Appendix B - Amended Biome Consulting Response

TABLE OF CONTENTS
1   INTRODUCTION ............................................................................................................... 1
    1.1      Scope of this report ................................................................................................. 2
    1.2      Previous Documentation ......................................................................................... 2
    1.3      Response to Approval Conditions ........................................................................... 3
2   SITE CHARACTERISTICS ................................................................................................ 5
    2.1      Location................................................................................................................... 5
    2.2      Topography and Site Drainage ............................................................................... 6
    2.3      Site Discharge locations.......................................................................................... 6
3   PEAK FLOW INVESTIGATION ......................................................................................... 7
    3.1      Existing Scenario .................................................................................................... 7
             3.1.1    Catchment Characteristics ........................................................................ 7
             3.1.2    Infiltration Loss & Lag Parameters ............................................................ 8
             3.1.3    Channel Routing ........................................................................................ 8
             3.1.4    Rainfall Data .............................................................................................. 8
             3.1.5    Existing Peaks Flow .................................................................................. 8
             3.1.6    Model Verification Check - Rational Method ............................................. 9
    3.2      Developed Mitigated Scenario ................................................................................ 9
             3.2.1    Catchment Characteristics ........................................................................ 9
             3.2.2    Infiltration Loss & Lag Parameters .......................................................... 10
             3.2.3    Channel Routing ...................................................................................... 10
             3.2.4    Rainfall Data ............................................................................................ 10
             3.2.5    Proposed Mitigation Strategy .................................................................. 10
             3.2.6    Developed Mitigated Peaks Flow Results ............................................... 12
             3.2.7    Extreme Event Sensitivity Check ............................................................. 13
             3.2.8    Internal Drainage Strategy ....................................................................... 14
4   STORMWATER QUALITY .............................................................................................. 15
    4.1      Pollutants of Concern ............................................................................................ 15
    4.2      Water Quality Objectives....................................................................................... 15
    4.3      Stormwater Quality Management Strategy ........................................................... 15
             4.3.1   Utilised Treatment Systems ..................................................................... 16
             4.3.2   Proposed End-of-Line Systems ............................................................... 16
    4.4      MUSIC Modelling .................................................................................................. 17
             4.4.1   Meteorological Data ................................................................................. 18
             4.4.2   Source Nodes .......................................................................................... 18
             4.4.3   Primary and Secondary Drainage Links .................................................. 18
             4.4.4   Treatment Nodes ..................................................................................... 19
    4.5      MUSIC Modelling Results ..................................................................................... 21
5   WATERWAY STABILITY MANAGEMENT ...................................................................... 22
6   CONCLUSION ................................................................................................................. 23
7   RECOMMENDATIONS ................................................................................................... 23
8   DISCLAIMER ................................................................................................................... 24
9   REFERENCES ................................................................................................................ 24