Compiled Reference Document - MCU25/0020 (As Published)

7.2          Desktop Study
7.2.1        Geology and Groundwater
The mapped regional geological setting is detailed in Section 5.1 of this report and comprises recent
reclamation fill, and Quaternary age interlayered alluvial/estuarine deposits. The site-specific geology is
detailed in Section 5.2 where it can be seen that mostly silty sands (natural and fill), with minor sandy
clays, are expected to the proposed excavation depths.
Groundwater encountered during the investigation was at about 1.8 m BGL (with the potential to
become shallower following rainfall and high tide events). External dewatering will not be carried out
below 1.5 m BGL. An internal dewatering system (e.g. a series of sand spears or wells connected to an
extraction pump) will likely be required to pick up any seepage that migrates up through the sands
across the basement excavation floor. It should be possible to manage the groundwater extraction
system such that the impact on the surrounding, external groundwater table is negligible.


7.3          Regional ASS Mapping
An extract from the Queensland Government’s Redcliffe to Teewah Acid Sulfate Soils Map 2 (NR&M-
SEA-I-A0 3261) covering the region is shown in Text Figure 10. The mapping classifies the site as ‘SDL’
(purple shading), which is described as “disturbed land…likely to contain ASS”, and that only a “limited
field investigation” has been undertaken as part of the mapping program.
It should be noted that ASS risk mapping does not definitively indicate the presence nor absence of ASS
at a particular site, but rather provides an indication of terrain where ASS is likely to occur. The presence
or absence of ASS at a site may only be confirmed by completion of a site investigation, involving an
appropriate degree of site assessment and quantitative analysis.




                                                                  Approx. Site location




   Text Figure 10: Extract from Redcliffe to Teewah Acid Sulfate Soils Map 2 (NR&M-SEA-I-A0 3261)




Geo-environmental Investigation Proposed Residence
4 June 2025 | 25040-001-Rev1                                                                               20