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Many parts of Australia have experienced their worst single- and multi-year droughts on record over the last decade. These recent climate conditions have severely stressed our water supply systems and the communities that depend on them. With the threat of climate change potentially further exacerbating droughts in the years ahead, Engineers Australia firmly believes that: (i) A national review of the adequacy of drought response plans is urgently required. A recent national overview of long-term water resources planning by the Academy of Technological Sciences and Engineering (ATSE, 2007) revealed large inconsistencies and inadequacies in the standard of that planning. Based on the knowledge of the authors of this paper, similar outcomes are expected in the area of drought response planning. The scope of the review should include assessment of the transparency and defensibility of the timing of implementation of drought response actions; (ii) Continuing investment is needed in climate research to better understand the underlying drivers of our climate variability and their interactions at a range of time scales. The majority of research to date has focused on short -term sea surface temperature or pressure differentials across the globe (eg. the El Niño/Southern Oscillation) without understanding the longer-term drivers behind these temperature and pressure responses, which are being investigated through the Indian Ocean Climate Initiative and, more recently, the South East Australia Climate Initiative. This investment should include consolidation for and communication to the water industry of existing knowledge of links between long-term climate variability and key climate drivers including Earth’s orbital cycles, solar activity, atmospheric chemistry, major volcanic eruptions, surface and deeper ocean circulations (including the thermohaline circulation – the “great ocean conveyor belt”), sea ice, and major bush fires; (iii) Greater collaboration is required between climatologists, paleoclimatologists and water resource engineers to take advantage of recent scientific advances that have direct implications for drought response planning. Engineers Australia proposes that the National Water Commission should conduct a national forum to bring these three industry groups together with the aim of providing meaningful, useful advice to water industry practitioners from the latest climate research and to guide research activities towards more practical outcomes. This will enable water resource planners to better understand natural climate variability in the longer term and appropriately take into account greenhouse gas induced climate change, including an understanding of uncertainties surrounding both current and future climate; (iv) The development of an industry standard end-use demand model for urban areas should be accelerated. The absence of an industry standard tool in this area currently inhibits the ability to rapidly assess the financial costs of imposing restrictions on particular sectors of the community versus supply augmentation costs to avoid those restrictions. Such a tool is needed to make informed decisions about preparedness to pay for new infrastructure to avoid or reduce restrictions; and (v) More sophisticated water products and market mechanisms have a strong role to play in better managing scarce resources between similar types of users during times of drought. This has become increasingly important with demand hardening over recent decades, which has reduced the water savings that are achievable from water restrictions. Any expansion of water markets as a drought management tool must, however, occur within a regulatory framework that seeks to achieve equitable social outcomes by acknowledging the inherent social value of water to communities and the food security value of water to the nation. It is acknowledged in preparing this position paper that our understanding of drought and our responses to it are rapidly changing, particularly in light of climate change. This is particularly the case with the current reviews of aspects of the National Drought Policy, which were being undertaken by several government agencies at the time of drafting this paper. It is hoped that this position paper will encourage both greater dialogue and investment in drought forecasting, planning, adaptation and mitigation to enable Australia to be well placed to cope with future climate conditions. [ABSTRACT FROM AUTHOR]

Governments in Australia are purchasing water entitlements to secure water for environmental benefit, but entitlements generate an allocation profile that does not correspond fully to environmental flow requirements. Therefore, how environmental managers will operate to deliver small and medium-sized inundation environmental flows remains uncertain. To assist environmental managers with the supply of inundation flows at variable times, it has been suggested that allocation trade be incorporated into efforts aimed at securing water. This paper provides some qualitative and quantitative perspective on what influences southern Murray-Darling Basin irrigators to trade allocation water at specific times across and within seasons using a market transaction framework. The results suggest that while irrigators now have access to greater risk-management options, environmental managers should consider the possible impact of institutional change before intervening in traditional market activity. The findings may help improve the design of intervention strategies to minimise possible market intervention impacts and strategic behaviour. [ABSTRACT FROM AUTHOR]

