H Swqmp · 132007.2398

                                                                                                  CALIBRE CONSULTING




systems. The treatment of external catchments is consistent with the strategy previously provided to Council (Report
No. B07086-2A).

It is noted that any stormwater likely to contain grease and oil (i.e. from carparking areas) shall be managed via grease
and oil arrestors prior to treatment to bioretention basins and constructed. This requirement will identified and
incorporated if necessary during the detailed design.

4.3.1     UTILISED TREATMENT SYSTEMS

Bioretention Systems, Water Quality Control Ponds (WQCP) & Constructed Wetlands have been incorporated in the site
stormwater quality management strategy. The details of the treatment systems are provided below.

Bioretention Systems - utilise a sandy loam soil based media to filter runoff. Sediment particles and suspended solids are
trapped on the surface of the filter media, while micro-organisms and vegetation planted in the filter removes dissolved
nutrients (nitrogen and phosphorus) through biological uptake processes. Subsoil drainage provided below the filter
media allows for the treated runoff to discharge from the bioretention basin.
Constructed Wetland – Constructed wetlands are shallow, extensively vegetated water bodies that use enhanced
sedimentation, fine filtration, and pollutant uptake processes to remove pollutants from stormwater.
Water Quality Control Pond (WQCP) –The WQCP reduces stormwater pollutants associated with fine particulates such
as TSS, metals, nutrients and toxicants as well as soluble contaminants. The water bodies/ponds will have enhanced
nutrient removal by incorporating macrophyte planting areas and open water zones. They will ensure that adequate
pollutant retention is achieved before discharging offsite to adjacent properties. WQCP have a permanent water storage
volume.

4.3.2     PROPOSED END-OF-LINE SYSTEMS

Three end-of-line stormwater quality systems are proposed in the detention basin for the development and are
summarised below.

Northern Basin (Bioretention System) - The northern portion of the development site (Catchment A) is to be treated by a
bioretention system. The system has no permanent water. Refer to Drawing No. B14158.W-SK07 for system details.

Central Basin (Constructed Wetland) - The central basin is proposed to be an open water feature and is to be treated by
incorporating macrophyte planting areas. This system will act as a constructed wetland for stormwater quality treatment
purposes with a deep open water zone. The open water body will be topped up with treated stormwater from the
Southern Basin during rainfall events. The Central Basin will treat Catchment B of the development. Refer to Drawing
No. B14158.W-SK08 for system details.

Southern Basin (WQCP and Bioretention System) – The southern basin comprises of a bioretention system and WQCP.
Stormwater is treated by a bioretention filter prior to discharging in into the WQCP. There is no permanent water body in
the bioretention system. The southern basin treats stormwater from Catchment C of the development which includes the
Clubhouse, Bowling Green, and the Aged Care Facility. Refer to Drawing No. B14158.W-SK09 for system details.

4.4       MUSIC MODELLING
Water quality modelling of the proposed development has been undertaken using the Model for Urban Stormwater
Improvement Conceptualisation (MUSIC) Version 5.1.16, developed by the Cooperative Research Centre for Catchment
Hydrology (CRCCH). MUSIC enables the user to conceptualise the transfer of pollutants through a stormwater drainage
system and provides an aid in quantifying the effectiveness of the proposed stormwater quality management strategy.
MUSIC only provides quantitative modelling for Total Suspended Solids (TSS), Total Phosphorous (TP), Total Nitrogen
(TN), and Gross Pollutants (GP).




B14158.W-01A | COOROY RETIREMENT COMMUNITY| PALM LAKE RESORTS                                                               |6