OPW052025 Report - Part 2

 4.1             Topography
 Publicly available contours for the site are shown below in Text Figure 3.




                              Highly irregular ground
                               downslope of driveway
                                           alignment




                                                                                               Approx. driveway
                                                                                               alignment along crest of
                                                                                               ridgelines


Approx. house site on
        crest of knob


                                                                                Saddle in ridgeline


                                                               Short section of driveway
                                                               sidelong to northern flank
                                                               of ridgeline




           Text Figure 3: Topography of site and surrounds, hillshade applied (courtesy Qld Globe)

 On a wider scale, the site and surrounds consist of moderately steeply incised drainage lines and strongly
 defined ridgelines. The south-western boundary of the site (adjacent to the Black Mountain Road
 corridor) traces the highest local areas of topography, connecting between a number of elevated knobs.
 Ground slopes down from the knobs to the south, and through the site to the north/north-east.
 Within the site a strongly defined ridgeline connects the north-western corner (where the residence is
 proposed) to the north-eastern corner, where some existing sheds and the access off Middle Creek Road
 was present. This ridgeline provides the alignment for the proposed driveway, and connects a number of
 intermediate knobs and saddles, generally separating a broad southern and northern drainage regime.
 The crest of the ridgeline was rounded, sloping at no more than 8° to either side. The crest area was
 estimated to be between about 10 m and 20 m wide, before dropping to steeper slopes, ranging from
 about 15° to 20°. Beyond this, steeper slopes were present extending down towards the inverts of larger
 gullies and drainage lines.
 The surface of the track followed the crest of the ridgeline and was inclined at between about 10° to 15°
 mostly, increasing to around 17° to 21° locally just before the crests of the intermediate knobs.
 A ‘saddle’ was located approximately central to the driveway alignment, where the gently sloping crest
 narrowed slightly, and slopes of about 15° extended over about 15 m to either side.

 Geotechnical Investigation & Slope Stability Assessment
 9 April 2025 | 25050-001-Rev0                                                                                            4