Summary Large overbank flood events play an important role in maintaining large-scale ecological processes and connectivity along and across the floodplains and between the rivers and their floodplains in the southern Murray-Darling Basin. However, the regulation of rivers means that extensive overbank flooding can only occur in the rare circumstance of extreme flood events. Recent environmental water allocations have focussed on the largest floodplain blocks ('icon' sites) and a small set of specific values (e.g. colonial nesting waterbirds), as well as on trialling fine-scale manipulation of infrastructure (e.g. pumping) to water relatively small areas. There has been no comprehensive systematic assessment of the entire floodplain and its wider set of flood-dependent natural assets (such as ecosystems and species; herein referred to as 'natural values') to maximise the effectiveness of environmental water use and to catalogue values likely to be lost. This paper describes an assessment of some 220 000 ha found to support flood-dependent natural values in Victoria. We mapped the geographic distribution and estimated components of the flooding requirements (natural flooding frequency, and maximum period without flooding and minimum duration of each flooding event before significant deterioration) for each natural value. Using an example of one stretch of the River Murray, we show how the resultant spatial data can be used with floodplain inundation modelling to compare the outcomes of real or planned environmental watering events; potentially providing tools for management agencies to conserve a wider range of floodplain values than is currently the case. That is, water managers and the public can see what ecosystems and threatened species are intended to be maintained by environmental watering and what values are intended to be abandoned across the whole floodplain, rather than just seeing the small subset of values and 'icon' sites that are intended to be maintained. Examples are provided to illustrate how information about the location, water requirements and extent covered by potential floods for specific values can be used to build adaptive watering strategies for areas as large as the whole floodplain. [ABSTRACT FROM AUTHOR]

Policy to protect river ecosystems has changed rapidly in Australia, and the mechanisms to both establish and manage environmental water are still evolving. Policy has moved from providing a fixed environmental target (albeit varying between years) to one in which the environment can actively participate in the market, with the possibility of better fulfilling variable water requirements. However, the inherent nature of the sustainable diversion limit (SDL), established under the Water Act 2007, is that it represents a fixed allocation to the environment. This paper considers the interaction of the new SDL for the Murray-Darling Basin and potential issues arising from the interaction with the government buyback initiative. While both the SDL and buyback have been discussed extensively, the interaction between the two policies has received little debate. Pairing these two policy initiatives will have implications for the flexibility of management of the environmental water, and the ability for on-going trade between the environment and consumptive water users. Our position is that the SDL, or preferably rules-based water, should reflect an absolute minimum limit on environmental water requirements, while the buyback should provide the environmental water as tradable water rights with the flexibility to respond to shifts in the environmental water demand curve by providing environmental water over and above the SDL. If both a buyback and minimum flow rules are in place, the SDL will provide little additional benefits but increase administrative costs and reduce flexibility. This has significant implications for the way the SDL and buyback strategy are structured. [ABSTRACT FROM AUTHOR]

Conjunctive use of groundwater is a common irrigation response to limited surface water availability. In the late 1970s, under a “one resource policy”, the New South Wales (NSW) government of Australia began issuing a form of conjunctive licence to irrigators with access to both surface water and groundwater. These licences were intended to provide the licence owners with the water supply security offered by conjunctive use. Institutional separation of groundwater and surface water prevented accounting across the resources. As a result, the licences contributed towards over-allocation of groundwater. Conjunctive licences were subsequently discontinued and separated into surface water and groundwater components in the late 1990s. This paper explores the NSW experience of conjunctive licences in light of Australia’s 2004 national agreement to manage connected surface water and groundwater as one resource. The conclusion is that fl ow systems cannot be allocated as “one resource” if managed through independent groundwater and surface water planning institutions. Some implications and options for allocation across local water resources with hydraulic connectivity are considered. [ABSTRACT FROM AUTHOR]

Over the past few decades, many numerical streamflow prediction techniques using observed time series (TS) have been developed and widely used in water resources planning and management. Recent advances in quantitative rainfall forecasting by numerical weather prediction (NWP) models have made it possible to produce improved streamflow forecasts using continuous rainfall-runoff (RR) models. In the absence of a suitable integrated system of NWP, RR and river system models, river operators in Australia mostly use spreadsheet-based tools to forecast streamflow using gauged records. The eWater Cooperative Research Centre of Australia has recently developed a new generation software package called eWater Source, which allows a seamless integration of continuous RR and river system models for operational and planning purposes. This paper presents the outcomes of a study that was carried out using Source for a comparative evaluation of streamflow forecasting by several well-known TS based linear techniques and RR models in two selected sub-basins in the upper Murray river system of the Murray-Darling Basin in Australia. The results were compared with the actual forecasts made by the Murray River operators and the observed data. The results show that while streamflow forecasts by the river operators were reasonably accurate up to day 3 and traditional TS based approaches were reasonably accurate up to 2 days. Well calibrated RR models can provide better forecasts for longer periods when using high quality quantitative precipitation forecasts. The river operators tended to underestimate large magnitude flows. [ABSTRACT FROM AUTHOR]

