Environmental Flows and Water Quality for the River Murray

Since development of the River Murray for water supply in the early 1900's, the amount of water diverted for consumptive use has steadily increased.

An audit of water use in the Murray-Darling Basin was conducted in 1994 to assess the long-term sustainability of ever-increasing development and water diversion. An interim moratorium on water diversions (the Cap) from the rivers of the Murray-Darling Basin was introduced in 1995 in response to findings of the Audit. A long-term Cap is now in place to arrest declining sustainability of the water resources and to balance the needs of industry and communities dependent on Rivers of the Basin. See The Cap.

At the time that the Audit was being conducted, it became widely acknowledged that the health of the River Murray and its environs had degraded to a precarious state. Of particular concern was the destructive impact that modified flow patterns were having on the riverine environment.

Historically, flows in the River Murray were unpredictable, though seasonal patterns predominated. High flows occurred most often in spring and early summer whilst low flows were typical in autumn and winter. With development came the need to deliver more water during summer and autumn to satisfy peak demand. This is at a time when under natural conditions, the riverine system would be experiencing much lower flows.

Water storage, too, has led to a decline in water quality. Storages in the upper catchment experience stratification during summer and autumn. In summer, water at temperatures of less than 10 degrees Celsius is released into rivers when natural temperatures would have been in the order of 16-20 degrees. Few native plant and animal species have evolved to cope with such unseasonally cold temperatures.

Interstate Working Group on River Murray Flows

The Commission responded to these concerns by establishing a working group of representatives from NSW, Victoria, South Australia and the Commission. This group was given the responsibility to develop a flow management plan for the River Murray which considered the long-term sustainability of the riverine environment and the needs of existing users. Striking a balance between consumptive demand and the demands of the environment would not be a trivial exercise.

Environmental Flows and Water Quality of the River Murray Project

Also see
Corowa Communique

In 1998 the Commission established a Project Board to look further at environmental flows and water quality issues.

At its 2^nd meeting of 22 September 1999, the Project Board reviewed recent reports that present options for flow management and water quality that might benefit the riverine environment. Some of these reports address river reaches whilst others address operation of storages, weirs and infrastructure. Still others propose alternative operating regimes for the River as an integrated system.

That such a range of options exists led the Project Board to initiate a detailed review of all options and recommendations to assess the impacts that groups of options might impose upon the water users, river operators and on the environment. The Interstate Working Group on River Murray Flows had commenced such an analysis during 1997 in the form of a draft Interim Flow Management Plan for the River Murray. Completion of this interim plan was suspended whilst other supporting investigations were completed such as the Hume and Dartmouth Dams Operations Review. This review considered alternative management of these two major storages and their impacts on the river system, the environment and local communities. The final report from this review is now available and has been referred to the Environmental Flows Project Board for consideration.

The Project Board is now overseeing a range of tasks to develop a flow management plan for the River Murray by mid-2001:

A Review of options for achieving environmental flows
Analysis of trade-offs that might be considered through the adoption of new River operation procedure
Participation of community, industry and jurisdictions in developing the flow management plan.
A framework for adaptive management.
Establishing research and investigation to improve knowledge of the River System and its response to environmental flow provisions.

In November 1995 the Commission focussed on arresting the River Murray's declining
environmental values by asking eminent scientists to recommend changes to how the
River is managed which could improve the river environment. Two panels of experts
reported, one addressing the upper Murray and lower Darling, and the other, the
Coorong and Lower Lakes. The Panel reports highlight the many complex interactions
between River Murray as a water supply system and its environmental values.

The major objective of the Scientific Panels was to identify changes in river operations
for the Murray River and Lower Darling that should result in general improvements in the
environmental condition of these Rivers whilst considering the current needs of existing
water users.

The upper Murray and lower Darling Panel examined the geomorphology, riparian
vegetation, macrophytes, invertebrates, floodplain ecology, fish habitat, algae and
hydrology at specific sites along the length of the River Murray, from the Mitta Mitta
River above Dartmouth Dam to Murray Bridge and the Lower Darling and Great Darling
Anabranch between Menindee Lakes and Wentworth. The Panel focused on determining
the key hydrological factors that need to be preserved or re-established to sustain a
healthy river system. Its final report is titled 'Report of the River Murray Scientific
Panel on Environmental Flows' and is available from the contact below.

Since that panel did not consider itself qualified in estuarine ecology, an additional
Scientific Panel was established to examine the operation of the Barrages with respect
to the environment of the Coorong and the Lower Lakes. It examined the current status,
key issues and ecological needs of the Lower Lakes and Coorong and identified
opportunities for improved environmental conditions. The final report of this Panel is
titled 'River Murray Barrages Environmental Flows' and is available from the contact below.

Developing and implementing flow management procedures to achieve environmental benefits throughout the River Murray is a significant commitment of the Murray-Darling Basin Commission. Only through the cooperative efforts of the States, river operators, water users, community interests and environmental groups can a balance be struck to achieve a sustainable River Murray.

For further information, contact the project manager

Last updated on: 4/ 6/ 104