C2. Eng Report

                                                  Proposed Service Station – 175 Eumundi Noosa Road, Noosaville
                                                                               Ref: 20769 C R001 Rev 06 09.02.17
                                                                                                  February 2018


Contents
EXECUTIVE SUMMARY                                                                                             6
1     INTRODUCTION                                                                                            7
      1.1   Background                                                                                        7
      1.2   Property Detail                                                                                   7
2     EXISTING SITE                                                                                           9
      2.1   Existing Site Features                                                                            9
3     ACID SULFATE SOILS                                                                                     10
4     EARTHWORKS                                                                                             11
      4.1   Bulk Earthworks                                                                                  11
5     ROADWORKS                                                                                              12
      5.1   Existing Infrastructure                                                                          12
      5.2   Proposed Infrastructure                                                                          12
6     FLOODING                                                                                               13
      6.1   Flooding Considerations                                                                          13
7     STORMWATER INFRASTRUCTURE                                                                              14
      7.1   Existing Infrastructure                                                                          14
      7.2   Lawful Point of Discharge (LPD)                                                                  14
            7.2.1    Existing LPD                                                                            14
            7.2.2    Proposed LPD                                                                            14
8     STORMWATER QUANTITY ASSESSMENT                                                                         15
      8.1   Proposed Development and Associated Issues                                                       15
      8.2   Flow Rate Methodology                                                                            15
            8.2.1    Design Storm Events                                                                     15
            8.2.2    Rational Method for Peak Flow Rate                                                      15
            8.2.3    Catchment Area (A)                                                                      16
            8.2.4    Co-efficient of runoff (C)                                                              16
            8.2.5    Time of Concentration                                                                   16
      8.3   External Catchment                                                                               16
      8.4   Pre-Development Hydrology                                                                        16
      8.5   Post-Development Hydrology                                                                       17
      8.6   Detention Analysis and Strategy                                                                  17
      8.7   Lifecycle Costs                                                                                  17
9     STORMWATER QUALITY ASSESSMENT                                                                          18
      9.1   Treatment Objectives                                                                             18
      9.2   Site Analysis and Design Strategy                                                                18
            9.2.1    Low-Risk Area Treatment                                                                 18
            9.2.2    High-Risk Area Treatment                                                                19
      9.3   Erosion and Sediment Control                                                                     19
            9.3.1    Pre-Development Phase                                                                   19


BRISBANE / SYDNEY / MELBOURNE / GOLD COAST / SUNSHINE COAST / DARWIN / PERTH                             Page 3