Brisbane, Australia

In Case Studies by Ambiental Environmental Assessment

Brisbane, Australia

Ambiental model achieves 95% accuracy vs existing national flood model at just 37%

Flood map Australia

With estimated damages of US$2.38 billion and an impact on Australia’s GDP of US$30 billion the Brisbane flooding of 2011 represented a major event, well into the 1-in-100 year profile.

At the time of the flood most insurers, planners and other flood evaluators employed a commonly used dataset which, as our tests demonstrate, is nowhere near as accurate and comprehensive as they need it to be.

Ambiental carried out a validation test using actual inundation data and comparing the flood profile predictions from the commonly used national dataset as well as from Ambiental’s 1-in-100 year Flowroute data.

Ambiental’s Flowroute model was considerably more accurate, achieving around 95% accuracy vs. just 37%. In simple tangible terms that means Ambiental data missed just 1 in 20 damaged properties whilst the other dataset missed almost 2 in every 3 of the properties which flooded.

Brisbane validation

Ambiental’s drawn (red) validation flood extent reflects actual flooding very closely.

Brisbane flood

Actual Brisbane 2011 flooding

 Brisbane flood model

Ambiental 1-in-100 year Flood Model

Brisbane flowroute

Ambiental Model

Brisbane existing

Existing National Flood Model

Top: Ambiental 100yr flood model with Ambiental data overlaid
Bottom: Actual flooding profile with existing National Flood Model data overlaid


Ambiental Flowroute™ correctly predicts 19 out of every 20 flooded properties. Existing Model misses almost 2 in 3

Steven Brown Ambiental Associate

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