Anyone who’s seen the draft on our website is probably well aware that there’s a lot of information there – so much that it could be quite difficult to find what you’re looking for. To help make it easier for you, we’ll be using Free Flow to go over some of the major elements of the draft Plan, outlining the Authority’s proposed approach and highlighting some documents that will give you more information.
Today’s post focuses on how we determined the amount of water that needs to be returned to the environment.
One of the concerns we’ve been hearing is that the environmental watering plan (EWP) lacks enough detail on what sites will be watered, how much water they need and when they will be watered. It’s written this way in response to feedback we received on the Guide. People told us that they didn’t want a prescriptive approach – they didn’t want the MDBA telling them exactly what to do with their water. They wanted a plan that recognised the in-depth understanding local people have of their area. Because of this, the environmental watering plan outlines a framework on how decisions on environmental water use will be made. It’s an approach that provides flexibility and allows adaptive management and local engagement in environmental water use. The EWP is one of the main parts of the draft Plan where localism has been hardwired in.
ESLT: Methods and Outcomes
There has been substantial work determining environmental objectives, flow targets and modelling the environmental outcomes for sites throughout the Basin. You can read more about this work in our report, The proposed “environmentally sustainable level of take” for surface water of the Murray–Darling Basin: Methods and outcomes (‘ESLT: Methods and Outcomes’).
The report – like its title – is quite long! To help you work your way through it, here are some of the key parts you may be interested in:
- Catchment and site-specific objectives, targets and flow indicators used in hydrological indicator method: Appendix D (page 199)
- The proposed Basin-wide objectives and ecological targets: page 22
- the environmental outcomes that can be achieved for each region in the Basin based on a proposed water use limit of 10,873 GL/y (that is a 2,750 GL reduction in water use): Chapter 9 (page 102)
- a comparison of the broad environmental outcomes that can be achieved with returning either 2,400 GL, 2,800 GL or 3,200 GL to the environment: Chapter 8 (page 88). The differences are particularly clear for sites along the length of the Murray under drought conditions and the salinity levels for the Coorong
- The multiple lines of evidence (including socio-economic) used to work out the broad scale of change in water use required. This process found that 2,800 GL/y returned to the environment was a sensible volume to further investigate with more detailed analysis: Chapter 6 (page 55)
- A flow chart summarising the steps taken to determine how much water needs to be returned to the environment: page 17
- The method for determining environmental water needs and the ‘hydrological indicator’ method: Chapter 5 (starting from page 32).
- A map of the hydrological indicator sites used in assessing environmental water needs: page 38
- tables that outline some of the key constraints which can limit the delivery of environmental water: pages 47 and 52
Want something shorter to read? We also have a fact sheet (pdf) [NOTE: Link removed as content is no longer online] that summarises the method in 6 pages.
We’ve also put up some other documents that relate to environmental water needs in the Basin.
- Constraints and river management [NOTE: Link removed as content is no longer online] – a 4 page pdf fact sheet about constraints and what could be done about them
- River management: challenges and opportunities – a 28 page discussion paper that looks at some of the challenges that can limit environmental water use and what opportunities there are to modify these to improve environmental outcomes and/or deliver environmental water more efficiently
The methods and outcomes have been peer reviewed by a team of experts led by CSIRO. While there is always a need for on-going improvements to the science and methods used, the review team found that the substantial body of work undertaken represents a sufficient basis to begin an adaptive process of managing the level of take in the future and that the methods of modelling and analysis used were generally robust and defensible. Check out a summary of the review from CSIRO panel member, Dr Bill Young on the CSIRO News blog.
Like we said, there’s a lot of information online! If it gets too confusing, let us know by leaving a comment or getting in touch with the MDBA using any of the contact options listed in the footer, below.
**Featured Image: A possum near Coonamble in New South Wales. Photographer: Arthur Mostead.**