The National Water Initiative (NWI) definition of sustainable yield (refer
to Sustainable yield-definitions) is used
in this assessment to consider groundwater resource sustainability. Specifically,
this assessment considers whether the sustainable yield of the resource has
been determined for each groundwater management unit. The sustainable yield
is then compared with the level of water entitlements and with the cap that
has been set within that management area.
A national definition of sustainable groundwater yield (refer to Sustainable
yield-definitions) has been adopted in some
state and territory legislation, including South Australia 's Natural Resource
Management Act 2002 .
Windmill in arid Australia
The disparity between jurisdictions and their definition of sustainable yield
means that comparison across jurisdictions is difficult. For some jurisdictions,
sustainable yields are calculated for only high quality aquifers (e.g. salinity
levels less than 3000 milligrams per litre), and elsewhere yields have been
calculated for groundwater with salinity levels up to 5000 milligrams per litre.
With this in mind, the yield data have been compared with caps and the level
of entitlements within groundwater management units.
Some groundwater aquifers are managed differently because they have been identified
as non-renewable' (refer to Sustainable
Groundwater sustainability is discussed in more detail in the following sections: