REPS - Updated SWMP

Figure 2.3: Excerpt of the Catchment Plan from Design Drawing (catchment 1/3)

TABLE 4.8: WBNM SUB-CATCHMENT FRACTION IMPERVIOUS VALUES – DEVELOPED SCENARIO

    WBNM Sub-Catchment                  Area (ha)                          Design Impervious (%)             Proposed Impervious (%)

    Townhouse                           0.506                              50                                90

    Balance                             0.181                              50                                50

    Total                               0.687                              -                                 -


     4.2.1        Results
The aim of this assessment is to size a detention tank within the townhouse site to ensure peak flows in the 10% AEP are reduced to be below
the TOD 10% AEP pipe capacity, from which the drainage network was designed (that is going from 50% to 90% impervious). The drainage
design flows reporting from Catchment 1/3 are 0.24m3/s in the 10% AEP, which align with estimates from the WBNM model (0.26m3/s).

A summary of the storage size and outlet configuration and key details provided below:

•     Detention Tank Summary:

      –     Size = 50m3

      –     Outlet 1 = 2 x 225mm at RL0.0m.

      –     Outlet 2 = 3m weir at RL1.30 (this allows for surcharge of the tank back to the driveway in events larger than the 1% AEP).

      –     Flow Depth in 10% AEP = RL1.0m




73 EUMUNDI - NOOSA ROAD, NOOSAVILLE I BBNE00529_0002_0001-REP-001-2                                                                       17