that there is a Low (L) Risk of global slope instability affecting
the proposed development. Regulators (NSC) normally require that a Very Low or Low Risk of landslide
affecting the property must be demonstrated to enable development approval. Summarised in Table 2 below
is our qualitative assessment of landslide risk for the development site. A summary of qualitative terminology
for use in assessing risk to property is attached in Appendix B (taken from AGS 2007).
Table 2: Details of Qualitative Risk Assessment for Property (AGS 2007
                                                              Assessed
 Hazard                          Likelihood   Consequence
                                                                Risk
                                                                           Comments

                                                                           Given the mostly shallow depth of loose sands
                                                                           (above medium dense and dense sand), lack of
                                                                           groundwater and low to moderate to steep ground
                                                                           slopes (away from the steep bank), it is considered
 1: Shallow failure through
                                                                           Unlikely that a landslip would develop in these
natural soils above foundation    Unlikely       Medium          Low
                                                                           materials. Subject to implementation of the
level (
                                                                           recommendations in Section 4 (including founding in
                                                                           dense sand), there would be a potential Medium
                                                                           impact from such instability, and the resultant risk
                                                                           being Low as per AGS 2007.


                                                                           The likelihood of a deep failure through the medium
                                                                           dense to very dense sands is assessed as Rare due
 2: Deep failure through
                                                                           to the strength of these materials, lack of groundwater,
medium dense to very dense         Rare           Major          Low
                                                                           and no signs of any slope instability. Although the
sands
                                                                           consequence of such a failure could be Major, the
                                                                           resultant risk is Low as per AGS 2007.




The potential impacts on slope stability of the development components have been assessed, and the
measures recommended below in Section 4 have been designed to mitigate those impacts.




11 November 2015
Report No. 15193-002-Rev0                                   10