RFI - stormwater report

3.1.4 Regional Existing Scenario
Sub-catchment fraction impervious values have been calculated based on aerial imagery
data and consistent to with existing rural residential land-use. The existing scenario sub-
catchment areas and fraction impervious values for each sub-catchment are tabulated
below in Table 3-6. The existing catchment plan is shown below in Figure 3-3.
Table 3-6: WBNM Sub-Catchment Fraction Impervious Values – Regional Existing Scenario

                                                                  Existing Scenario
     WBNM Sub-Catchment                 Area (ha)
                                                                   Impervious (%)
               A1                         4.371                           0
               A2                         4.694                          5
               A3                         4.298                          5
               B1                         3.499                          0
               B2                         4.991                          1
               C1                         11.805                         15
             TOTAL                        33.658                          -




Figure 3-3: Existing WBNM Regional Catchment Plan

3.1.5 Regional Rational Method Validation (C1 Outlet)
The WBNM model has been validated to the Rational Method derived peak flows at the
outlet of the catchment (WBNM catchment node ‘Outlet’). Validation has been achieved
by the catchment lag parameter.



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