The over-allocation and over-use of water in the Murray-Darling Basin has impacted adversely on the environment surrounding the Coorong and Lower Lakes and has caused the system to endure the longest period ever of reduced freshwater inflows and levels. Although the drought has broken and the Murray-Darling Basin has received significant rainfall in the past twelve months, paradoxically State governments are still fighting over water allocations. This article will explore current data regarding the social and planning implications of the degradation of the Coorong and Lower Lakes. It primarily focuses on the social impacts that will occur if the Coorong and Lower Lakes area is significantly environmentally degraded. Economic and environmental implications will also be explored to provide an understanding of the interdependencies. Interdependencies are complicated by legislative ambiguity about Federal and State legislation and responsibilities for the area, significant proportions of, which are subject to international environmental agreements. Further research is required on the functionality of these communities, which are challenged by significant environmental change and ambiguous responses from Federal and State Governments. Drawing on Beck's (2007) risk theory, this paper analyses the adaptive capacity of settlements in the Coorong and Lower Lakes area and how they respond to the stresses and risks caused by environmental degradation. The Coorong and Lower Lakes environmental state is an issue that requires immediate action by governments and the surrounding community. This article provides a foundation and theoretical structure for further investigative research to be undertaken. [ABSTRACT FROM AUTHOR]

This paper presents a hedonic property price model of rural land in a natural resource management region of the Murray-Darling Basin in Australia. In traditional hedonic models, the marginal value of environmental amenities is estimated using distance to or size of the environmental asset. The approach applied in this study offers the potential for a richer set of information, where environmental assets are described in terms of their ‘recreational attractiveness’. The level of recreational attractiveness is represented as latent variables that are based on park facilities and recreational activities offered at each site. For a property in the study area that is 1 km away from the River Murray, moving half a kilometre closer will increase the property price by $245,000, holding every other variable constant at the mean. This value is magnified by $27,000 if the house is in an area where there is high river recreational attractiveness and drops by $14,000 if river recreational attractiveness is low. By including recreational quality indices in a typical hedonic framework that is corrected for spatial dependency, the model is able to capture how individuals value environmental amenities around their homes based on the site’s natural characteristics as well as recreational services. [Copyright &y& Elsevier]

There is currently a distinct gap between what climate science can provide and information that is practically useful for (and needed by) natural resource managers. Improved understanding, and model representations, of interactions between the various climate drivers (both regional and global scale), combined with increased knowledge about the interactions between climate processes and hydrological processes at the regional scale, is necessary for improved attribution of climate change impacts, forecasting at a range of temporal scales and extreme event risk profiling (e.g., flood, drought, and bushfire). It is clear that the science has a long way to go in closing these research gaps; however, in the meantime water resource managers in the Murray-Darling Basin, and elsewhere, require hydroclimatic projections (i.e., seasonal to multidecadal future scenarios) that are regionally specific and, importantly, take into account the impacts, and associated uncertainties, of both natural climate variability and anthropogenic change. The strengths and weaknesses of various approaches for supplying this information are discussed in this paper. [ABSTRACT FROM AUTHOR]

In Australia's Murray-Darling Basin the Australian and state governments are attempting to introduce a system of water management that will halt ongoing decline in environmental conditions and resource security and provide a robust foundation for managing climate change. This parallels similar efforts being undertaken in regions such as southern Africa, the southern United States, and Spain. Central to the project is the Australian government's Water Act 2007, which requires the preparation of a comprehensive basin plan expected to be finalized in 2011. This paper places recent and expected developments occurring as part of this process in their historical context and examines factors that could affect implementation. Significant challenges to the success of the basin plan include human resource constraints, legislative tensions within the Australian federal system, difficulties in coordinating the network of water-related agencies in the six jurisdictions with responsibilities in the Murray-Darling Basin, and social, economic, and environmental limitations that restrict policy implementation. [ABSTRACT FROM AUTHOR]

