Compliance with water limits works in a number of ways
Basin state governments are the regulators and the frontline for policing water use in the Basin. Individual compliance with local rules and licences is the responsibility of the Basin state governments. They are responsible for ensuring state compliance systems are effective, and for enforcing the rules, many of which are outlined in water resource plans.
Sustainable diversion limit compliance
The establishment of the Inspector-General of Water Compliance (IGWC) in August 2021 means that decisions on compliance with sustainable diversion limits from the 2020–2021 water year and onwards, rest with the IGWC.
The Murray–Darling Basin Authority was responsible for decisions on SDL compliance for the 2019–2020 water year.
Sustainable diversion limit compliance outcomes 2019–2020
The MDBA analysed water use across all 29 surface water and 80 groundwater SDL resource units for the 2019–20 water year.
A summary of the outcomes is provided in the Murray–Darling Basin sustainable diversion limit compliance outcomes report 2019–20, the first compliance report that examined how water use by Basin state governments is tracking in accordance with the Basin Plan. This report includes the registers of take for 2019–20.
Decisions on compliance with sustainable diversion limits from the 2020–2021 water year on will rest with the IGWC.
The Annual Water Take Report 2019–20 provides further information about the availability and use of water from the Murray–Darling Basin. It also reports on environmental water held, available and used in 2019–20, and compliance under the Murray–Darling Basin Cap on diversions.
Cap compliance
Under the Cap, Basin state governments must provide data to the Murray–Darling Basin Authority about how much water was actually taken each year compared to the annual Cap targets.
Once the MDBA receives annual data from the Basin state governments, the data is entered into the Cap Register and an assessment of compliance with Cap limits is made.
The Cap Register records a credit for the year if annual diversions were less than the annual Cap target and records a debit if annual diversions were more than the annual Cap target.
For most Cap valleys, the annual credits and debits are added together from year to year to create a cumulative balance, which is also recorded on the Cap Register.
If it appears that more water has been taken in a particular valley than allowed under its Cap limit, the MDBA arranges for a special audit to be conducted by an Independent Audit Group. For most Cap valleys, the trigger for a special audit is when the cumulative balance is a debit of 20% or more of the long-term Cap limit.
If the Independent Audit Group confirms that too much water has been taken, the MDBA advises the Murray–Darling Basin Ministerial Council of the breach.
The state in which the breach occurred then must advise the Ministerial Council how it will address the issue
Once diversions in a Cap valley where a breach has occurred come back into balance with the Cap, and the MDBA is satisfied that the valley is once more compliant with the Cap, the MDBA revokes the declaration and advises the Ministerial Council.
Since 1997–98, 18 special audits have been triggered across 7 Cap valleys. Of these, 14 have resulted in a declaration of a breach in particular water years. The valleys in which breaches have occurred were:
- the Barwon–Darling/Lower Darling
- Gwydir
- Lachlan
- Moonie
- Namoi.
There are no current declarations of breaches of the Cap. Read more about Cap compliance.
Reporting on Cap compliance
Following the introduction of the Cap in 1995, interim arrangements were put in place to establish Cap compliance and reporting, starting with the 1994–95 year. Formal Cap reporting and compliance started with the 1997–98 water year.
For the period 1997–98 to 2011–2012, the MDBA reported annually on Basin state government compliance with the Cap by publishing Water Audit Monitoring Reports. These reports provide a comprehensive analysis of water availability and take by state for each water year.
The Cap continues in parallel with sustainable diversion limit (SDL) accounting until Schedule E of the Murray–Darling Basin Agreement is amended or repealed.
The MDBA is working with Basin state governments to cease Cap reporting once sustainable diversion limits are fully implemented through water resource plans.
Read the Cap compliance reports.
Last updated: 27 June 2023