Brisbane Overland Flow Flood Extent for 1% Annual Chance

Brisbane City Council's dataset maps areas subject to overland flow flooding within its local government area. It delineates high, medium, and low impact zones based on a 1% Annual Exceedance Probability flood extent from a 2017 mapping study. The dataset was created in June 2013 and is maintained by the council.

Use Cases

• Model flood risk by classifying property locations into high, medium, or low impact areas.
• Analyze spatial distribution of flood hazards for urban planning and infrastructure development.
• Assess annual exceedance probability (1% AEP) for specific land parcels to inform insurance or development approvals.

Strengths

• Data is sourced from the authoritative Citywide Creek and Overland Flow Path mapping study completed in 2017.
• Provides clear probabilistic definitions for high (5% annual chance), medium (2%), and low (1%) impact areas.
• Explicitly defines hazard levels for people, vehicles, and buildings within each impact category.

Limitations

• The core flood extent mapping is from 2017 and may not reflect recent changes in terrain or drainage.
• Original dataset creation date is June 2013, indicating potential staleness in underlying methodology or assumptions.
• Data format is listed as HTML, which is atypical for geospatial analysis and may require conversion for standard GIS tools.

Provenance

Source

Brisbane City Council, from the Citywide Creek and Overland Flow Path mapping study (GHD, 2017).

Collection Method

Derived from a professional flood mapping study to model 1% Annual Exceedance Probability overland flow.

Time Range

Study source date is 2017; dataset created in June 2013.

Freshness

Last updated metadata indicates 2026-03-25, but the underlying study data is from 2017.

Geography

Brisbane City Council local government area, Queensland, Australia.