FAQs

Flood risk information helps us understand the likelihood and potential impact of flooding in certain areas. It is based on studies that look at different flood events and use scientific tools to predict where and how much water may flow during a flood.

Flood risk information helps everyone from government planners to homeowners make informed decisions about preparing for, responding to, and recovering from floods.

Flood risk information includes:

Flood studies
Detailed investigations that use models and data to map out how floodwaters move across the landscape, how deep they might get, and how fast they could flow. These studies help predict what could happen during floods of various sizes.

Flood maps
Visual tools that show how far floodwaters might reach, how deep they could be, and what areas are at greater risk. These maps are based on flood studies and can show different scenarios, from smaller, more frequent floods to large, rare events.

• Flood inundation mapping (Riverine and Stormwater): Includes flood scenarios for different likelihoods (% Annual Exceedance Probability) based on current and future conditions. 
• Flood inundation mapping for River Murray: Visualisations of potential flooding for specific flow rates, such as X ML/day. 
• Coastal flood mapping: Flooding scenarios related to storm surges and sea level rise based on current and future conditions. 
• Historical flood mapping: Maps showing areas affected by past flood events, such as significant River Murray floods. 

Annual Exceedance Probability (AEP) is a term used to the express the percentage of likelihood of a flood of a given size or larger occurring within the period of one year. If a flood has an AEP of 1%, it has a one in 100 likelihood of occurring in any given year.

The risk of flood at any given location is dynamic and will vary from a number of factors including, but not limited to: type of flooding, intensity, frequency and duration of rainfall experienced, time of flooding, weather factors including catchment soil moisture content, new building development and changes to or unforeseen factors associated with water management infrastructure. Due to this, while the information presented attempts to represent what may be experienced during a flood, actual flood events may differ substantially.

1. The WaterConnect portal - Flood Awareness information, reports and map.

The Flood Awareness map allows you to check (where data is available) the likelihood of floods at your location, search for flood risks in your area, and obtain more information about flood risks in your area.

Further information can be obtained by:

• talking to neighbours and your local council about past flood events
• contacting the South Australian State Emergency Service (SES)
• requesting historical flood records from the Bureau of Meteorology
• going to your local council website.

To work out your flood risk, find out how often you might experience flooding (likelihood), how bad the flood might be (consequences), and your personal circumstances (level of exposure and vulnerability).

Once you understand your risk, get prepared by following the guide on the SA State Emergency Service Flood website.

2. The Coastal Flood Mapping Viewer identifies areas that may be vulnerable to coastal flooding. 

The absence of maps in an area of South Australia does not mean there is no flood risk. It may be that no maps are available at the location, or that the location is not affected by the scenario displayed.

Currently, viewing flood information can be difficult and time consuming. DEW is developing a new or improved online resource to make it easier to view flood risk information. The project will deliver an easy to use, modern online resource for South Australia.

No. The current website and new or improved solution will not depict real-time information about a flood. In the event of a flood, please refer to the Bureau of Meteorology, the State Emergency Service and Alert SA websites for emergency information.

South Australians are encouraged to complete the survey. Flood risk information may be useful to:

• People living in a flood-prone area or at risk of flood 
• Business owner with premises in a flood-prone area or at risk of flood 
• Prospective property buyer 
• Property developer 
• Irrigator 
• Farmer 
• Interested member of the public 
• Interest in the environment 
• Interest in climate change 
• Researcher 
• Insurance industry 
• Tourism industry or operator 
• Emergency services 
• Local, state or federal government official 
• Community group representative 

A flood study is a comprehensive technical investigation of flood behaviour. It defines the nature of flood hazard across the floodplain by providing information on the extent, level and velocity of floodwaters, and on the distribution of flood flows. The flood study forms the basis for subsequent management studies and needs to take into account a full range of flood events up to and including the probable maximum flood. 

A flood map is the result of a flood study and shows flood inundation (depth, velocity, and hazard) for various scenarios.  A numerical hydraulic model will be used to get these flood inundation maps. Inputs from the hydrology model (design flow hydrographs), understanding the available topographic data, model parameters (e.g. roughness) and how the catchment and floodplain may have changed over time and historical flood data (particularly for calibration and verification) are required to perform this hydraulic model.