Abstract: The “Big Dry”, a prolonged dry period in Australia from 1997 to 2009, dried out much of the Murray-Darling Basin (MDB) and resulted in large agricultural losses and degraded river ecosystems. Climate projections are that dry conditions in the MDB are likely to be more regular and severe than ever before, and recent policy initiatives are likely to reduce consumptive water use and redirect water to ecosystem management. This paper aims to develop an understanding of the interactions between water policy and irrigation practices by deriving lessons from drought management in irrigated agriculture of the MDB during the Big Dry, and furthermore, to draw out lessons to enhance the preparedness of irrigated agriculture for a future drier climate and reduced water availability. Reviews of irrigation farmers’ practices, attitudes and capacity to manage during prolonged droughts in the MDB, and the evolution of agricultural water policy in Australia since 1990 were made. It is clear that farmers could be better prepared to deal with a drier climate if their water management practices, e.g. irrigation methods and soil moisture measuring tools are improved, if the impediments to the uncertainty of water allocation and low water availability could be overcome, and if well-targeted research and extension could assist farmers to use water more wisely. It is also clear that Australian water policy could be better prepared in terms of assisting irrigated agriculture to deal with a drier climate. Key areas are reduction of barriers and distortions to water trading, optimizing the environmental water allocation, and seeking mutual benefits between environmental water allocation and irrigated agriculture, improvement of the cost-effectiveness of investments in water supply infrastructure, facilitating carryover and capacity sharing at larger scales, and provision of accurate, accessible and useful water information at different scales. An approach to irrigation practice and water policy is proposed based on past experience and potential opportunities. The approach is a set of linked strategies for more robust agricultural production and a more sustainable environment under a drier climate and reduced water availability. [Copyright &y& Elsevier]

Water markets have featured prominently in the reallocation of water rights to restore freshwater ecosystem health. Incentive-based water rights acquisition and transactions have emerged as a market-oriented policy approach to reallocate water resources from existing uses to enhance the provision, regulation, and sustainability of freshwater ecosystem services. This paper develops a conceptual framework to examine factors enabling and constraining successful policy reform and implementation in market-based environmental water allocation. This analysis distills and extends the findings and lessons of a September 2007 workshop in Brisbane, Australia on environmental water transactions. Two case studies were selected in water stressed basins – the Columbia (U.S.) and Murray-Darling (Australia) Basins – where transactional approaches to environmental water allocation first emerged. The case studies draw upon practitioner perspectives and previous policy and economic analysis in two regions where shared political economic and physical conditions lend a strong analytical basis for comparison. A common set of policy and regulatory reforms has occurred in both cases – albeit in different forms and via distinct paths – to develop three enabling conditions: (1) establishment of rights to and limits on freshwater extraction and alteration; (2) recognition of the environment as a legitimate water use; and (3) authority to transfer existing water rights to an environmental purpose. However, these elements of policy reform are necessary but not sufficient for effective implementation; a second set of driving forces, barriers, and adaptations explains the ability to achieve larger scale ecological outcomes. These conditions include the physical, social and economic factors driving demand for environmental water allocation; administrative procedures, organizational development and institutional capacity to effect transfers; and adaptive mechanisms to overcome legal, cultural, economic, and environmental barriers. The case study analysis suggests that environmental water transactions can play an important role in establishing environmental water allocations, although water markets require ongoing institutional capacity and adaptive governance. The conceptual framework and empirical lessons generated through this cross-case comparison provide the basis for an expanded research agenda to evaluate the design and performance of market-oriented reforms as implementation experience accrues and new programs emerge in diverse ecological and political economic settings. [Copyright &y& Elsevier]

Policy instruments designed to increase environmental flows in the Murray-Darling Basin are compared using TERM-H2O, a detailed, dynamic regional CGE model. Voluntary and fully compensated buybacks are much less costly than infrastructure upgrades as a means of obtaining a target volume of environmental water, even during drought, when highly secure water created by infrastructure upgrades is more valuable. As an instrument of regional economic management, infrastructure upgrades are inferior to public spending on health, education and other services in the Basin. For each job created from upgrades, the money spent on services could create between three and four jobs in the Basin. [ABSTRACT FROM AUTHOR]

Isolating the causes of extreme variations or changes in the hydroclimate is difficult due to the complexities of the driving mechanisms, but it is crucial for effective natural resource management. In Australia's Murray-Darling Basin (MDB), ocean-atmosphere processes causing hydroclimatic variations occur on time scales from days to centuries, all are important, and none are likely to act in isolation. Instead, interactions between all hydroclimatic drivers, on multiple time scales, are likely to have caused the variations observed in MDB instrumental records. A simplified framework is presented to assist natural resource managers in identifying the potential causes of hydroclimatic anomalies. The framework condenses an event into its fundamental elements, including its spatial and temporal signal and smallscale evolution. The climatic processes that are potentially responsible are then examined to determine possible causes. The framework was applied to a period of prolonged and severe dry conditions occurring in the southern MDB from 1997-2010, providing insights into possible causal mechanisms that are consistent with recent studies. The framework also assists in identifying uncertainties and gaps in our understanding that need to be addressed. [ABSTRACT FROM AUTHOR]

