A flood is an inundation or overland flow of water on land not normally submerged. The depth and speed of floodwater flows varies with location and time and can be unpredictable. Canberra is affected by riverine and flash floods. Predominantly in the urban area flash flooding occurs after local heavy rainfall, such as a thunderstorm that generates more runoff into an area than can be drained away in a short period of time. The main risk to people is from fast flowing water that can sweep pedestrians and vehicles away if they enter floodwaters.
The ACT Government advises the community of the dangers associated with stormwater within concrete lined and identified grassed floodways. Floodwaters may rise quickly in these locations and, as such, Roads ACT on behalf of the ACT Government provide floodway advisory signage in locations where the public congregate, such as pedestrian bridges, playing fields, community paths and cycle paths running parallel to or crossing over the floodway.
When floodwaters cover community paths that cross floodways for your personal safety Pedestrians and cyclists should take an alternative route around and over the floodway at a road or pedestrian bridge.
The Transport Canberra and City Services "Design Standards for Urban Infrastructure, 1 Stormwater, Section 126.96.36.199 and 188.8.131.52" provides a broad outline on the usage of these signs including the size and type of material to be used.
Floodway warning signs are placed along formal concrete or identified grassed channels and waterways generally at points of congregation and at intervals of approximately 500 metres, or shorter if there is a line of sight issue between posts.
The floodway advisory symbol is widely used throughout Australia and as such is recognisable without the need to understand the language. The sign shape and the language component changes between each Australian region, thus only the symbol is standard.
These signs are placed to warn the ACT community that it is important to remember that storm water and floodwater can be very dangerous and rise quickly. The signage provides awareness to members of the public to discourage them from playing in stormwater drains and floodways.
Remember "If it's flooded, forget it"