Chapter 6: Understanding flood behaviour

Flood behaviour and its impacts vary within and across the floodplain and between events of different scales. Understanding this variation is an important element in being able to make informed decisions about managing the varying aspects of flood risk and developing in the areas affected by flooding, cognisant of this risk.

Flood risk management generally starts with an understanding of historical floods and their impacts. The historical record is generally incomplete and cannot provide a full understanding of all the areas affected by historical floods or their impacts on the community that existed at the time. In addition, catchments and floodplains are not static. This means that if the same rainfall event of 50 years ago occurred today, the flood and its impacts would probably be more severe because of the growth of the community and the effects of this growth on both flood flows and the exposure of the community to flood risk.