Over-abstraction of water places unsustainable pressures on river ecosystems, with the impacts amplified under drought conditions. Freshwater fishes are particularly vulnerable due to associated changes in water quality, and habitat availability, condition and connectivity. Accordingly, fish assemblages are ideal indicators of the impacts of drought and over-abstraction. The Murray-Darling Basin (MDB), south-eastern Australia, terminates at the Ramsar listed Coorong and Lower Lakes, which comprise Lake Alexandrina and Lake Albert. Over-abstraction and extreme drought during the last decade has placed these lakes under severe environmental stress. The purpose of this study was to investigate shifts in fish assemblages caused by substantial water level recession and salinization in the Lower Lakes. Small-bodied fish assemblages were sampled at the beginning and several years into the drought. Off-lake habitats held diverse fish assemblages in 2003, but most sites were dry by 2009. Remaining habitats were disconnected, salinities increased substantially, and aquatic vegetation shifted from freshwater to salt-tolerant species. There was a substantial decline in the proportion of specialist species, especially diadromous and threatened species, and an emerging dominance of generalist freshwater and estuarine species. The findings warn of the inevitable ecological impact of over-allocating water for human use in drought-prone regions, and highlight the need for adequate environmental water allocations. This study also emphasises that understanding the ecological attributes of a fish species, and the subsequent assignment to a functional group, will help predict vulnerability to decline and extirpation. [ABSTRACT FROM AUTHOR]

The ecology of dryland rivers is driven by their highly variable hydrology, particularly flooding regimes, whereby intermittent floods typically generate 'booms' of primary and secondary productivity, including massive fish production. We tested these concepts in the Moonie River, Australia, using the percichthyid, Macquaria ambigua, a dryland river species known to display pronounced 'boom and bust' abundance patterns in response to floodplain inundation followed by extended periods of low to no channel flow. We expected that body condition (as measured by whole body lipid content) and biomass of M. ambigua would be related to prey biomass, and that these factors would all 'spike' following widespread flooding. Instead we found more subtle responses. There were 'booms' in biomass of Macrobrachium and zooplankton, two important food items, whereas M. ambigua maintained relatively low but sustained lipid and biomass levels following flooding. It appears that instead of a 'boom' in fish biomass, abundant invertebrate food resources and sustained lipid levels contributed to high survivorship of this species during the 'bust' period over cool dry months. [ABSTRACT FROM AUTHOR]

The desire to base policy at least in part upon scientific information is a clear trend in Australian governance. The growing literature on how to facilitate this intent highlights a few important principles complemented by examples from the application of social sciences. An example from a very large research project based on physical sciences responding to a national crisis is presented in the context of how it approached delivery to policy-makers. The Murray-Darling Basin Sustainable Yields Assessment, widely considered an outstanding success in both scientific terms and for its impact, is reviewed with respect to how the scientific challenge of assessing the future security of water resources in Australia's most important and politically contentious catchment translated into the policy domain. The lessons learned offer a potential template for science with policy intent. [ABSTRACT FROM AUTHOR]

Water buybacks in the Murray-Darling Basin entail compensation at market prices for water sold by farmers to the Commonwealth. Despite this, the Murray Darling Basin Authority met with hostility at public meetings in basin communities late in 2010. This reflects hardship arising from three consecutive years of drought rather than the consequences of buybacks. Dynamic CGE modelling results indicate that around 6000 jobs were lost due to the 2006-07 to 2008-09 drought in the Murray Darling Basin. Even in the long run, years after a rainfall recovery, jobs will remain 1500 below forecast due to lost years of investment during prolonged drought. This contrasts with 500 jobs lost across the basin due to buybacks. Some industry groups and politicians have asserted that buybacks will result in rural catastrophe. This underestimates the adaptability of farmers in response to a voluntary and fully compensated process, and confuses the impacts of drought and buybacks. Nevertheless, there are aspects of the 2007 Water Act that warrant modification in order to move towards a socially optimal restoration of environmental flows in the Murray-Darling Basin. [ABSTRACT FROM AUTHOR]

This article presents an integrated framework for assessing water markets in terms of their institutional foundations, economic efficiency, and environmental sustainability. This framework can be a tool for (a) comparing different water markets, (b) tracking performance over time, and (c) identifying ways in which water markets might be adjusted by policy makers to achieve desired goals. The framework is used to identify the strengths and limitations of five water markets: (a) Australia’s Murray-Darling Basin, (b) the western United States, (c) Chile (in particular the Limarí Valley), (d) South Africa; and (v) China (in particular, the North). The framework helps identify which of these water markets are currently able to contribute to integrated water resource management, which criteria underpin these markets, and which features of these markets may require further development. The findings for each market, as well as comparisons between them, provide general insights into water markets and how water governance can be improved. [ABSTRACT FROM AUTHOR]

