Photo 6: Raw Square Rail Underpass

and a 0.9 m rise by the year 2100.

9.3. Results

The sensitivity scenario results were compared to the 1% AEP rainfall event and a summary of peak flood level and peak flow differences at various locations are provided in the sections below.

9.3.1. Roughness Variations

Overall peak flood level results were shown to be relatively insensitive to variations in the roughness parameter. Generally, these results were found to be within ± 0.1 m.

Table 27: Results of Roughness Variation – Change in Peak Depth (m)

ID Location

H01 Pedestrian Bridge 2

Peak Flood Depth 5% AEP Difference with 5% AEP (m)

Decrease roughness by 25% Increase roughness by 25%

Peak Flood Depth 1% AEP Difference with 1% AEP (m)

Decrease roughness by 25%

Increase roughness by 25%

0.63 -0.01 0.00 0.71 -0.02 0.01 H02 Pedestrian Bridge 1 1.04 -0.02 0.01 1.11 -0.02 0.01 H03 Front of community Centre 0.20 0.00 0.00 0.22 0.00 0.00 H04 Railway underpass 2 East side 0.12 -0.01 0.01 0.16 -0.01 0.01 H05 Railway underpass east side 0.47 0.00 -0.01 0.68 0.02 -0.02 H06 Railway underpass west Side 0.57 -0.01 0.01 0.72 -0.01 0.01 H07 7 Concord Avenue low point 0.44 0.00 0.00 0.55 0.00 0.00 H08 George Street low point near soccer field 0.81 0.12 -0.01 1.08 0.08 0.03 H09 Powells Creek @ Argonne Street 0.19 0.00 -0.01 0.35 0.00 -0.01 H10 Powells Creek @ Pomeroy Bridge 0.20 0.00 0.00 0.29 -0.02 0.01 H11 Powells Creek @ Allen Street 1.92 0.00 -0.01 2.09 0.00 0.00 H12 Powells Creek @ Brussels Street 0.40 0.00 -0.01 0.56 0.00 0.00 H13 Powells Creek @ Warsaw Street 0.75 0.00 -0.01 0.92 -0.01 0.00

9.3.2. Blockage Variations

Peak flood level results were found to be relatively insensitive to blockage of pipes; although generally peak flood levels increased in the upstream areas and decreased in the downstream areas (due to the retarding effect in the upstream areas).