Callaghan and Toth IWMP Report revised

                                                                                     Callaghan & Toth

TABLE 4.1           MUSIC CATCHMENT AREAS (DEVELOPED)

                       Catchment                           Land Use           Music         Area (ha)
                                                                            Impervious

CATCHMENT A

Roof Areas – Villas 1 to 4 + Service Core               Urban Residential     100%                0.121

Northern Pathways / Landscaped areas                    Urban Residential      35%                0.169

CATCHMENT B

Roof Areas – Entry building                             Urban Residential     100%                0.047

Southern Pathways / Landscaped areas                    Urban Residential      35%                0.011

CATCHMENT C – 10 new Carpark Areas                      Urban Residential      90%                0.013

              TOTAL                                                                          0.36ha


4.2.2 Treatment Nodes

The “MUSIC Modelling Guidelines for South East Queensland” Version 1.0 prepared by Water
by Design and dated December 2010 has been used to set the rainfall runoff parameters and
pollutant export parameters for the site.

The land use type used for this model was “Commercial” and the values in the guideline shown
in Table 3.7 and Table 3.8 of the guidelines have been used in this model. Figure 4.1 shows
the MUSIC Model layout for the site.

Bioretention Basins (Biopods) have been placed to treat flows from proposed villas, entry
building and the tank overflows, landscaped areas, and pathways. To treat the new areas, two
biopods have been placed to catch flows draining from the listed areas. The Biopods are sized
as Biopod A is 32m2 and Biopod B is 10m2; a total . Each biopod has a filter layer depth of
0.4m and an extended detention depth of 0.2m. The size and depth of these systems has been
designed in accordance with Water by Design guidelines. The bio-pods drain to the unnamed
waterway on site to the east of the proposed development.

Six (6) Rainwater Tanks have been provided for the roof catchments as shown on Plan No
1714-01. The Reuse allowed is for:

     1. Villas – toilets daily re-use – allow 1500 litres / pedestal in accordance with QDC.
     2. Some watering of landscaping.

Sizing checks for the six rainwater tanks is detailed in Section 5.0 below.

In comparison the Deemed to Comply Solutions requires 2.2% of the catchment size for the
North Coast region for Solutions C11. This would equate to 79m2. In comparison the MUSIC
model has determined that a total of 42m2 across two biopods achieves the target reductions
for pollutants – see Table 4.2.




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1714-Cartwrigth Village Extension_IWMP_Revision 3.doc                                April 2019