Showing papers on "Water supply published in 2010"

A Drinking Water Crisis in Lake Taihu, China: Linkage to Climatic Variability and Lake Management

Abstract: In late May, 2007, a drinking water crisis took place in Wuxi, Jiangsu Province, China, following a massive bloom of the toxin producing cyanobacteria Microcystis spp. in Lake Taihu, China’s third largest freshwater lake. Taihu was the city’s sole water supply, leaving approximately two million people without drinking water for at least a week. This cyanobacterial bloom event began two months earlier than previously documented for Microcystis blooms in Taihu. This was attributed to an unusually warm spring. The prevailing wind direction during this period caused the bloom to accumulate at the shoreline near the intake of the water plant. Water was diverted from the nearby Yangtze River in an effort to flush the lake of the bloom. However, this management action was counterproductive, because it produced a current which transported the bloom into the intake, exacerbating the drinking water contamination problem. The severity of this microcystin toxin containing bloom and the ensuing drinking water crisis were attributable to excessive nutrient enrichment; however, a multi-annual warming trend extended the bloom period and amplified its severity, and this was made worse by unanticipated negative impacts of water management. Long-term management must therefore consider both the human and climatic factors controlling these blooms and their impacts on water supply in this and other large lakes threatened by accelerating eutrophication.

Hygiene, sanitation, and water: forgotten foundations of health.

Abstract: As the first article in a four-part PLoS Medicine series on water and sanitation, Jamie Bartram and Sandy Cairncross argue that the massive burden of ill health associated with poor hygiene, sanitation, and water supply demands more attention from health professionals and policymakers.

State of the Art for Genetic Algorithms and Beyond in Water Resources Planning and Management

Abstract: During the last two decades, the water resources planning and management profession has seen a dramatic increase in the development and application of various types of evolutionary algorithms (EAs). This observation is especially true for application of genetic algorithms, arguably the most popular of the several types of EAs. Generally speaking, EAs repeatedly prove to be flexible and powerful tools in solving an array of complex water resources problems. This paper provides a comprehensive review of state-of-the-art methods and their applications in the field of water resources planning and management. A primary goal in this ASCE Task Committee effort is to identify in an organized fashion some of the seminal contributions of EAs in the areas of water distribution systems, urban drainage and sewer systems, water supply and wastewater treatment, hydrologic and fluvial modeling, groundwater systems, and parameter identification. The paper also identifies major challenges and opportunities for the future, ...

A revised approach to water footprinting to make transparent the impacts of consumption and production on global freshwater scarcity

Abstract: Through the interconnectedness of global business, the local consumption of products and services is intervening in the hydrological cycle throughout the world to an unprecedented extent. In order to address the unsustainable use of global freshwater resources, indicators are needed which make the impacts of production systems and consumption patterns transparent. In this paper, a revised water footprint calculation method, incorporating water stress characterisation factors, is presented and demonstrated for two case study products, Dolmio ® pasta sauce and Peanut M&M's ® using primary production data. The method offers a simple, yet meaningful way of making quantitative comparisons between products, production systems and services in terms of their potential to contribute to water scarcity. As such, capacity is created for change through public policy as well as corporate and individual action. This revised method represents an alternative to existing volumetric water footprint calculation methods which combine green and blue water consumption from water scarce and water abundant regions such that they give no clear indication about where the actual potential for harm exists.

Eutrophication of Lake Waters in China: Cost, Causes, and Control

Abstract: Lake water eutrophication has become one of the most important factors impeding sustainable economic development in China. Knowledge of the current status of lake water eutrophicatoin and determination of its mechanism are prerequisites to devising a sound solution to the problem. Based on reviewing the literature, this paper elaborates on the evolutional process and current state of shallow inland lake water eutrophication in China. The mechanism of lake water eutrophication is explored from nutrient sources. In light of the identified mechanism strategies are proposed to control and tackle lake water eutrophication. This review reveals that water eutrophication in most lakes was initiated in the 1980s when the national economy underwent rapid development. At present, the problem of water eutrophication is still serious, with frequent occurrence of damaging algal blooms, which have disrupted the normal supply of drinking water in shore cities. Each destructive bloom caused a direct economic loss valued at billions of yuan. Nonpoint pollution sources, namely, waste discharge from agricultural fields and nutrients released from floor deposits, are identified as the two major sources of nitrogen and phosphorus. Therefore, all control and rehabilitation measures of lake water eutrophication should target these nutrient sources. Biological measures are recommended to rehabilitate eutrophied lake waters and restore the lake ecosystem in order to bring the problem under control.

