Geotechnical Report

                               PROPOSED UNIT DEVELOPMENT
                               31 BOTTLEBRUSH AVENUE, NOOSA HEADS

5.0      SLOPE STABILITY ASSESSMENT
5.1      Existing Conditions
The Noosa Planning Scheme 2020 includes a landslide hazard overlay map (Ref. extract in Text Figure 9).
Mapping indicates that the site is within a Moderate Landslide Hazard Area.




                                                                Lot boundary




Text Figure 1: Extract from NSC landslide hazard overlay mapping

It should be noted that the Noosa landslide hazard map is a broad-scale indication of the potential
landslide susceptibility and is superseded by this site specific assessment. No visual signs of global slope
instability were observed across the site. No landslide back scarps or areas of naturally ‘hummocky’
ground were observed.

5.2       Stability 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 2 and the
Qualitative Terminology for Use in Assessing Risk to Property is also attached in Appendix B.
 Table 2: 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.




17 December 2020
Report No. 20370-001-Rev0                                   8