stormwater mgJ00300R1V1_25_Kauri_St_Cooroy_Complete · MCU18/0165

25 Kauri St Cooroy




5 STORMWATER QUALITY

5.1      Water Quality Objectives
In Queensland, the State Planning Policy sets out best practice urban stormwater quality design
objectives for development. Water quality objectives (WQO’s) for the proposed residential
development site are those stipulated in the State Planning Policy for the South-East Queensland
region. The specified water quality objectives for the site are shown in Table 5-1:

Table 5-1: Stormwater Quality Objectives

                         Pollutant                           Load Based Reduction
           Total Suspended Solids (TSS)                               80%
               Total Phosphorous (TP)                                 60%
                     Total Nitrogen (TN)                              45%
                Gross Pollutants (GP)                                 90%



5.2      Modelling Details

5.2.1 Software

A quantitative assessment of stormwater runoff quality has been undertaken for the operational
phase of the proposed development. Stormwater quality modelling has been carried out using
version 6.2.1 of eWater’s ‘MUSIC’ software (Model for Urban Stormwater Improvement
Conceptualisation). MUSIC is a decision support tool, used to plan and design appropriate urban
stormwater management systems at the conceptual level.

MUSIC modelling has been undertaken in accordance with the Water by Design’s (WbD) ‘MUSIC
Modelling Guidelines version 1.0 – 2010’ and the 2014 WbD ‘Bioretention Technical Design
Guidelines’.



5.2.2 Model Parameters

Rainfall and evapo-transpiration data for the investigation have been sourced from the Cooroy
Composite rainfall station. The ten-year period from 1973 to 1983 has been adopted for
modelling in accordance with the WbD modelling guidelines.

Modelling has been carried out using a 6-minute time step.

Music modelling parameters associated with the generation of run-off and with pollutant
generation have been incorporated using the values recommended in the WbD guidelines.
These values are provided below in Table 5-2 and 5-3.




J00300R1V1                                                                                   11