07/1841 - Response to Information Request [As Published] · 132007.1841

STORMWATER QUALITY MANAGEMENT PLAN

 

2.0 Pollutant Export Modelling

As previously mentioned the MUSIC modelling software was utilised to predict performance

characteristics of the proposed water treatment train. Modelling parameters were set up in

accordance with Brisbane City Council's recommendations as specified in “Guidelines for
Export Pollutant Modelling in Brisbane Version 7” (October 2003), and Gold Coast City
Council’s “MUSIC Modelling Guidelines” (2006). The node layout of the music model is

provided in appendix B.

2.1 — Water Quality Objectives

This model uses the water quality objectives set out by Noosa Shire Council. A

summary of the key indicator standards is set out below in table 2.1.

Table 2.1: Noosa Shire Council Water Quality Objectives

 

 

 

 

 

 

Indicator % Reduction Value
Total Suspended Solids (TSS) 90 15 mg/L
Total Phosphorus (TP) 70 0.05 mg/L
Total Nitrogen (TN) 50 0.5 mg/L

 

 

 

2.2 — Treatment Nodes

The recommended BCC values for commercial source nodes have been used in

MUSIC to generate predicted pollutant loads from the site. The following devices have

been used in the treatment train to reduce these pollutant loads to an acceptable level.

+ Gross Pollutant Trap — The model has used a GPT at the downstream end of

drainage systems prior to discharge. This GPT was modelled to remove 90% of

gross pollutants for up to a Q3 month ARI storm. The exact location of this GPT's

will be detailed on future operational works drawings.

+ Bio-Retention Areas ~ These areas will be placed at the edges of carparks around

the site, and adjacent to the eastern boundary. These areas will have an extended

detention depth of 0.15m with a combined storage surface area of 3 10m’. The filter

material will consist of a 0.4m deep sandy loam layer overlying a 0.1m deep

drainage layer. The total area of bio-retention is to be 310 m’. Perforated pipes in

 

BARLOW GREGG VDM

M3048
DECEMBER 2007