ECM_22343539_v1_Stormwater Management Report

                 4. 2       Con st ruc t io n Ph a se

                 Management of stormwater runoff during construction and the implementation of an erosion & sediment
                 control program is necessary to avoid impacts to receiving waters from pollutants typically generated
                 during the construction phase. Typical pollutants are described in Table 1 below:

                 Table 1 – Pollutants Typically Generated During the Construction Phase

                               Pollutant                                            Sources

                  Litter (Gross Pollutants)         Paper, construction packaging, food packaging, cement bags.

                  Sediment                          Unprotected exposed soils and stockpiles during earthworks and building.

                  Hydrocarbons                      Fuel and oil spills, leaks from construction equipment.

                  Toxic materials                   Cement slurry, asphalt prime, solvents, cleaning agents, wash waters.

                  pH altering substances            Acid sulphate soils, cement slurry and wash waters.

                 In addition to the degradation of receiving waters, impacts of inadequate erosion and sediment control
                 downstream from the site include:
                        •    traffic safety problems;

                        •    blocked drains;

                        •    local flooding problems;
                        •    aesthetic pollution of drainage paths; and

                        •    damage to local ecosystems.
                 4.2.1 De si gn O bj e ct i v es

                 Management of stormwater runoff during construction should be undertaken in accordance with
                 Appendix 2 of the SPP (July 2017). The SPP outlines the design objectives for construction phase
                 stormwater management. These are presented in Table 2, Table 3 and Table 4.

                 Table 2 – SPP Appendix 2: Part 1 Construction Phase – Stormwater Management Design Objectives

                                Issue             Desired Outcomes




                  Drainage Control                1. Manage stormwater flows around or through areas of exposed soil to
                                                     avoid contamination.

                                                  2. Manage sheet flows in order to avoid or minimise the generation of rill or
                                                     gully erosion.

                                                  3. Provide stable concentrated flow paths to achieve the construction
                                                     phase stormwater management design objectives for temporary
                                                     drainage works (part 2).

                                                  4. Provide emergency spillways for sediment basins to achieve the
                                                     construction phase stormwater management design objectives for
                                                     emergency spillways on temporary sediment basins (part 3).



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Document Set ID: 22343539
Version: 1, Version Date: 16/03/2023