4 Inland water | 7 Outlook for inland water environments
State of the Environment 2011 Committee. Australia state of the environment 2011.
Independent report to the Australian Government Minister for Sustainability, Environment, Water, Population and Communities.
Canberra: DSEWPaC, 2011.
At a glance
Although the capacity to reverse many historical impacts is limited, there is reason to believe that projected population and economic growth can be significantly decoupled from future pressures on our inland water ecosystems. Mitigating the risks to inland water ecosystems arising from a changing climate will be far more challenging and may not be entirely possible. With some additional management intervention and investment, the inland water environment is likely to remain in generally good condition in northern Australia and in poor, but potentially improving, condition across much of the south, with only limited regions showing continuing serious deterioration. Much of the potential for improvement relies on adjusting future levels of water abstraction to meet environmental flow requirements, in a future that is likely to be drier in the south due to climate change.
Australia can potentially meet the projected growth in population and maintain its overall prosperity while improving the protection of inland water environments and, in places, reversing historical and detrimental flow regime changes. This will require that we continue to progress towards full realisation of the principles in the NWI, and that metropolitan water strategies continue to emphasise an increasing mix of demand management, water recycling and desalination to meet future needs. A major uncertainty in this outlook is the complex hydrological consequences of a changing climate. A second serious uncertainty is the degree to which river, wetland and floodplain environments will recover after an unprecedented drought followed by extensive floods in south-eastern Australia. These are two key points to take into account for future specification and protection of environmental flows.
Australia’s history of land clearing and extensive land-use practices have left us with a challenging legacy of ongoing impacts on our water quality. Redressing these impacts is not a prominent feature of the NWI, and there is uneven commitment across jurisdictions to reduce diffuse pollution and salinisation. There is little evidence that water quality is generally further deteriorating, but, with some notable local exceptions, relatively low levels of investment are being made to improve water quality.
Australia is good at identifying and monitoring the spread of weeds and pests affecting inland water environments, but has had only limited success in controlling their spread and impact. It is not clear whether further investment of resources in tackling these issues with current strategies and tools would improve control.
Many of Australia’s inland water environments are in a degraded condition. Nutrient levels exceed guidelines in all metropolitan and agricultural regions, and ecological processes have been altered across most parts of the continent. However, some areas of northern and central Australia and Tasmania largely retain their original character despite widespread pressures from pests and weeds and changed fire regimes.Water ecosystems supporting many of our irrigation areas and near our cities are likely to remain under significant pressure, and maintaining or improving their ecological condition remains a serious national challenge. This is particularly true for two regions: the Murray–Darling Basin, where the need to rebalance use and environmental flows is widely recognised but difficult; and the south-west of the country, where the remaining inland water ecosystems are generally in poor condition as a result of salinisation, agricultural run-off, water diversions and an unbroken 36-year drought.