The degraded (and still degrading) circumstances of many of Australia's major waterways can in part be attributed to eleven important assumptions underlying Australian water management frameworks. Most of these assumptions were once valid. The first three of these assumptions relate to the cumulative impacts of incremental water infrastructure development:

• although very large dams were subject to environmental assessment, it was assumed that small and medium-sized dams needed only cursory assessment on a case by case basis - no assessment of the catchment's capacity to support increasing numbers of small dams was thought to be necessary. In other words, it was assumed that "the little ones don't matter";

• similar assumptions were made concerning small users of surface and groundwaters, and the construction of levee banks. These escaped catchment-based strategic assessments on the basis that "the little ones don't matter";
  
• it was assumed that the harvesting of surface flows away from watercourses did not need to be controlled - that these flows comprised a minor proportion of total surface flows and that their harvesting (through channelling surface flows into farm dams) would not significantly reduce overall catchment flows;
  
• it was assumed that landholders should, by and large, be allowed to place dams across small watercourses, on the basis of generally cursory case-by-case assessments and licensing arrangements - ie: that it was unreasonable for State water agencies to ask landholders to pay the additional costs involved in off-stream dams;
  
• it was assumed that the plants and animals living in the streams would look after themselves, and that no particular attention was needed regarding the provision of guaranteed environmental flows to keep them alive, or to support their life-cycle requirements;
  
• it was assumed that, while the need to protect biodiversity necessitated the development of systems of representative reserves conserving key examples of terrestrial and marine ecosystems, it was unnecessary and impractical to apply the concept of representative reserves to freshwater ecosystems;
  
• it was assumed that the provision of fish passage facilities was either impractical, uneconomic, or unnecessary;
  
• it was assumed that surface groundwaters and surface waterways were somehow separate, and could be managed independently;
  
• it was assumed that, in the main, grazing wetlands and riparian zones would not produce significant long-term damage;
  
• it was assumed that there was no need for rigorous program implementation, compliance auditing and enforcement; that illegal dams, bores, off-takes, drains and levee banks would be minor and insignificant features in overall water management programs; and finally
  
• because completely natural waterways are self-maintaining, and provide their services (at least in the early stages of human modification) without the need for financial expenditure, it was assumed that it was unnecessary to value them as capital assets (infrastructure), or to provide significant annual budgets for their maintenance, as they were increasingly modified over time for human use.

While the Council of Australian Governments (COAG) water reform agenda signalled the death of some of these assumptions (concerning environmental flows, for example) others live on, to a large extent unscathed by the agenda. I argue below that, while all of these assumptions were probably correct many decades ago, this is no longer the case, and it is now dangerous to make any of these assumptions in the development of State water management frameworks. I believe that, as far as the freshwater ecosystems of Australia are concerned, it is a key challenge of the next decade to reverse all of these assumptions.

The focus of natural resource management within Western society has tended to focus on values as the starting blocks on which management objectives and procedures rest. These values tend to be defined in terms of human use: agricultural, landscape, industrial, recreational, cultural… It has been argued that management frameworks need to move beyond these values to encompass intrinsic values. This issue is also considered in passing in this paper.

The paper concludes that there is a need to review Commonwealth and State freshwater biodiversity policies, and re-examine opportunities available for managing freshwater resources in ways which protect biodiversity. The paper focuses on four key issues:

The lack of comprehensive State-wide inventories of freshwater ecosystems (and the strategic planning which such inventories would allow) is seen as inhibiting existing environmental assessment mechanisms, particularly relating to the cumulative effects of incremental water infrastructure development (or "cumulative effects" for short).

In order to manage cumulative effects, catchment plans must be developed which include precautionary caps on water development, set well ahead of water demand. This is the reverse of the existing situation, where caps are only considered in catchments under serious stress; here it is already too late. These catchment plans must take into account ecosystem inventories on a strategic basis, using both river basins and IBRA regions. Additionally, catchment plans must integrate the management of both surface and groundwaters, and must include effective quality assurance processes. Effective integrated management (of surface / groundwater) is not currently occurring anywhere in Australia, except in a few highly-stressed catchments in New South Wales, Queensland, and Western Australia (see discussion below).