Response to Information Request - REC13/0015

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                                                                                           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. Plan
01. The proposed treatment train for the development site is illustrated on Plan No. 02 and
listed below:


The Bioretention Basin will treat the stormwater runoff from the road widening and verge works,
and allotments. The treated runoff will then be directed to a Bioretention Basin within new
drainage reserve. The bio-retention component 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. 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 guidelines detail of urban residential pollutant export parameters have
been used for each node.



TABLE 4.1            MUSIC CATCHMENT AREAS (DEVELOPED)


              Catchment                                   land Use          Music Impervious   Area (ha)


  Habitable Roof Area Lot 17                 -
                                                 20     Urban   -
                                                                     Roof        100%             0.08


          Yard   -
                     Lot 17 to 20                       Urban   -
                                                                     Yard         30%             0.167



        Road Widening + Verge                           Urban   -
                                                                     Road         90%             0.125


              TOTAL                                                                            O.372ha



4.2.2    Treatment Nodes


The "MUSIC Modelling Guidelines for South East Queensland" Version 1 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 "Urban" and the values in the guideline shown in
Table 3.7 and Table 3.8 of the guidelines have been used in this model.




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55 Lake MacDonalld Drive   -

                               Stage I                SMP Revl.doc                         May 2013   1225