RFI - Attachment 1 - Amended Stormwater Management Plan

considered to significantly alter the potential for pollutant generation, stormwater quality treatment
processes are not proposed for the development.


4. Conclusion and Recommendations
This Stormwater Management Report demonstrates how the stormwater run-off from the site is to be
managed to comply with the relevant requirements and mitigate adverse impacts to the downstream
catchment. Of note, QUDM assessment has been undertaken against the LPOD criteria demonstrating
no actionable nuisance arising from the proposed development.

       The proposed site stormwater run-off maintains the existing drainage regime. The existing
        surface runoff from the upstream properties remains unchanged compared to the existing state.

       An assessment against the LPOD criteria of QUDM has been detailed in this revised report
        with the outcomes incorporated into the concept stormwater layout, demonstrating no
        actionable nuisance outcomes because of the development.

       Pre and post development modelling of the resultant peak flows has been carried out, with
        attenuation using two 3kL rainwater tanks identified to mitigate peak flows. Outlets from the
        tanks discharge via a level spreader device to the LPOD, to maintain the pre-development
        drainage regime. The driveway surface flows are intercepted and piped to the level spreader via
        a trench drain.

       A site-specific erosion and sediment control plan is to be prepared and submitted with the
        Operational Works approval to mitigate impacts to the receiving catchments and fulfil the
        general environmental duty of care and Appendix 2 of the SPP.

       The proposed development is not considered to significantly alter the pollutant generating
        potential of the site; therefore, stormwater quality treatment processes are not proposed for the
        development.