J000154-001-R-Rev0_ASS Investigation Report · RAP15/0034

J000154-001-R-Rev0                                                                                               November 2015


material produces acidic conditions and oxidation typically occurs as the material is exposed above the water
table by excavation, and by lowering the water table during dewatering processes.
Previous experience and available guidelines indicate that ASS are normally restricted in extent to recent
(Holocene to Pleistocene age) soil horizons deposited in a saline environment below RL 5 m. The State
Planning Policy 2014 (SPP14) "State Interest Guideline – Water Quality” (August 2014) (SPP14) applies to
land, soil and sediment at or below 5 m AHD where the natural ground level is less than 20 m AHD. Within
such areas the SPP14 applies to development involving any of the following:

       Excavating or otherwise removing 100 m³ or more of soil or sediment; or
       Filling of land involving 500 m³ or more of material with an average depth of 0.5 m or greater.
The topography of the site is consistent with the above criteria (i.e. surface elevation below RL 5 m AHD)
and the proposed development involves excavations that would exceed the above trigger levels. Therefore
the SPP14 is applicable to this site due to the proposed excavations and an assessment of potential
disturbance of ASS is required.
The aims of this investigation were to:
       Conduct an ASS investigation in general accordance with the requirements of the State Planning Policy
        2014 "State Interest Guideline – Water Quality” (August 2014) with sampling and analysis planned using
        the Queensland Department of Natural Resources and Mines (NRM) "Guidelines for Sampling and
        Analysis of Lowland Acid Sulfate Soils in Queensland - 1998", developed by the Queensland Acid
        Sulfate Soils Investigation Team (QASSIT).

       Identify the presence or absence of ASS across the proposed development area;

       If necessary, assess the likely impact of the proposed development on ASS and groundwater;

       If necessary, provide prudent management measures so that the release of acid leachate from
        disturbed soil and groundwater does not have significant adverse effects on the natural and built
        environment or human health; and

       Advise whether a stand-alone ASS Management Plan is required for the proposed works.
The investigation method, findings and recommendations are discussed in Sections 5, 6 and 7, respectively.

5.0        METHODOLOGY
5.1          Published Information
A desktop review of published geological and ASS maps was undertaken. Information reviewed as part of
the assessment included the following:

       1:100,000 Series Gympie Special Geological Map, Sheet 9445 & Part 954, First Edition 1999
       1:100,000 Acid Sulfate Soils, Redcliffe to Teewah, Map 2 (DNR-SEA-I-AO-3235),
        Department of Natural Resources & Mines, First Edition 1999
The findings from the desktop assessment are presented in Section 6.1.
5.2          Fieldwork
The ASS investigation was planned with reference to State Government policies 1, the Queensland Sampling
Guidelines2 and the findings of the desktop assessment. For disturbances below RL 5 m, the Guidelines
recommend 4 locations for sites up to one hectare. The Guidelines also require ASS sampling to at least 1
m below the depth of disturbance.



1
    State Planning Policy SPP14
2
 Ahern, CR, Ahern, MR, and Powell, B (1998) “Guidelines for sampling and analysis of lowland Acid Sulfate Soils (ASS) in Queensland
1998” QASSIT, Department of Natural Resources, Resource science Centre, Indooroopilly.



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