RFI - P0478-26-001_45_Maple_Street_Cooroy_SWMP

List of Tables and Figures




Table of Contents
Executive Summary ............................................................................................................................. 3

        1.1      Lawful Point of Discharge .......................................................................................................................... 3
        1.2      Stormwater Quantity .................................................................................................................................. 3
        1.3      Stormwater Quality ..................................................................................................................................... 3
        1.4      Erosion and Sediment Control ................................................................................................................... 3
2       Introduction ................................................................................................................................ 4

        2.1      Background and Scope .............................................................................................................................. 4
        2.2      Stormwater Management Objectives and Design Approach .................................................................. 4
        2.3      Supporting Documentation and Reports ................................................................................................... 5
3       Existing Site ................................................................................................................................ 6

        3.1      Site Overview .............................................................................................................................................. 6
        3.2      Flow Calculation Using the Rational Method ............................................................................................ 6
        3.3      DRAINS Model and Comparison to Rational Method ............................................................................... 8
4       Proposed Development Works ................................................................................................. 11

        4.1      Proposed Site Description......................................................................................................................... 11
        4.2      Time of Concentration Inputs into DRAINS ............................................................................................. 12
        4.3      Hydrological Modelling Results ................................................................................................................ 13
        4.4      Required Mitigation – Installation of a Detention Tank .......................................................................... 14
        4.5      Stormwater Detention and Mitigation Strategy ...................................................................................... 14
        4.6      Stormwater Mitigation Results ................................................................................................................. 15
5       Stormwater Quality .................................................................................................................. 16

        5.1      Introduction ............................................................................................................................................... 16
        5.2      Proposed Treatment System ................................................................................................................... 16
        5.3      Expected Pollutant Reduction Performance ........................................................................................... 16
        5.4      Compliance and Regulatory Alignment ....................................................................................................17
        5.5      Conclusion and Recommendations ..........................................................................................................17
6       Erosion and Sediment Control.................................................................................................. 18

7       Conclusion ................................................................................................................................ 19

        7.1      Hydrological and Hydraulic Considerations ............................................................................................ 19
        7.2      Stormwater Quantity Management ......................................................................................................... 19
        7.3      Stormwater Quality Management ............................................................................................................ 20
        7.4      Erosion and Sediment Control ................................................................................................................. 20
        7.5      Regulatory Compliance and Sustainable Outcomes .............................................................................. 20
        7.6      Final Recommendations ........................................................................................................................... 20




 45 MAPLE STREET, COOROY
                                                          24 June 2026
 Stormwater Management Plan
 Client Reference: P0478-26-001
 Prepared for Myall Rise PTY LTD