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The economy of Apulia Region largely depends on agriculture but the scarce water resources are the main factor threatening the sustainable production of this sector. This paper describes a geographical information system (GIS) based water balance tool that integrates maps of crops, climate and soil parameters with various scenarios of cropping pattern and farming practice changes. The aim is to assess the implication of these scenarios on the spatial and volumetric water needs of the region's irrigated agriculture. The total net volumetric irrigation needs, under current land use and full irrigation practices, were estimated on an average year to be 973 million m3. The deficit irrigation practices currently used in Capitanata water districts can save a volume of 302 million m3 if they are extrapolated over the entire region. Based on the Common Agricultural Policy (CAP), a replacement of 30% of the actual tomato areas in Foggia Province with sunflowers (energy crop) or durum wheat (rainfed crop) has potential water saving of 9 million m3 and 67 million m3, respectively. An additional 103 million m3 of water saving may be obtained through modernisation of the vineyards' growing practices. Findings of this paper could be used to address the agricultural policies towards a sustainable use of the scarce fresh water.

River Yamuna is an important river in India that flows through the national capital—New Delhi. The river water offers a variety of functional uses in its basin area. A progressive deterioration of river water quality had rendered it to become almost a channel of wastewater. However, there is a willingness-to-pay (WTP) for the conservation of river water quality among the citizens of the basin. This paper reports on an application of Contingent Valuation Method (CVM) for estimating the economic value of river water conservation (both for current water quality maintenance and for the restoration of river water quality). The results show that there exists a WTP for the conservation of river water quality, which is about 14.93% higher for water quality restoration than that for maintenance of current water quality. Some of the issues in undertaking the CVM studies in developing countries are also discussed in the paper.

The countries of the Middle East are characterized by large temporal and spatial variations in precipitation and with limited surface and groundwater resources. The rapid growth and development in the region have led to mounting pressures on scarce resources to satisfy water demands. The dwindling availability of water to meet development needs has become a significant regional issue, especially as a number of countries are facing serious water deficit. Syria is becoming progressively shorter of water as future demand is coming close to or even surpassing available resources. Syria had a population of 18 million in 2002, and its total renewable water resources (TRWR) is estimated around 16 × 109 m3 per year. In other words, the per capita TRWR is less than the water scarcity index (1,000 m3 per person per year) which will make the country experience chronic stress that will hinder its economic development and entail serious degradation. Unfortunately, if water demand at current prices continues to increase in the same way, Syria will experience an alarming deficit between the available resources and the potential needs in the near future. In Syria, until fairly recently, emphasis has been placed on the supply side of water development. Demand management and improvement of patterns of water use has received less attention. The aim was always to augment the national water budget with new water. The most popular way of achieving this aim was to control surface flows by building new dams and creating multi-purpose reservoirs (there are now around 160 dams in Syria with a total capacity of 14 × 109 m3). Irrigation schemes were also built and agricultural activities were expanded greatly to achieve self-sufficiency in essential food products and food security. However, this is no longer achievable with the limited water resources available; water demand is rapidly increasing and easily mobilizable resources have already been exploited. The objective of this paper is to think of different possible ways to manage water demand in the agricultural sector of Syria. It mainly involves two main management options: taxation as a centralized option and water markets as a decentralized one. While water demand management refers to improving both productive and allocative efficiency of water use, this paper focuses on two allocative measures (taxation and water markets) and does not thoroughly cover productive measures such as rehabilitation and upgrading of irrigation schemes or improving operation. However, the paper does not attempt to settle the question for or against each option but tries to find some elements to determine under which conditions the option can lead to expected outcomes taking into account the history of management and the local conditions in Syria: political, social and economical. The paper also looks at other alternatives such as cooperative action and lifting subsidies and argues their possible association to the main management options that may help in reducing the difficulties of implementation.

