20517 App J.pdf [As Published] · 132007.1259

Concept Stormwater Management Plan
Essence of Peregian

 

The following models were set up to examine the effectiveness of the water quality treatment train:

Model No. 1 Existing Site plus External Catchment
Model name: B07047 Existing - Split.sqz

NMoua”

Model No. 2 Developed Site (without mitigation measures applied)
Model name: B07047 Developed Site.sqz
Model No. 3 Developed Site plus an External Catchment (without mitigation measures applied)

Mode! name: B07047 Developed Extended.sqz
Model No. 4 Mitigated Site (Model No. 2 with mitigation measures applied)
Model name: B07047 Mitigated Site.sqz
Model No. 5 Mitigated Site plus an External Catchment (Model No. 2 with mitigation measures applied)
‘ Model name: B07047 Mitigated Extended.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. The following sections summarise the parameters and procedures adopted from these
guidelines.

4.31 Meteorological Data

Six minute pluviographic data was sourced from the Bureau of Meteorology (BOM) for the Caloundra Water
Treatment Station No. 040496, approximately 35 km to the south of the site. Caloundra Water Treatment Station
was chosen as it was the closest coastal station with rainfall data available in a suitable format for MUSIC modelling
(continuous rainfall data). It is a coastal rainfall station at similar elevation as the site. The 10 year period from 4"
December 1989 to 4 December 1999 has been adopted for the rainfall duration. This period was selected due to
its mean annual rainfall of 1415 mm, compared with that of Coolum (1445 mm), which is 5 km south of the site. 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 Maroochy River Basin and
applied to the model.

4.3.2 Source Nodes

Source node land-use characteristics must be defined for MUSIC modelling purposes. The site under existing and
developed scenarios was divided into a number of distinct sub-catchments for modelling purposes. These have
been labelled and are presented in Drawing No.’s B07047-SK02 and B07047-SK03 in Appendix A.

One part’of the site was not included in the water quality analysis. This area is the highly vegetated western portion
of the site beyond the low embankment (referred to as Sub-Catchment G under Developed and Mitigated scenarios).

Sub-Catchments within the site were classifted as either ‘Urban Residential’, ‘Rural Residential’ or ‘Commercial’ land
use type. The soil and pollutant concentration properties of source nodes have been configured according to their
land use category (as per Tables 2.3 and 2.4 of the Pollutant Export Modelling Guidelines, BCC 2003).

Developed scenario sub-catchments were further apportioned into roofed and non-roofed nodes in-order to model
rainwater tanks. The impervious percentage for all roofed areas was assumed to be 100%. For non-roofed areas,
percentage impervious values were determined based on proposed road and other impervious surface areas (such
as driveways, paths and courtyards). Proposed road surface areas were measured and input as part of the
impervious cover. The effective impervious factor was applied to each impervious percentage value for the non-
roofed area of each sub-catchment in accordance with Table 2.2 of the Pollutant Export Modelling Guidelines. See
Appendix C for impervious areas details.

 

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