OPW16-0020 information request · OPW16/0020

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Information Required
2      Demonstrate whether any design amendment is possible to limit necessary
       excavations to be shallower than 2m below the existing ground level, and therefore
       avoid the identified medium acid sulphate soil risks.

Issue
Specific Outcome O6 of the Water Sensitive Design Code requires that:
Run-off that leaves the site is treated so as not to adversely impact on the ecology and
hydrology of downstream environmental flows.

And Specific Outcome O22 of the Natural Hazards and Natural Resources Overlay Code
outlines that:
Works do not disturb acid sulfate soils or are managed to avoid the release of acid or
associated metal contaminants

Common metal contaminants released from oxidation of Acid Sulfate Soil via drawdown
from dewatering are Iron and Aluminium. Table 3.4.1 of the ANZECC guidelines outlines
that in order to protect 80% of aquatic species, Aluminium and Iron should not be able to be
detected in the receiving waters.

The application outlines that waters will continually need to be pumped until such time as
the house is properly settled. There is no indication of the maximum depth of excavation for
foundations and pipework , the depth groundwater’s will need to be pumped, or how far the
cone of depression of the groundwater drawdown will extend. This information is necessary
to determine the full extent where oxidation and therefore new metal release into ground
water is possible.

There is no information regarding the existing concentration of metals in the groundwater
from previous acid sulphate soil disturbance and whether there is an associated possibility
for release of those metal contaminants, existing or potential, from groundwater into the
receiving waters.

Additionally, there is no detail provided whether there will be continual dewatering along
bedding material surrounding pipework after pumping for settlement of the house ceases.

Information Required
3      Provide longitudinal section plans showing the maximum depth of excavations
       needed in relation to the medium risk acid sulphate soil horizon and groundwater
       fluctuation zone and detail the expected cone of depression.
4      Detail management measures to prevent any continual dewatering via the bedding
       material surrounding the house and pipework.
5      Demonstrate how the development will not increase oxidation of Potential Acid
       Sulfate soils within the expected cone of depression via dewatering for house
       settlement, or continual dewaters due to bedding material surrounding the building
       and pipework.
6      Demonstrate how there will be no release of metals within groundwater that will
       affect Aquatic Ecosystem Environmental Values in the receiving waters.

Issue
The Acid Sulfate Soil Investigation by Core Consultants recommends for an Acid Sulfate
Soils Management Plan.




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Information Required
7      Where design cannot be amended to raise all excavations above 2m below existing
       ground level, provide an Acid Sulfate Soil Management Plan prepared by a suitably
       qualified person and in accordance with the current version of the Queensland Acid
       Sulfate Soil Technical Manual. The Acid Sulfate Soil Management Plan must
       provide methods to be implemented to manage acid sulphate soils on the site,
       reduce and avoid oxidation of soils on offsite areas due to the cone of depression
       caused by dewatering, detail treatment, monitoring and discharge of groundwaters
       during construction and house settlement, contingency planning in the event of
       testing and treatment failures, and details regarding the management of Acid Sulfate
       Soil impacts on building material selection and maintenance.
       Please note that it may be possible to discharge the water directly to the sewer but
       prior approval from Unitywater will be required.

End of Information Request

Under the provisions of the Sustainable Planning Act 2009, you have three options
available in response to this Information Request. You may give the assessment manager
(in this instance Council) and each referral agency (if any):

(a)    all of the information requested; or
(b)    part of the information requested together with a letter asking the assessment
       manager and each referral agency to proceed with the assessment of the
       application; or
(c)    a letter;
       (i)      stating that you do not intend to supply any of the information requested; and
       (ii)     asking the assessment manager and each referral agency to proceed with
                the assessment of the application.




Please be aware that under Section 279 of the Sustainable Planning Act 2009
the applicant must respond to the Information Request within 3 / 6 months of the request or
otherwise the application lapses.

A response to the above is required to be submitted, prior to further assessment of the
application. If any further matters arise as part of assessment of this application, you will be
advised accordingly.

Council prefers that all the information requested be submitted as one package. A
preliminary assessment only of the application has been undertaken and during the formal
decision stage, or as a result of public exhibition, other matters may arise.

You may wish to follow the progress of this application online at www.noosa.qld.gov.au .
The “PD Online” page can be accessed via "Quick Links" on the left hand side of the
screen. A disclaimer will appear; upon clicking “agree”, a search for a development
application or property address can be carried out.




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Should you have any further queries in relation to the above, please do not hesitate to
contact on the above number.

Yours faithfully




MARK LEWIS
COORDINATOR ENGINEERING




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