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More than a third of humanity lives in regions with less than 1 million liters of fresh water per person per year. Population growth will increase water demand while climate change in arid and semi-arid areas may reduce water availability. The Murray-Darling Basin in Australia is a region where water reform and planning have been used to reduce consumptive extraction to better sustain river ecosystems under climate variability. Using actual data and previously published models that account for climate variability and climate change, the trade-off between water extractions and water essential to the long-term ecological function of river systems is analysed. The findings indicate that better water planning and a more complete understanding of the effects of irrigation on regional climate evapotranspiration could: (1) increase the overall benefits of consumptive and non-consumptive water use; (2) improve riparian environments under climate variability; and (3) be achieved with only small effects on the profits and gross value of food and fiber production.

Risks to shared water resources in the Murray–Darling Basin are reviewed after the report by CSIRO on the same topic in 2006. CSIRO outlined six major risks to shared water resources in the Basin. Herein, six groups of researchers have reviewed the risks of climate change, forest growth, groundwater, water infrastructure, water quality, and governance. These reviews bring an updated understanding of risk assessment and management that can contribute to the forthcoming reviews of the Water Act and Basin Plan in 2024–26. Drawing on these six papers, the authors synthesise knowledge of the risks to shared water resources and identify policy and management options and information gaps. We find that few risk factors have decreased in significance. Most risks remain and new risks are identified. Water managers must plan for a significant decrease in water availability and governments need to actively manage these risks under conditions of increasing uncertainty. [ABSTRACT FROM AUTHOR]

The threats of climate change and the trade-offs between extractions and flows are examined for the Colorado, the Murray, the Orange and the Yellow Rivers. In all four basins, and over a long period of time, outflows have greatly reduced as a direct result of increased water extractions. Although climate change will aggravate hydrological impacts on river systems, currently high levels of water extractions remain the principal contributor to reduced system flows. Changes in governance, including sharing the variability between the environment and consumers, are urgently required if the health of these rivers is to be maintained. [ABSTRACT FROM AUTHOR]

Responding to the threat of climate change, conserving freshwater ecosystems and securing adequate energy and water supplies are among the greatest challenges facing modern societies. Yet recognition of the interdependencies between climate, energy and water policy—with resulting synergies and trade-offs—remains limited, leaving societies and governments alike vulnerable to the dangers of conflicted or unintended policy outcomes from sectoral decisions. In this paper, we analyse current Australian climate, energy and water policies to identify the risks of perverse outcomes between the three policy sectors. In doing so we categorise the conflicts and synergies between particular energy generation, carbon sequestration and water supply policies to improve understandings of the challenges facing decision makers in Australia and internationally. Four types of interventions are identified that would enable integration and optimisation of policies, namely: better cross-sectoral knowledge to inform decisions; the identification of technologies with co-benefits; markets with broader cross-sectoral participation (including linking water and carbon markets); and better-integrated governance institutions. [ABSTRACT FROM AUTHOR]

Abstract: Proposed dam construction in the Lower Mekong Basin will considerably reduce fish catch and place heightened demands on the resources necessary to replace lost protein and calories. Additional land and water required to replace lost fish protein with livestock products are modelled using land and water footprint methods. Two main scenarios cover projections of these increased demands and enable the specific impact from the main stem dam proposals to be considered in the context of basin-wide hydropower development. Scenario 1 models 11 main stem dams and estimates a 4–7% increase overall in water use for food production, with much higher estimations for countries entirely within the Basin: Cambodia (29–64%) and Laos (12–24%). Land increases run to a 13–27% increase. In scenario 2, covering another 77 dams planned in the Basin by 2030 and reservoir fisheries, projections are much higher: 6–17% for water, and 19–63% for land. These are first estimates of impacts of dam development on fisheries and will be strongly mediated by cultural and economic factors. The results suggest that basic food security is potentially at a high risk of disruption and therefore basin stakeholders should be fully engaged in strategies to offset these impacts. [Copyright &y& Elsevier]

Water and energy are each recognized as indispensable inputs to modern economies. And, in recent years, driven by the three imperatives of security of supply, sustainability, and economic efficiency, the energy and water sectors have undergone rapid reform. However, it is when water and energy rely on each other that the most complex challenges are posed for policymakers. Despite the links and the urgency in both sectors for security of supply, in existing policy frameworks, energy and water policies are developed largely in isolation from one another--a degree of policy fragmentation that is seeing erroneous developments in both sectors. Examples of the trade-offs between energy and water security include: the proliferation of desalination plants and interbasin transfers to deal with water scarcity; extensive groundwater pumping for water supplies; first-generation biofuels; the proliferation of hydropower plants; decentralized water supply solutions such as rainwater tanks; and even some forms of modern irrigation techniques. Drawing on case studies from Australia, Europe, and the United States, this Special Issue attempts to develop a comprehensive understanding of the links between energy and water, to identify where better-integrated policy and management strategies and solutions are needed or available, and to understand where barriers exist to achieve that integration. In this paper we draw out some of the themes emerging from the Special Issue, and, particularly, where insights might be valuable for policymakers, practitioners, and scientists across the many relevant domains. [ABSTRACT FROM AUTHOR]

Water infrastructure development is key to attaining sustainable development, especially for water supply, sanitation and health, agricultural development, and energy production. However, sub-Saharan African countries face specific challenges around infrastructure financing, systemic and repeated malfunctioning, and decentralised infrastructure types. Using Nigeria as a case, this article aims to analyse historical water infrastructure development in Nigeria with a specific focus on dams and standpipes. Seven themes are discussed: infrastructure divisions; deprioritising water supply; political infrastructures; infrastructure failure and sustainability; infrastructure classification and typologies; optimal use of water resources and infrastructure; and a commentary on the future of water infrastructure development. The article concludes with policy and research suggestions for policymakers and other relevant stakeholders. [ABSTRACT FROM AUTHOR]

Improving crop productivity is crucial to food security and rural livelihoods in southern Africa. However, agricultural intensification at irrigation schemes may place greater demands on water resources, even where water use efficiency (WUE) is improved, due to the paradox of irrigation efficiency. We analysed trends in water use efficiency (WUE), Gross Primary Productivity (GPP), evapotranspiration (ET), evaporation (E), and transpiration (T) at six irrigation schemes which received technological and social interventions. GPP was decoupled from ET at some schemes. For example, at the Landela sub-block of the Silalatshani irrigation scheme in Zimbabwe, GPP and T increased at 4.8% and 4.6% per year, respectively. Conversely, E decreased at 13.5% per year, giving a 3.6% decrease in ET per year from 2013 to 2021. This suggests that crop production can be decoupled from water consumption at southern African irrigation schemes, meaning it is possible to produce more food with less water. [Display omitted] • Water use efficiency was estimated with remote sensing for smallholder irrigation schemes in southern Africa. • Gross primary productivity (GPP) was decoupled from evapotranspiration (ET) at some schemes. This means more crops have been grown with less water. • Decoupling was not observed at all irrigation schemes and is likely to be context dependent. [ABSTRACT FROM AUTHOR]