Sustainable diversion limits
The Basin Plan sets limits on the amount of water that people can extract from the Murray–Darling Basin. These are called sustainable diversion limits, and they reflect an environmentally sustainable level of water use.
To reduce water use to sustainable limits water is ‘recovered’ for the environment. This water is used to improve and maintain the health of rivers, lakes, major wetlands and floodplains within the Basin and support prosperity of river communities, the long-term viability and productivity of river-dependent industries, and the quality of life for all South Australians.
Sustainable diversion limits became law on 1 July 2019 and are implemented through state water resource plans. Basin state governments are responsible for complying with limits on the volume of surface water and groundwater that can be taken and used.
Factors for water recovery
Long-term diversion limit equivalence factors (LTDLE, known colloquially as the cap factors) are used to convert water entitlements to a long-term equivalent annual average yield (LTAAY) volume to calculate how much water has been recovered for the environment under the Basin Plan. A consistent approach across the Basin allows a comparison of all types of water entitlements.
South Australia has met its share of the Basin Plan bridging the gap water recovery targets based on the current implementation of the Basin Plan. Recovery of water to meet the 450 GL target is being led by the Australian Government, for information on this program see Restoring Our Rivers Framework.
Adjustment mechanism
Sustainable diversion limits in the Southern Connected Basin can be adjusted up and down through projects, providing flexibility when needed. There are:
- Supply measure projects
- Efficiency measure projects via the Restoring Our Rivers Framework
Prerequisite policy measures
Basin Plan modelling to determine sustainable diversion limits assumed a range of measures actions, processes and procedures would be in place to maximise the benefits of environmental water. These aim to:
- protect environmental flows throughout the length of the river and between rivers from extraction, re-regulation or substitution
- allow water for the environment to be released on top of other instream flows, including during unregulated flow events.
These measures have been in place since 30 June 2019 and without these policy measures, more water would be required to meet the environmental outcomes of the Basin Plan, leaving less for consumptive purposes.
