2014-03-25 Planning & Organisation Committee Agenda Pages 81-167

PLANNING & ORGANISATION COMMITTEE MEETING AGENDA                                  25 MARCH 2014


The submitted strategy proposes a treatment train approach including staging of the area opened
up at any one time. Compliance with such a strategy over the years of construction will be
dependent on the effectiveness of an erosion and sediment control compliance and enforcement
program. Staging the earthworks will be a costly exercise based on the preliminary earthworks
design results summarised in the engineering report. The nature of the development and the
filling required for Precinct 2 results in unbalanced earthworks volumes within each precinct.
This severely hampers an earthworks contractor’s ability to stage the earthworks and limit the
disturbed area at any one time.

Although best practice may be conditioned upon the bulk earthworks, once the bulk earthworks is
completed the house building phase will commence. Erosion and sediment control for individual
house building sites is regulated under the Environment Protection Act and similar to bulk
earthworks is dependent on an effective Council compliance and enforcement program with
multiple owners and builders and contractors. The house building phase of the development
represents another potentially significant source of water contamination.

Depending on the scale of uncontrolled releases the coarse sediment typically settles out in the
drainage lines downstream of the site (areas identified as open space conservation and National
Park dedication) with finer materials extending down through the system through Eenie Creek,
Lake Weyba and Weyba Creek.

Overall, the scale of the bulk earthworks proposed for this development, without any doubt, will
introduce a potentially significant source of water contamination and lead to degradation of the
receiving catchment area.

Acid Sulphate Soils

The applicant proposes substantial areas of cut and fill, within areas identified as potentially
having acid sulphate soils. An Acid Sulphate Soil Assessment was provided with the application.
Whilst the number of boreholes on site does not meet the specific guidelines, the results from
testing 16 samples show that there is a presence of Acid Sulphate Soil material in certain soils to
a depth commensurate with the envisaged works (0.0 – 1.5metres). The applicant has also
acknowledged that further sampling and testing will be required when the nature and area of
disturbance is determined.

This is a potentially low risk strategy for acid sulphate soils if the development can implement an
appropriate management plan to mitigate the release of acid and associated metals during
earthworks. This strategy is heavily reliant on high quality implementation programmes and
enforcement from the local government and other state agencies. Without successful
implementation, this is a potentially significant source of water contamination on nearby sensitive
receiving environments as identified in other areas of this report. If the development were to limit
the extent of cut and fill, the potential risks would be significantly reduced.

Bushfire

The vegetation surrounding the subject site is mapped under Maroochy Plan 2000 as medium
bushfire hazard. The applicant submitted a bushfire report that outlines a number of mitigation
measures proposed to enable the development layout to comply with the relevant planning
scheme provisions. Under the proposal, most buildings will be setback from the hazardous
vegetation by a nominal distance of 30 metres for access and fire management purposes.




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