Appendix E - Stormwater Management Plan

Thank you for sending through the draft conditions.

Please note the following:
    a. Please refer to the attached B14158.W-SK102 for your review.
This design is changed again. If Calibre is seeking approval of this plan please provide me the music model that
shows the changes (i.e. 0.9% treatment of D3 and 80/60/45) will still achieve the overall outcomes.
It is intended to keep the strategy you have recently reviewed and accepted. Biopod D3 will provide 75m2 filter area.
We have reworded this label for clarity. Refer to Amended Issue D of Drawing No. B14158.W‐SK102 attached for
details.

    b. We will update the design of the central basin and hydrological modelling to achieve no increase in peak
       flows from the pre-development condition.
Does this mean another plan is on its way to get approved?
Updates to design of central basin is a Monkeith query to ensure peak flows are mitigated back to existing
conditions (recent changes to central bio‐basin will change hydrology and so will be updated in the revised report).
There will be no change to recent stormwater quality strategy (shown in Issue D of Drawing No. B14158.W‐SK102
attached)
    c.   Outlet from Southern basin to Central Basin is 900mm dia.
Noted

Our comments on the draft conditions are as follows (The first three (3) items are the major ones):

    1. Item 19 – This line should read “The pre-start meeting for stormwater management infrastructure only, must
       be scheduled…….”
Unable to change. The MCU required the SWQMP to be approved prior to issue of any Op Works. The agreement
was then for its to be provided prior to issue of op works that involve stormwater infrastructure. Accepting it prior
to the pre start meeting, i.e. before the Op Works commence, is as far as I can justify to push is back in line with the
conditions.
Noted.
No Stormwater Management Plan works will progress before Stormwater Quality Management Plan is approved.

    2. Item 19.11 – Based on DA conditions and as per approved Letter Report (No.14158W.07L dated 8 October
       2015), minimum 20% coverage is acceptable for ponds.
Noted‐ will change to 20% coverage across the pond to be consistent with s3.1 of the letter report (apologies for the
mix up with the wetland coverage)
Noted

    3. 500 m2 Functional Filter Media Area size for Bio-pod C2 (Age Care Facility) – B14158.W-SK102 Rev C
       (attached) specified the provision of multiple bio-retention pods with combined fill area of 500m2 or
       combination with proprietary product, to achieve 80/60/45 load reduction objective.
While this principle is supported ‐ I will need you to please demonstrate that the same overall pollutant reduction
targets outcome will still be achieved in the music model.
Noted – We have modelled a generic node at C2 that individually achieves 90/60/45 for Catchment C2. This meets
the same overall objectives for entire development as previously provided. Refer to the table below for a summary
table of the control measures – only change is the generic node on C2. Also refer to the latest MUSIC model with the
generic node.

 Location of Stormwater Quality Treatment              Functional Filter Media Area Size

 Northern Basin                                        525m2

 Central Basin                                         650m2

 Southern Basin                                        305m2

 Biopod D3                                             75m2

 Biopod D2                                             75m2
                                                           2