LATE RFI - SCG 33114 (SWM) Rev A

5.3      Completed Development
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.


Water quality objectives specified by Noosa Council are above. These reductions are achieved by
adopting best practice techniques in accordance with the abovementioned guidelines.
5.3.1    Proposed Treatment Measures
Implementing the water quality objectives for the site as mentioned above and to ensure that on-site
stormwater management facilities can be economically maintained, it was deemed the most appropriate
method for treatment is the inclusion of small grass swales and bio-retention basins. Roof and surface
runoff will be collected via an internal drainage network and directed to the on-site bio retention basins
prior to the lawful point of discharge.
5.3.2    Pollutant Modelling
The impact of the stormwater quality management strategy of runoff discharged from the site has been
assessed using the Pollutant Export Model, Model for Urban Stormwater Improvement
Conceptualisation (MUSIC).
For our model the proposed treatment train has been modelled: -
         1.     Roof water from all units will be collected by a 14kL rainwater re-use tank with an
                overflow to an onsite Bio retention basin, located in the south-western corner of the site.
                The rainwater tank will be re-used for area landscaping irrigation only, to all common
                areas.
         2.     Surface runoff from hardstand and landscaping areas will be collected by numerous catch
                pits and pipes. The internal drainage network will then discharge into the onsite bio
                retention basin for treatment.

The Music Model was set up in accordance with the Water By Design Music Modelling Guidelines for
South East Queensland. Design parameters are listed below:
Bioretention Bed
         •      Surface Area                           =     25m2
         •      Filter Media Area                      =     25m2
         •      Filter Depth                           =     0.5m
         •      Extended Detention                     =     0.25m
         •      Hydraulic Conductivity                 =     180mm/ Hr
         •      TN content of Filter Media             =     500mg/ kg
         •      Orthophosphate content of Filter Media       =        5mg/ kg



SCG Consulting Engineers                     Page 9                                 SCG Ref: 33114(SWMP)