Microsatellite markers were utilized to examine the genetic structure of Murray cod Maccullochella peelii throughout its distribution in the Murray-Darling Basin (MDB) of eastern Australia, and to assess the genetic effects of over three decades of stocking hatchery-reared fingerlings. Bayesian analysis using the programme Structure indicated that the species is largely genetically panmictic throughout much of its extensive range, most probably due to the high level of connectivity between catchments. Three catchments with terminal wetlands (the Lachlan, Macquarie and Gwydir), however, contained genetically distinct populations. No stocking effects were detected in the catchments that were genetically panmictic (either because of low genetic power or lack of effects), but the genetically differentiated Gwydir and Macquarie catchment populations were clearly affected by stocking. Conversely, there was no genetic evidence for survival and reproduction of stocked fish in the Lachlan catchment. Therefore, stocking of M. peelii throughout the MDB has resulted in a range of genetic effects ranging from minimal detectable effect, to substantial change in wild population genetic structure. [ABSTRACT FROM AUTHOR]

The study used a modelling approach to assess the potential impacts of likely climate change and increase in CO concentration on the wheat growth and water balance in Murray-Darling Basin in Australia. Impacts of individual changes in temperature, rainfall or CO concentration as, well as the 2050 and 2070 climate change scenarios, were analysed. Along an E-W transect, wheat yield at western sites (warmer and drier) was simulated to be more sensitive to temperature increase than that at eastern sites; along the S-N transect, wheat yield at northern warmer sites was simulated to be more sensitive to temperature increase, within 1-3°C temperature increase. Along the E-W and S-N transects, wheat at drier sites would benefit more from elevated [CO] than at wetter sites, but more sensitive to the decline in rainfall. The increase in temperature only did not have much impact on water balance. Elevated [CO] increased the drainage in all the sites, whilst rainfall reduction decreased evapotranspiration, runoff and drainage, especially at drier sites. In 2050, wheat yield would increase by 1-10% under all climate change scenarios along the S-N transect, except for the northernmost site (Dalby). Along the E-W transect, the most obvious increase of wheat yields under all climate change scenarios occurred in cooler and wetter eastern sites (Yass and Young), with an average increase rate of 7%. The biggest loss occurred at the driest sites (Griffith and Swan Hill) under A1FI and B2 scenarios, ranging from −5% to −16%. In 2070, there would be an increased risk of yield loss in general, except for the cool and wet sites. Water use efficiency was simulated to increase at most of the study sites under all the climate change scenarios, except for the driest site. Yield variability would increase at drier sites (Ardlethan, Griffith and Swan Hill). Soil types would also impact on the response of wheat yield and water balance to future climate change. [ABSTRACT FROM AUTHOR]

Major modifications to river systems and their associated floodplains throughout the world have detrimental consequences for biodiversity. A reduction in the frequency of large-scale flooding events is one change that could have significant negative effects. In the Murray-Darling Basin of Australia many species of waterbirds breed in large colonies on inland floodplain systems when appropriate flooding occurs. Across the Murray-Darling Basin populations of many of these species are now at very low levels and breeding events occur much more infrequently than they did historically. I used an age-structured population model of a generic egret to assess how frequently breeding must occur to maintain populations. Using simulation I explored how sensitive results were to demographic parameter values. The results indicated that: (1) most egrets must breed every one to two years for populations to persist; and (2) the results are sensitive to adult survival, suggesting that management may also need to consider habitat availability between breeding events to ensure high adult survival. The results highlight a need to determine over what spatial scale egret populations function so that a sufficient frequency of breeding events is provided at the appropriate scale. Results were less sensitive to juvenile survival, but juvenile survival rates that average between 25 and 35% per year are probably required for persistence. Hence it is important that future research also determines whether the recent practice of managing breeding events only until fledging is achieved does not have a detrimental effect on juvenile survival. Maintaining a high frequency of flooding events that lead to successful breeding will be necessary for any species with similar life-histories. [ABSTRACT FROM AUTHOR]

