RFI - SWMP.pdf

Table of Contents
1.0     INTRODUCTION ................................................................................................................................... 3
2.0     EXISTING SITE DESCRIPTION ......................................................................................................... 4
3.0     PROPOSED DEVELOPMENT ............................................................................................................. 5
4.0     EXISTING DRAINAGE.......................................................................................................................... 5
  4.1         Existing Drainage and Infrastructure .................................................................................................... 5

  4.2         Lawful Point of Discharge ........................................................................................................................... 6

5.0     STORMWATER QUALITY .................................................................................................................. 8
  5.1         State Planning Policy and Water by Design Assessment ................................................................. 8

  5.2         Construction Phase ....................................................................................................................................... 9

      5.2.1       Silt and Sediment Erosion ...................................................................................................................................... 9

  5.3         Completed Development.......................................................................................................................... 10

      5.3.1       Water Quality Objectives ..................................................................................................................................... 10

      5.3.2       Sources of Contaminants ..................................................................................................................................... 11

      5.3.3       Proposed Treatment Measures ......................................................................................................................... 13

      5.3.4       Pollutant Modelling ................................................................................................................................................ 13

6.0     STORMWATER QUANTITY ............................................................................................................ 15
  6.1         Rational Method .......................................................................................................................................... 16

      6.1.1       Design Storms........................................................................................................................................................... 16

      6.1.2       Rainfall Intensity ..................................................................................................................................................... 16

      6.1.3       Time of Concentration .......................................................................................................................................... 16

      6.1.4       Runoff Coefficient (C10)......................................................................................................................................... 17

      6.1.5       Peak Flows ................................................................................................................................................................. 17

  6.2         Proposed Drainage .................................................................................................................................... 18

      6.2.1       Catchments ................................................................................................................................................................ 18

      6.2.2       Peak Flow Mitigation ............................................................................................................................................. 18

  6.3         Hydraulic Modelling (PC Drains) .......................................................................................................... 19

      6.3.1       Rainfall Data .............................................................................................................................................................. 19



SCG Consulting Engineers                                                   Page 1                                                                     SCG Ref: 31131(SWMP)