BsmFinal_1

The consequent affluxes downstream of the site are summarised in Table 3, below. The affluxes are zero,
apart from +/- 0.01 on the 20 year and 2 year flood levels at the upstream side of Church Street.

Table 3: Impacts On Flood Levels Downstream Of Site, For Existing Climate Regime
 ARI      U/S Side Church St, N62   Midway Church/Rectory, N65        U/S Side Rectory St, N67
 (yrs)    Exg       Dev     Afflux   Exg     Dev       Afflux          Exg      Dev      Afflux
  100    91.16     91.16      0.00  89.88   89.88       0.00          89.82    89.82        0.00
   50    91.12     91.12      0.00  89.82   89.82       0.00          89.77    89.77        0.00
   20    91.05     91.06      0.01  89.75   89.75       0.00          89.71    89.71        0.00
   10    90.95     90.95      0.00  89.67   89.67       0.00          89.64    89.64        0.00
   5     90.75     90.75      0.00  89.64   89.64       0.00          89.62    89.62        0.00
   2     90.40     90.39     -0.01  89.58   89.58       0.00          89.56    89.56        0.00
   1     90.06     90.06      0.00  89.37   89.37       0.00          89.35    89.35        0.00


3.3     100 Year Flood Levels With And Without Climate Change

The 100 year flood levels on the existing and developed site, with and without climate change (15%
increase in rainfall intensities), are summarised in Table 4, below:

Table 4: 100 Year Flood Levels With And Without Climate Change
 Node Existing                       Developed
                Without Climate Change       With Climate Change
 N44 91.28               91.28                      91.35
 N45 91.24               91.24                       91.31
 N46 91.19               91.20                       91.26
 N47 91.17               91.17                       91.22
 N48 91.17               91.18                       91.23
 N49 91.16               91.18                       91.23
 N50 91.16               91.17                       91.22
 N51 91.16               91.17                       91.22
 N52 91.16               91.16                       91.21
 N53 91.16               91.16                       91.21
 N54 91.16               91.16                       91.21
 N58 92.65               92.65                       92.69
 N59 91.83               91.83                       91.84
 N60 91.31               91.38                       91.54
 N61 91.16               91.16                       91.21
 N62 91.16               91.16                       91.21


3.4     100 Year Flood Boundaries

The 100 year flood boundaries on the existing and developed site are marked on Figure 5 on page 13 of
this report. Since the balance lot (Lot 4) is regarded as a temporary entity which will almost certainly be
subdivided further in the next few years, and may have a different driveway configuration, with any
required adjustments to flood modelling completed at that time, the 100 year flood boundary marked in
the area upstream of the driveway on Lot 4 in this report is therefore appropriate to a short-term scenario
– i.e. without climate change. All other areas of the marked 100 year flood boundaries are applicable to a
longer-term scenario – i.e. with climate change.


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      Brisbane Stormwater Management Pty Ltd Document File: ChurchSt.Doc