Logan Flood Mapping: 2026 Update
“If approved and implemented, Council estimates the changes will reduce the number of properties included in its flood planning overlay by 56.8%.”
Logan City Council has endorsed significant changes to its flood mapping and planning controls, with thousands of properties potentially affected.
Following extensive community feedback and an independent review of its flood studies, Logan City Council has taken another step towards changing how flood risk is represented and managed across the city.
On 6 October 2026, Council endorsed Temporary Local Planning Instrument (TLPI) No. 1/2026, introducing proposed changes to flood hazard mapping and development assessment requirements.
If approved and implemented, Council estimates the changes will reduce the number of properties included in its flood planning overlay by 56.8%.
But what does this mean for property owners, developers and anyone considering building in Logan?
In our previous article, Why was Logan’s Flood Mapping Reviewed?, we explored the community concerns surrounding Logan’s flood mapping and the subsequent independent technical review.
During consultation on the draft Logan Plan in 2025, Council received more than 4,000 submissions, with the majority relating to flood mapping and planning policy.
A key concern was the inclusion of rare and extreme flood events, including the Probable Maximum Flood (PMF), in the planning framework.
The independent review found that the Logan and Albert Rivers Flood Study had been developed using accepted national standards and industry practices. However, it identified opportunities to improve how rare and extreme flood scenarios were presented and applied in planning decisions.
Following further investigation, Council endorsed changes in June 2026 and has now progressed these through the proposed TLPI No. 1/2026.
One of the most significant changes is Council’s decision to limit the flood hazard overlay to the extent of the 1% Annual Exceedance Probability (AEP) flood event.
A 1% AEP flood has a 1% chance of occurring or being exceeded in any given year. It is commonly referred to as a 1-in-100-year flood, although this does not mean such an event can only occur once every 100 years.
Under the proposed changes, rarer flood events, including the PMF, will be removed from the general flood hazard overlay mapping.
Council estimates this will reduce the number of properties included in the overlay by 56.8%.
For property owners, this could mean some land currently identified within a flood planning overlay will no longer be subject to the same overlay-based development controls once the changes commence.
However, removal from a planning overlay does not necessarily mean a property is free from flooding.
Council is also proposing clearer flood risk terminology through revised Flood Planning Areas.
These areas distinguish between different flood conditions and associated planning considerations.
For example, the existing High Flow Area will be renamed Flood Planning Area 1.
Under the proposed policy, some open structures, such as carports, may be considered within this area, provided their design does not obstruct floodwater movement or adversely affect floodplain function.
This distinction is important because flood hazard is not determined by water depth alone.
Flood velocity, flow paths and the potential for structures to obstruct or redirect floodwater can also influence development suitability.
The changes do not mean all development within flood-affected areas will be permitted. Site-specific conditions and applicable planning requirements will remain important.
Another area under review is the treatment of dry creeks, minor gullies and overland flow paths.
Some properties may experience relatively shallow but frequent stormwater flows during heavy rainfall, particularly where runoff follows natural depressions or drainage pathways.
These conditions can differ considerably from flooding associated with major rivers and established creek systems.
Council has recognised the need for planning controls that better reflect these differences.
Further technical investigations into creek flood mapping are continuing, with outcomes expected in 2027.
For property owners and developers, this reinforces the importance of understanding the source and behaviour of flooding rather than relying solely on the appearance of a mapped flood overlay.
So the absence of coloured flood shading over a house does not necessarily mean there are no flood-related constraints.
Also keep in mind that some ground and floor levels in the report are indicative rather than survey-accurate.
The proposed TLPI also incorporates updated flood studies for several catchments, including:
These studies were accepted and published in May 2025 and formed part of the mapping presented during consultation on the draft Logan Plan.
Their inclusion means that, while the overall extent of the proposed planning overlay is expected to reduce, updated flood information will continue to influence planning decisions in particular catchments.
Council is introducing a dedicated development code for vulnerable uses and essential community infrastructure.
This includes facilities such as hospitals and childcare centres, where flood consequences may extend beyond property damage to affect people who require additional assistance during emergencies.
The proposed framework recognises that some developments require consideration of larger flood events, even where those events are no longer included in the general flood hazard overlay.
Not necessarily.
A planning overlay identifies areas where particular development controls apply. It does not represent every possible flooding scenario.
A property outside the revised overlay could still experience flooding during an event larger than the 1% AEP flood or be affected by local stormwater runoff, drainage constraints or other site-specific conditions.
Likewise, removing an extreme flood event from a planning overlay does not change the physical behaviour of floodwater.
For developments where flood behaviour is uncertain, a site-specific flood assessment may still be necessary to understand flood levels, flow velocities, overland flow paths and potential impacts on surrounding properties.
Changes to planning overlays may be relevant to property owners reviewing their flood information, but they do not automatically result in lower insurance premiums.
Insurers may use a range of information to assess flood risk, including their own flood models, historical claims and property-specific characteristics.
A property being removed from Council’s planning overlay does not necessarily mean an insurer will classify it as having no flood risk.
Property owners concerned about their premiums should ask their insurer what flood information has been used in assessing their property.
Although Council endorsed TLPI No. 1/2026 on 6 October 2026, the instrument is not yet in force.
The proposed changes must first receive Queensland Government approval before returning to Council for formal adoption.
Council currently anticipates implementation in early 2027, subject to the necessary approvals.
Until the new instrument commences, the existing applicable planning provisions remain in place.
Property owners and development applicants should therefore confirm the current planning requirements before relying on any proposed changes.
For anyone considering purchasing, building or developing land in Logan, the proposed changes provide an important reason to review available flood information.
It is worth considering whether the property is affected by the current flood overlay, whether its classification may change under the proposed mapping, and whether there are other flood or stormwater constraints that could affect development.
Where a development is proposed, a flood assessment can help establish how floodwater may behave across the site and whether additional design considerations are required.
The key is to distinguish between a change in planning controls and a change in the underlying flood conditions.
Logan City Council’s proposed 2026 flood mapping changes represent a significant shift in how flood information will be applied through the city’s planning framework.
While the expected reduction in flood overlay coverage may change development assessment requirements for many properties, understanding actual flood behaviour remains essential.
With the new TLPI awaiting approval and further creek mapping investigations continuing, property owners and developers should keep informed as the planning framework evolves.
For the latest official information, visit Logan City Council’s Flood Maps page.
Storm Water Consulting provides professional flood assessments and flood reports to help property owners and developers understand flood risks and navigate Council requirements.
