Geotech Report - techtonic · RAL22/0021

                                PROPOSED RESIDENTIAL DEVELOPMENT
                                39 PICTURE POINT CRESCENT, NOOSA HEADS

Table 1: Summary of Subsurface Profiles
                      Very Loose         Very Loose
                                                                                Medium             Dense (or
  Borehole No.        Sands (Fill)         Sands             Loose Sands
                                                                              Dense Sands        denser) Sands
                                          (Natural)

       BH1
      (Global           0.0 – 0.4          0.4 – 1.9           1.9 – 2.8         2.8 – 3.8          3.8 – 4.8TD
      Testing)


       BH2
      (Global           0.0 – 0.3          0.3 – 2.0           2.0 – 3.6         3.6 – 4.6          4.6 – 5.3TD
      Testing)


      BHT-1                 -              0.0 – 1.0           1.0 – 2.1         2.1 – 4.6          4.6 – 5.6TD


      BHT-2             0.0 – 0.7              -               0.7 – 2.0         2.0 – 4.0         4.0 – 5.7 TD



      DCPT-3                -              0.0 – 1.2           1.2 – 2.0        2.0 – 3.6 TD             -

Notes: 1.        Depths noted in m BGL at time of investigation (BH1 & BH2, 11 April 2022, BHT-1, T-2 and DCPT-3,
                 16 January 2023)
        2.       - denotes not encountered
        3.       TD denotes borehole terminated at test target depth




4.5          Groundwater
No signs of groundwater seepage (‘springs’) were observed during our walk-over. Groundwater was not
encountered in the boreholes at the time of investigation.

Groundwater conditions are expected to be reflective of prevailing weather conditions and seepage may
develop, particularly following periods of prolonged or heavy rainfall.

4.6          Surface Drainage
Surface drainage would be expected to follow natural surface contours to the north/north-west towards
Noosa Drive (vegetated reserve, or indeed ultimately the road corridor). It is noted that the site has a limited
catchment, being close to the localised back dune crest. While there is a positive change in elevation to the
south of the site to residences on the opposite side of Picture Point Crescent, some protection may be
afforded to the site by the presence of kerb and channel drainage over the frontage. It also noted that
Picture Point Crescent tends to fall slightly south and north-east, away from the site in both directions.

Given the sandy nature of the site, rainfall would normally be anticipated to infiltrate the ground surface.
However, as the proposed development will occupy a large part of the block, significant run-off from hard
surfaces will occur. Nevertheless, where directed into swales rather than pipes, such run-off would be
expected to infiltrate into the natural sands relatively rapidly. The road reserve between Noosa Drive and
the subject site is also well vegetated, and about 30 m width.
No significant surface run-off features were noted during our assessment (e.g. deep rilling or scour/wash out
scars). This indicates that significant overland flow is generally not significant during rainfall events,

Recommendations to improve surface drainage as part of the development works are provided in
Section 6.5.



10 February 2023
Report No. 22511-001-Rev0                                6