“Water conservation” means different things to different people and the principles of depletion and diversion are often confounded and misconstrued, particularly when the different perceptions of the value of water and units of analysis are involved. Many public policies and public and private investments have been implemented in the name of conserving water, particularly in irrigated agriculture. Unfortunately, many of these policies and investments cannot make additional water available to new users owing to the nature of closed basin hydrology. The assumption that farmers are low-efficiency irrigators is used to justify transfer of income and wealth to agricultural water users and others through direct investments and cost sharing programs. Instead, these programs serve to sustain and increase consumptive use of water in agriculture and disrupt the existing hydrologic balance. In arid climates, where deficit irrigation is practiced, conventional water conservation measures such as drip irrigation often result in increased depletion at the individual farm level and less water available for other users. This paper discusses water conservation misconceptions, particularly those related to irrigated agriculture in the arid southwestern United States. Deficit irrigation is a common practice throughout the southwest, the region is experiencing rapid population growth and naturally limited water supplies have been exacerbated by current drought conditions. In this paper, the water conservation impacts of drip irrigation, irrigation scheduling and canal lining are discussed in the context of the hydrological assumptions that are used to promote these technologies. The potential of drip irrigation, irrigation scheduling and canal lining to sustain and increase crop evapotranspiration in deficit irrigation environments is illustrated. Given hydrologic conditions, the authors conclude that accurate basin-wide accounting of water use, including equitable distribution based on existing legal entitlements would significantly contribute to water conservation efforts.

Achieving basic water security, both harnessing the productive potential of water and limiting its destructive impact, has always been a societal priority. To capture this duality, water security is defined here as the availability of an acceptable quantity and quality of water for health, livelihoods, ecosystems and production, coupled with an acceptable level of water-related risks to people, environments and economies. This paper looks broadly at those countries that have achieved water security, the paths they chose and the costs they paid, and those countries that have not achieved water security and how this constrains economies and societies. It defines three typologies: countries that have harnessed hydrology, those hampered by hydrology and those that are hostage to hydrology. It finds that countries remaining hostage to hydrology are typically among the world's poorest. They face “difficult” hydrologies often characterized by high inter- and intra-annual rainfall and runoff variability, where the level of institutional and infrastructure investment needed is very high and the ability to invest is low. This paper seeks to capture the dynamics of achieving water security in a hypothetical water and growth “S-curve”, which illustrates how a minimum platform of investments in water institutions and infrastructure can produce a tipping point beyond which water makes an increasingly positive contribution to growth and how that tipping point will vary in different circumstances. As there are inevitable trade-offs, achieving water security is never without social and environmental costs; in some countries these are significant, often unforeseen and even unacceptable. This brief analysis suggests that the only historically demonstrated path to achieving water security at the national level has been through investment in an evolving balance of complementary institutions and infrastructure, but that lessons exist for following this basic path in more sustainable and balanced ways. Insights are provided for balancing and sequencing investments, adapting to changing values and priorities, and pushing down the social and environmental costs. The paper concludes that most water-insecure countries today face far greater challenges than those that achieved water security in the last century and are wealthy countries today. They face more difficult hydrologies and a greater understanding of and therefore greater responsibility for, the social and environment trade-offs inherent in water management. As the costs of poor countries not achieving water security, in terms of human suffering, sustained poverty, constrained growth and social unrest, would be very high, achieving water security is a challenge that must be recognized and must be met.

China, like many countries, is experiencing an unprecedented rate of urbanization. Urbanization is usually thought to intensify inter-sectoral water conflicts. In contrast, this paper considers urbanization as part of a viable solution to the problem. By evaluating water consumption, or depletion, in terms of actual evaporation and transpiration, as opposed to the amount withdrawn from water sources, this paper argues that urbanization has a positive role to play in lessening inter-sectoral water competition and in reversing groundwater declines. At the regional scale, urbanization can help achieve these goals by replacing some agricultural land use, particularly under two conditions: (1) both the industrial and agricultural sectors adopt water-saving technologies, and (2) urban wastewater and runoff are treated and reused directly in agriculture or indirectly through artificial recharge. Combined, the two conditions must result in a net decrease in water consumption at the regional scale. These points are illustrated with a case study of rural Luancheng County and adjacent industrialized Shijiazhuang City in Hebei Province. A water-balance approach provides a simple, quantitative framework for evaluating the potential for various land-use mosaics to stabilize groundwater levels.

Beijing is facing the considerable challenge of water shortage, as it is just able to meet current water demand in a year with average precipitation and a shortfall between water supply and demand is estimated to be around 1.8 billion[109] cubic meters (BCM) by 2010. Aiming to find the solution to such a severe challenge, this paper investigates Beijing's current and future water resources availability and water-use configurations, as well as past and current effort on both areas of water supply and demand. The analysis shows a continuously growing demand for water and an aggravating deficit of traditionally available water resources. The paper concludes that it is necessary to establish well-structured water-use data and employ more advanced forecasting methods if sound future decisions regarding water balance are expected to be made. In order to realize Beijing Municipality's full urban water conservation potential, it is suggested that a comprehensive and integrated long-term conservation program be implemented, which is technically feasible and economically justified, to conserve water consistently for many years.

