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Australia's rivers are among the most variable in the world and this has been a major challenge in catchments such as the Murray-Darling Basin where management has focused on increasing agricultural production while reducing risks from fluctuating water availability. Pressure for development and over-optimistic assessments of available water have resulted in over-allocation and increasing ecological decline, which has been severely exacerbated by record-breaking drought. In recent years, governments have agreed to radical policies such as the National Water Initiative 2004 and allocated substantial funds in response. Implementation is in gridlock, however, as the socio-economic implications have become clearer. Most debate is focused on the draft Murray-Darling Basin Plan due for release in mid-2010 before finalization in 2011. It will be the first Basin-wide plan and is intended to deal with inequities across borders and risks such as climate change and drought. Climate change scenarios for 2030 foresee a range of potential surface water availability outcomes, ranging from a 7% increase to a 37% decrease, yet greater water scarcity is being experienced in the current (2002+) drought with inflows reduced by 70% or more in extreme years. Contradictory policies are hindering the more open adaptation required to manage a drier future. [ABSTRACT FROM AUTHOR]

Inland recreational swimming sites provide significant social value globally. This study focused on public recreational swimming sites across the Murrumbidgee River and its tributaries in the Australian Capital Territory (ACT) throughout the swimming season (September-April) from 2009 to 2020 to determine whether high intestinal enterococci concentrations could be predicted with flow exceedance and routinely monitored physical and chemical parameters of water quality. Enterococci concentrations were positively correlated with the turbidity associated with high-flow conditions. The predictive accuracy of high enterococci levels during high-flow conditions was good (mean percentage correctly classified, 60%). The prediction of high enterococci levels at low flows was significantly less reliable (mean percentage correctly classified, 12-15%). As the ACT is expected to experience decreases in rainfall overall but increases in extreme rainfall events due to climate change, understanding the drivers of elevated intestinal enterococci under extreme flow conditions remains important from a public health perspective. [ABSTRACT FROM AUTHOR]

The Murray–Darling Basin covers parts of four States of Australia and the whole of the Australian Capital Territory. As at 2002, its water management was well regarded internationally. Basin flows are low and variable. The most reliable streams show variations of about 12:1 between maximum and minimum annual natural flows. The longest tributary, the Darling, has a ratio of infinity. It was recognized in the 1980s that extractions from the system, largely for irrigation, had to be constrained. That led to the introduction of the "Murray‐Darling Basin Cap" which limited extractions and recognized the probability of average inflows declining, which was already being predicted by climate change modelling. The "millennium drought" of 2000–2009 was very severe and led to fears that the drop in inflows was happening faster than modelling was predicting. In 2007, the National Government, on the eve of an election, declared that the Basin had been mismanaged for a century by the States and legislated to transfer management powers from the States to the Commonwealth. That transfer has been pursued since then by National Governments of both major parties. Government claims to have "taken the politics out of Basin management and returned to the science." The evidence is that the exact opposite has occurred. The paper traces the history of water management in the Basin. © 2020 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Anthropogenic warming of the global climate system is beyond doubt. Impacts from a changing climate are already occurring and the latest scientific research suggests that some aspects are locked in for centuries to come. Climate change therefore poses one of the greatest challenges to Australia's environment and water resources. Historical experience and past trends may no longer be a reliable predictor of the future. This article provides a brief overview of the latest scientific research and thinking on the climate change challenge. Observed changes and projections for temperature, rainfall, extreme events and ocean acidification are presented in an Australian context. The impacts of a range of climate change drivers are summarised, expanding upon the well-accepted general warming and drying trend for southern and eastern Australia. Current thinking regarding 'dangerous' climate change is that we are tracking on the higher end scale or above of the worst case scenario predictions reported by the IPCC Fourth Assessment Report (IPCC AR4) released in 2007. The implications for Australia's water resources, and in particular the Murray-Darling Basin, are significant. There appears to be a brief window of opportunity to act and adapt to enhance resilience to climate change; however, this requires an urgent and sustained commitment, and investment in Australia's environmental assets. [ABSTRACT FROM AUTHOR]

Droughts, changing weather patterns due to climate change, unsustainable state and federal government policies and parochial self interest has brought the major irrigated agricultural region of Australia, the Murray-Darling Basin close to collapse. The present state of the Basin together with the predictions of computer modelling of future climate changes over the next few decades is discussed in relation to the existing attitudes of vested interests at all levels and the various policies now being undertaken by governments in an attempt to address the major problems. [ABSTRACT FROM AUTHOR]