Water Supply and Health

Abstract: As one article in a four-part PLoS Medicine series on water and sanitation, Paul Hunter and colleagues argue that much more effort is needed to improve access to safe and sustainable water supplies.

Is physical water scarcity a new phenomenon? Global assessment of water shortage over the last two millennia

Abstract: In this letter we analyse the temporal development of physical population-driven water scarcity, i.e. water shortage, over the period 0 AD to 2005 AD. This was done using population data derived from the HYDE dataset, and water resource availability based on the WaterGAP model results for the period 1961‐90. Changes in historical water resources availability were simulated with the STREAM model, forced by climate output data of the ECBilt‐CLIO‐VECODE climate model. The water crowding index, i.e. Falkenmark water stress indicator, was used to identify water shortage in 284 sub-basins. Although our results show a few areas with moderate water shortage (1000‐1700 m 3 /capita/yr) around the year 1800, water shortage began in earnest at around 1900, when 2% of the world population was under chronic water shortage (<1000 m 3 /capita/yr). By 1960, this percentage had risen to 9%. From then on, the number of people under water shortage increased rapidly to the year 2005, by which time 35% of the world population lived in areas with chronic water shortage. In this study, the effects of changes in population on water shortage are roughly four times more important than changes in water availability as a result of long-term climatic change. Global trends in adaptation measures to cope with reduced water resources per capita, such as irrigated area, reservoir storage, groundwater abstraction, and global trade of agricultural products, closely follow the recent increase in global water shortage.

Using adaptation tipping points to prepare for climate change and sea level rise: a case study in the Netherlands

Abstract: Studies on the impact of climate change and sea level rise usually take climate scenarios as their starting point. To support long-term water management planning in the Netherlands, we carried out a study that started at the opposite end of the effect chain. In the study we refer to three aspects of water management, flood defense, drinking water supply, and protection of the Rotterdam Harbour. We examined whether, and for how long, current water management strategies will continue to be effective under different climate change scenarios. We did this by applying the concept of ‘adaptation tipping points’, and reached it if the magnitude of change is such that the current management strategy can no longer meet its objectives. Beyond the tipping points, an alternative adaptive strategy is needed. By applying this approach, the following basic questions of decision makers are answered: what are the first issues that we will face as a result of climate change and when can we expect this. The results show, for instance, that climate change and the rise in sea level are more likely to cause a threat to the fresh water supply in the west of the Netherlands than flooding. Expressing uncertainty in terms of the period that the existing strategy is effective (when will a critical point be reached) was found to be useful for the policy makers. © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website

Peak water limits to freshwater withdrawal and use

Abstract: Freshwater resources are fundamental for maintaining human health, agricultural production, economic activity as well as critical ecosystem functions. As populations and economies grow, new constraints on water resources are appearing, raising questions about limits to water availability. Such resource questions are not new. The specter of “peak oil”—a peaking and then decline in oil production—has long been predicted and debated. We present here a detailed assessment and definition of three concepts of “peak water”: peak renewable water, peak nonrenewable water, and peak ecological water. These concepts can help hydrologists, water managers, policy makers, and the public understand and manage different water systems more effectively and sustainably. Peak renewable water applies where flow constraints limit total water availability over time. Peak nonrenewable water is observable in groundwater systems where production rates substantially exceed natural recharge rates and where overpumping or contamination leads to a peak of production followed by a decline, similar to more traditional peak-oil curves. Peak “ecological” water is defined as the point beyond which the total costs of ecological disruptions and damages exceed the total value provided by human use of that water. Despite uncertainties in quantifying many of these costs and benefits in consistent ways, more and more watersheds appear to have already passed the point of peak water. Applying these concepts can help shift the way freshwater resources are managed toward more productive, equitable, efficient, and sustainable use.

