Reference Documents

                                             PROPOSED SUBDIVISION
                                             41 TALLOWWOOD PLACE, BLACK MOUNTAIN

            4.9         Buildings and Other Structures
            Although not covered by this slope stability assessment, the existing residence in the central part of the site
            comprised a single storey structure elevated on posts, with a formalised undercroft area. Based on an
            external assessment the residence appeared to be in good structural condition, considering age, with no
            obvious signs of distress (e.g. tilting, cracking, misalignment etc.) which would indicate global slope
            instability.

            As mentioned previously, timber sleeper and boulder walls up to about 1.5 m high supported previous
            earthworks undertaken around the residence. Some of the timber sleeper walls were noted to be
            tilting/leaning, with large voids present within the boulder walls. Horizontal separations up to about 30 mm
            were present between a concrete pathway and the north-wester corner of the residence, with parts of the
            slab undermined. The distress observed in these structures appeared to be related to age, poor
            construction, and adverse drainage conditions rather than global slope instability.


            5.0         SLOPE STABILITY ASSESSMENT

            5.1         Existing Conditions
            The Noosa Planning Scheme 2020 includes a landslide hazard overlay map (Ref. extract in Text Figure 11)
            which indicates that most of the site, including the proposed new development area has a Moderate to High
            Landslide Hazard.




                               Proposed Development Area

                                                                         Subject Site




            Text Figure 11: Extract from NSC landslide hazard overlay mapping

            It should be noted that the NC map is a broad-scale indication of the potential landslide susceptibility only
            and is superseded by this site-specific assessment. The recommended building area as defined in
            Section 6.1 did not exhibit any indicators of global, natural slope instability, with competent natural
            materials and weathered rock encountered at shallow depths in the test pits excavated across the area.
            Building exclusions and setbacks from areas of identified instability are recommended.

            Surface cracks up to about 20 mm wide were observed across the proposed new building area which
            appeared to be related to soil shrinkage due to drying, rather than slope instability.




             22 May 2023
             Report No. 23099-001-Rev0                               9

Document Set ID: 22826802
Version: 1, Version Date: 23/02/2024