Swmp

5.3      Completed Development


We are proposing to use a combination of active and passive stormwater treatment measures. Active
measures will include bio-retention basins, water storage tanks for re-use and passive measures via gross
pollutant inserts into stormwater pits across the site.

For the proposed development we have proposed incorporate Water Sensitive Urban Design (WSUD)
principles stormwater harvesting has been proposed for stormwater re-use for communal landscaping.
The proposed water re-use tank has been sized in accordance with the Sunshine Coast Council Flooding
and Stormwater Management Guidelines adopting 1kl per 25m2 of communal landscaping area water
tank for stormwater re-use have been incorporated into the proposed development.

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%


5.3.2    Sources of Contaminants
Gross Pollutants

Gross pollutants include litter, grit and heavier sediments which can be mobilised from within or from
neighbouring sites.

Potential Causes

         •      Unsecured refuse areas.
         •      Un-landscaped areas prone to stormwater scour.
         •      Insufficient drainage for surface runoff from within the site.
         •      Wind Bourne transportation.



SCG Consulting Engineers                    Page 10                              SCG Ref: 33132(SWMP).RevB