What Is Water?: The History of a Modern Abstraction

Abstract: Foreword: Making Waves / Graeme Wynn Preface Part 1: Introduction 1 Fixing the Flow: The Things We Make of Water 2 Relational Dialectics: Putting Things in Fluid Terms Part 2: The History of Modern Water 3 Intimations of Modern Water 4 From Premodern Waters to Modern Water 5 The Hydrologic Cycle(s): Scientific and Sacred 6 The Hortonian Hydrologic Cycle 7 Reading the Resource: Modern Water, the Hydrologic Cycle, and the Stat 8 Culmination: Global Water Part 3: The Constitutional Crisis of Modern Water 9 The Constitution of Modern Water 10 Modern Water in Crisis 11 Sustaining Modern Water: The New "Global Water Regime" Part 4: Conclusion: What Becomes of Water 12 Hydrolectics Notes Bibliography Index

Life-cycle uses of water in U.S. electricity generation

Abstract: Water use by the electric power industry is attracting renewed interest as periods and zones of arid weather are increasingly encountered, and various regional energy-production scenarios are evaluated. However, there is a scarcity of data on upstream water factors and discrepancies of data from different sources. We reviewed previous studies of water use in electricity generation and used full-life cycle accounting to evaluate water demand factors, both withdrawal and consumption, for conventional- and renewable-electrical power plants. Our investigation showed that moving to technologies like photovoltaics and wind offers the best option for conserving our water supply. We also emphasize the importance of employing a transparent, balanced approach in accounting life-cycle water usages.

Water, climate change, and sustainability in the southwest

Abstract: The current Southwest drought is exceptional for its high temperatures and arguably the most severe in history. Coincidentally, there has been an increase in forest and woodland mortality due to fires and pathogenic outbreaks. Although the high temperatures and aridity are consistent with projected impacts of greenhouse warming, it is unclear whether the drought can be attributed to increased greenhouse gasses or is a product of natural climatic variability. Climate models indicate that the 21st century will be increasingly arid and droughts more severe and prolonged. Forest and woodland mortality due to fires and pathogens will increase. Demography and food security dictate that water demand in the Southwest will remain appreciable. If projected population growth is twinned with suburb-centered development, domestic demands will intensify. Meeting domestic demands through transference from agriculture presents concerns for rural sustainability and food security. Environmental concerns will limit additional transference from rivers. It is unlikely that traditional supply-side solutions such as more dams will securely meet demands at current per-capita levels. Significant savings in domestic usage can be realized through decreased applications of potable water to landscaping, but this is a small fraction of total regional water use, which is dominated by agriculture. Technical innovations, policy measures, and market-based solutions that increase supply and decrease water demand are all needed. Meeting 21st-century sustainability challenges in the Southwest will also require planning, cooperation, and integration that surpass 20th-century efforts in terms of geographic scope, jurisdictional breadth, multisectoral engagement, and the length of planning timelines.

Improving Productivity of Crops in Water-Limited Environments

Abstract: This review deals with improving the performance of dryland crops in dry, mainly semiarid, environments. Although such crops are often limited by water, the development of the notion of water-limited potential yield has shown that their yields are often limited strongly by other factors. These factors are explored by dissecting the water-limited potential yield into a framework involving four largely independent components, namely, the potential water supply for the crop; the fraction of that water supply that is transpired; the efficiency with which the crop exchanges water for CO 2 in producing biomass (Transpiration Efficiency); and the fraction of the biomass that ends up in the grain (Harvest Index). This framework is used to explore a wide range of agronomic possibilities for managing crops so as to get close to the water-limited potential, including managing previous crops, forages and fallows to increase soil water at sowing; reducing evaporative losses from the soil surface; ensuring that sowing and flowering occur at the right times; maximizing soil water extraction by the crop; and ensuring that there is adequate water available during late floral development and grain filling. Such operations often involve trade-offs and risks that must be managed.

Water Sustainability: Anthropological Approaches and Prospects

Abstract: Water has become an urgent theme in anthropology as the worldwide need to provide adequate supplies of clean water to all people becomes more challenging. Anthropologists contribute by seeing water not only as a resource, but also as a substance that connects many realms of social life. They trace the different forms of valuing water, examine the often unequal distribution of water, explore the rules and institutions that govern water use and shape water politics, and study the multiple, often conflicting knowledge systems through which actors understand water. They offer ethnographic insights into key water sites—watersheds, water regimes, and waterscapes—found in all settings, though with widely varying characteristics. Anthropologists provide a critical examination of a concept called integrated water resource management (IWRM), which has become hegemonic in the global discourse of sustainable development.

