This engagement has now closed
Irrigators and river communities are invited to have their say on proposed changes to the River Murray Salinity Zoning Policy.
The changes aim to support sustainable irrigation development along the River Murray while still meeting South Australia’s commitment to manage salinity under the Murray-Darling Basin Agreement.
What is being decided?
The availability of low salinity water from the River Murray underpins the health of the environment, productivity of the $2.2 billion Murraylands and Riverland food and wine industry and is critical to providing good quality drinking water to up to 90% of the State’s population.
South Australia has an obligation to manage its salinity impacts under the Murray-Darling Basin Agreement and ongoing effort is needed even with the implementation of the Basin Plan and significant improvements to irrigation efficiency.
The River Murray Salinity Zoning Policy is a key element of South Australia’s salinity management program as it minimises salinity impacts from new irrigation development. The salinity zoning policy is implemented through site use approvals that specify the maximum volume of water that can be applied for irrigation on defined land parcels.
Stakeholders have raised concerns that the current policy may be unnecessarily restricting new development in high salinity impact zones and that it provides limited flexibility for irrigators to respond to changing market conditions (e.g. changing to a crop type with higher water requirements).
As a result of stakeholder feedback, changes have been explored to better support new irrigation development within South Australia’s existing available capacity on the Basin Salinity Register and to make it easier for irrigators to change to higher water use crops.
After considering a range of possible approaches along with advice from stakeholders and an expert review panel, a consultation paper that outlines options and a proposal for change has been developed to seek feedback from stakeholders:
Three fact sheets are also available to inform the discussion about the proposal to amend the Salinity Zoning Policy:
How can your input influence the decision?
By providing your views on the Consultation Paper you can influence the development of a proposal to amend the Salinity Zoning Policy.
A series of questions have been included in the paper to assist stakeholders to provide input and feedback. We want to hear your ideas, suggestions and opinions on the options, but we are also requesting particular consideration of the following questions:
- Do you support the proposal to proceed with option 1 as the preferred option for implementation?
- Do you see any issues with implementing or administering option 1?
- Do you believe there is merit in further considering and consulting on the conversion of site use approval volumes to a maximum irrigated area under option 2 in the future?
- Do you have any suggestions as to how either option could be improved?
Submissions are requested by close of business 20 November 2017.
Provide your feedback by:
How will your input be used?
Once stakeholder feedback has been received and considered, any necessary changes will be made to the proposal to amend the River Murray Salinity Zoning Policy. A recommendation will be developed by the Department in consultation with the expert review panel and South Australian Murray-Darling Basin Natural Resources Management Board for consideration by the Minister for Water and the River Murray.
Salinity emerged as a significant problem for irrigated agriculture, water supplies and the environment in the Murray-Darling Basin in the 1960s when drought and elevated salinity levels caused significant irrigated crop damage.
Salinity begins to have an impact on sensitive irrigated crops above 400 EC and drinking water palatability when levels approach and exceed the Basin Plan targets for managing water flows of 800 EC at Morgan and 830 EC at Murray Bridge.
The degree to which horticulture is susceptible to salinity is a factor of crop sensitivity to salt, irrigation method, soil type, growth stage, rootstock, rainfall and leaching.
To maintain crop productivity salt must be removed from the root zone. Leaching is the most common approach to removing salt and is achieved by applying more water than is needed by the crop. This results in drainage of water (and salt) past the root zone and eventually to the groundwater table.
Within South Australia, saline groundwater that is generally saltier than seawater naturally flows towards the river channel where it enters floodplains and the River Murray.
The flow of irrigation drainage water below the root zone to the groundwater table creates pressure which increases the rate which naturally saline groundwater discharges salt into the river and floodplains. Groundwater mounds grew significantly in the 1970s to early 1990’s due to excessive drainage under irrigation areas. Today advances in irrigation technology result in significantly less water draining below irrigation areas; however, there is still an effect particularly as leaching is required to remove salt from the root zone of crops.
In some areas it can take over 50 years from the commencement of irrigation, for drainage water to reach the groundwater table. This means that the effect of current irrigation on salinity in the River Murray may not be observed for many years. Without further intervention, salt loads from irrigation are predicted to increase from 560 tonnes per day in 2015 to 850 tonnes per day in 2050 and 1,000 tonnes per day in 2100.
For the past 30 years the salinity threat has been successfully and jointly managed via a collaborative salinity management program established under the Murray-Darling Basin Agreement. Management initiatives that have been implemented to reduce salt loads entering the River Murray include:
- Improved irrigation systems and irrigation management practices that increase application efficiencies and reduce drainage.
- Construction and operation of salt interception schemes that divert saline groundwater away from the River Murray to disposal basins (www.mdba.gov.au).
- A Basin wide salinity accountability framework, including the Basin Salinity Register, that requires adverse salinity impacts from future actions to be fully offset.
- State based policies and programs to manage salinity impacts from irrigation development.
The Basin Plan will further contribute to the management of salinity by increasing dilution flows through the recovery and use of environmental water. However, even with the Basin Plan, management action is still required to protect water users from elevated levels of salinity.
The River Murray Salinity Zoning Policy is a key element of South Australia’s salinity management program as it minimises salinity impacts from new irrigation development. Supporting sustainable irrigation development is a Government priority and a review of irrigation salinity management policies was initiated in late 2016 in response to stakeholder feedback.
Further information is available in the form of fact sheets and a short video on salinity management which and can be found at: www.naturalresources.sa.gov.au.