Attachment G - Stormwater Quality Management plan

                                                                               Callaghan & Toth


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

The site i.e. Lot 1 and Lot 2 RP153299 and part of Lot 3 SP230055 was divided into MUSIC
model sub-catchments as shown on Plan No. 2001-02. The proposed treatment train for the
developed site is also illustrated on Plan 2001-02 and listed below:

    1. Bioretention Systems including:
              a. Tree Pits will treat the stormwater runoff from the pathways, gardens, and
                  some shelters.
              b. Biopods will treat stormwater runoff from the pathways, gardens, softfall and
                  some shelters.
              c. Bioretention Swale will treat stormwater runoff from the open field area.
              The treated runoff from the bioretention systems will partly be directed to the
              existing vegetated swale, whilst some will flow to subsurface drainage to outlet to
              Cooroy Creek. The bio-retention component of these systems will remove the
              nutrients, heavy metals, and retard flow.

    2. Vegetated Swale – the existing vegetated swale will be partly retained and will collect
       stormwater flows from treepits, biopods and areas of pathway, gardens and softfall. The
       vegetated swale will outlet to the Cooroy Creek.

    3. Rainwater Tanks will be required to collect water from the new roof areas. The tank
       capacity will be top-up supply potentially for toilet flushing and landscaped areas.


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 shown on Plan No. 2001-02.

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 an “Urban Residential” land use and
pollutant export parameters detailed in the Guidelines for this land use have been used for each
node.




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2001 Hinterland Playground SWMP                                             February 2020