Flood Information for New Building Work

Building in a flood hazard area requires compliance with building regulations to ensure new dwellings are built with consideration for the impacts of flooding.

As of the 1 January 2024, council updated its flood data to reflect improved terrain detail, effects of sub-catchments, and provide greater understanding of the impact of underground drainage networks and flow obstructions such as culverts and bridges. This has resulted in better information for the following catchments:

  • Mary River
  • Amamoor Creek
  • Widgee Creek
  • Nangur Creek (at Goomeri only
  • Yabba Creek
  • Eel Creek
  • Wide Bay Creek
  • Cooloola Cove
  • Kandanga Creek
  • Tinana Creek
  • Curra Creek
  • Tin Can Bay

What are the new changes?

With the new data, council has updated its flood mapping to declare a flood hazard area for building assessment purposes.

New standard - The new mapping has been updated from the 1-in-100 year model to include an allowance for the impacts of climate change in line with the State Planning Policy (SPP). This new modelling is called 'Future Climate 1% AEP' and is the new defined flood event (DFE).

This new defined flood event model provides data to help predict the impacts of future flooding on new buildings. New dwellings in the Gympie Region are to be built to a minimum finished floor level in the flood hazard areas. 

What is a minimum finished floor level (FFL)?

Finished floor level is the required height of the habitable floors for the proposed new dwelling.

For the Cooloola Coast region this level is based on existing storm tide data and is set for each specific location (Tin Can Bay, Cooloola Cove, Rainbow Beach).

However, for the rest of the region, the information provided on council’s online mapping will provide the defined flood level based on the Mary River and surrounding catchments. The finished floor level will need to be calculated by adding freeboard of 300mm to the defined flood level.

Finished Floor Level = Defined Flood Level + 300mm freeboard

This level will apply to building work for new habitable buildings (and in some cases major renovation work to existing habitable buildings) and limited commercial applications in accordance with Queensland Development Code MP3.5 requirements.

How do I check if my property is impacted by the updated flooding requirements?

Council’s town planning public mapping system has been updated with two new layers. You can enable these layers by selecting 'Building Regulations 2021 Flood Resolutions' under the layers tab on the left side of the screen.

  • New defined flood event
  • Habitable floor level (Cooloola Coast only)

From here, you can determine whether your property is impacted by the defined flood event 

How will this impact me/my client?

All new dwelling applications that are within the Future Climate 1% AEP are required to meet minimum finished floor levels as mentioned above. Existing approved dwellings are not subject to the new building requirements. Major renovation work to existing habitable buildings and limited commercial applications may also be subject to Queensland Development Code MP3.5 requirements.

Are there circumstances where council might permit a new dwelling to be built below the adopted DFL?

The DFL has been adopted for each individual lot using the highest future climate 1% AEP flood level calculated within that lot. For larger lots (especially in the Rural zone), there may be legitimate differences in flood levels across the lot. Where a proposed dwelling is to be located below the nominated DFL, customers are encouraged to contact council’s Building Section in the first instance – building@gympie.qld.gov.au

Industry Resources

Council hosted industry relevant presentations to discuss the changes to Flood Hazard Areas for new building work, to view the presentation watch below video.

FAQ

  • The updated model will impact more properties in comparison to the existing 2012 flood data due to both an increase in available flood modelling across catchments that were previously unstudied and the requirement to consider the likely impacts of the future climate scenario. Existing habitable buildings will not be affected by the update.

    The update will primarily apply to building work for new habitable buildings (and in some cases major renovation work to existing habitable buildings) and limited commercial applications in accordance with Queensland Development Code MP3.5 requirements.

    The resolution by Council ensures new habitable building works are undertaken with consideration for the possible impacts of flooding in a future climate, increasing the region’s resilience to future flood events.

  • Many Insurance companies rely on the National Flood Information Database. The database is made up of local and state government information as well as external data that determines each individual property’s flood risk based on building type, location, claims history and the characteristics of flooding (frequency and how severe the flooding may be).

    As individual insurance companies address this risk differently, it is best to speak directly with your relevant insurance provider.

  • Flooding is one of many factors which can affect the value of a property, however council is unable to advise how flood mapping may directly impact individual property values. Updated public flood mapping and information is provided so residents, professionals and local government can prepare for and manage the possible impacts of flooding in a future climate, increasing the region’s resilience to future flood events.

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