Negotiated - Compiled Reference Document - RAL25 0011 (As Published)

  LINDSAY CONSULTING PTY LTD
  STRUCTURAL AND CIVIL ENGINEERS
  ACN 079 744 808 ABN 61 478 386 385 GST REGISTERED

  AS TRUSTEE FOR THE LINDSAY FAMILY TRUST




  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        Design Objectives

  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).

   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% hydrological effectiveness) to 50mg/L
                                                      Total Suspended Solids (TSS) or less, and pH in the range (6.5–8.5).




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