Consequences of failure
Natural flooding can be the cause of considerable devastation and even loss of life from time to time. However, it has been recognised internationally that dam owners should not be accountable for the consequences of natural flooding which passes through their dam without dam failure.
However, many dams have failed, and continue to fail, throughout the world, often with disastrous consequences including loss of life and property, environmental damage and loss of the purpose of the dam (e.g. townwater supply). A small number of large dams have failed, or partially failed, in Australia but only one of those failures involved loss of life (i.e. 14 lives lost in the failure of Breisis Dam in Tasmania in 1929).
In line with international practice, the DSC assigns dams a Consequence Category according to their potential failure consequences (see Guidance Sheet DSC13 for details. It does not involve any assessment of the likelihood of dam failure and a dam, meeting all recognised safety standards, can have a high consequence category. It is used to determine the need to prescribe a dam, the level and frequency of surveillance of a dam to ensure its continuing safety, and the extent and priority for any safety improvement measures.