Noosa River DMP V1

Investigations by BMT (2022) undertaken in accordance with NAGD 2009 (National Assessment Guidelines for
Dredging) for contaminants confirms that sediments are not contaminated and are suitable for onshore disposal.
Testing was undertaken in accordance with QASSIT requirements for acid sulfate soils. While investigations by
BMT (2022) indicate locations with very low levels of potential acid sulfate soils that are not fully offset by the
natural buffering capacity of the soils and one isolated high spot, subsequent testing around the hot spot by
Pacific Geotech (14 November 2022) “confirmed the material initially encountered has either been naturally
scoured away or is of such an isolated volume so as to not be significant and acid sulfate treatment will not be
required.”
Acid sulfate management of the Noosa River is to be undertaken in accordance with Pacific Geotech
recommendations as follows: “Considering the proposed dredging methodology (ie. use of a cyclone separator)
and the natural buffering capacity of the sands, treatment for the acid sulfate neutralisation is not likely to be
required. This should be confirmed with validation testing at the time of the dredging operation. Validation testing
should be undertaken at a rate of 1 test per 250m3 of disturbed material. … If the validation testing indicates the
material is providing results above 18molH+/tonne (ie. above the action criteria) the material should be neutralised
at the time of dredging”.
Objective: To minimise the impacts of disturbance of soils on the surrounding environment.
Issues: Adverse impacts associated with unexpected sediment types (that may be acidic or contaminated).
Performance Criteria: Compliance with Queensland Acid Sulfate Soils Technical Manual and NAGD (2009).
Control Measures:

                                                                                                                         Responsible
                                                   Control Measures
                                                                                                                            Party
 1.   Dredge to be fitted with a cyclone when working in areas that don’t have adequate buffering capacity             Contractor
 2.   Nourishment to consist of suitable sandy sediments ONLY. Dredged sediment to be monitored. In the                Contractor
      event that sediment types that are unsuitable for nourishment or are indicative of acid sulfates or
      contaminated sediment, dredging is to cease or move to an adjacent area.
 3.   Acid sulfate validation testing to be undertaken at a rate of 1 test per 250m3 of disturbed material.            Contractor
      In the event that the validation testing indicates the material is providing results above 18molH+/tonne (i.e.
      above the action criteria) a geotechnical expert is to be consulted and material is to be neutralised at the
      time of dredging”


Monitoring: Monitoring is to be undertaken in accordance with Table 4.


            CULTURAL HERITAGE
The dredge and nourishment area has historically been dredged and used for re-nourishment. Given the level of
previous disturbance, it is considered unlikely that items of indigenous cultural heritage significance are present.




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