Halting the groundwater decline in north-west India--which crop technologies will be winners?

Abstract: Increasing the productivity of the rice–wheat (RW) system in north-west India is critical for the food security of India. However, yields are stagnating or declining, and the rate of groundwater use is not sustainable. Many improved technologies are under development for RW systems, with multiple objectives including increased production, improved soil fertility, greater input use efficiency, reduced environmental pollution, and higher profitability for farmers. There are large reductions in irrigation amount with many of these technologies compared with conventional practice, such as laser land leveling, alternate wetting and drying (AWD) water management in rice, delayed rice transplanting, shorter duration rice varieties, zero till wheat, raised beds, and replacing rice with other crops. However, the nature of the irrigation water savings has seldom been determined. It is often likely to be due to reduced deep drainage, with little effect on evapotranspiration (ET). Reducing deep drainage has major benefits, including reduced energy consumption to pump groundwater, nutrient loss by leaching, and groundwater pollution. The impacts of alternative technologies on deep drainage (and thus on irrigation water savings) vary greatly depending on site conditions, especially soil permeability, depth to the watertable, and water management. More than 90% of the major RW areas in north-west India are irrigated using groundwater. Here, reducing deep drainage will not “save water” nor reduce the rate of decline of the watertable. In these regions, it is critical that technologies that decrease ET and increase the amount of crop produced per amount of water lost as ET (i.e., crop water productivity, WPET) are implemented. The best technologies for achieving this are delaying rice transplanting and short duration rice varieties. The potential for replacing rice with other crops with lower ET is less clear.

Estimation of water demand in developing countries : an overview

Abstract: A better understanding of household water use in developing countries is necessary to manage and expand water systems more effectively. Several meta-analyzes have examined the determinants of household water demand in industrialized countries, but little effort has been made to synthesize the growing body of literature evaluating household water demand in developing countries. This article reviews what is known and what is missing from that literature thus far. Analysis of demand for water in developing countries is complicated by abundant evidence that, contrary to what is observed in most developed countries, households in developing countries; have access to, and may use more than one of several types of, water sources. The authors describe the different modeling strategies that researchers have adopted to estimate water demand in developing countries and discuss issues related to data collection. The findings from the literature on the main determinants of water demand in these countries suggest that, despite heterogeneity in the places and time periods studied, most estimates of own-price elasticity of water from private connections are in the range from 20.3 to 20.6, close to what is usually reported for industrialized countries. The empirical findings on decisions relating to household water sources are much less robust and should be a high priority for future research.

Water technology an introduction for environmental scientists and engineers

Abstract: Basic Considerations in Hydrobiology Water Resources and Demand Factors Determining the Distribution of Animals and Plants in Freshwaters Basic Aquatic Ecosystems Micro-organisms and Pollution Control Water Pollution Water Basin Management Water Quality and Regulation Water Quality Assessment Water Treatment and Distribution Drinking Water Contamination Pathogens and Their Removal Nature of Wastewater Introduction to Wastewater Treatment Biological Aspects of Secondary Sewage Treatment Fixed-film Systems Activated Sludge Other Biological Treatment Systems Anaerobic Treatment Physio-chemical Treatment Processes Sludge Treatment and Disposal Household and Small-scale Treatment Systems Sustainability Principles in Water Management

Ground water security and drought in Africa: linking availability, access, and demand.