Beijing, the capital of China, is one of the most water-scarce metropolises in the world. The present water policies are leading to serious water scarcity in agriculture. The proportion of agricultural water to total water has been dropping continuously in Beijing in past years. The influence of water scarcity on grain yield and planting production value has been analyzed in this paper. The problems of ecological environment and rural social problems that arise from water scarcity are also discussed in the paper. Based on the above analysis, the paper gives some suggestions for alleviating the tension, such as developing water-saving agriculture, adjusting planting structure and properly developing sewage irrigation.

The paper analyses the water scarcity problems in Gujarat in Western India using definitions of water scarcity propounded by Falkenmark, and Raskin and others, and a more universal definition based on supply and demand. While a lion's share of the scarce water goes for irrigating cash crops at the cost of subsistence farming and rural drinking, the pricing of canal water and electricity used for groundwater pumping is highly inefficient and inequitable. To manage demands for water, the paper suggests the use of water market as the institutional arrangement for promoting economically efficient uses, along with rational pricing of canal water and electricity for encouraging conservation. The paper advocates policies that enable: reforms in the governance and management of water for decentralisation and local institutional development; and increased investment in the irrigation and power supply sector for technological innovations and improvements in infrastructure, which are the fountainhead of the demand management strategy.

Water pricing can be used for improving water use efficiency. Prices, if accurately designed, give information to users, to make choices regarding water use. In practice water pricing schemes may be designed to meet many objectives, including political ones. This paper reviews water pricing experiences across 22 countries in various sectors and over time. The information shows that countries have different reasons for charging for water, including cost recovery, redistribution of income, improvement of water allocation and water conservation. The paper compares both the fixed and the variable rates for urban, agricultural and industrial sectors. Main findings are that fixed rates vary greatly between countries, while per unit rates are in a reasonable range. For urban and agricultural water, all developing countries, and some developed countries, set charges on the basis of average rather than marginal cost of supply. The willingness of countries to undertake water pricing reforms and successfully implement them cannot be solely explained by their water scarcity levels nor by the size of their budget deficits. However, high income countries are relatively more open to reforming water pricing policies.

Public participation in water conservation projects is gaining more and more attention in the information era. Public opinion, showing the focus and interests of the public, is the basis of public participation. This paper proposes a social sensing system based on social media platforms, which employs two natural language processing technologies, namely, sentiment analysis and topic modeling. The public opinion on water conservation projects is monitored from three perspectives: public opinion intensity (POI) monitoring, topic detection, and sentiment analysis. To test their effectiveness, a case study on the South-to-North Water Transfer Project (SNWTP) in China is conducted. The public opinion data were acquired from Sina Weibo, China's largest social media platform. The results indicate that: (1) POI peaks when hot project-related events occur, and POI of direct stakeholders apparently exceeds indirect stakeholders; (2) different stakeholders have different topics of concern closely associated with their interests; (3) negative events always lead to dramatic decreases in the sentiment value (SV), while positive events only slightly lift SV. The proposed system has achieved real-time monitoring of the public opinion on water conservation projects. Consequently, it can help to improve the level of public participation and provide a valuable reference in project management and policy-making.

The leap-forward development policy emphasizes water resource scarcity. Given the importance of water resources to an economy, especially in arid areas, this paper explores various management strategies that could be used in the semi-arid region of Xinjiang to increase the effectiveness and efficiency of multifunctional water projects and support sustainable ‘leap-forward’ economic growth. Embedding the logistic growth function within a system dynamics framework, our model provides a universally implementable model for sustainable water planning. The dynamic current and projected water supply and demand and water use efficiency are captured. Potential water management strategies are simulated to test system performance. The results suggest that, as water scarcity becomes more acute, the current water supply will not be able to support the leap-forward development policy with current water usage efficiency. In the short term, implementing efficient industrial water consumption technology and promoting water-saving irrigation technology may postpone the cultivated land reduction process. In the long term, developing more water-saving industrial enterprises, and planning to use more drought-tolerant plants, will be effective ways to avoid a decrease in cultivated land area.

