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In a recent issue of Water International, three authors discuss their views of the virtual water metaphor that is used to describe the water embedded in crops that are traded in international markets. The term 'virtual water' was created originally to gain the attention of public officials responsible for choosing policies that influence water use in arid regions. Over time, both the terminology and the scope of the virtual water metaphor have been extended beyond the original purpose. This paper supports the view that the virtual water metaphor is helpful in encouraging public officials to consider the scarcity value (opportunity cost) of water when designing policies that influence water use. The paper proposes, also, that the policy relevance of the virtual water metaphor is found primarily in its application to issues regarding the supply of agricultural products, rather than demand. The distinction between supply and demand issues and the potential value of the virtual water metaphor in policy discussions regarding supply are demonstrated using three examples of water allocation decisions, described within the framework of economic optimization. The examples include wheat production in Saudi Arabia and the production of sudangrass and ethanol in the United States. [ABSTRACT FROM AUTHOR]

This article presents information on the achievements and activities of the International Water Resources Association (IWRA) of the United States. IWRA has achieved considerable landmarks in the year 2005. The Association has leaped forward despite major water disasters in the world starting with South Asian Tsunami and the major damage of Hurricanes in the United States and the persistent drought in Africa. The Association has also completed the 12th World Water Congress in New Delhi, India. Around 500 participants from 50 countries attended the conference. They presented some 200 papers and key note addresses focusing on the contemporary water issues of the day. In this conference, the members of the Association added several special sessions to highlight specific regional water issues of interest to all the participants. It was a learning experience for all the participants. The occasion was accompanied by an excellent dose of cultural events and surrounded with traditional Indian hospitality. Apart from the New Delhi conference IWRA has sponsored and co-sponsored several events in the United States, Finland, Sweden, Italy, Egypt, China and elsewhere to strengthen the dialogue on water issues across the world.

The Water Evaluation and Planning Version 21 (WEAP21) Integrated Water Resource Management (IWRM) model seamlessly integrates water supplies generated through watershed-scale hydrologic processes with a water management model driven by water demands and environmental requirements and is governed by the natural watershed and physical network of reservoirs, canals, and diversions. This version (WEAP21) extends the previous WEAP model by introducing the concept of demand priorities and supply preferences, which are used in a linear programming heuristic to solve the water allocation problem as an alternative to multi-criteria weighting or rule-based logic approaches. WEAP21 introduces a transparent set of model objects and procedures that can be used to analyze a full range of issues faced by water planners through a scenario-based approach. These issues include climate variability and change, watershed condition, anticipated demands, ecosystem needs, the regulatory environment, operational objectives, and available infrastructure. [ABSTRACT FROM AUTHOR]

Water quality is an urgent problem in Harare's main water supply source, Lake Chivero, while water scarcity will be a problem soon. This study focuses on sustainable ways of urban water and nutrient (nitrogen and phosphorus) management in Harare, part of the Lake Chivero catchment. The Dublin Principles on water conservation, environmental protection, reuse, and economic utilization of water were used as a basis for formulating innovative and responsive solutions. External and internal drivers for future evolution of wastewater approaches are identified. Water conservation, treatment, and reuse strategies are developed including water-saving devices, regulation, leak detection and repair and including wastewater treatment and reuse. The three levels where wastewater can be handled – onsite, decentralized, and centralized – are discussed and solutions formulated. Based on this, a strategic framework, the so-called "3-Step Strategic Approach," is then developed aimed at the sustainable use of water nutrients, and other resources in the urban environment. This 3-Step Strategic Approach consists of pollution prevention and minimization (Step 1), reuse after treatment (Step 2), and discharge into the environment with stimulation of self-purification capacity of the receiving environment (Step 3). The 3-Step Strategic Approach was subsequently applied to the Lake Chivero catchment, which demonstrated that these strategies could substantially reduce current water pollution and future water scarcity problems in Harare. [ABSTRACT FROM AUTHOR]