B07056.W-01A Complete - Stormwater [As Published] · 132007.2398

Concept Stormwater Management Plan
RSL Care – Cooroy Retirement Village



9.0       CONCLUSIONS AND RECOMMENDATIONS
This report has been prepared generally in accordance with Noosa Council’s ‘The Noosa Plan’ Planning Scheme
Policy. Information has been provided on the existing and developed scenario hydrological aspects, detention
basin measures, a stormwater quality management strategy and a water balance analysis.

Detention basins were modelled using DRAINS software. It has been demonstrated that the proposed detention
basins and outlet structures at both the northern and southern discharge points mitigate developed peak flows to
below existing rates for all analysed average recurrence interval storms.

The treatment train was modelled using the software program MUSIC and has been demonstrated to achieve
pollutant load reductions from treatment of both the developed site and external site catchments. Load
reductions have been compared to water quality objectives as required by Healthy Waterways (2006). Load
based objectives are considered more appropriate than concentration objectives as discussed in the report.

The developed scenario water balance model (with rainwater reuse measures) significantly reduces average
annual runoff volumes from the proposed development.

It is recommended that the Concept Stormwater Management Plan be approved and incorporated into the
Operational Works design. Detailed construction drawings for proposed water quality treatment devices will be
submitted with the Operational Works application.




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