The reliability at which a specific quantity of water can be provided.
The reliability at which a specific quantity of water can be provided, usually expressed either as a percentage or as a risk. For example 98% reliability means that, over a long period of time, the specified quantity of water can be supplied for 98% of the time, and less for the remaining 2%. Alternatively, this situation may be described as a '1 in 50 year risk of failure' meaning that, on average, the specified quantity of water will fail to be provided in 1 in 50 years, or 2% of the time.
Why is assurance of supply important?
Assurance of supply is important for the management of water resources.