J001783-001-R-Rev1

Ashley and Caroline Hermes


6.0      ASSESSMENT OF LAND STABILITY
  6.1 Existing Conditions
The Noosa Council (NC) Landslide Hazard Overlay Code indicates the site has areas of Moderate Landslide
Hazard (light yellow shading) (refer Image 4).




                                                        Approximate Site Location




Image 4: Extract from NC Landslide Hazard overlay map.
The Council Landslide Hazard Overlay Maps provide a broad-scale indication of potential landslide likelihood
based on ground slopes, geology and known landslip areas. The ratings can be superseded once site-
specific investigation and analysis are undertaken (i.e. this report).

Two small existing/historical landslides were identified on the site at the time of our fieldwork (refer attached
Figure 1 and Photograph 2). These are in steeper areas of the site, away from the proposed residence
footprint, and appear to be shallow slump/rotational failures in colluvium and/or residual soils. Colluvial
materials, due to their geological nature, are often associated with slope instability. In addition, our
experience indicates that residual soils and weathered rock of the Kin Kin Beds can be associated with slope
instability, particularly on steeper slopes and where surface/groundwater flows are prevalent. As a result,
recommendations have been provided in this report to manage the risk of slope instability.

  6.2 Stability Risk Assessment
A qualitative slope stability risk assessment has been carried out following the Australian Geomechanics
Society (AGS) Guidelines for Landslide Risk Management (March 2007). The risk assessment relates to
property and potential development. Relative levels of risk and their implications are given in Table 1 below
and the qualitative terminology (i.e. likelihood and consequence definitions) used in assessing risk to
property are attached in Appendix B.




J001783-001-R-Rev1