Attachment E - Stormwater Management Report · MCU24/0112

         Pollutant                                              Sources

 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.
4.3.1 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 4, Table 5 and Table 6.

Table 4 – 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).

 Erosion Control             1. Stage clearing and construction works to minimise the area of exposed
                                soil at any one time.

                             2. Effectively cover or stabilise exposed soils prior to predicted rainfall.

                             3. Prior to completion of works for the development, and prior to removal
                                of sediment controls, all site surfaces must be effectively stabilised
                                using methods which will achieve effective short-term stabilisation.

 Sediment Control            1. Direct runoff from exposed site soils to sediment controls that are
                                appropriate to the extent of disturbance and level of erosion risk.
                             2. All exposed areas greater than 2500 metres must be provided with
                                sediment controls which are designed, implemented and maintained
                                to a standard which would achieve at least 80% of the average annual
                                runoff volume of the contributing catchment treated (i.e. 80%

                                                                                                            5