12332_Council_Information Response_081118

                                    AND

                                    S28.6 Garden mounding is            Complies -Alternative solution
                                    incorporated into carparking        Due to the intent to retain
                                    areas adjacent to frontages;        existing vegetation along the site
                                    AND                                 frontages, mounding is not
                                                                        possible due to the impact on the
                                                                        trees.      The    retention    of
                                                                        established     vegetation     far
                                                                        outweighs     any    benefit    of
                                                                        mounding.

                                    S28.7 Surface and subsurface        Complies
                                    drainage swales are used to         A central landscaped drainage
                                    maximise stormwater infiltration;   swale is proposed to maximise
                                    AND                                 stormwater infiltration.

                                    S28.8 A planting bed of at least    Not Applicable
                                    1m width with screen fencing and    The carpark does not adjoin any
                                    dense planting is provided to any   residential development
                                    property boundary with an
                                    adjacent residential development.



Issue

The MUSIC model demonstrated in the Stormwater Report shows that all runoff will flow via pervious
paving prior to entering bioretention basins. However, the detail design plans demonstrate that only a
small portion of the runoff will flow via pervious paving areas prior to entering the bioretention basins,
and therefore is inconsistent with the MUSIC model. Additionally, the Water By Design Music
Modelling Guidelines states that porous paving and associated drainage layer and filter media must be
free draining (i.e. does not hold water after rainfall), the information provided does not demonstrate
this is the situation on this site.

Information Required

11. Provide a MUSIC model, that is consistent with the detail design plans in terms of the low flow and
    high flow bypass to achieve the required pollutant reduction targets.

12. Demonstrate that the drainage features underlying any pervious paving is consistent with the
    requirement of The Water by Design Music Modelling Guidelines.

13. Also, provide a copy of the MUSIC model, prepared in accordance with the Water by Design
    MUSIC modelling Guidelines, that demonstrates the required pollution reduction targets are
    achieved.

Response
Refer attached amended Stormwater Management plan, MUSIC modal and response from Odyssey
Consulting within Attachment 1. These documents demonstrate consistency with the MUSIC model
and Water by Design Music Modelling Guidelines.


Issue

Specific Outcome O8 of the Water Sensitive Design Code requires that the Development design
including density and scale provides adequate footprint to integrate all elements of stormwater quality
and quantity treatment infrastructure including, where relevant, bio retention basin batters and
maintenance access, without the need for retaining walls. The incorporation of the detention
component with the bioretention water quality treatment component has resulted in retaining walls