Public Consultation

Why did I receive this letter?

This letter was sent to land owners of sites which are:

• already located in the flood hazard area as identified by the Flood Hazard Overlay in the Planning Scheme; and/or 
• located outside of the flood hazard area and are only located in an area with potential to be impacted by a larger flood event (probable maximum flood area).

Council’s analysis of these site’s identifies that the flood studies are unlikely to change your development rights, however it is encouraged that you still review the flood study and mapping to understand the impacts that flooding may have on your property.

What is a Probable Maximum Flood (PMF) area?

The PMF is the worst case scenario for flooding that shows the maximum extent of the flood plain. The PMF is a theoretical flood resulting from the largest rainfall that could possibly occur within the catchment and therefore is extremely rare and unlikely. It is also used to determine which areas are potentially flood prone (in the floodplain) and which areas are flood free (only land outside the PMF extent is truly ‘flood free’). 

What is a defined flood hazard area?

The Building Act 1975 and the Building Regulations 2021 requires council to declare a flood hazard area for building regulation purposes (i.e. determining minimum floor levels).

Historically, the planning scheme’s flood hazard overlay map has been used for the purpose of determining the flood hazard area. To this regard, if you are currently undertaking development over a site in the flood hazard area (as identified by the Flood Hazard overlay in the Planning Scheme), you are required to undertake an independent flood study to determine the minimum habitable flood level for your development.

Following adoption of the draft flood studies, Council will adopt their modelled 1% AEP flood events (with an allowance for climate change), as the defined flood hazard areas. This will mean that new development located in these defined flood hazard areas will need to meet minimum building levels based off the defined flood levels of the flood studies and the building regulation requirements of the Queensland Development Code.

If your development is not located within a defined flood hazard area, you are not required to meet these requirements, however it is still recommended that you familarise yourself with the impacts of flood on surrounding properties for the purpose of evacuation planning and disaster preparedness.

What is a 1% AEP flood event?

A 1% AEP flood event (commonly known as Q100) is a flood event that has on average, a 1 in 100 chance (1% probability) of being equaled or exceeded in any given year. The 1% AEP flood or the Q100, (the terms are interchangeable), is sometimes called the '100 year flood'

A common misunderstanding is that a 100-year flood is likely to occur only once in a 100-year period. This does not imply that 100 years elapses between such floods. While this is true in terms of long-term averages (over several thousand years), it is not true in terms of the immediate future. Thus, it is possible (but unlikely) for '100 year floods' to occur in consecutive years or within relatively short periods. Certainly, there is no guarantee that a 100 year period will elapse between such floods. Even if the 1% AEP floods occurred last year, there is a 1% chance that this flood will occur this year - and in each and every future year.

The 1% AEP flood events are what are commonly used for establishing minimum floor levels for building and development purposes in accordance with the Planning Act 2016.

 What is the flood hazard overlay in the Planning Scheme?

The flood hazard overlay forms part of the current Isaac Regional Planning Scheme and defines the extent of Council’s existing flood hazard area. If you are currently proposing development over a site contained within the flood hazard overlay, you are required to undertake an independent flood study to determine the minimum habitable floor level for your development. Once adopted by Council, the flood studies will be utilized for determining flood levels and minimum floor levels and will remove the need for the development of site-specific flood studies by the developer.

How does this all impact me?

From a regulatory perspective, the flood studies will have no impact on you unless you are proposing to develop and/or build in a flood hazard area (1% AEP flood event (with an allowance for climate change).

The flood studies do no effect exiting use rights and do not remove the ability for you to rebuild an existing lawful use should it be required (i.e. rebuilding after a natural disaster or house fire). 

If you proposing to build on your site and are located within a defined flood hazard area(1% AEP flood event (with an allowance for climate change), you will be required to build to a minimum floor level in accordance with Section MP 3.5 – Construction of buildings in flood hazard areas of the Queensland Development Code (include hyperlink - MP 3.5 – Construction of buildings in flood hazard areas (epw.qld.gov.au) existing assessment provisions of the Isaac Regional Planning Scheme.

If you are looking at building in the defined flood hazard area (1% AEP flood event (with an allowance for climate change), please discuss with Council and/or contact a Private Building Certifier.

How can I tell if my property is impacted by flood events?

1. Open Council’s interactive flood mapping program
2. Click on 'Lotplan Search’ or ‘Address Search’ on the ribbon towards the bottom of the page and type your relevant property details
3. Select the relevant flood studies from the Layers section on the left hand side of the page.
4. Select the desired flood modelling events available for your property on the left hand side of the page.

Note: Council’s interactive online mapping also allows you to view the properties which are impacted by the existing Flood hazard overlay code in the Isaac Regional Planning Scheme. To do this select the ‘Flood Hazard Overlay’ from the Layers section on the left hand side of the page.  

