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Dryland Rivers policy document

AUSTRALIAN SOCIETY FOR LIMNOLOGY

A Dryland Rivers Policy Document

Northwest branch of
Cooper Creek

Australia's arid zone is not completely dry, it contains wetlands of national and international significance including numerous large river systems - the dryland rivers of Australia. These rivers differ from those in temperate zones, particularly in the unpredictable variability of their climatic and hydrological regimes, and in the physical, chemical and biological characteristics that depend on these regimes. The flow regimes of Australia’s arid rivers, with their erratic extremes of drought and flood, are probably the most variable in the world. They flow down gentle gradients through landscapes of low relief, so their floodwaters spread over vast and complex floodplains, encompassing networks of meandering channels and mosaics of floodplain lakes. This combination of flow variability and geomorphic complexity in an arid environment creates a distinctive boom and bust ecology, characterised by episodic intense reproduction and high productivity, by opportunistic, hardy plants and animals. Unlike most arid zone rivers elsewhere in the world, Australia’s still has a few unregulated and unpolluted arid zone rivers. They are foci of arid zone biodiversity. Appropriate management of these rivers is critical to ensure a sustainable and wise use of their resources, and to conserve their extraordinary values.

Koonchera waterhole,
Diamantina River

The AUSTRALIAN SOCIETY FOR LIMNOLOGY (ASL) is an Australian-based scientific society whose focus is on research and further understanding of inland aquatic environments. The ASL was established in 1961, and has a current membership of over 600 scientists, managers, engineers, teachers and tertiary level students from all states and territories as well as some overseas members. Members have a strong professional interest in inland aquatic issues, in the maintenance of biodiversity and water quality, and the wise use of Australia’s inland aquatic resources. The Society includes professionals working in most relevant government agencies, tertiary institutions and many industries related to aquatic resources. Through their daily activities, members have constant contact with local communities and are in a sound position to interpret and advise on their concerns over dryland river issues. The Society has both a substantial knowledge base, and a collective responsibility, to ensure that rivers are managed in a sustainable manner.

Photo: Fran Sheldon (16kb)
Creek bed, Broken Hill

Photo: Erika Calder (13kb)
Channel Country,
Cooper Creek

It is the belief of the ASL Dryland Rivers Working Group (DRWG) that the Society's knowledge base gives it a responsibility to contribute where possible to decision-making with respect to river management in Australia. DRWG Members have collectively over 100 years’ research experience on dryland rivers. Using this experience the ASL offers its scientific expertise to governments and the public to assist in management issues. The Society can help! The Society wants to help!

This document has been prepared by the DRWG, and has the full support of the ASL executive. The ASL goal for dryland rivers is:

"To provide scientifically-based information to conserve and manage Australia’s dryland rivers."

What are the dryland river values we seek to conserve, manage and rehabilitate?

Diamantina River channel, Birdsville	Intrinsic values AUSTRALIA'S DRYLAND RIVERS have features in common with dryland rivers elsewhere, but they exhibit these features to an extreme degree. They flow in the driest part of the world’s driest inhabited continent, apart from those of the Murray-darling Basin, most others are almost entirely unregulated and are exceptionally variable in flow. Cooper Creek, for example, may not flow at all for months at a time, and then may experience flow rates as great as the Nile. Many Australian dryland rivers terminate in extensive inland wetlands, and exist on a large scale - the Lake Eyre Basin for example covers 1,140,000 km², one-seventh of the continent, and its largest rivers are 1,500 km long. Their floodplains feature a diversity of forms, including channel networks, waterholes, internal deltas, swamps and lakes giving these rivers ecological features such as extreme variability of habitat in space and time, pulsed productivity and distinctive adaptations of fauna and flora. The rivers also function in the arid zone as refugia for aquatic and terrestrial biodiversity. All these characteristics mark out Australian dryland rivers as distinctive and of great intrinsic value.
Floodplain, lower Cooper Creek	Beneficial values AUSTRALIA'S DRYLAND RIVERS play a major role in making our inland habitable, not only by supplying the practical requirements of water and shade, but by creating those diverse, complex environments flourishing with animals and plants, and are the focus of many human pastimes and activities. For these reasons, many of Australia’s dryland rivers are key tourist destinations (eg. River Murray, Cooper Creek, Darling River, Finke River, Todd River, Gascoyne River). The episodic inundation of their floodplains (eg. Darling Downs, Cooper and Diamantina Channel Country, Gwydir River wetlands) also supports extensive and profitable grazing industries, worth $187m annually in the Lake Eyre Basin alone.
Advancing floodwaters, Cooper Creek	Elsewhere (eg. Darling and Narran Rivers) the floodplain and lakes support opportunistic cropping industries which thrive after flooding. Some of these rivers (eg. Cooper Creek and the Diamantina/Georgina River) are among the few remaining unregulated large dryland river systems in the world and thus provide irreplaceable international scientific benchmarks for the study of the role of flow in dryland river ecology. Such studies are essential to inform the management, conservation and rehabilitation of dryland rivers nationally and worldwide. Some dryland rivers also form oases in the central Australian dunefield and gibber deserts which have been widely celebrated in art, literature and song, and form a vital part of our European and Aboriginal cultural heritage.
Green tree frog, lower Cooper Creek	"The Australian Society of Limnology is well placed to help governments, industry and the public define dryland river values."

DRWP: Jim Puckridge, Fran Sheldon & Keith Walker (CRCFE, University of Adelaide), Kerri Muller (Botany, University of Adelaide), Stuart Bunn (Griffith University), Andrew Boulton & Kim Jenkins (UNE).

Do we know enough?

