Engineering Hydrology Plans (IWMP)

The fraction impervious value applied for each of the source nodes are detailed
below in Table 5.
Table 5: Impervious Percentage

                 Impervious Percentage          Roof          Road
                           %                   100%            90%

2.3.2 Catchment Areas
The development site has been split into four (4) sub-catchments. Two catchments
represent the tavern site which drains to two outlets. The other two catchments
represent the new road area which also drains to two different outlets (drainage
reserve and Lanyana Way). Catchment A and C have buildings whose roofed areas
are modeled roof. The rest of each catchment is modeled as road. Table 6 outlines
the catchment areas represented within the MUSIC model. The stormwater quality
catchments are provided in Figure 5.
Table 6: Catchment Areas

  Catchment        Area           Roof          Road           Total
      A             1.11          0.36           0.75           1.11
      B             0.65          0.03           0.62           0.65
      C             0.46          0.30           0.16           0.46
      D             0.31          0.04           0.27           0.31
    TOTAL           2.52          0.74          1.792           2.52

2.3.3 MUSIC Model Layout
As the management of urban stormwater needs to take a holistic approach, a
number of management measures need to be implemented in series to form a
treatment train. The correct utilisation of various devices within the treatment train
is imperative to target the desired pollutants, from the gross solids to the fine
colloidal partials. Figure 4 shows the MUSIC model layout for the development.




Figure 4: Model Layout



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