Overview
This lecture discusses the challenges facing Australia's Murray-Darling Basin, the importance of sustainable river management, and the implementation of the Basin Plan to balance environmental and human water needs.
Importance of the Murray-Darling Basin
- The Murray-Darling Basin is crucial for Australia’s environment, economy, and supports about two million people.
- It provides habitat for 95 threatened animal and fish species and holds cultural significance for many Aboriginal communities.
- The Basin is the largest integrated agricultural area in Australia.
Environmental Challenges
- Excessive water extraction has left rivers in a drought-like state before actual droughts arrive.
- Built dams, altered flows, and irrigation have changed river-floodplain relationships, reducing water reaching lower areas and the sea.
- Droughts, reduced flows, and high salinity have caused acidification and environmental degradation.
- Climate science predicts the Basin could be 10-11% drier in the next 20-30 years.
The Basin Plan and Water Management
- The Murray-Darling Basin Authority proposed returning 2,750 gigalitres (GL) of surface water per year to the environment by 2019.
- An additional 450GL is to be recovered by 2024, backed by $1.7 billion for infrastructure and removing system constraints.
- The Plan sets a “sustainability benchmark” to guide water allocation between environmental and human uses.
- Constraints like dam release limits and channel capacities restrict the effectiveness of increased environmental flows.
- Projects may be implemented to achieve environmental outcomes using up to 650GL less water if equivalent benefits are demonstrated.
Balancing Environmental and Community Needs
- The plan aims to assure both environmental recovery and regional economic stability.
- Community involvement and feedback have shifted the process from a top-down to a more consultative approach.
- The sustainable diversion limit (SDL) can be adjusted in 2016 based on project outcomes.
Infrastructure and Efficiency
- Government funding supports infrastructure upgrades for more efficient water use.
- Raising bridge heights, enlarging storage outlets, and purchasing flood easements are part of system improvements.
Key Terms & Definitions
- Murray-Darling Basin — Australia’s major river system covering parts of Queensland, New South Wales, ACT, Victoria, and South Australia.
- Environmental Flows — Water reserved or returned to sustain river ecosystems.
- Sustainable Diversion Limit (SDL) — The maximum amount of water that can be taken for human use while maintaining environmental health.
- Salinity — High concentration of salt in water, harmful to ecosystems.
- Constraints — Physical or regulatory limits on water movement, such as dam capacities or river rules.
Action Items / Next Steps
- Monitor progress towards the 2,750GL and additional 450GL water recovery targets by 2019 and 2024 respectively.
- Identify and review infrastructure and efficiency projects to achieve environmental outcomes with less water.
- Prepare for possible adjustments of the sustainable diversion limit in 2016.