Approved Plan - EXE21-0015

Mr Dean Frith                                                                                              21182-001-Rev0
                                                                                                              28 May 2021

Considering the existing site conditions (Ref. Section 2), and proposed development works, it is assessed that
there would be a Low (L) Risk of global slope instability affecting the proposed shed subject to the
implementation of recommendations given below. Regulators (NC) 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 is our qualitative assessment of landslide risk for the site. A summary of qualitative terminology for
use in assessing risk to property is attached (taken from AGS 2007).
Table 2: Details of Qualitative Risk Assessment for Property (AGS 2007
                                                               Assessed
 Hazard                             Likelihood   Consequence
                                                                 Risk
                                                                          Comments

                                                                          The likelihood of a failure through the existing fill
                                                                          embankment to the north of the proposed shed
                                                                          location is assessed as Possible due to the firm
                                                                          consistency of the fill materials and slopes of the
                                                                          batters. The consequence of such a failure would be
                                                                          Minor with the resultant risk being Moderate as per
 1: Failure through fill             Possible                  Moderate   AGS 2007.
                                                    Minor
embankments                         (Unlikely)                  (Low)
                                                                          Failure of the fill embankment following remediation
                                                                          works as specified in Section 4 would be Unlikely.
                                                                          The consequence of such a failure would be
                                                                          Medium, with the resultant risk would reduce to
                                                                          Low as per AGS 2007.

                                                                          Given the presence of stiff residual soils and
                                                                          weathered rock materials at shallow depth, apparent
                                                                          lack of groundwater, and no evidence of instability in
                                                                          natural strata the vicinity of the proposed shed, it is
 2: Failure through natural soils
                                     Unlikely      Medium           Low   considered Unlikely that a landslip would develop,
above the foundation depths
                                                                          subject to implementation of the recommendations
                                                                          in Section 4. With a potential Medium impact from
                                                                          such shallow instability the resultant risk would be
                                                                          Low as per AGS 2007.

                                                                          The likelihood of a deep failure through the phyllite
                                                                          rock is assessed as Barely Credible due to the
 3: Deep seated failure in           Barely                               strength of these materials and no evidence of existing
                                                    Major      Very Low
weathered rock                      Credible                              instability in these materials. Although the
                                                                          consequence of such a failure could be Major, the
                                                                          resultant risk is Very 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.




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