In order to alleviate the water supply–demand problem, a flood resource utilization strategy is proposed, called ‘Flood Utilization’. The strategy focuses on building large-scale water conservancy facilities and improving management measures. This paper presents the probability analysis of floodwater utilization in a confluence area, where a tributary joins a main river. Baicheng is used as the study area, where the Taoer River joins the Nenjiang River. After a large number of analyses, the main results and conclusions are as follows: First, the upper limit of available floodwater corresponds to the Taoer River's flood with a 5% probability of occurrence. Secondly, there are compensation characteristics between the two rivers which mean that the Nenjiang River can supply water to the Taoer River area. The analysis of monthly runoff, shows that there are compensation characteristics in 50.9% of the data period. The compensation rates (CRs) for the months from June to October are 0.2, 0.27, 0.25, 0.27, and 0.2, respectively. Thirdly, the differences in the runoff characteristics show that it is suitable for floodwater utilization. Finally, it is proposed that floodwater utilization measures are based on local conditions, such as the regional water storage characteristics and the runoff characteristics of the two rivers, and should be applied for different periods.

Religious and cultural values related to water use and management are important motivation for many people of the world. Although much has been written related to water management and use in Islam, fewer authors have attempted to evaluate water management through the lens of other religions. The common thread of monotheism, specifically worship of the one God of Abraham, binds together the world's largest two religions (Islam and Christianity). Judaism also falls within this monotheistic group and is especially important in the context of Middle Eastern water management. As agriculture consumes approximately 70% of all fresh water used in the world today, proper management of water within its context is of critical and global importance. This paper presents an effort to build consensus from a monotheistic scripture-based perspective related to water management in agriculture. If greater dialog and agreement about water management can be attained within and among monotheists, complex issues related to transboundary water management, reuse and conservation could be resolved with less conflict, creating a shared overall management vision.

Governments are developing policy to reallocate water to environmental uses in many of the world's major river basins developed for irrigation. These policies can place considerable pressure on the irrigation sector to adjust, and may be perceived to conflict with food security and rural development goals. This paper reviews the literature examining opportunities to reduce irrigation district and third party externalities associated with rapid adjustment to water reallocation, with emphasis on recent water reform in the Murray-Darling Basin (MDB), Australia. We focus on opportunities to improve joint environmental and regional economic outcomes, by targeting and sequencing policy instruments operating at different scales. Refereed/Peer-reviewed

Participants at the international conference on policies for water and food security in the dry areas, held in June 2013, agreed that, given the fast pace of depletion of groundwater, the issue of water valuation in the dry areas is no longer one of whether or not, but rather of how. Policies that have been or are perceived to have adverse effects on the cost of agricultural production or food prices in the dry areas are often not well received and have historically led to popular uprisings. As a result, despite clear evidence of misuse of irrigation water by many farmers, governments have been avoiding the idea of water pricing. This government stance is mainly based on the assumption that policies that aim at valuing water will necessarily affect farmers negatively. Using a case study from Syria and applying a simple optimization model, this paper provides empirical evidence that a policy which introduces a penalty for excessive application of irrigation water would compel farmers to adopt water saving technologies. By so doing, the policy will not only lead to groundwater conservation but also to Pareto-optimal distribution of benefits (i.e., a situation where nobody loses and at best some or all gain).

Irrigation is an essential element of agricultural production whose absence would create great economic hardship in many regions of the global South. Yet irrigated agriculture uses 70% of global fresh water withdrawals, putting major pressure on global water resources. Whilst much research has focused on technological solutions to improve irrigation efficiency, irrigation water governance arrangements remain poorly investigated. This paper examines the irrigation water governance arrangements in place in the Canale Emiliano Romagnolo (CER) district in Italy. The objective is to understand key factors driving or hindering irrigation efficiency, and to identify context-relevant policy-making dynamics that could enable greater efficiency. The analysis is conducted following the Policy Arrangement Approach, which describes a policy domain in terms of actors, rules, resources and discourses, and identifies opportunities for change in the interplay of these dimensions. Findings suggest that the existing governance arrangements have led to improvements in irrigation efficiency over the past decades in the CER district. Key factors of this performance include public financial investment in research and farm modernization, the existence of local capacity building and social capital, and the presence of a public-private organization with capacity to raise resources and to generate and transfer knowledge to both policy-makers and farmers. © 2014 IWA Publishing.

