DHI hydraulic model providing insight in Australian
Rapid Flood Hazard Assessments
application providing information suitable for emergency and
strategic planning purposes.
The 2010 / 2011 wet season has so far been the most devastating
in over 30 years for large regions of Australia, especially
Queensland and northern New South Wales.
Detailed flood studies have been undertaken for many parts of
Australia. However, these are generally focused on large urbanised
areas where the economic consequences of floods are significant.
Yet flood risks may be apparent in the many smaller, rural
communities scattered throughout the country. Undertaking detailed
flood studies for each and every community would be prohibitively
expensive and very time consuming.
The solution is a rapid assessment that can be applied over a
large geographical extent in a short time. DHI have pioneered the
application of so called Rapid Flood Hazard Assessments that aim to
provide a sufficient level of flood hazard information suitable for
emergency and strategic planning purposes. The technique utilises a
two-dimensional hydraulic model (MIKE 21) of the catchment surface
upon which rainfall is directly applied. The technique removes the
need to develop a separate hydrologic model.
The main advantages are:
- Fast results, very little pre-processing;
- Production of hydraulically consistent flood inundation maps,
showing depth, water velocity and hazard;
- Outputs are highly visible and easily understood by
- Animations showing the timeline of the evolution of the flood
can be produced.
Whilst the approach is a simplified one, our experience has
shown the method capable of reproducing the most important aspects
of flood behaviour.