Applicant's Information Response

Due to the above, the current development design does not demonstrate how the development has
been designed with regard to the natural drainage features or to avoid areas of acid sulphate soil across
the site in interest of protecting the High Ecological Value receiving waters directly across the road.

Information Required

    22. In order to demonstrate that PO1 is met:
            a. Provide a drainage plan which shows direction of flow of site stormwater during
                construction and operation phases of the development and demonstrate that all
                waters will flow to the water quality treatment features as proposed.
            b. Engage a Certified Professional in Erosion and Sediment Control to work in
                conjunction with designers and demonstrate that construction of the proposed
                development can be practically achieved whilst meeting Appendix 2 requirements
                of the State Planning Policy and IECA Best Practice Sediment Erosion Control
                standards.
            c. Provide and Acid Sulphate Soils investigation undertaken by a suitable qualified
                and experienced soil scientist to demonstrate areas containing actual and
                potential Acid Sulphate soil across the site including levels of standing
                groundwater in accordance with current State government investigation
                requirements. Where applicable, provide updated design plans in response to the
                locations of any potential or actual acid sulphate soil areas and permanent
                groundwater levels. In particular drainage design will need to demonstrate that it
                is constructed in a way that it will not cause continual dewatering of any
                permanent groundwaters along bedding materials.

Applicant’s Response
The Engineering Plans and Report have been updated to provide the requested drainage details and
include a Sediment and Erosion Control Plan.

As mentioned above, an Acid Sulfate Soils Assessment has been prepared and is included in the
supporting documents. The report concludes that the proposed development is unlikely to disturb Acid
Sulfate Soils.

Council Issue - Drainage and footprint allocation

“PO 6 of the of the water quality and drainage code requires development is located, designed,
constructed and operated to protect and enhance environmental values and water quality of waterways,
wetlands, lakes, ground waters and drainage systems. The MUSIC model provided proposed for the
entire site to drain to the bio-retention basin for treatment.

Given that a significant portion of the site drains to the road frontage, and not the eastern boundary, it
is unclear from the information provided how the water from all catchments across the site will drain to
the bio-retention basin as proposed.

Additionally, while it is acknowledged that different pollutant reductions are achieved in each stochastic
MUSIC model run, internal running of MUSIC found only 78% reduction in Total Suspended solids was
achieved. This does not meet the minimum threshold of 80%. Also, it is expected that the current design
will necessitate for some catchments across the site to bypass the bio-retention basin, which will further
reduce the pollutant reduction ability of the current design.”

Information Required

    23. Provide a catchment drainage plan and integrate the catchment areas of that into an
        updated MUSIC model. Demonstrate that every catchment will be treated and that the
        overall pollutant reduction targets are achievable.

Applicant’s Response
Alta Engineers have updated the Music Model, Engineering Plans and the Engineering Report and SWMP
(Attachment I) accordingly and these are included in the supporting documents. It should be noted