Definition and approach to sustainable groundwater yield
National Groundwater Committee
Department of the Environment and Heritage, 2004
About the publication
Sustainable groundwater yield is defined as:
"The groundwater extraction regime, measured over a specified planning timeframe, that allows acceptable levels of stress and protects dependent economic, social, and environmental values."
This definition is based on adopting the following approach to its implementation:
It is recognised that sustainable groundwater yield should be expressed in the form of an extraction regime, not just an extraction volume. The concept is that a regime is a set of management practices that are defined within a specified time (or planning period) and space. Extraction limits may be expressed in volumetric quantity terms and may further specify the extraction or withdrawal regime by way of accounting rules and/or rates of extraction over a given period and/or impact, water level or quality trigger rules. The limits may be probabilistic and/or conditional.
An often-used means of defining the extraction regime has been by way of a maximum volume that may be taken in any single year. In some cases, where draw beyond the rate of recharge may be acceptable, it may be only for a specified period, after which time the rate may be less than the rate of recharge to compensate. In some cases and under specific circumstances (for example, high or low rainfall years) the amount of water that may be taken may be greater or less than the longer-term value and the conditions for this can be specified.