Banana Shire Flood Study

BILOELA 

Historic flooding

Biloela is located between Callide Creek and Kroombit Creek. The majority of Biloela itself is located outside of the floodplain from most flood events. The greatest flooding impacts on Biloela towns originate from Kroombit Creek via Washpool Gully. Due to its location, Biloela can also become isolated as roads become flooded.

Extent of flooding

The below table explains the multiple Annual Exceedance Probability (AEP) flood events analysed as part of the Study. AEP indicates the probability of a flood event occurring each year expressed as a percentage. Flood probability can also be expressed as an Annual Recurrence Interval (ARI).

Annual Exceedance Probability, AEP

Approximate Annual Recurrence Interval, ARI

Impact on Township

10% chance of occurring each year or 10% AEP

Approximately 1 in 10 year event

  • Burnett Highway (north-west and south) and Dawson Highway (west) severed across the Kroombit and Grevillea Creek floodplain

2% chance of occurring each year or 2% AEP

Approximately 1 in 50 year event

  • Breakout flows from Washpool Gully impact some properties fronting Tognolini Baldwin Road
  • Dawson Highway (north) severed

1% chance of occurring each year or 1% AEP

Approximately 1 in 100 year event

  • Large number of properties impacted
  • Similar magnitude to the 2015 flood event

1% AEP event Climate Change (CC) sensitivity simulation or 1% + CC AEP

Approximately 1 in 100 year event - adjusted for climate change sensitivity

  • Identified in image below

 

A Probable Maximum Flood (PMF) event is the largest flood event that could occur at any given location. It is usually an estimated rainfall depth calculated using a range of methods and patterns.

  • Majority of properties located above the PMF event
  • Biloela Civic Centre and evacuation centre remains flood immune for all events up to the PMF

 

Considering the information above, the proposed areas of investigation to protect residents from the impact of flooding are shown below.

Image: Proposed areas of investigation with 1% + CC AEP flood inundation depths shown

 

Potential flood mitigation options

Flood mitigation strategies are aimed at reducing residual risk, improving safety, minimising damage by reducing peak flood levels and depths, improving warning times and reducing flow velocities. This can be achieved through both structural and non-structural measures.

Some non-structural measures already form part of Council’s current Local Disaster Management Plan and Planning Scheme. After the completion of the Floodplain Management Plan, additional measures and updates to Council’s plans and schemes may occur.

As flood inundation in Biloela is primarily governed by breakout flows from Kroombit Creek and Callide Creek, there are multiple structural measures that could be implemented to reduce the flood risk in the proposed areas of investigation. These areas are shown in the image above.

The structural measures identified that may reduce flood risk within the proposed areas of investigation include:

  • Low levees, large levees or a combination of both to provide some level of flood protection to residents
  • Individual property levees
  • Raising of existing stumped houses.

 

Submit your feedback

Community feedback is a vital tool when analysing the viability and acceptance of proposed areas of investigation. To submit your feedback, please fill out the survey by clicking on the link below.

When answering Question 4, please rate your most preferred option as 1, your second most preferred option as 2, your third option as 3, and least preferred option as 4.

Surveys can be downloaded and submitted by email at floodstudies@kbr.com or by mail at Reply Paid GPO BOX 633, Brisbane QLD 4001.

 

Survey for Biloela