Flood Extent Mapping for Western Australian Rivers

2026-03-24 updated geospatial dataset from the Department of Water and Environmental Regulation defines flood boundaries for 20 distinct event types, including 1-in-10 to 1-in-500 Annual Exceedance Probability floods. It covers 17 specific river systems and townsites in Western Australia, such as the Avon, Blackwood, and Fitzroy Rivers, to inform floodplain development advice.

Use Cases

• Model flood risk for property development by analyzing the 'Extent of 1 in 100 (1%) AEP flooding' boundary layer.
• Compare floodway extents across different probabilities, such as 'Extent of 1 in - 200 (0.5%) AEP flooding' versus 'Probable maximum flooding'.
• Assess infrastructure exposure by overlaying the 'Extent of Designated flood event' with asset locations in covered townsites like Bunbury or Carnarvon.
• Study channel capacity constraints using the 'Extent of maximum channel capacity' feature for hydraulic modeling.

Strengths

• Contains 20 distinct flood extent types for detailed probability analysis.
• Covers 17 specific river systems and associated townsites in Western Australia.
• Maintained by the authoritative state Department of Water and Environmental Regulation.

Limitations

• Dataset scope is limited to major river flooding, excluding stormwater drainage and ecological flood impacts.
• Requires loading 12 separate dataset layers in a specific order for full floodplain mapping context.
• Spatial coverage is specific to listed Western Australian townsites, not statewide.

Provenance

Source

Department of Water and Environmental Regulation, Geospatial and Data Services Manager.

Collection Method

Floodplain mapping produced for development advice.

Time Range

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Freshness

Updated 2026-03-24.

Geography

Avon, Blackwood, Brunswick, Bow, Capel, Cemetery Creek, Chapman, Coblinine River & Dorderyemunning Creek, Collie, Denmark, Fitzroy, Five Mile Brook, Gascoyne, Greenough, Gribble Creek, Harding Rivers in Western Australia.