Reference Document - MCU25 0060 (As Published)

                      Text Figure 1: Section through north of building (courtesy SLa)



3.           Method of Investigation
As part of our assessment, a desk-top study was carried out comprising a review of published geological
maps, slope stability studies as well as Noosa Council (NC) planning overlays and site information.
An experienced geotechnical engineer from Tectonic undertook a site walk-over on 20 February 2025 to
visually assess any indicators of past slope instability. The walk-over included assessment of soil
exposures, surface drainage conditions, topography, evidence of erosion or past instability, and
vegetation coverage/condition.
This was followed by a subsurface investigation comprising the drilling of three boreholes (designated
BH1 to BH3) in accessible areas across the site. Borehole BH1 was drilled toward the north-western
corner of the site using Tectonic’s 4WD mounted solid flight auger rig to a depth of 6 m below ground
level (BGL). Due to access restrictions boreholes BH2 and BH3 were drilled using hand augering
techniques to 3 m BGL (limited due to hole collapse) further to the east of the site.
In-situ testing, using the dynamic cone penetrometer (DCP) method, was carried out from the ground
surface and at selected depths within each borehole. DCP testing was extended below the base of the
hand augered boreholes to depths of 3.9 m BGL. Boreholes were backfilled on completion with drilling
spoil, with excess material slightly mounded at surface.
Laboratory classification testing was not warranted due to the sandy nature of the subsurface conditions
encountered.
Borehole locations are shown in Figure 1 attached at the end of this report, with borehole and DCP logs
presented in Appendix A, together with explanatory notes. Subsurface conditions are discussed in
Section 4.4. Borehole coordinates were recorded using a handheld global positioning system (GPS).
The results of the desk-top study and walk-over survey are included in Section 4 below.




Proposed Residential Development
25 August 2025 | 25038-001-Rev0                                                                           2