Irrigated agricultural production is the backbone of the Chinese agricultural sector, but the increasing demand for irrigation water, its inefficient utilization and overuse of chemical inputs, accompanied by the short supply of water resources have endangered the nation's agricultural and environmental sustainability. The Chinese government has proposed a water pricing policy with the expectation of improving the efficiency of utilizing irrigation water and fertilizer, to mitigate these problems. With the main objective of this paper being to assess the impact of this policy on water demand and environmental sustainability, a positive mathematical programming model was adopted to simulate different irrigation water pricing scenarios based on farm-level primary data from three irrigation districts along the Weihe River basin. The main parameter for assessing water demand was the change in total water consumption relative to the base year, while change in fertilizer consumption and water demand was determined to evaluate the impact of pricing policy on environment sustainability. According to the results, irrigation water demand and fertilizer consumption were mostly price inelastic to water pricing. This implies that water pricing policy can have only a minor role in regulating the water demand and environment in the region even when the base-year water price is doubled.

Cities around the world are struggling to access additional water supplies to support their continued growth because their freshwater sources are becoming exhausted. Half of all cities with populations greater than 100,000 are located in water-scarce basins, and in these basins agricultural water consumption accounts for more than 90% of all freshwater depletions. In this paper we review the water development histories of four major cities: Adelaide, Phoenix, San Antonio and San Diego. We identify a similar pattern of water development in these cities, which begins with the exhaustion of local surface and groundwater supplies, continues with importation of water from other basins, and then turns to recycling of wastewater or stormwater, or desalination of either seawater or brackish groundwater. Demand management through water conservation has mitigated, to varying degrees, the timing of water-system expansions and the extent to which cities rely on new sources of supply. This typical water development pattern in cities is undesirable from a sustainability perspective, as it is usually associated with serious ecological and social impacts as well as sub-optimal cost effectiveness. We highlight case examples and opportunities to invest in water conservation measures, particularly through urban–rural partnerships under which cities work with farmers to implement irrigation conservation measures, thereby freeing up water for ecological restoration and use by cities.

The more sustainable use of scarce water resources is a policy goal in several countries. In this regard, current discussions on potential policy reforms in Switzerland revolve around the subsidization of water-saving irrigation technologies. Today, the share of drip irrigation systems is low, at 3%. In Switzerland, environmental laws specify levels of water flow that must not be undercut. Variable pricing of water, however, has not yet been used. This paper analyzes whether subsidies on water-saving irrigation techniques would be beneficial in this legislative setting, and shows that such subsidies may have crowding out effects because they could provide incentives to switch from non-irrigated crops (e.g. wheat) to the production of crops (e.g. potatoes) that require irrigation. This may result in even higher water withdrawal rates. Such an increased competition for water resources may also result in adverse conditions for farmers. By contrast, our analysis shows the implementation of water prices could lead to a sustainable increase in the share of water-saving technologies, to a shift from irrigated to non-irrigated crops, and therefore to a reduction of overall water use in agriculture. Thus, the introduction of water prices should have absolute priority if agricultural water policies are reformed in Switzerland.

This paper examines water use efficiency and economic efficiency with a particular focus on the Murray-Darling Basin of Australia and the stated policy goal of increasing environmental flows of water in the Basin. The different measures of efficiency are explained, and their implications for water reform and the efficacy of market based approaches to addressing the water scarcity issues and environmental flow needs are explored. Public policies to subsidize investments for improvements in irrigation efficiency are shown not to be currently cost effective compared to alternatives, such as buying water through water markets. The implications of these findings, and the factors that determine the demand for irrigation water by competing uses, can guide policy makers undertaking water reforms in the agricultural sector to mitigate the environmental consequences of overuse of water resources.

Drip irrigation has received considerable attention from policy makers because of its significant contribution towards resource saving, enhanced agricultural productivity and environmental sustainability. This paper explores the potential benefits of drip irrigation adoption by addressing the social benefits and costs in Southern India. The study shows that adoption of drip irrigation technology has resulted in significant external and private benefits. The social benefit–cost ratio (SBCR) ranged from 4.33 to 5.19 at a 2% discount rate under different scenarios across regions. This confirms that a wide adoption of drip irrigation produces sufficient social benefits to justify the subsidization of drip irrigation. Water management policy should focus attention on the promotion of drip irrigation in regions where water and labour scarcity are critical.

