RFI - Attachment C - Slope Stability Assessment and Geotechnical report · MCU20/0026

Project No. 1-22543                                                                                                                     Page | 11
June, 2020
Ref: 1-22543, 2020-05-20, BR SSA VER 1
Sanya Holdings – Slope Stability Assessment and Geotechnical Report - Proposed Residence, 40 Park Crescent, Sunshine Beach




          Hazard C – Initially Insignificant due to shallow soil profile but could be Medium if not
           addressed in the long term.

           4.4.4       Consequence to Persons

For the purposes of this study, the methodology as outlined in Section 7 of PNGLRM 2007, will
adopt the following assumptions with respect to persons on the lot. Different hazards have
been deemed to have varying probabilities based on their location on the site (Section 5.2):-

          The affected study site will contain a proposed residential dwelling.
          The probability of spatial impact (P(S:H)) - this has been based on the total width of the
           site exposed to possible instability compared to the total width of the proposed structure
           within that length. Assessed as 100%.
          Proportion of time dwelling occupied - 50%.
          Probability of not being able to escape - 20%.
          Temporal Spatial Probability (P(T:S)) - Proportion of time dwelling occupied multiplied by
           the Probability of not being able to escape - 10%.
          Vulnerability (V(D:T)), (Appendix F - PNGLRM 2007):- 70%

Note: the consequences to Persons have not been assessed for hazard C prior to construction
as it is not considered applicable.

    4.5 Risk Determination and Evaluation - Property
Appendix C of “PNGLRM (2007)” outlines a method of assessing Risk to Property. The
calculation of likelihood is based on the estimate outlined in Sections 4.3.3 to 4.3.5 of this
report.

The consequence is based on the proposed development and the effects on the property of the
specific hazards in Section 4.4.

The risk is then assessed based on the Risk Matrix from LRMPNG, 2007. The assessment is
summarised in Table 3.

TABLE 3            SUMMARY OF RISK TO PROPERTY
                                            Hazard                   Assessed                     Assessed                   Assessed Risk
Hazard          Area of Site
                                            Rating                   Likelihood                  Consequence                  to Property
     A           Overall Site                  Low                Rare to Unlikely              Minor to Medium              Very Low to Low
                 Proposed
     B                         2               Low                Rare to Unlikely                    Medium                      Low
               internal cuts
               Overall Site –            Moderate to
                                                                 Unlikely to Likely                Insignificant             Very Low to Low
                   initially                High
    C
               Overall Site –            Very Low to             Barely Credible to
                             3                                                                        Medium                 Very Low to Low
                long term .                 Low                        Rare
Note:-
1. Refer Appendix B of “Practice Note Guidelines for Landslides Risk Management (2007)”.
2. Assumes all cuts supported by engineer designed retaining walls.
3. Assumes it’s addressed by landscaping and control of drainage and overland flow.

A review of the table above indicates that provided the recommendations outlined in this
report are carried out, the risk of slope instability occurring on the site has been
assessed as no higher than Low.



                                                                                                               SOIL SURVEYS