Arrangements for Flood Warning Services in Victoria
February 2001

The Australian Emergency Manual Series Guide 5 on Flood Warning (1999), sets out guidelines with regard to flood warning services from a total system concept. The Guide focuses on flood warning and promotes a community consultative approach to address flood warning issues, problems and solutions.

In terms of flood context the primary focus is on riverine flooding, rather than localised flash flooding from thunderstorms or surcharging drains, flooding from lakes, flooding from oceans as a result of storm surge or tsunami conditions, or flooding which results from dam failure. Nevertheless the principles apply across the range of flood types. Definitions of flood categories and warning definitions are presented in Appendix 4.

The main components of a flood warning system (repeated in part from the Guide) are shown in Figure 1.

• collection of real time data and prediction of flood severity and time of onset of particular levels of flooding;
• construction of warning messages describing what is happening, predictions, expected impact, and can include what action should be taken;
• the communication and dissemination of such messages;
• interpretation of the prediction and other flood information to determine flood impacts on the community;
• response to the warnings by the agencies involved and the community to entice protective behaviour; and
• reviews of the warning system and improvements to the system after flood events.

Outside of the Woolstore downstream of the Princes Highway Bridge, Bairnsdale, 23 April 1990. Photograph, Ian Gauntlett

For a flood warning system to work effectively, these components must all be present and they must be integrated rather than operating in isolation from each other. All these are parts of a flood warning system but by themselves are not the totality of it.

Figure 2 details the process and reflects the operation of flood warning services from a total system concept.

It is on the above fundamentals that the ARRANGEMENTS for Flood Warning Services in Victoria are derived and services achieved through cooperation.