Attachment 4 - Stormwater Management Plan by O2 · MCU13/0251

4.            Operational Phase Stormwater Quality Management
It is proposed to divert site runoff to bioretention systems to capture and treat runoff from the
development site. The bioretention systems will be incorporated into the landscape buffers located around
the carpark areas.

4.1.          Bioretention Systems
A bioretention system’s primary function is to remove pollutants from stormwater prior to the stormwater
being discharged from the site and ultimately into a local waterway.

Bioretention systems operate by filtering stormwater through a prescribed soil media prior to being
collected at the base of the system via perforated pipes located within a gravel drainage layer. During
percolation through the soil media, pollutants are retained through fine filtration, adsorption and some
biological uptake.

The vegetation on the surface of the soil media is vital to the overall performance of the system. In
conjunction with facilitating pollutant removal, the species also need to be relatively hardy and tolerant of
freely draining sandy soils and regular inundation.

A typical section of a bio-retention system is shown below in Figure 5.




Figure 5– Typical Cross-Section through a Bioretention System (Source: Water by Design, 2009)

Details of the proposed system are detailed in Section 5.9. MUSIC modelling has been undertaken to size
the systems, as detailed in Section 5.

4.1.1.        Maintenance
It is recommended that a Bioretention System Maintenance Plan for the site be provided at the Operational
Works stage of the development.




STORMWATER MANAGEMENT PLAN – PEREGIAN VILLAGE MARKET                                                   Page 5

Scanlon Property Group
R002616