The growing demand for municipal water due to population increase and urbanization impels water managers to reconsider the existing traditional supply-sided management approach. Strengthening of water demand management (WDM) policies by improving water use efficiency has been adopted as a key target in arid regions, in particular. Indeed, increasing the added value per m3 of water used is gaining importance, since it is a more environmentally-friendly strategy with regard to water resource management than expanding water infrastructure assets. Monitoring the water use efficiency index is the commonly applied method for assessing the performance of municipal water management that depends on physical (real) losses and non-physical (apparent) losses constituting non-revenue water (NRW). In this paper, the results of the study conducted in three medium-size urban settlements, namely Ordu, Çarşamba and Ceyhan, are presented. Field surveys and evaluation of the data relating to municipal customer service have been carried out. In the light of the findings covering a four-year period between 2004–2007, the origin and reasons for NRW, and the means and tools for reducing it in order to improve water use efficiency are discussed.

Often, information on spatial water use efficiencies in a whole-of-the-catchment context does not exist or does not feed into the water policy process to guide investments. Significant gains in water use efficiency are achievable but the water savings are often assumed rather than identified systematically. This paper used a whole-of-the-catchment water accounting framework to identify the main pathways to enhance water use efficiency, taking the Murrumbidgee catchment in the Murray–Darling Basin in Australia as an example. The results show that large amounts of water remain unaccounted for in the river system account; the true water losses occur in the nearfarm and onfarm zones, most of which can be saved cost effectively. The catchment water accounting procedure thus offers a useful framework for bringing unaccounted/lost water flows into human and environmental uses, for enhancing water use efficiency, for targeting investments to the water system components with the largest potential gains in efficiency, and for garnering private sector investments to realize true water savings. The pro-investment technical and institutional, as well as governance and policy, interventions to revamp private sector participation in water infrastructure are articulated.

Participatory management of water resources presents special problems because the interests of the farmers located at the head and the tail of a canal do not match and government machinery is usually the sole arbiter. This paper attempts to quantify the benefits of participation in irrigation systems in Cambodia through a survey of 50 irrigation projects in the country. We find that participation by stakeholders does improve project performance. We find that even in the absence of a coherent state bureaucracy, state-society synergy can exist and participation can lead to better project outcomes.

Integrated water resource management (IWRM) is a widely recognized management framework that is currently being adopted throughout post-Soviet Central Asia to inform and guide national water sector reforms, and to keep up with the pace of the faster moving land reforms taking place in the region. With hydrographic principles and public participation being at the core of this framework, the process in the region has started with the reform of on-farm irrigation systems by creating water users associations (WUAs), transferring irrigation management to them and introducing irrigation service fees. This paper draws on the experiences, over four years, of three study WUAs set up in the Ferghana Valley in Uzbekistan, Tajikistan and the Kyrgyz Republic. Aiming to explore the differences in institutional environment and arrangements in these three countries for establishing WUAs, as well as assessing WUA performances (particularly from users' perspectives), the study reveals that it is not only the newly-established institutional arrangements in the irrigation sector but also their internal operations, coupled with other important factors such as size of area farmed, overall viability of agriculture and a wider economic context that crucially determine overall irrigation performance.

This paper estimates the economic value of irrigation water shortfalls and mitigation responses of farmers in the Lower Rio Grande Valley of Texas. The water shortage levels closely correspond to supply shortfalls experienced by the U.S. during the 1990s when Mexico fell behind on treaty delivery obligations. We identify and evaluate a range of crop choices, appropriate irrigation technology use, water source substitution, and other mitigation strategies used by farmers to deal with water shortages. The effects of exogenous crop price and yield risk, as well as other structural considerations are incorporated in the estimation of the marginal value of irrigation water. Results show that South Texas farmers react to risk by diversifying their crop mix, with implications for the imputed value of water and soil resources. The inclusion of exogenous risk refines the prediction of what decision makers would have grown assuming strict Mexican treaty compliance. The resulting marginal values reflect grower adjustments for risk using crop mix, irrigation level, and irrigation technology. The aggregate damage estimates using this approach are realistically smaller than previous damage estimates that were based on fixed cropping patterns and average water values.