Lake Apanburra, lower Cooper Creek

BECAUSE THE FOCUS of river scientists and managers has inevitably been on rivers close to population centres and subject to major development, our understanding of the often remote and relatively undeveloped dryland rivers is meagre. We do know enough to say that they function differently in important ways from rivers in more humid zones, but their extreme variability over time and the size of the major systems mean that many years of study will be required to develop a substantial understanding of their ecology. However, major proposals to develop these rivers have appeared recently, and it is a matter of urgency that funding for ecological studies be provided so that assessment and management of such proposals be adequately informed. Such studies should focus on:

Tirawarra Swamp, Cooper Creek

Distinctive ecological processes, particularly the role of flow variability
The functions and roles of riparian zones, particularly in channel networks like the Channel Country of the upper Cooper Creek in south-west Queensland.
The functions and roles of floodplains, including rarely inundated floodplain wetlands.
The functions, roles and flow requirements of refugia for aquatic fauna, particularly the large permanent waterholes.
Endangered, endemic and undescribed species.
Impacts of terrestrial land uses, particularly riparian and floodplain grazing and vegetation clearance in headwaters
Present and potential impacts of water diversions and impoundment’s
Groundwater issues

Why do we need to conserve Dryland Rivers?

Lake Toontoowaranie,
lower Cooper Creek

RIVERS WORLDWIDE HAVE suffered enormous damage from the demands we have made of them, and in other parts of the world dryland rivers (e.g. the Colorado, Orange-Vaal, Syr-Darya, Amu-Darya) have probably suffered worst of all. Impoundment, water diversions, huge irrigation schemes, inter-basin transfers, grazing and cropping pressure on floodplains and riparian zones and mining pollution all have taken their toll. The outcomes of these interventions are obvious in diminished flows, pollution, salinisation, algal blooms, declines and extinctions of animals and plants. In Australia dryland rivers like Cooper Creek and the Diamantina River have so far escaped the most severe of these impacts, but others, particularly most rivers in the Murray-Darling, are in a critical state of ecological decline. Public awareness of this decline is growing. When Australia hosted the world’s largest blue-green algal bloom in the Darling River in 1991, this stark example of a toxic dryland river sparked international concern for the state of one of our most important river systems.

Interdune channel,
Cooper Creek

The costs of rehabilitation, to the extent that it is still possible, are enormous. We must ensure that our resources are optimally directed, and this means using our best science to assess impacts, design remedial programs, assess results and adapt these programs interactively. We must also conserve the integrity of those dryland rivers which are still relatively undamaged, in part because we need them to model the goals of our rehabilitation programs, and to help us understand the ecological processes we are trying to manipulate. Where we consider it is justifiable to continue with resource development, we have to assess, monitor and adapt these developments far more wisely than we have done in the past.

Management of Dryland Rivers

Glossy ibis, lower Cooper Creek	Key Principles and Practices for Management Recognising Variability The inherent variability of dryland rivers should be a central theme in long-term perspective’s for research, monitoring and management. Models developed for low-variability systems should not be applied to these extremely variable ones. New modelling approaches are needed Episodic rivers and their wetlands have different biological functions from permanent ones, but are as biologically important. In fact, since episodic systems have been especially depleted by water resource development, they may be more important. For example, rarely inundated floodplain wetlands apparently play a crucial role in episodic waterbird breeding. To augment short-term hydrological and biological data, long-term monitoring and research programs should be established, and historical and anecdotal knowledge, including Aboriginal knowledge, should be utilized. New modelling approaches, incorporating flow variability, should be developed for dryland rivers. Ecological studies should be undertaken as part of all assessments of development proposals on dryland rivers. These must span an appropriate period of time.
Floating water plants, lower Cooper Creek	A Catchment Based Approach Some dryland river catchments cover large areas of inland Australia, and cross many private and political boundaries. Management must use a whole of catchment approach. Many dryland rivers have extensive floodplains, and their channel networks have multiple riparian zones. These are essential elements in the functioning of such rivers. The floodplain is part of the riverbed and must not be alienated from the main channel. Catchment management strategies should be established for all dryland rivers and involve national as well as local stakeholders, and have mechanisms for input of scientific advice. Riparian stock access should be minimised by off-river watering, and its impact monitored. Water harvesting, grazing, mining and other industry activities on floodplains should be managed for their impact on whole river functioning.
Headwaters of the Finke River	Adaptive Management The management of dryland rivers must adopt a precautionary approach, particularly as there are very few data for many of them. However, adaptive management approaches should only be employed where development impacts have been shown to be reversible. Adaptive management should require that adequate impact assessment programs be set up and binding agreements be made with developers to respond to the results of assessment. This may include interstate agreements for total catchment management. Maintaining Dryland River Values
Diamantina River channel	Social and cultural values should be considered for conservation, management and restoration. Australia’s dryland rivers are a national asset: they have value for all of the Australian community, and in some cases for the international community. This should be reflected in their management. Cooperation must be developed between scientists, regulatory authorities, industry, local communities and conservation organisations to establish common goals for conservation, management and restoration of dryland rivers. These rivers have important educational values yet are often distant from educational centres - this should be a focus for future environmental education. Representative examples of relatively ecologically intact dryland rivers should be selected by national survey (e.g. the Near-Pristine Rivers Survey) to act as benchmark systems. Such rivers should be quarantined from further development.

Further information?

This document has been compiled for, and on behalf of, the ASL by the ASL DRWP. For further information concerning ASL, or ASL assistance with management issues, please contact the Society's Secretary, Dr Richard Marchant, Museum of Victoria, 71 Victoria Cres, Abbotsford, VIC 3170. Ph: +61 3 9284 0200. Fax: +61 3 9416 0475 (Email: rmarch@pioneer.mov.vic.gov.au)

Australian Society for Limnology