Why did I receive this letter?

This letter was sent to land owners of sites which are:

• located in the proposed flood hazard area; and

• are not currently located in the flood hazard area as identified by the Flood Hazard Overlay in the Planning Scheme.

Land owners of these sites have been notified as the flood studies may impact the future building requirements for development proposed within a flood hazard area.

Land owners are encouraged to view the Interactive Online Mapping to understand the location of proposed flood hazard area in the context of their site.

What is a defined flood hazard area?

The Building Act 1975 and the Building Regulations 2021 requires council to declare a flood hazard area for building regulation purposes (i.e. determining minimum floor levels).

Historically, the planning scheme’s flood hazard overlay map has been used for the purpose of determining the flood hazard area. To this regard, if you are currently undertaking development over a site in the flood hazard area (as identified by the Flood Hazard overlay in the Planning Scheme), you are required to undertake an independent flood study to determine the minimum habitable flood level for your development.

Following adoption of the draft flood studies, Council will adopt their modelled 1% AEP flood events (with an allowance for climate change), as the defined flood hazard areas. This will mean that new development located in these defined flood hazard areas will need to meet minimum building levels based off the defined flood levels of the flood studies and the building regulation requirements of the Queensland Development Code.

What is a 1% AEP flood event?

A 1% AEP flood event (commonly known as Q100) is a flood event that has on average, a 1 in 100 chance (1% probability) of being equaled or exceeded in any given year. The 1% AEP flood or the Q100, (the terms are interchangeable), is sometimes called the '100 year flood'

A common misunderstanding is that a 100-year flood is likely to occur only once in a 100-year period. This does not imply that 100 years elapses between such floods. While this is true in terms of long-term averages (over several thousand years), it is not true in terms of the immediate future. Thus, it is possible (but unlikely) for '100 year floods' to occur in consecutive years or within relatively short periods. Certainly, there is no guarantee that a 100 year period will elapse between such floods. Even if the 1% AEP floods occurred last year, there is a 1% chance that this flood will occur this year - and in each and every future year.

The 1% AEP flood events are what are commonly used for establishing minimum floor levels for building and development purposes in accordance with the Planning Act 2016.

What is a Probable Maximum Flood (PMF) area?

The PMF is the worst case scenario for flooding that shows the maximum  extent of the flood plain. The PMF is a theoretical flood resulting from the largest rainfall that could possibly occur within the catchment and therefore is extremely rare and unlikely. It is also used to determine which areas are potentially flood prone (in the floodplain) and which areas are flood free (only land outside the PMF extent is truly ‘flood free’).

 What is the flood hazard overlay in the Planning Scheme?

The flood hazard overlay forms part of the current Isaac Regional Planning Scheme and defines the extent of Council’s existing flood hazard area. If you are currently proposing development over a site contained within the flood hazard overlay, you are required to undertake an independent flood study to determine the minimum habitable floor level for your development. Once adopted by Council, the flood studies will be utilized for determining flood levels and minimum floor levels and will remove the need for the development of site-specific flood studies by the developer.

Why am I impacted by these flood studies when I wasn’t previously located within the flood hazard area?

Flood studies identify land which may be impacted in various flood events. The 1% AEP, annual exceedance probability event is commonly used for planning purposes.

Rain events are highly variable and do not occur in a regular pattern. Just because you have not personally experienced flooding at your home before does not mean that it is not at risk. Consider that every flood is different and how the flood behaves will depend on a very large number of variables which are considered as far as possible when floods are modelled. The probability (or chance) of flooding hasn’t changed because of this study, and your property is no more flood affected than it was previously. 

How does this all impact me?

From a regulatory perspective, the flood studies will have no impact on you unless you are proposing to develop and/or build in a flood hazard area (1% AEP flood event (with an allowance for climate change).

The flood studies do no effect exiting use rights and do not remove the ability for you to rebuild an existing lawful use should it be required (i.e. rebuilding after a natural disaster or house fire). 

If you are proposing to build on your site and are located within a defined flood hazard area (1% AEP flood event (with an allowance for climate change), you will be required to build to a minimum floor level in accordance with Section MP 3.5 – Construction of buildings in flood hazard areas of the Queensland Development Code (include hyperlink - MP 3.5 – Construction of buildings in flood hazard areas (epw.qld.gov.au) and the existing assessment provisions of the Isaac Regional Planning Scheme.

You may have received a letter because a small portion of a site is mapped in a flood hazard area. To this regard, the flood building requirements only apply to the area of land impacted by the flood hazard area.

If you are looking at building in the defined flood hazard area (1% AEP flood event (with an allowance for climate change), please discuss with Council and/or contact a Private Building Certifier.

How can I tell if my property is impacted by flood events?

