RFI - Appendix G SWMP by MPN Consulting

 16 December 2021



5         STORMWATER
5.1       Flooding

Based on Noosa Shire Council flood mapping, the site is not subject to flooding from any sources.

5.2       Lawful Point of Discharge

The lawful point of discharge for the development site is the existing internal Noosa Civic Shopping
Centre stormwater infrastructure south of the proposed development. The existing Noosa Civic
Shopping Centre lawful point of discharge is the Creek to the South of the site.

5.3       Site Based Stormwater Management Plan

The aim of the Stormwater Management Plan outlined below is to:

      •   Prevent or minimise adverse social or environmental impacts from stormwater runoff
          originating from the proposed development.
      •   Achieve acceptable levels of stormwater runoff quality and quantity.

The Stormwater Management Plan aims to identify Stormwater Quantity and Quality Best
Management Practice for the site and demonstrate that water quantity and quality impacts will be
minimised in receiving waters.

The Stormwater Management Plan outlines the site in two sections, the operational phase and the
construction phase. The operational phase addresses treatment of contaminated runoff from the
developed site by natural methods before discharging into receiving waters whilst the construction
phase of the Stormwater Management Plan addresses erosion and sediment control to prevent
contamination of water sources by stormwater runoff during construction of the site.


5.4       Operational Phase

5.4.1 Proposed Site Drainage

Stormwater runoff from the proposed development will be collected and conveyed in a new
stormwater pit and pipe network to the existing internal infrastructure.

Stormwater runoff from the new roof, carpark, internal road and servicing areas will be directed to
3 bioretention basins for stormwater quality treatment. High flow bypasses will be constructed
around the bioretention basins for flows exceeding the treatment flows.

Stormwater runoff from the landscape areas at the North and South East boundaries will remain
generally as per pre-developed conditions, with some re-shaping required to ensure stormwater
infrastructure remains clear of the proposed building works.

Approximately 260m2 of the access driveway and the carpark will bypass the bioretention basins to
allow the driveways to join neatly into the existing internal road system. The treated areas will be
over treated so the overall net water quality objectives are achieved for the development.




 Excellence with Economy in Engineering                                                                8
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