Attachment 4a - Engineering Report Part 1 · MCU18/0015

The pollutant load concentrations for each source catchment have been taken from Table
3.8 of the Water By Design’s – MUSIC Modelling Guidelines, Version 1.0 2010, using the
concentrations recommended for residential sites.


The source node catchment areas have been directly measured from development plans
in accordance with Water By Design’s – MUSIC Modelling Guidelines, Version 1.0 2010.


Refer to 7.3.1c below for details of the catchment areas used for water quality modelling.
Note, the site contains significant areas of undeveloped land and dedicated parkland. Only
those areas of the site subject to development works have been included in water quality
modelling.


                      Table 7.3-1c: Catchment Details
              Residential Catchment    Area (Ha)    Land Use      Imp (%)
              Roof 1                    0.210         Roof          100
              Driveway 1                0.146         Road          100
              Balance 1                 0.144        Balance         50
              Roof 2                    0.020         Roof          100
              Roof 3                    0.020         Roof          100




The model was run with average rainfall recorded at the Cooroy Composite Rainfall
Station 40496, between the years 1973-1983 and using a 6 minute time step. The mean
annual rainfall for this period was 1595mm with evapo-transpiration of 1630mm. Rainfall
data is in accordance with Water By Design’s – MUSIC Modelling Guidelines, Version 1.0
2010. Refer to the attached MUSIC model in Appendix F for details of the proposed
treatment train.




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