1. Open Council’s interactive flood mapping program
2. Click on 'Lotplan Search’ or ‘Address Search’ on the ribbon towards the bottom of the page and type your relevant property details
3. Select the relevant flood studies from the Layers section on the left hand side of the page.
4. Select the desired flood modelling events available for your property on the left hand side of the page.

Note: Council’s interactive online mapping also allows you to view the properties which are impacted by the existing Flood hazard overlay code in the Isaac Regional Planning Scheme. To do this select the ‘Flood Hazard Overlay’ from the Layers section on the left hand side of the page.  

Why did I receive this letter:

This letter was sent to land owners of property/ies which are located in the proposed flood hazard area as defined in the Moranbah Flood Model and Hazard Mapping Study (1% AEP with allowance for climate change flood event).

Land owners are encouraged to view the Interactive Online Mapping to understand the location of proposed flood hazard area in the context of their site.

What is a defined flood hazard area?

The Building Act 1975 and the Building Regulations 2021 requires council to declare a flood hazard area for building regulation purposes (i.e. determining minimum floor levels).

Historically, the planning scheme’s flood hazard overlay map has been used for the purpose of determining the flood hazard area. To this regard, if you are currently undertaking development over a site in the flood hazard area (as identified by the Flood Hazard overlay in the Planning Scheme), you are required to undertake an independent flood study to determine the minimum habitable flood level for your development.

Following adoption of the draft flood studies, Council will adopt their modelled 1% AEP flood events (with an allowance for climate change), as the defined flood hazard areas. This will mean that new development located in these defined flood hazard areas will need to meet minimum building levels based off the defined flood levels of the flood studies and the building regulation requirements of the Queensland Development Code.

What is a 1% AEP flood event?

A 1% AEP flood event (commonly known as Q100) is a flood event that has on average, a 1 in 100 chance (1% probability) of being equaled or exceeded in any given year. The 1% AEP flood or the Q100, (the terms are interchangeable), is sometimes called the '100 year flood'

A common misunderstanding is that a 100-year flood is likely to occur only once in a 100-year period. This does not imply that 100 years elapses between such floods. While this is true in terms of long-term averages (over several thousand years), it is not true in terms of the immediate future. Thus, it is possible (but unlikely) for '100 year floods' to occur in consecutive years or within relatively short periods. Certainly, there is no guarantee that a 100 year period will elapse between such floods. Even if the 1% AEP floods occurred last year, there is a 1% chance that this flood will occur this year - and in each and every future year.

The 1% AEP flood events are what are commonly used for establishing minimum floor levels for building and development purposes in accordance with the Planning Act 2016.

 What is the flood hazard overlay in the Planning Scheme?

The flood hazard overlay forms part of the current Isaac Regional Planning Scheme and defines the extent of Council’s existing flood hazard area. If you are currently proposing development over a site contained within the flood hazard overlay, you are required to undertake an independent flood study to determine the minimum habitable floor level for your development. Once adopted by Council, the flood studies will be utilized for determining flood levels and minimum floor levels and will remove the need for the development of site-specific flood studies by the developer.

How does this all impact me?

From a regulatory perspective, the flood studies will have no impact on you unless you are proposing to develop and/or build in a flood hazard area (1% AEP flood event (with an allowance for climate change).

The flood studies do no effect exiting use rights and do not remove the ability for you to rebuild an existing lawful use should it be required (i.e. rebuilding after a natural disaster or house fire). 

If you are proposing to build on your site and are located within a defined flood hazard area (1% AEP flood event (with an allowance for climate change), you will be required to build to a minimum floor level in accordance with Section MP 3.5 – Construction of buildings in flood hazard areas of the Queensland Development Code (include hyperlink - MP 3.5 – Construction of buildings in flood hazard areas (epw.qld.gov.au) and the existing assessment provisions of the Isaac Regional Planning Scheme.

You may have received a letter because a small portion of a site is mapped in a flood hazard area. To this regard, the flood building requirements only apply to the area of land impacted by the flood hazard area.

If you are looking at building in the defined flood hazard area (1% AEP flood event (with an allowance for climate change), please discuss with Council and/or contact a Private Building Certifier.

How can I tell if my property is impacted by flood events?

1. Open Council’s interactive flood mapping program
2. Click on 'Lotplan Search’ or ‘Address Search’ on the ribbon towards the bottom of the page and type your relevant property details
3. Select the relevant flood studies from the Layers section on the left hand side of the page.
4. Select the desired flood modelling events available for your property on the left hand side of the page.

Note: Council’s interactive online mapping also allows you to view the properties which are impacted by the existing Flood hazard overlay code in the Isaac Regional Planning Scheme. To do this select the ‘Flood Hazard Overlay’ from the Layers section on the left hand side of the page.