Flood preparedness for dam failure (and extreme events).

Conference Dates 21-25 November 1988

The paper considers the risks imposed by extreme flooding, either above the level of historical flooding or above the level determined as acceptable for flood plain development. The risk of natural flooding from extreme events, a risk that society accepts, is contrasted to the very well defined risk levels that are deemed acceptable for dam safety. Recent examples are given of dam safety planning and preparedness planning for extreme natural flooding. The degree of exposure to natural flooding in the Nepean Hawkesbury valley is being examined by the Sydney Water Board as part of the planning for upgrading the safety of Warragamba Dam. Risk assessment studies for flooding in the river valleys downstream of these dams provide for interesting comparisons