SCG 31131(SWM).RevB - REceived 3.3.22.pdf

         •      Provide rumble grates at exit points from the site for passing earthmoving vehicles.
         •      Where possible maintain existing landscaping/grasses downslope from construction areas
                to act as buffer/silt trap.
         •      Install temporary downpipes from completed roof structures and ensure runoff passes
                through silt fences.
         •      Minimise concentrating surface flows.
         •      Place silt barriers around council stormwater pits that the site drains to.
         •      Cover soil stockpiles with hessian or similar.



5.3      Completed Development


We are proposing to use a combination of active and passive stormwater treatment measures. Active
measures will include a bio-retention basin and a water storage tank for re-use and passive measures via
gross pollutant inserts into stormwater pits within paved areas that receive runoff from areas prone to
gross pollutants.



5.3.1    Water Quality Objectives



Water quality objectives for South East Queensland are outlined in the State Planning Policy 2017 and
are displayed in Table 5.1. These reductions are achieved by adopting best practice techniques in
accordance with the abovementioned guidelines.



                               Table 5.1: Minimum Mean Annual Load Reductions

               POLLUTANT / ISSUE                    MINIMAL MEAN ANNUAL LOAD REDUCTIONS

          Total Suspended Solids (TSS)                                     80%

             Total Phosphorous (TP)                                        60%

               Total Nitrogen (TN)                                         45%

              Gross Pollutants (GP)                                        90%




SCG Consulting Engineers                      Page 10                            SCG Ref: 31131(SWMP).RevB