B07056.W-01A Complete - Stormwater [As Published] · 132007.2398

Concept Stormwater Management Plan
RSL Care – Cooroy Retirement Village

buildings. Therefore, separate drainage systems will be required such that rainwater runoff from these buildings
is separated from street drainage stormwater runoff. The tanks are designated as ‘Northern Rainwater Tank’,
‘Central Rainwater Tank’ and ‘Southern Rainwater Tank’. Rainwater collected in each tank will be pumped back
in a separate reticulation line to the same buildings that drain to the tank. Water will be used by toilets, laundries
and for external use. A fourth rainwater tank is proposed for the Residential Aged Care building. These tanks
will reduce runoff volumes by reuse. Reuse will also assist in meeting water quality objectives by reducing
contaminant loads entering the stormwater system.

(f)      Gross Pollutant Traps (GPTs)

Installed immediately upstream of WQCP’s to provide pre-treatment of stormwater discharges. The GPTs will
capture litter, coarse sediment and hydrocarbons, while significantly reducing the amount of fine sediments
entering the WQCP’s and leaving the site.

6.3                MUSIC Modelling
Water quality modelling of the proposed development has been undertaken using the Model for Urban
Stormwater Improvement Conceptualisation (MUSIC) Version 3.01, developed by the Cooperative Research
Centre for Catchment Hydrology (CRCCH). MUSIC enables the user to model the transfer of pollutants through
a catchment and provides an aid in determining how effective the stormwater quality treatment train is at meeting
WQOs. The critical pollutants to be modelled are Total Suspended Solids (TSS), Total Phosphorous (TP), Total
Nitrogen (TN) and Gross Pollutants.

The following models were set up to examine the effectiveness of the water quality treatment train:
          Developed Site Only (without mitigation measures applied)
          Model name: B07056 Developed Site Only Unmitigated.sqz

          Developed Site plus an External Catchment (without mitigation measures applied)
          Model name: B07056 Developed Total Unmitigated.sqz
          Developed Site plus an External Catchment (with mitigation measures applied)
          (B07056 Developed Total Unmitigated.sqz with mitigation measures applied)
          Model name: B07056 Developed Total Mitigated.sqz


As there are no specific guidelines issued by Noosa Council for MUSIC modelling, Brisbane City Council’s
Guidelines for Pollutant Export Modelling in Brisbane Version 7 – Draft Revision 2 (October 2003) have been
used to configure each model. These are the current widely accepted guidelines for MUSIC modelling. The
following sections summarise the parameters and procedures adopted from these guidelines.

6.3.1              Meteorological Data

Six minute pluviographic data was sourced from the Bureau of Meteorology (BOM) for the Cooroy Composite
Station No. 040059, approximately 1.5 km to the south of the site. Cooroy Composite Station was chosen as it
was the closest station with rainfall data available in a suitable format for MUSIC modelling (continuous rainfall
data). The 11 year period from 1st January 1972 to 31st December 1982 has been adopted for the rainfall
duration. This period was selected due to its mean annual rainfall of 1613 mm, compared with that of Cooroy
(1602 mm). In addition, series of zero recorded data were limited within the dataset.

Monthly areal potential evapo-transpiration (PET) data was sourced from BOM for the Mary River Basin and
applied to the model (Bureau of Meteorology, 2001).

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