Australian Rainfall and Runoff Newcastle Flood Model

Client: Australian Rainfall and Runoff - Engineers Australia
Year: 2010-2012
Project Reference: 2010026

The floods in Queensland and Victoria in 2011 have been a timely reminder of how destructive and dangerous these types of natural disasters can be. While State and Local government authorities are busy with the important task of restoring infrastructure for communities in these flood affected areas, researchers at the University of New South Wales Water Research Laboratory (WRL) are working to assist planners and emergency managers to more effectively deal with future floods.

Sophisticated, two-dimensional numerical computer models are commonly being used to provide baseline data describing flood levels, depths and velocities in flood prone areas. Statistically analysed, these data can be used by planners and managers to define the risk and relative hazard (safety) of flood prone areas. The data can be used to determine a wide range of planning outcomes from safe evacuation routes out of flooded regions to whether areas are suitable for rebuilding or future development.

But how accurate and reliable are the baseline data from these models? A recent research project by Grantley Smith and Conrad Wasko, using funding from the Federal Department of Climate Change and Energy Efficiency and Engineers Australia, as part of the review of Australian Rainfall and Runoff, has used the advanced numerical and physical modelling capabilities of WRL to review current industry modelling practice.

A physical model of an urban floodplain in Merewether, a suburb of Newcastle, NSW has been built at WRL and calibrated to the famous ‘Pasha Bulker’ storm of June 2007. Detailed flow measurements from the physical model have been compared with predictions of the June 2007 flood from various numerical flood software packages commonly used by industry. The research has shown that there are numerous areas where modelling approaches can be improved. WRL’s report will inform the revision of industry guidelines and be included in the next edition of Australian Rainfall and Runoff. The findings can also be used to provide an improved assessment of building stability on floodplains.