Historical and Design Flood Extents for Greater Geelong

Flood extent data for the City of Greater Geelong, representing the largest recorded historical flood or a 1% Annual Exceedance Probability design flood event. The dataset is produced and maintained by the City of Greater Geelong local government authority, with a last recorded update in April 2026. Data quality varies from high, based on detailed flood studies, to lower quality estimates from geological maps.

Use Cases

• Identify land parcels designated as liable to flooding for building regulation compliance using the flood extent polygons.
• Compare high-quality floodmapping from detailed studies (e.g., Barwon River) with lower-quality estimated extents (e.g., Hovells Creek) for accuracy assessment.
• Model potential flood impact scenarios by overlaying the 1% AEP design flood extent with other geospatial layers like population or infrastructure.
• Support historical flood analysis by examining the spatial footprint of the largest recorded flood event in the region.

Strengths

• Explicitly maps both historical maximum flood and a standardized 1% Annual Exceedance Probability design event.
• Data is provided in multiple standard geospatial formats (GEOJSON, SHP, WFS, WMS) for interoperability.
• Clear provenance and maintenance by the local government authority (City of Greater Geelong).

Limitations

• Data quality is explicitly noted to vary significantly across the region, from high to low quality.
• The temporal range of the historical flood event or the date of the design flood modeling is not specified.
• Row count and total spatial area covered are unknown.

Provenance

Source

City of Greater Geelong local government.

Collection Method

Combination of detailed flood studies for some areas and subjective estimation from geological maps for others.

Time Range

null

Freshness

Last updated in April 2026, indicating active maintenance.

Geography

City of Greater Geelong, Victoria, Australia.