We use TERM-HO in analysing the effects of the Government buying back water from irrigators in the Southern Murray-Darling Basin (SMDB) and thereby increasing river flows. TERM-HO is a dynamic multiregional computable general equilibrium model containing water accounts. Controversially, our results suggest that buyback would increase economic activity in SMDB. Although a scheme of environmentally useful size would sharply increase the price of irrigation water, there would be little effect on aggregate SMDB farm output. Instead, farm resources would be reallocated between activities. Because farmers are owners of water rights, they would benefit from the price increase induced by buyback. [ABSTRACT FROM AUTHOR]

Climate change has potentially significant implications for hydrology and the quantity and quality of water resources. This study investigated the impacts of climate change and revegetation on water and salt balance, and stream salt concentration for catchments within the Murray-Darling Basin, Australia. The Biophysical Capacity to Change model was used with climate change scenarios obtained using the CSIRO DARLAM 125 (125 km resolution) and Cubic Conformal (50 km resolution) regional climate models. These models predicted up to 25% reduction in mean annual rainfall and a similar magnitude of increase in potential evapotranspiration by 2070. Relatively modest changes in rainfall and temperature can lead to significant reductions in mean annual runoff and salt yield and increases in stream salt concentrations within the Basin. The modelled reductions in mean annual runoff were up to 45% in the wetter/cooler southern catchments and up to 64% in the drier/hotter western and northern catchments. The maximum reductions in salt yield were estimated to be up to 34% in the southern catchments and up to 49% in the northern and western catchments. These changes are associated with average catchment rainfall decreases of 13 to 21%. The results suggest that percentage changes in rainfall will be amplified in runoff. This study demonstrates that climate change poses significant challenges to natural resource management in Australia. [ABSTRACT FROM AUTHOR]

The article presents information on the undertakings of the Commonwealth of Australia from July to December 2009. Topics covered include the Henry Tax Review, the Council of Australian Government's increased focus on health issues, water conservation and the management of the Murray-Darling Basin, foreign relations with China and efforts by Liberal parliamentarians to undermine the leadership of politician Malcolm Turnbull. The article also includes examinations of the political undertakings of New South Wales, Victoria, Queensland, Western Australia, South Australia, Tasmania, the Australian Capital Territory.

We integrate information from several disparate data sources including agricultural statistics and remote sensing to quantify and map the distribution and dynamics of agricultural returns to land and water resources from 1996/1997 to 2000/2001 in the Murray–Darling Basin (MDB), Australia. Total profit to agriculture was estimated at AUD3.86B in 1996/1997 and AUD3.73B in 2000/2001. The mapping reveals a high spatial concentration of economic returns to land and water resources from agriculture. Dryland agriculture covers over 82% of the study area. Irrigated agriculture covers 1.7% of the land area (2000/2001) but returns one third of the total profit to agriculture. We found that around 80% of the profit to agriculture comes from just over 5% of the land area. The results from this regional scale economic mapping can inform regulatory policy and public investments in natural resource management through targeting industries and regions that provide low marginal returns to the natural resource base. [ABSTRACT FROM AUTHOR]

Silver perch, Bidyanus bidyanus (Mitchell), is a freshwater fish that is endemic to the Murray-Darling River System, Australia. Over recent decades, its distribution and abundance in the wild have declined, and it is now a threatened species with the conservation status of “vulnerable.” Silver perch is a schooling, omnivorous fish, with white flesh, few bones, and high levels of omega fatty acids, and its aquaculture potential has long been recognized. Hatchery techniques, based on hormone-induced spawning of captive broodfish in tanks and rearing of larvae in fertilized earthen ponds, were developed in the early 1980s. Fingerlings are currently used for stock enhancement and conservation or sold for commercial grow-out or stocking farm dams. Research into the grow-out of silver perch commenced in 1990 and demonstrated that it is an excellent fish for culture in static aerated earthen ponds with high survival rates (>90%), fast growth rates (2–5 g/fish/d) at high stocking densities (20,000/ha) leading to high production rates (10 tonnes/ha/yr). Since 1996, there has been research into nutrition, diet development, feeding strategies, broodfish domestication and management, culture in tanks and tank-based recirculating aquaculture systems, diseases, health management, genetic improvement, and cage culture. Silver perch is a hardy species that performs well under different culture conditions and on diets with no or low levels of fish meal. Technology has been transferred to industry through major conferences in 1994 and 2003 as well as workshops, field days, extension, seminars, and numerous scientific and technical publications. The high quality of silver perch and its excellent culture attributes suggest that the species has the potential to form a large industry based on high-volume, low-cost production. However, despite these features and a strong technical base provided by research and development, industry growth has been limited and a relatively small industry currently produces only around 500 tonnes annually. Development has been restricted by a number of factors: poor site selection and design of some farms; use of inappropriate husbandry and/or production strategies; difficulties with pond production, including significant losses to bird predation and diseases; high costs of feeds; limited marketing and promotion; no processing component; no large-scale investment; and the failure of many farms that were too small to be economically viable. Recent research has found that silver perch performs well in cages (high survival [>90%], good growth [1.7–3.5 g/fish/d], and high production rates [50–90 kg/m3]), and cage culture has advantages such as ease of management and prevention of bird predation that may help overcome some of the problems associated with pond production. Improved health management, new production strategies, cage culture, use of interstrain hybrids and other genetically improved fish, and integration with cotton and other irrigation industries offer opportunities for increased production and efficiencies, and further development of the silver perch industry. The potential of silver perch for commercial aquaculture remains very high. [ABSTRACT FROM AUTHOR]

