What are prerequisite policy measures?
Prerequisite policy measures are legislative and operational rule changes to maximise the beneficial outcome of water recovered for the environment under the Basin Plan.
They provide secure and enduring arrangements for the efficient and effective use of held environmental water. The measures improve the use and accounting of water delivered for the environment in the southern-connected Basin.
There are 2 prerequisite policy measures, both of which are in place in the regulated Murray Lower Darling and Murrumbidgee River systems. These are:
- Environmental flow reuse - if water used in an environmental event returns to the river, it’s recognised as a returned flow and can be used for downstream environmental purposes.
- Piggybacking, or directed release - environmental water holders can order water from storage during a flow event, and the water is released on top of the event.
Why do we have prerequisite policy measures?
When the Murray-Darling Basin Authority set the Sustainable Diversion Limit(s), they assumed that certain measures would be in place to maximise the benefits provided by environmental water. Without these measures, larger quantities of water would need to be recovered to achieve the same results. These measures are known as prerequisite policy measures.
PPMs apply only to held environmental water in the regulated Murray Lower Darling and Murrumbidgee river systems. In the NSW Murray, PPMs also apply to River Murray Increased Flows accounting water. PPMs permit held environmental water to be used more effectively and flexibly, by letting it be used across multiple sites, and allowing water for the environment to be released on top of natural flow events.
The PPMs will mean held environmental water can be used more efficiently, maximising the benefits of water recovered for the environment, while maintaining the reliability of other licence holders.
In NSW, PPMs have been in place by 30 June 2019, as per requirements under the Basin Plan. The Murray Darling Basin Authority has information on prerequisite policy measures.
What is held environmental water?
Held environmental water is water allocated to water licences which are held exclusively for environmental use. Both the NSW and Commonwealth governments have acquired water licences for environmental purposes in regulated, unregulated and groundwater sources.
PPMs apply to held environmental water in the regulated NSW Murray and Lower Darling and Murrumbidgee river systems. In the NSW Murray regulated river water source, PPMs also apply to River Murray Increased Flows (RMIF) account water. They apply because of the supply measure projects in these valleys. These projects make it important for water for the environment to be able to be delivered in the way the projects anticipate.
Working with stakeholders
To successfully use PPMs to deliver water for the environment, we consult with stakeholders on PPM arrangements and the adequacy of mitigation measures. This ensures our approach is transparent and appropriate.
Our key stakeholders include environmental water holders (primarily the Commonwealth Environmental Water Holder), the NSW Environmental Water Manager (the Department of Planning and Environment–Environment and Heritage Group), WaterNSW, the Murray Darling Basin Authority and licensed water users or their representative groups.
Details of the consultation requirements are provided in the PPMs Procedures Manuals below.
Annual evaluation and review
The management and delivery of environmental water is evolving. We’ll use adaptive management to learn, refine and continuously improve the framework for PPMs.
Each year, the NSW Environmental Water Manager and WaterNSW are required to report on environmental watering actions that used PPMs. We use these reports to evaluate and review PPMs to inform and improve the way we manage PPMs.
An evaluation framework has been developed to guide the ongoing and objective annual process evaluation of the consistency, efficiency and effectiveness of the implementation of PPMs in NSW.
The 21-22 Annual evaluation and review report was the first report that has used the NSW PPMs evaluation framework.
Reviews of PPM implementation in NSW
We have completed the following reviews in NSW:
- Prerequisite Policy Measures: NSW Annual Evaluation and Review 2021-22 water year
PDF, 2438.05 KB
- Evaluation Framework for PPMs Implementation in NSW PDF, 1059.13 KB
- Prerequisite Policy Measures: NSW Annual Evaluation and Review 2020-21 water year PDF, 1266.14 KB
- Prerequisite Policy Measures: NSW Annual Evaluation and Review 2019-2020 water year
PDF, 877.47 KB
- Review of Murrumbidgee environmental water releases - 2016/17 and 2017/18 PDF, 1743.56 KB
The Procedures Manual for the NSW Murray and Lower Darling Regulated Rivers was updated in 2022 to include new arrangements developed since 2019.
The Procedures Manual for the Murrumbidgee Regulated River was updated in 2022 to include new arrangements developed since 2019.