1714 IWMP_Report_Carramar_Version2 Oct 2018

                                                                               Callaghan & Toth

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

The developed site was divided into MUSIC model sub-catchments as shown on Plan No.
1714-01. The proposed treatment train for the development site is also illustrated on Plan No.
1714-01 and listed below:

1. The Biopods – small bioretention basins will treat the stormwater runoff from the access
   roads, car parks, landscaped areas and rainwater tank overflows, landscaped podium, etc.
   The treated runoff will then be directed to an existing storm water pipe within the property.
   The bio-retention component will remove the nutrients and retard flow.

2. Rainwater Tanks will be required to collect water from the new roofs. Five tanks all of
   14,000 litre capacity will be above ground and have potable top-up supply when 80% empty
   with an overflow pipe discharging to the underground detention system. The tank capacity is
   to be adequate for the supply of toilets and some landscape watering.



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, carparks, road and verge areas. MUSIC allows for the
characteristics of these source nodes to be amended to ensure that accurate pollution
generation and hydraulic characteristics 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 levels of
imperviousness. The site has been related to a “Commercial” land use and pollutant export
parameters detailed in the Guidelines for this land use have been used for each node.




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1714-Cartwrigth Village Extension_IWMP_Version2.doc                          October 2018