Ltr-20190925-IR Response-Noosa Marketplace_FINAL (1)

        O7 Natural treatment strategies, including grass swales and bio-retention systems, vegetated
        filtration strips and gross pollutant traps, are used wherever possible
Proprietary devices have been removed from the development and treatment provided with a
proposed combination of trash baskets, bio-retention tree pits and/or filter strips.
Section 6 of the Integrated Water Management Plan outlines the typical bio-retention basin
parameters (Table 6.5).
The proposal now includes a series of appropriately sized bio-retention gardens on the margins and
central areas of the car park and integrated into the landscaped areas surrounding the buildings - see
Figure 45 below. These are appropriately sized to filter stormwater run-off, whilst including a variety of
vegetation including perennial native plants and shrubs. These treatment nodes have been modelled
as two representative areas in the updated MUSIC model.
Figure 45 – Bioretention areas (green areas)




 Source: Cardno

For part (c) and as required for response to Issue 10 below, the updated MUSIC model is provided for
review and forms part of Appendix H.
This includes justification and updated to water reuse rates and clarifies litter basket removal rates.
Litter basket removal rates were sourced from the supplier.
We consider the revised stormwater strategy with inclusion of bioretention and other mitigation
features adopts best practice principles in accordance with industry standards and guidelines.

ISSUE 10: HYDROLOGY
The pre-development hydrologic model uses relatively low initial loss values, particularly for the rarer
AEP events. The IWMP acknowledges that the values differ from those provided by ARR Datahub but
states that the values adopted are conservative. While the values (low initial loss) would be


 Ltr-20190925-IR Response-Noosa Marketplace_FINAL                                                         73