Reference Document - MCU24/0023

GJ Gardner Homes Gympie                                                                              23236-001-Rev0
C/- Covey Associates Pty Ltd                                                                           7 August 2023




                                                                             Subject Site Boundary




                                                                 Indicative Proposed House Site




Text Figure4: Image showing ground surface contours (courtesy NC ‘Intramaps’)

The proposed residence is located in a favorable position atop the crest of the hill, however the natural
slopes below were, in places, very steep (up to and exceeding 30°) particularly in the drainage or gully lines.
In those areas, where surface drainage was assessed to be poor, there was evidence of previous slope
instability comprising:

       The backscarp of a relatively large landslide to the south-east of the house site;
       Scour/slumping on the steep slope to the east;
       Creep as evidenced by tilted trees to the north-west; and
       A number of slumps along the driveway cutting with signs of downslope creep movements below.

Some of these features are illustrated in Text Figure 5 overleaf.
It would appear that where the ground surface dipped at ≥25°, the friction angle of the upper gravelly
rockmass was exceeded and so, under saturated conditions, where cohesion was reduced or lost, landslide
movements were prone to occur.




                                                        4/17