With limited evidence linking Australia's Murray-Darling Basin fish species and flooding, this study assessed annual variation in abundance and recruitment levels of a small-bodied, threatened floodplain species, the Southern Pygmy Perch ( Nannoperca australis), in floodplain habitats (creeks, lakes and wetlands) in the Barmah-Millewa Forest, Murray River, Australia. Spring and summer sampling over a 5-year period encompassed large hydrological variation, including 1 year of extended floodplain inundation which was largely driven by an environmental water release, and 2 years of severe regional drought. Recruitment and dispersal of Southern Pygmy Perch significantly increased during the floodplain inundation event compared with the other examined years. This study provides valuable support for an environmental water allocation benefiting a native species, and explores the link between flooding and its advantages to native fish. This suggests that the reduced flooding frequency and magnitude as a result of river regulation may well be a major contributing factor in the species’ decline in the Murray-Darling Basin. [ABSTRACT FROM AUTHOR]

A second stygobitic carnivorous water beetle is reported from eastern Australia. Unlike the recently discovered Carabhydrus stephanieae (Watts et al.) from the same general region, the new species is from the inland draining Peel River, part of the Murray-Darling basin. Its morphology and mitochondrial DNA sequences, place it in the Hydroporine genus Paroster Sharp. Phylogenetic analysis shows that the new species is more closely related to the Western Australian species of Paroster than to the geographical less distant Paroster species of the Northern Territory. [ABSTRACT FROM AUTHOR]

The Standard Precipitation Index (SPI) is employed to track drought and assess the impact of rainfall on shallow groundwater levels in three selected irrigation areas of the Murray-Darling Basin in Australia. The continuous SPI method can provide better means of quantifying rainfall variability and correlating it with changes of shallow watertable levels since it is based on continuous statistical functions comparing rainfall variability over the entire rainfall record. Drought analysis in the Australian irrigation areas using SPI indicates that the recent 2000–2006 drought is not the worst drought that has occurred in the recorded history, however if the current low rainfall pattern continues, it would be one of the most prolonged drought. The shallow groundwater fluctuations in the Murrumbidgee Irrigation Area show a very strong correlation with winter rainfall variation. The shallow piezometric levels in the Coleambally Irrigation Area show a weaker degree of correlation with the SPI due to local and regional groundwater dynamics and changes in rice water use. The groundwater levels in the Murray Irrigation Area show least correlation with the SPI, which may be attributed to improved irrigation management practices and complex nature of the groundwater recharge and discharge processes in this area. The overall results however show that the SPI correlates well with fluctuations in shallow ground water table in irrigation areas, and can also capture major drought patterns in Australia. The correlation of SPI with groundwater levels can be adopted for environmental reporting and used as a method of relating climatic impacts on watertables. Differences in piezometric response between years with similar winter and yearly SPI values can be attributed to improvement in irrigators’ management practices. [ABSTRACT FROM AUTHOR]

Ideas of ‘community’ and ‘community voice’ have been mobilised in collaborative programs developed between the National Museum of Australia and the Murray-Darling Basin Commission since 1992. This collaboration is set within a broader context of changing ideas and practice around governance, community and environmental issues. The recent Murray-Darling Outreach Project (MDOP), a series of museum outreach projects with regional communities aiming to increase community engagement in local environmental issues in the Murray-Darling Basin, is specifically examined. Evaluation research on the MDOP found that the approach to program development significantly shaped the types of voices, range of issues presented and the nature of the communicative forums established. The potential impacts on online audiences are discussed along with broader implications for government agencies involved in community partnerships. [ABSTRACT FROM AUTHOR]