Abstract: Drought in Africa has been extensively researched, particularly from meteorological, agricultural, and food security perspectives However, the impact of drought on water security, particularly ground water dependent rural water supplies, has received much less attention Policy responses have concentrated on food needs, and it has often been difficult to mobilize resources for water interventions, despite evidence that access to safe water is a serious and interrelated concern Studies carried out in Ghana, Malawi, South Africa, and Ethiopia highlight how rural livelihoods are affected by seasonal stress and longer-term drought Declining access to food and water is a common and interrelated problem Although ground water plays a vital role in buffering the effects of rainfall variability, water shortages and difficulties in accessing water that is available can affect domestic and productive water uses, with knock-on effects on food consumption and production Total depletion of available ground water resources is rarely the main concern A more common scenario is a spiral of water insecurity as shallow water sources fail, additional demands are put on remaining sources, and mechanical failures increase These problems can be planned for within normal development programs Water security mapping can help identify vulnerable areas, and changes to monitoring systems can ensure early detection of problems Above all, increasing the coverage of ground water–based rural water supplies, and ensuring that the design and siting of water points is informed by an understanding of hydrogeological conditions and user demand, can significantly increase the resilience of rural communities to climate variability

Estimating the Scope of Household Water Treatment in Low- and Medium-Income Countries

Abstract: For populations without reliable access to safe drinking water, household water treatment (HWT) provides a means of improving water quality and preventing disease. We extracted data on reported HWT practices from 67 national surveys and reports on the scope of HWT. An estimated 33.0% of the households (1.1 billion people) in these countries report treating their drinking water at home. The practice is widespread in the Western Pacific (66.8%) and Southeast Asia (45.4%) regions, and it is less common in the Eastern Mediterranean (13.6%) and Africa (18.2%). Boiling is the most dominant method with 21.0% of the study households (598 million people) using the method. Despite being at higher risk of waterborne disease because of lower coverage of improved water sources, African and rural households are less likely to practice HWT or use microbiologically adequate methods. Validation of the household surveys and further analysis of these data could help optimize HWT practices.

Assessing the Potential for Rainwater Harvesting

Abstract: Rainwater harvesting is one of the promising ways of supplementing the surface and underground scarce water resources in areas where existing water supply system is inadequate to meet demand. Rainwater harvesting is one of the measure for reducing impact of climate change on water supplies. Abeokuta has a mean annual rainfall of 1,156 mm which makes rainwater harvesting ideal. Intra annual variability lies betwen 0.7 and 1.0 while the inter annual variability was 0.2. Annually 74.0 m3 of rainwater can be harvested per household. Estimated annual water demand for flushing, laundry and flushing were 21.6 and 29.4 m3 respectively. Harvested rainwater in Abeokuta can satisfy household monthly water demand for WC flushing and laundry except for November, December, January and February. The excess rainwater stored in September and October is sufficient to supplement the short fall in the dry months provided there is adequate storage.Water savings potential is highest in June and September which is the two rainfall peak period in Southwest Nigeria.

Comparison of Multivariate Regression and Artificial Neural Networks for Peak Urban Water-Demand Forecasting: Evaluation of Different ANN Learning Algorithms

Abstract: For the past several years, Cyprus has been facing an unprecedented water crisis. Four options that have been considered to help resolve the problem of drought in Cyprus include imposing effective water use restrictions, implementing water-demand reduction programs, optimizing water supply systems, and developing sustainable alternative water source strategies. An important aspect of these initiatives is the accurate forecasting of short-term water demands, and in particular, peak water demands. This study compared multiple linear regression and three types of multilayer perceptron artificial neural networks (each of which used a different type of learning algorithm) as methods for peak weekly water-demand forecast modeling. The analysis was performed on 6 years of peak weekly water-demand data and meteorological variables (maximum weekly temperature and total weekly rainfall) for two different regions (Athalassa and Public Garden) in the city of Nicosia, Cyprus. 20 multiple linear regression models, 20 L...

New perspectives in monitoring drinking water microbial quality.

Abstract: The safety of drinking water is evaluated by the results obtained from faecal indicators during the stipulated controls fixed by the legislation. However, drinking-water related illness outbreaks are still occurring worldwide. The failures that lead to these outbreaks are relatively common and typically involve preceding heavy rain and inadequate disinfection processes. The role that classical faecal indicators have played in the protection of public health is reviewed and the turning points expected for the future explored. The legislation for protecting the quality of drinking water in Europe is under revision, and the planned modifications include an update of current indicators and methods as well as the introduction of Water Safety Plans (WSPs), in line with WHO recommendations. The principles of the WSP approach and the advances signified by the introduction of these preventive measures in the future improvement of dinking water quality are presented. The expected impact that climate change will have in the quality of drinking water is also critically evaluated.