Table 2.1
Vulnerability Thresholds Classification Limits of Flood Hazard Curves [9]
Hazard vulnerability classification
Depth velocity product (DV) (m 2 /s)
Limiting still water depth (m)
Limiting velocity (m/s)
Description of hazard classification
Generally safe for vehicles, people and buildings.
H1
≤ 0.3
0.3
2.0
H2
Unsafe for small vehicles.
≤ 0.6
0.5
2.0
Unsafe for vehicles, children and the elderly.
H3
≤ 0.6
1.2
2.0
H4
Unsafe for vehicles and people.
≤ 1.0
2.0
2.0
Unsafe for vehicles and people. All buildings vulnerable to structural damage. Some less robust buildings subject to failure.
H5
≤ 4.0
4.0
4.0
Unsafe for vehicles and people. All building types considered vulnerable to failure.
H6
> 4.0
-
-
2.6
Downstream modelling extents
According to ANCOLD [2], the extents of a dam break model could be terminated when it is possible to demonstrate the following:
— The flood event is contained within the bed and banks of the stream at the extremities of the model.
— The Consequence Category is unlikely to change with any extension of the model.
Dam break effects are negligible.
—
— Travel time is long enough to allow reliable emergency procedures to be activated and enforced (at least 12 hours).
Project No PS213278 Upper Mundic Gully TSF Stage 1 and 2 DBA and CCA Mount Morgan Gold Mine Heritage Minerals
WSP JUly 2025 Page 8
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