Request to Amend Application and Response to DSDIP's Information Request · MCU14/0009

4 Conclusions
It can be seen from the results, presented in Table 8 that the treatment proposed for
the development site achieves the performance criteria set by the NSC. Annual Load
Reductions of Total Suspended Solids (TSS), Total Phosphorus, Total Nitrogen (TN)
and Gross Pollutants (GP) between the Mitigated and Unmitigated Scenarios have
been achieved.
It is proposed that a detention system be constructed within the site in order to
achieve Council’s non-worsening criteria. Table 16 provides a comparison of the
peak existing, developed and mitigated flows. It can be seen that whilst peaks flows
increase under the developed scenario, the modeled mitigation solutions ensure
non-worsening is achieved.
The site is affected by flooding from Cooroora Creek and it is recommended a flood
search is completed so as to set the minimum floor heights of the building. Buildings
will be raised on stumps to be above the flood height as to not impede flood flows.
This plan demonstrates that effective treatment of stormwater at the proposed
development can be achieved through the integration of Water Sensitive Urban
Design (WSUD) principles. Through the incorporation of a bioretention and
detention system, the plan successfully demonstrates:
    Compliance with the requirements of NSC’s Load Based Objectives;
    Ecological sustainability in terms of the development’s impact upon receiving
     waters and the viability of the proposed site development; and
    Compliance with NSC non-worsening of peak flows in the 1, 2, 5, 10, 20, 50 and
     100 year ARI storm event.




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