1714 IWMP_Report_Carramar_Version2 Oct 2018

                                                                                     Callaghan & Toth

TABLE 4.1          MUSIC CATCHMENT AREAS (DEVELOPED)

                       Catchment                         Land Use           Music           Area (ha)
                                                                          Impervious

CATCHMENT A

Roof Areas – Villas 3 and 4                           Urban Residential     100%                  0.107

Northern Pathways / Landscaped areas                  Urban Residential      35%                  0.156

CATCHMENT B

Southern Pathways / landscaped areas                  Urban Residential      35%                  0.062

Landscaped Podium                                     Urban Residential      75%                  0.040

Roof Areas – Villas 1 and 2                                                 100%                  0.107
                                                      Urban Residential
              - Entry building                                                                    0.035

CATCHMENT E - Existing driveways / 3 carparks         Urban Residential      90%                  0.021

CATCHMENT D - Exposed Carpark Areas                   Urban Residential      90%                  0.025

CATCHMENT F - Exposed Carpark Areas                   Urban Residential      90%                  0.037

              TOTAL                                                                          0.59ha


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 carparks, existing roads,
proposed villas, entry building and the tank overflows, landscaped areas, and pathways. To
treat the new areas, five biopods have been placed to catch flows draining from the listed areas.
The Biopods range in size from 5 to 15m2 dependent on catchment size. Each biopod has a
filter layer depth of 0.4m and an extended detention depth of 0.2 to 0.3m. 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.

Seven (7) 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 five rainwater tanks is detailed in Section 5.0 below.

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1714-Cartwrigth Village Extension_IWMP_Version2.doc                                October 2018