RFI - Attachment 7 - Updated SWMP

2. Hydrologic Analysis
In accordance with the Queensland Urban Drainage Manual 2017, peak stormwater flows are calculated
based on impervious fractions. As shown in Table 2-1 the impervious fraction between the existing and
proposed (renovated) areas does not significantly change. This indicates that there will not be any
significant changes to peak flows, and as such, detention is not required.

Table 2-1: Catchment %Impervious fractions
Existing Surface-     Existing (m2)     %Impervious   Proposed (Split)   %Impervious       Proposed (m2)
       Split
                                                       Arts Centre          100               1,219
        A             2591.336            90
                                                         Ground              90                1,372
        B              944.35             60             Ground              60               944.35
        C              3524.78            90             Ground              90              3524.78
   Total (m2)         7060.466                                                              7060.466




21-0211SMP01V1 | Stormwater Management Plan | Good Shepherd Lutheran College Arts Centre         Page 7