This paper deals with heavy pressures to save water in natural resource management due to increased water scarcity. We take the example of a Chinese watershed and investigate the water use efficiency in Chinese irrigated agriculture through a field study as dependent on investments in on-farm water saving technologies and canal water conveyance. The economic and environmental impacts of farmers adopting modern irrigation technologies and public sectors improving water transit systems are studied in particular. A spatial mathematical programming model is employed for optimization. The emphasis is on private and public investments in water saving. Water saving in a canal system enables an extension of the system and provides food and income for more farmers. The model results are of great value for policy makers and project managers, who want to optimize irrigation projects, because scenarios (for instance water and product pricing) are provided. We also provide references for farmers in applying suitable irrigation technologies.

Water planners facing a choice between water “supply” options (including conservation) customarily use the average unit cost of each option as a decision criterion. This approach is misleading and potentially costly when comparing options with very different reliability characteristics. For example, surface water, desalinated seawater or recycled wastewater and some outdoor demand management programs have very different yield patterns. This paper presents a method for calculating constant-reliability unit costs that adapts some concepts and mathematics from financial portfolio theory. Comparison on a constant-reliability basis can significantly change the relative attractiveness of options. In particular, surface water, usually a low cost option, is more expensive after its variability has been accounted for. Further, options that are uncorrelated or inversely correlated with existing supply sources—such as outdoor water conservation—will be more attractive than they initially appear. This insight, which implies options should be evaluated and chosen as packages rather than individually, opens up a new dimension of yield and financial analysis for water planners.

Increasing agricultural water productivity will be a key factor in China's ability to maintain food security in the face of rapidly growing water demand from other sectors. This paper highlights how such achievements can be considered and made by examining and contrasting water institutions, policies and management strategies across scales in two irrigation systems in China situated within strikingly different environments, the Zhanghe Irrigation System (ZIS) in the relatively water-abundant Yangtze River basin and the Liuyuankou Irrigation System (LIS) in the highly water-stressed Yellow River basin. The results show, perhaps surprisingly, that institutional arrangements which have evolved in the water-abundant system are more conducive to water savings. However, the particular conclusions on water productivity and savings also depend in part on definitions of scale and other factors. These findings form part of a changing trend in thinking about irrigation, water productivity and water savings that considers the analysis of scales, multiple uses, and practices of irrigation in the context of water scarcity and has direct implications for China's efforts to better use its scarce water resources.

There is an urgent need to increase the existing water use efficiency in Indian agriculture, mainly due to the increasing demand for water from different sectors and the rapid decline of the available potential of water. Water use efficiency under the flood method of irrigation (FMI), predominantly practised in India, is very low owing to enormous losses in distribution and evaporation. The drip method of irrigation (DMI) introduced recently helps to increase water use efficiency significantly, besides increasing the productivity of crops. However, not many studies are available focusing on the effectiveness of the drip method of irrigation in the context of the sustainable use of irrigation water. An attempt is made in this paper to bring out the importance of the drip method of irrigation in the sustainable use of irrigation water using both primary and secondary level information. The results of experimental station data show that water saving from DMI varies from 12% to 84% per hectare for different crops besides increasing the productivity of crops. The farm level data do confirm that DMI helps to save water by 29% for bananas and 37% for grapes per hectare over FMI in addition to substantial increases in productivity. The core and net potential areas of DMI are estimated to be 51.42 million hectares (mha) and 21.27 mha, respectively, for the country as a whole. The achievable total saving of water, by utilising the net potential area of DMI, is estimated to be about 11.271 million ha m. From the saving of water, an additional irrigated area of 11.22 mha under FMI or 24.12 mha under DMI can be created.

Observations in Tanzania indicate that the improvement of traditional smallholder irrigation does not necessarily result in improved water performance, greater equity and reduced conflict. The usual outcomes of such projects is a gain in water for the system being upgraded, especially if located upstream, accompanied by less ability to share water at the river basin scale. This paper concludes that these projects do not commonly understand, match and respond to the complexities of well-developed and evolving smallholder irrigation found in multi-user river basins. Without re-appraisal, the risk is that donors will be unsuccessful with smallholder irrigation and turn away from this sector, as they did with large-scale irrigation.

Increasing economic pressures on water resources are causing countries to (re)consider various mechanisms to improve water use efficiency. This is especially true for irrigation agriculture, a major consumer of water. ‘‘Getting prices right’’ is seen as one way to allocate water, but how to accomplish this remains a debatable issue. Methods of allocating water are sensitive to physical, social, institutional and political settings, making it necessary to design allocation mechanisms accordingly. This paper surveys current and past views on allocating irrigation water with a focus on efficiency, equity, water institutions, and the political economy of water allocation. r 2002 Elsevier Science Ltd. All rights reserved.

