Compiled Reference Document - MCU25/0020 (As Published)

Table 1: Summary of Subsurface Profiles

                                                                                          Medium
                                                                                                                  Stiff
                                                                                           Dense
    Location                     Fill          Firm Clays           Loose Sands                                (or Stiffer)
                                                                                         (or Denser)
                                                                                                                  Clays
                                                                                           Sands
                                               4.8 – 5.5 &                                5.5 – 13.2
  BH1 (m BGL)                 0 – 3.0                                   3–4                                    14.0 – 16.5TD
                                                13.2 – 14                                (8.3 – 9.0*)

                                                                                          5.2 – 13.8
  BH2 (m BGL)                 0 – 2.3            4.8 – 5.2             2.3 – 4.8                               13.8 – 15.0TD
                                                                                         (7.2 – 10.2*)
Notes:    1.       Depths and levels noted at time of investigation (18 February 2025)
          2.       (*) denotes very dense indurated sand
          3.       TD denotes borehole terminated at target depth


5.3            Groundwater
Groundwater seepage and inflow was encountered during solid flight augering at depths between
1.8 m and 2 m BGL. A standing groundwater level of 1.8 m BGL was measured in the standpipe installed
in borehole BH1 at the completion of fieldwork. Groundwater levels are anticipated to fluctuate with
prevailing weather conditions and are likely to be strongly influenced by the tidal surface water level in
the adjacent Noosa River/Weyba Creek, possibly rising closer to the ground surface. The groundwater
level and results from testing of a sample recovered from the standpipe in borehole BH1 are summarised
in Table 2.

Table 2: Summary of Groundwater Monitoring

                Parameter                                    Units                                       BH1
                  Depth                                      m BGL                                       1.8
                pH (at 25°)                                  pH unit                                     10
   Electrical Conductivity (at 25°)                          mS/cm                                       1.4
                  Redox                                       mV                                         180
          Acidity as CaCO3                                    mg/L                                       <10
           Sulfate (as S04)                                   mg/L                                       120
                 Chloride                                     mg/L                                       470
                Aluminium                                     mg/L                                       36
         Aluminium (filtered)                                 mg/L                                       7.5
                    Iron                                      mg/L                                       24
               Iron (filtered)                                mg/L                                       1.1




Geo-environmental Investigation Proposed Residence
4 June 2025 | 25040-001-Rev1                                                                                                   8