SUPERSEDED Reference Document

                                                                                        ADG Consulting Pty Ltd


3    Previous investigations
     This DMP is based on site specific information sourced from the following, provided to ADG by Douglas
     Partners:
             Acid Sulfate Soil Investigation, Proposed Residential Development, 13 Mermaid Quay, Noosaville.
              May 2024. Douglas Partners. Ref: 229073.00.R.001.Rev0, 2024‐04‐11.
             Geotechnical Investigation, Proposed Residential Development, 13 Mermaid Quay, Noosaville. May
              2024. Douglas Partners. Ref: 229073.00.R.001.Rev0, 2024‐04‐11.
             Proposed Development – 13 Mermaid Quay, Noosaville, QLD. June 2024. Paul Clout Designs Pty Ltd.
              Council Drawing Project Ref: 229073.00, 2024‐06‐05. (Refer Appendix C).
     It is noted that dilapidation reports for surrounding structures and services are proposed to be
     undertaken prior to commencement of construction and dewatering, however are to be provided to
     Council separately from this DMP.

     A brief discussion of relevant soil and groundwater conditions is provided below.
3.1 Douglas Partners Geotech Report 2024
     A Geotechnical Investigation alongside an Acid Sulfate Soil Investigation was undertaken at the site in
     May 2024 (reported July 2024) by Douglas Partners (DP).
3.1.1 Soils
     A total of two (2) boreholes (BH01 & BH02) were drilled on the proposed development footprint to
     between 1.5 and 6.0 mbgl.

     The subsurface profile encountered is generally described as clay and sand fill material at the ground
     surface, extending to depths ranging between 1.5 m and 6.0 m. Fill material is underlain by natural sand
     which is fine to medium dense throughout the soil profile with traces of silt until the borehole termination
     depths.

     Alongside the Geotechnical Investigation (2024), Acid Sulfate Soil (ASS) samples were collected at 0.25 m
     intervals in BH01 from the surface until 6.0 m & BH02 to from the surface until 1.5 m depth. A total of
     thirty (30) samples were collected for ASS screening and six (6) samples were selected for further analysis
     by the Chromium Reducible Sulfur suite (CRS).

     ADG notes that the testing was limited to two boreholes with ASS testing to 6.0 m depth, and DP reports
     that within part of this depth profile the clayey sand and natural sands are considered to contain potential
     ASS requiring management of ASS disturbance. All excavated spoil from depths between 1.5 to 6.0 mbgl
     within the excavation footprint will need to be appropriately neutralised with lime and validated in
     accordance with recommendations by DP in the ASS Investigation Report (DP, 2024), and therefore the
     presence of ASS has the potential to impact water quality during dewatering for construction.
3.1.2 Groundwater
     During drilling activities for the Preliminary Geotechnical Investigation, groundwater seepage/inflow was
     encountered at 0.6 to 1.9 m depth below the ground surface (standing groundwater level was later
     measured at 0.58 m in depth in borehole 2)(DP, 2024). ADG notes based on the RLs supplied in the DP
     Report that this equates to a maximum groundwater elevation of approximately 0.3 m AHD.

     It should be noted however, that groundwater depths and ground moisture conditions are affected by
     weather and climatic conditions, tidal variations, surface and subsurface drainage/permeability
     conditions, and human influence and will therefore vary with time. Groundwater levels are expected to
     be similar to the water level in the canal to the east and river to the north, albeit somewhat a dampened
     response to tidal variations.




ADG1668.24 Dewatering Management Plan_Rev0_12.07.24                                                        Page 4