Treated wastewater may be considered as a ‘new’ water resource, which can be added to the general water balance of a region. This ‘new’ source can substitute conventional water used for irrigation. Israel is presently reusing more than 65% of the total domestic sewage production of the country, and it is planned to reach more than 90% reuse during the next decade. This paper addresses the introduction of reclaimed wastewater in the water balance of the country, its contribution to the protection of the conventional water resources, the similarities and differences between water and wastewater resources management, and the economic benefits of wastewater reuse. # 2001 Elsevier Science Ltd. All rights reserved.

Sudan's irrigated agriculture faces water shortages with the current method of water use. How can Sudan allocate its water quota stipulated in the 1959 Nile Waters Agreement? This paper examines water policy with a dynamic optimal control model to determine steady-state optimal inter-crop and inter-temporal allocation. Control of land, water, and price to ensure that cotton is grown has a negative impact on overall farm income, and water conservation. Incomes drop significantly if free market prices are adopted without the freedom to allocate land. Water shortages could develop if other schemes claim more water, irrigated area increases, and/or high water requiring crops are planted.

The main source of water for Abu Dhabi City is desalinated seawater from the Arabian Gulf. The cost of water production through desalination is higher than other conventional methods of potable water production. In spite of all awareness campaigns to advise the consumers in Abu Dhabi of the importance of the water and its high cost, the average consumption rate is still one of the highest in the world (636 1/cap d). This means that, with respect to water, the worst combination of conditions are existing in Abu Dhabi (high consumption rate and high production cost). As a result, the Water and Electricity Department (WED) of Abu Dhabi (now it is a private company) which is the Department responsible for water production, transmission and distribution, has decided to change the pricing policy of water. The new policy is based on fixing meters in buildings and charging the consumers for the actual amount of water consumed, instead of a system which was based on a flat rate of 50 Dhs per month (1 US$=3.7 Dhs) irrespective of the amount of consumption. This paper attempts to evaluate the effect of introducing the new pricing mechanism in Abu Dhabi City, and compares it with the old flat rate tariff. The water consumption of randomly selected 90 households with different socio-economic levels were analyzed before and after introducing the new pricing system. As a result of the new pricing policy, 73% of the households in the sample reduced their consumption by an average of 29%. The calculated price elasticity of demand revealed an elasticity coefficient e=−0.1. The new price of water (2.2 Dhs/m3) accounts for only 29% of the total cost to produce and supply the water to consumer taps.

Lebanon depends primarily, for its water resources on ground water that is deteriorating rapidly. The increased demand on water resources in Lebanon as a result of: progressive urbanization, socio-economic growth, development of agricultural and industrial activities will lead to critical water limitations factor by the year 2010. Consequently, other resources such as the availability of surface water in terms of quality and quantity is of major importance. The political instability in the country limited the development of a comprehensive data-base for surface water. The paper focuses on assessing the water quality of the Qaraaoun reservoir, an impoundment of the river Litani for multipurpose utilization. This would serve as a prototype for the development of comprehensive plans for optimal utilization of surface water sources in Lebanon, as a venue to meet the water needs of Lebanon. The Qaraaoun reservoir, which till now has limited utilization of hydroelectric power and agricultural activities, proved to posses other usage. A master plan for the management of the Qaraaoun reservoir, as a prototype for surface water, should address policy constrains relative to environmental, institutional and financial issues.

Significant increases in water demands, in conjunction with economic and population growth, stress already scarce water supplies in dry areas. This paper shows that the principle of confronting all water users with the opportunity cost of their actions can be applied to the design of institutions that reduce barriers to water conservation. We apply the principle to the case of temporary water transfers from agriculture to cities, in which the opportunity cost of water used for agriculture is what cities are willing to pay for the water. A significant institutional barrier that blocks temporary market transfers of water is the `use it or lose it' principle of western US water law. Legislation that removes that institutional barrier to conservation by defining short-term water trading to be a beneficial use of water can promote greater total economic benefit from scarce water, if combined with measures for protecting third parties. By removing this barrier to the free flow of information on the opportunity cost of water used in agriculture, legislation can create a market for agricultural water and reduce the cost to cities of securing needed water.