the nature of flooding
While numerous climatic and topographic factors determine the likelihood and severity of a flood event, it is important to be aware of the four main types of floods:
Creek flooding (rapid-onset floods)
The result of intense localised rainfall, creek flooding occurs in hill and mountain regions when the capacity of a creek is exceeded.
Often occurring with little warning time, creek flooding can pose a significant risk to life and property, with much less time for preventative action and faster flow of water.
Possible effects include damage to infrastructure, property, short-term road closures, service disruption, erosion, property isolation and evacuation.
River flooding (slow-onset floods)
Flooding of river systems generally results from widespread and prolonged rainfall over the river's catchment area.
Affecting coastal and inland plains, floods may last a couple of days to several weeks, representing a major impact on life and property.
Possible effects include damage to infrastructure, property, longer-term road closures, service disruption, property isolation and evacuation.
storm surge
Usually associated with tropical storms and cyclones, storm surges involve rapid seawater flooding resulting from a combination of high tides and heavy seas.
While inundation of seawater alone poses a threat to the coastline and low-lying inland areas, storm surges often coincide with periods of intense and prolonged rainfall. Consequently storm surges threaten to impact on already swollen river systems and can increase the severity and extent of inland river and creek floods.
LOCALised FLOODING
Localised flooding occurs when parts of the storm water drainage system (such as pipes, gully traps and minor culverts) are blocked or capacity is exceeded.
Possible effects include water damage to property, fittings and furniture, pooling of water in backyards, surface depressions, and outdoor areas.
Liability for damages may apply if the building or filling on a property increases or worsens flooding to a neighbouring property.
tsunamis
An extremely rare event, a tsunami results from under-sea events such as earthquakes, landslides or volcanic eruptions. While unrelated to normal flood conditions, it is important to be familiar with warning signs and know what to do in the unlikely event of a tsunami.
Warning signs may include:
- earth tremor
- dramatically receding shoreline
- official emergency warnings, sirens and broadcasts
If you notice any of the above warnings it is important to evacuate coastal areas immediately and move to higher ground until you receive the 'all clear' from authorities. For more information contact Geoscience Australia.
