1909-13367 SRA referral response approved docs

Table 9 – Pollutant load reductions achieved

                                            Mean annual % load reduction from unmitigated development
               Pollutant
                                                     Required                                Achieved

     Total Suspended Solids (TSS)                        80                                   84 (+4.0)

        Total Phosphorous (TP)                           60                                  60.0 (+0.0)

          Total Nitrogen (TN)                            45                                  54.4 (+9.4)

       Gross Pollutants>5mm (GP)                         90                                  100 (+10.0)


The proposed treatment train exceeds all the required pollutant load reductions stipulated by NSC.
Refer Appendix AB for further MUSIC modelling details.



4. 3     Con st ruc t io n Ph a se

Management of stormwater run-off during construction is necessary to avoid pollution of downstream
waterways from sediment and gross pollutant loading. Pollutants typically generated during construction
phase are described in table 9.

Table 10 – 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.


Refer Table A in separate SPP Appendix 2 for further stormwater management design objectives that
are applicable to all climatic regions.


4.3.1 E ro sio n and Se di men t Co ntr ol

Impacts of inadequate erosion and sediment control downstream from the site include:

1.        Traffic safety problems

2.        Blocked drains

3.        Local flooding problems

4.        Aesthetic pollution of drainage paths, and

5.        Damage to local ecosystems

Best practice erosion and sediment controls must be installed to minimise the discharge of sediment
laden run-off during construction.


                                         Stormwater Management Report                                         15
S19-007                                    122 & 144 Myall St, Cooroy