Appendix B - Biome Consulting Response

Response

Based upon the level of detail provided in the SWMP previously submitted for assessment, it has not
been deemed necessary to provide an addendum or duplicate Stormwater Management Plan in order
to detail aspects of Sub-catchment D3. Stormwater management designs and associated
construction requirements are instead detailed within drawings DWG-300 to DWG-330 – Attachment
A. These drawings demonstrate that:

      the bioretention bed sized by Calibre Consulting, and its associated setbacks and
        maintenance requirements will be able to be contained within the designated space; and
      maintenance provisions for the bioretention are in accordance with the Water by Design
        Bioretention Technical Design Guidelines (2014), including a 2.5 m wide concrete access
        with a maximum grade of 1:4.

MUSIC modelling has also shown that 100% of gross pollutants entering the bioretention bed are
removed from discharged flows.

Request Item 6.

The provided stormwater management plan only addresses the area needed for water quality
management and does not address any stormwater detention requirements necessary for flood or
frequent flow management.

    6    Demonstrate that Specific Outcome O1 of the Water Sensitive Design Code of the Noosa
         Plan, as well as Appendix 2, Table B of the State Planning Policy, in terms of changes to flow
         are met.

Response

The previously submitted SWMP by Calibre Consulting manages stormwater detention on a whole of
site basis with some catchment areas detained and others undetained. The area subject to the
current development proposal has been included within the quantity management plan (Attachment
B) as follows:

        The site area has been included within the pre-development Catchment D2 as shown on
         Drawing B14158.W-SK100 and as such the flows reported within Table 3-1 include flows from
         the pre-development catchment area; and
        The site area has been included within the post-development Catchment D3 as shown on
         Drawing B14158.W-SK101 and as such the flows reported within Table 3-5 include flows from
         the post-development catchment area.

Based on the SP-RAFTS Layout Summary no detention has been included for the development area
(Sub-catchment D3). Sub-catchment D3 will discharge unmitigated flows at Discharge Location B
(shown on Calibre Consulting Drawing No. B14158.W-SK101 E – Appendix B and Pinnacle Drawing
No. PEG0360-DA-SK01 A – Appendix C).

Table 3-9 of the submitted SWMP shows that the Central Basin is expected to mitigate the peak flow
at Discharge Location B for all storm events considered up to the 0.01 AEP, without the need for
detention of Sub-catchment D3.

BIOME Consulting Pty Ltd
                                 M: 0415 935 222   E: [email protected]   ABN: 86 166 087 476   Page 5
PO Box 3469, Australia Fair
Southport QLD 4215