Appendix B - IWMP_2PearsonsRd_REV0

                                                                               Callaghan & Toth


4.0 WATER QUALITY MANAGEMENT PLAN
4.1      Proposed On-Site Stormwater Treatment Process

The developed site was divided into MUSIC model sub-catchments as follows:
    Roof areas for new lots (1 to 18),
    Yard areas for new lots; and
    Road reserve area.

The proposed stormwater treatment train for the overall development site is one Bioretention
Basin (BioBasin 1), incorporated into a detention basin. BioBasin 1 is located within the new
Parkland Area and discharges into the tributary to the east of the site.

The bio-retention component of this treatment system will remove the nutrients, heavy metals,
and retard flow.


4.2      MUSIC Model
4.2.1 Source Nodes

Catchment areas of source nodes within the proposed development have been identified as
sub-catchments such as roofs, yard, road and verge. See Figure 4.1 showing the MUSIC
model layout for this proposal.

MUSIC allows for characteristics of these source nodes to be amended to ensure that accurate
pollution generation and hydraulic characteristics for each sub-catchment are used to generate
stormwater runoff within the model. Table 4.1 below details the sub-catchments used in the
MUSIC model, land use, percent imperviousness and area of each sub-catchment. The MUSIC
Modelling Guidelines for South-East Queensland – Version 1 December 2010 have been used
to set level of imperviousness. The urban residential pollutant export parameters within the
guidelines have been used for each node.

The site has one main discharge point into the proposed biobasin / detention basin system,
which then outlets into the tributary of Six Mile Creek to the east of the lots.




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2035 2 Pearsons Road IWMP                                                  September 2020