SCG 0599 - Landslide Risk Assesment

Figure 4: Landslide hazard overly map showing lot boundary in red (from Noosa Shire Council)

Based on a desktop review of the provided data and understanding of the area, there are two potential failure
mechanisms can be considered, these include:

»     Hazard 1 – Small rotational failure through the natural loose sands – volume of failure less than 20m3
      (failure will required an unusual sever triggering event)
»     Hazard 2 – Large rotational failure through the natural loose sands – volume of failure less than 2000m3
      (failure will required an extreme triggering event)
A qualitative landslip risk assessment was completed for these potential failure mechanisms in general
accordance with Australian Geomechanics (2007) Guideline for Landslip Susceptibility, Hazard and Risk
Zoning for Land Use Planning). The slope risk assessment is summarised in Table 1.

Table 1: Summary of the qualitative slope risk assessment
                              Hazard 1 – small rotational failure           Hazard 2 - Large rotational failure
         Hazards            though the natural loose sands up to           though the natural loose sands up to
                                           20m3                                         2,000 m3
                                Property               People, who             Property               People, who
                                                   either live, or may                            either live, or may
                                                    that spend some                                that spend some
       Risk Element
                                                     time in the area                               time in the area
                                                     affected by the                                affected by the
                                                         landslip                                       landslip
    Likelihood                 POSSIBLE                 POSSIBLE         BARLEY CREDIBLE          BARLEY CREDIBLE
    Frequency                       C                       C                      F                      F
    estimate,
    expressed as an
    annualised
    probability and
    taking into account
    the probability of
    spatial impact



SCG Consulting Engineers                               Page 4 of 5                     SCG 0599    24 September 2025