Reference Document - MCU24/0143 (As Published)

        Table 2: Details of Qualitative Risk Assessment for Property (AGS 2007)
                                                                         Assessed
            Hazard                         Likelihood   Consequence                  Comments
                                                                           Risk
                                                                                     The landslide down slope from the
                                                                                     northern cabin is Unlikely to regress up
                                                                                     slope to a point where it would impact the
                                                                                     structure over the expected design life of
                                                                                     about 50 years. This is due to the lack of
                                                                                     regression of the slide observed following
                                                                                     recent heavy and prolonged rainfall,
            Relatively shallow landslide
                                                                                     together with the favourable natural
            through fill, natural soils
                                                                                     topography which would limit the spread
            and/or upper, fractured         Unlikely       Minor           Low
                                                                                     and up slope movement of the slide.
            phyllite impacting the tiny
                                                                                     Based on the expected cost to relocate the
            homes
                                                                                     tiny home in the unlikely event that the
                                                                                     landslide regresses close to the structure,
                                                                                     the consequence of such a failure would
                                                                                     be Minor. The resultant risk from this
                                                                                     hazard is therefore assessed as being Low
                                                                                     with respect to property as per the risk
                                                                                     matrix given in AGS 2007.

                                                                                     Considering the strength of these deeper
                                                                                     strata and relatively light loads imposed by
                                                                                     the structures, subject to implementation
            Deep-seated landslide
                                                                                     of the recommendations in Section 4, it is
            through deeper, less
                                             Rare          Minor         Very Low    considered Rare that a deep-seated
            weathered phyllite impacting
                                                                                     landslide would develop and impact the
            the tiny homes
                                                                                     buildings over the design life. Given a
                                                                                     potential Minor impact, the resultant risk
                                                                                     would be Very Low as per AGS 2007.



        4.            Recommendations
        General recommendations to help maintain the stability of the site are given in the document Some
        Guidelines for Hillside Construction, which is attached.
        Based on the results of the geotechnical investigation and our site observations, it is assessed that a Low
        Risk of global slope instability could be achieved for the tiny homes, subject to the following:
               The existing drainage system should be assessed by a civil/hydraulic RPEQ and, if necessary, the
                drainage system should be upgraded to ensure that stormwater is directed away from the existing
                structures, embankments and effluent disposal areas. For the northern tiny home, we consider that
                this should comprise excavation of a shallow swale (say around 300 mm deep) around the northern
                and western sides of the pad, graded at 1V:100H (minimum) to discharge into the existing piped
                culvert to the south. Soil won from the swale excavation could be used to form a low height bund
                (say 300 mm high) along the crest of the fill batter on the eastern side of the tiny home to prevent
                overtopping during storm events.
               All excess stormwater collected around the cabin area must be directed by pipes or surface channels
                (e.g. turfed or rock lined ‘dry creek’ beds) to discharge at least 10 m downslope of any structure,
                effluent disposal area or embankment, and not towards the landslide. A surface dissipation device
                such as rock weir or rock lined contour drain must be installed at the stormwater outlet(s).
               No additional surcharge loads, including filling and landscaping, are permitted across the ground
                surface around the tiny home area.




        4 June 2025
        24378-001-Rev1                                                                                                11 of 12
Document Set ID: 24125427
                  24010296
Version: 1, Version Date: 17/09/2025
                          07/08/2025