Council undertook flood studies across six of its major towns in 2014. Since this time, we have collected an additional 10 years of rainfall and runoff data which can improve our confidence in the estimate of frequent and rare flood events.

Over the past decade, changes have occurred in the guidance for how we estimate rainfall intensity across catchments. In some areas of our region, rainfall intensities have lowered, while others may have increased. This guidance, which was released in 2019, considers a much larger historical database than the previous guidance which was developed in 1987.

There have also been numerous floods and land use changes within the catchment which have the potential to change how water flows. The updated flood studies will use recent 2023 LiDAR (survey) data and current aerial photography to account for these changes.

Council is committed to maintaining and improving our region's flood risk information. Funding for these studies has been 100% provided by the National Flood Mitigation Infrastructure Program (NEMA) and the Queensland Reconstruction Authority (QRA).

Council will continue to liaise with QRA regarding future grant funding opportunity to expand its flood risk knowledge across high risk or populated areas of the region, with the selected locations identified as priority areas.

Flooding causes more damage in Queensland than any other weather event, so effective and strategic flood risk management is important for long-term economic, social and environmental sustainability.

Council is supporting the Queensland Reconstruction Authority (QRA) in their long-term vision for flood risk management in Queensland, helping communities to:

• understand their exposure to flood risk, leading to reduced community impacts of future flood events;
• have access to appropriate, timely and accurate warning of impending flood events; and
• have mitigated any unacceptable risks and have successfully managed the residual risks, now and into the future.

Although Council’s flood studies will not achieve all of the above goals, they are an important foundational step.

This is why the National Emergency Management Agency (NEMA) and QRA are funding the updated flood studies.

Yes! We would love to hear from you if you have any photographs or other evidence past flood events!

This handy information can be used by our consultants to help verify the flood results and make sure the new models match what really happened.

Be sure to include information such as:

• date of the photo (and time of day if available);
• location /direction taken / address; and
• any measurements (e.g. 0.4m high on the post).

Providing your local knowledge, experiences and photos will help us create better informed flood modelling.

A flood happens when water inundates land that is normally dry. Floods can be caused by a number of processes, but the dominant cause in Australia is rainfall.

Floods are a natural process, but the activities of people can affect flooding. Floods occur at irregular intervals and vary in size, area of extent, and duration.

Floods can occur suddenly or slowly.

Sudden, heavy and intense rainfall can cause floods to quickly rise in the minutes or hours that follow. These are known as flash floods and are typically associated with relatively small catchment areas.

Floods can occur slowly in large catchment areas, where rainfall can build up over hours, days or weeks. The runoff from this rainfall may create significant floods that inundate large areas of land for days, weeks or months.

More information explaining the types of floods can be found here: Types of flooding | Emergency services and safety | Queensland Government

Understanding the chance of different sized floods occurring is important for managing flood risk. The chance of a flood event can be described using a variety of terms, but the preferred method is the Annual Exceedance Probability (AEP).

AEP is the likelihood of occurrence of a flood of given size or larger occurring in any one year, and is expressed as a percentage (%). The likelihood is based on how often flooding has happened historically based on modelled data, and includes the size of the flood and how often a similar sized flood is possible.

A flood with a 1% AEP has a one in a hundred chance of being exceeded in any year. Currently, the 1% AEP event is designated as having an 'acceptable' risk for planning purposes nearly everywhere in Australia. However, good planning needs to consider more than just the 1% AEP flood.

We don’t refer to floods as One-in-100-Year flood anymore as its misleading and can be mistaken for a flood which will only occur once in 100 years.

A One-in-100-Year flood is the same as 1/100 = 0.01 OR 1%. Therefore, there is a 1% chance that a flood of that size will occur, or be exceeded in any year. Also, it means that a 1% AEP flood could occur, even if a 1% AEP flood occurred in the year prior.

Floods bigger than those we have experienced are inevitable. We have less than 200 years of formal flood records in Australia.

While there may be no living memory or formal record of your property flooding it does not mean that the land has not flooded in past centuries or that it won’t flood in coming years.

Floods across Queensland in 2011, 2013, 2017, 2022 and 2025 have all inundated properties which had never flooded before.

Just because we haven’t seen it, doesn’t mean it can’t happen.

Hills are not always free of floods. This can happen in two ways:

1. Creeks and rivers can rise several metres when they flood which means that land, we think would be high and dry can end up being well under water; or

2. When water is running down the hill to the creek or river it will find the easiest path to follow. Sometimes during a severe storm, the normal drainage paths cannot handle all the water and the water will find its own path which could even be through properties on hills.

Even if your property is not flooded, you may be isolated by floodwaters and you may not be able to leave or enter your property safely until floodwaters have subsided.

The studies being carried out may or may not change the current flood extents! This will only be determined through careful modelling of the current catchment conditions and rainfall intensity data.

The general insurance industry has developed and licensed the National Flood Information Database (NFID) for use by insurers in determining the flood risk to individual properties.

NFID is an address database containing 13.7 million property addresses, overlayed with the known flood risk according to government flood mapping. Commercial licensing arrangements between many governments and the specialist flood risk experts who prepare the flood maps means it is not a public database.

Most insurers use NFID to determine the flood risk to individual properties, and calculate the premium based on this risk and other criteria including building type, location and claims history.

However, it is up to individual insurers to decide what criteria they use to determine flood risk. They may examine information from many sources to identify properties that are prone to flooding. These may include local government flood mapping, historical flood information, terrain data and insurance claims information.

Insurers assess how often a property is expected to flood, how severe the flooding may be, and how deep the flood can get.

For more information visit: Flood insurance explained - Insurance Council of Australia